01 - Diameter

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What range of pipe diameters is available? PE100 can be manufactured in a wide range of pipe diameters from 16mm to 1600mm. Even larger diameters are possible with the development of appropriate extrusion dies. However the common range of pipe sizes is from 32mm to 630mm.

Nominal diameter of a PE100 pipe is its external diameter, not its internal bore diameter.

Standard diameters in this range are:

32 mm 63mm 90mm 110mm

125mm 160mm 180mm 225mm

250mm 280mm 315mm 355mm

400mm 450mm 500mm 560mm

630mm

The internal bore diameter for each of these sizes will depend on the SDR of the pipe. Non-standard pipe sizes can be manufactured for specific applications if necessary.

02 - Length

PE100+ Home page -> PE Pipe Model -> Materials -> Products -> 02 - Length

What pipe lengths are available?

As the pipe manufacture is a continuous process, in theory the lengths available are unlimited. In practice however the lengths are limited by transport, ease of handling on site, other general site conditions and local practices.

PE100 pipe is generally available in three forms:

1. Straight lengths of pipe (diameters 90mm and above) in standard lengths of 6, 10, 12, 15, 24, and 30 metres. For some special projects, e.g. sea outfall installations, where transport can be made by water (canal, river or sea), extremely long lengths can be supplied.

2. Coils. Free-standing coils of pipe up to pipe diameter 180mm. 3. Drums. Similar to coils but supplied wrapped onto a drum for support. Longer lengths are

available in this form than in coils.

For both coils and drums the range of pipe lengths available is usually limited by transport considerations.

The table below shows the typical range available. However specific requirements should be discussed with the pipe manufacturer.

PE100 Pipe diameter

Up to 63mm 90mm – 180mm Above 180mm

Coil V V

Drums V

Straight V V

03 - Fittings

PE100+ Home page -> PE Pipe Model -> Materials -> Products -> 03 - Fittings

What ranges and types of fittings are available?

A full range of fittings is available in pipe sizes up to 315mm including: tees; elbows; reducers; branch connections; etc. At diameters greater than 315mm fittings, tees, elbows, etc. are continually being developed. Additionally a range of long radius bends specially formed from the pipe is supplied in a wide range of diameters and angles. The manufacturers can supply information on the full range of fittings available.

Are any special pipes available for specific applications?

Yes. The PE pipe producing industry is very innovative in developing pipes for special applications and to be more cost-effective in dealing with installation and service needs.

The special pipes are mainly multi-layer materials. These are co-extrusions of different thermoplastic materials to form pipes with two or more layers in their walls, with each layer performing a specific function.

The multi-layer pipes may have:

A harder thin outer layer to protect the main body of the pipe from damage where good quality bedding is not available, where installation is with directional drilling through coarse, granular soils, or where installation is by pipe bursting.

A stiffer inner layer to improve crack resistance in specific conditions.

A thin, peelable outer layer to obviate the need for scraping prior to electrofusion, thus making the fusion process simpler in difficult conditions.

A metallic foil sandwiched between two layers of thermoplastic to protect potable water against any permeation of contaminants in the soil or ground water and to assist in detection of the buried pipe from the surface.

Certain combinations of the above.

How can PE pipe be connected to other pipe materials?

PE100 pipe can be connected to pipe in other materials by a range of mechanical fittings available from the relevant manufacturers. These can either be transition couplers to connect the pipes together directly or flange connections.

Transition couplers typically consist of an outer body compatible with the size of the pipes to be joined, an elastomeric sealing ring to provide the leak tightness and an internal pipe stiffener to provide long term integrity. It is imperative that the correct pipe sizes need to be specified when ordering the fittings to ensure compatibility of the pipes and fittings.

Flange fittings can be fused directly onto the PE pipe to provide a conventional bolted connection to the other pipe material or ancillary equipment.

References

ISO 9623:1997 PE/metal and PP/metal adapter fittings for pipes for fluids under pressure - Design lengths and size of threads - Metric series ISO 3663:1976 Polyethylene (PE) pressure pipes and fittings, metric series - Dimensions of flanges ISO 9624:1997 Thermoplastics pipes for fluids under pressure - Mating dimensions of flange adapters and loose backing flanges ISO/TS 10839:2000 Polyethylene pipes and fittings for the supply of gaseous fuels - Code of practice for design, handling and installation

04 - Valves

PE100+ Home page -> PE Pipe Model -> Materials -> Products -> 04 - Valves

Are PE valves available?

PE valves can be supplied by valve manufacturers in a range of sizes from 20mm to at least 400mm. They are designed for connection directly onto the PE pipe by either electrofusion or butt fusion, depending on the pipe diameter. The designs are typically based on a full through port ball valve.

Can PE pipe be connected to metal valves?

PE pipe can be connected to metal valves by either transition couplers or by flanges.

05 - Traceability

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National and International standards require that the PE pipe and fittings are clearly marked on the outer surface with the manufacturing details including: manufacturer‘s name or trade mark; code for the compound used; diameter and pressure rating; and date, or a code, of manufacture. This information allows traceability through the manufacturer‘s Quality Assurance system to determine further details as necessary, e.g. grade of the raw material used, batch test results, process conditions, etc.

Traceability is an integral part of modern, sophisticated, Quality Assurance systems used for PE pipe networks. The systems available, and mandatory at many end-users, enable tracing through the whole process, from the resin batch at the PE producer, through pipe extrusion, the utility company and the installation contractor‘s operations. All installations can be traced back to the resin batch from which they were produced, with full data on the history of the pipe or fitting at any location.

The most up-to-date traceability systems are based on the use of barcodes. The barcodes can record data covering:

fusion-jointing equipment data

fusion-jointing equipment operator data

site data (geographical location)

data on fittings and pipes

fusion-jointing parameters

installation dates

assembly procedures

This information on the barcodes can be affixed to the pipes and fittings insitu, and recorded in a database, ideally linked to a Geographical Information System (GIS). At any subsequent excavation or operation the barcode can be read and all data on the pipes and fittings concerned can be accessed. Similarly in planning operations and works the data is readily accessible from the GIS or database.

ISO 12176 Part 4 defines a traceability system for encoding the characteristics of the pipes, fittings, fusion-jointing equipment, fusion-jointing equipment operators and fusion-jointing protocols. It is applicable to PE pipes, fittings and valves conforming to ISO standards for gas supply piping systems and also to the assembly operation utilising methods such butt, socket and saddle fusion, electrofusion, induction fusion and mechanical jointing.

Traccoding, a database which supports ISO 12176 Part 4, has been established at www.traccoding.com

It is up to the user to create the link between the various elements in order to provide a complete traceability system. Care is necessary when determining which data are to be downloaded into the traceability system database and the minimum information to be stored in the database for later retrieval.

References

ISO 12176-4:2003 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 4: Traceability coding Gueugnaut, D. Mise en place de la traçabilité; l‘exemple des conduites de gas en polyéthylène à Gaz de France. Gas, Wasser, Abwasser (GWA); SVGW Zürich, October 2003.

01 - Methods

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What methods can be used to assemble a PE pipe network? PE pipe can be assembled into a pipeline network by means of fusion or mechanical assembly techniques. Fusion of PE pipe and fittings may be by either Butt Fusion or Electrofusion. Other techniques are available (socket fusion and induction fusion) but are not commonly available and will not be considered here.

Fusion Fusion comprises applying heat and pressure for a specified time to the mating surfaces to be joined. The application of heat and pressure under the correct conditions allows the molecular chains to flow and mix with each other creating a joint as strong as the pipe itself. More: Butt Fusion | Electrofusion

Mechanical assembly Mechanical assembly techniques utilise fittings that incorporate a compression component, usually an elastomeric sealing ring, to provide for pressure integrity, leak tightness and resistance to end loads. More: Mechanical assembly

Range of fittings (Ineos Polyolefins, Borealis)

Under what circumstances are the different methods used?

Butt fusion Butt fusion can be used for jointing pipes and fittings 63mm diameter and larger. However it is most commonly used for larger diameter pipes. Butt fusion jointing is equally suited to both coiled and straight pipe lengths. Only pipes and fittings of the same nominal diameter may be butt fused.

Butt fusion can be used in new installations using traditionalopen cut trenching techniques. Additionally due to the low profile of the butt joint it is ideal for use in trenchless technology installations; sliplining , pipe bursting, directional drilling, etc.

Butt fusion can also be used to fabricate a range offittings, bends, tees, reducers, etc.

Electrofusion Electrofusion is most commonly used for jointing pipes up to 250mm diameter but there is no technical upper limit. It is nevertheless most commonly used for smaller diameter pipes because the cost of fittings increases with diameter. Electrofusion is equally suited to bothcoiled andstraight pipe lengths, and can be used to joint pipes of different nominal diameters and SDR's using suitable fittings. Electrofusion is most commonly used in conventionalopen cut trenching installation, and in repair works. It is also used for adding new services to existing PE mains by means of saddle fittings or tees. It is less well suited to trenchless installation or rehabilitation methods because the fittings protrude on the outside of the pipe.

Electrofusion fittings are available in a range of forms; they may be straight connectors, bends, tees, stop ends, reducers, saddle fittings and repair fittings.

Mechanical Mechanical assembly is used for jointing where neither fusion method is suitable. Most commonly this is when PE and other pipe materials are being connected, or when PE pipe is connected to valves or similar appurtenances made from other materials.

Mechanical fittings used in gas networks will have an internal support to avoid creep of the pipe which can lead to leakage. Most end uses in the gas industry specify mechanical fittings without elastomeric seals, tightness is achieved by compression of the PE pipe to the fitting body or stiffener. What special equipment is needed for each assembly method?

Butt fusion To ensure that good quality butt fusion joints are made it is essential that the correct equipment is used. The equipment used must be robust enough to handle the size and weight of the pipe to be joined. It is essential that the correct pressures be maintained on the pipe ends during each phase of the procedure to achieve this only hydraulically operated equipment should be used.

Many modern butt fusion machines include data logging facilities of the fusion process and parameters for use within a Quality Assurance system.

It is essential that operators of the equipment are familiar with relevant health and safety issues for the equipment being used, and are fully trained it its correct use.

Ancillary equipment, rollers supports, etc. should also be used to aid alignment and reduce the effect of pipe drag during the fusion process.

Equipment suitable for butt jointing PE pipe can be supplied by several manufacturers. Butt fusion equipment must conform toISO 12176 Part 1

Electrofusion Specialist electrofusion controllers are required to make the joints. The controllers include data reading capabilities into which details of the fitting, pipes and diameters can be entered so that the correct fusion time/temperature cycle is automatically selected. Most fusion controllers have failsafe features so that incorrect procedures, or the wrong fittings, cannot be used.

Many modern electrofusion machines include data logging facilities of the fusion process and parameters for use within a Quality Assurance system. The data logger must conform toISO 12176 Part 4.

It is essential that operators of the equipment are familiar with relevant health and safety issues for the equipment being used, and are fully trained it its correct use. Operators must be qualified and hold an operator badge conforming toISO 12176 Part 3.

Ancillary equipment, rollers supports, etc. should also be used to aid alignment and reduce the effect of pipe drag during the fusion process.

Equipment suitable for electrofusion of PE pipe can be supplied by several manufacturers. Those certified for use may be found at www.traccoding.com

References

ISO 12176-1:1998 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 1: Butt fusion ISO 12176-2:2000 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 2: Electrofusion ISO 12176-3:2001 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 3: Operator's badge ISO 12176-4:2003 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 4: Traceability coding Can different grades of PE be connected to each other?

Butt fusion It is possible to butt fuse pipes and fittings of different grades and SDR, but this should only be carried out under controlled conditions. In case of doubt please contact the pipe and or fitting suppliers.

Electrofusion Similarly different grades and SDR's of pipe can be connected using electrofusion, again only under controlled conditions. Special care needs to be taken to avoid collapse of thinner pipes during the fusion period.

Electrofusion fittings may also be of different grade and SDR than the pipes, in which case the lower rating (pipe or fitting) governs the rating of the assembly as a whole.

Mechanical fittings Mechanical jointing may be used to connect different grades and SDR's, with the same limitations as above for the electrofusion method. Special care should be take to use the appropriate insert stiffeners to the corresponding SDR.

Note: the use of different grades and SDR's could reduce the maximum operating pressure of a network.

References

IS0/TR11647:1996 Fusion compatibility of polyethylene (PE) pipes and fittings Are there any standards or codes of practice applicable to the assembly methods?

The major users of PE piping systems have developed codes of practice for fusion assembly. Many of these have become national standards.

Butt fusion Butt fusion procedures require the application of temperature and pressure over time to the mated ends of the pipes or fittings. The procedures developed in different European countries are all similar in principle but different in detail. All have been tested and all produce satisfactory joints when the procedures are followed correctly.

The differences between the procedures are in the level of pressure to be applied and the time for which it is applied. All the procedures require a fusion temperature of 210°C to be applied. For the pressure/time regimes for the main procedures click the Fusion Cycles image on the right.

The various national codes of practice on butt fusion are the following:

Belgium Belgium Becetel NBNT 42-010

Germany Germany DVS 2207-1

Netherlands Netherlands NEN 7200

France France DVS 2207-1 and NEN 7200

UK UK WIS 4-32-08

Scandinavia Scandinavia DS/INF 70-2

Italy Italy UNI 10520 and UNI 10967

Spain Spain ISO 11414

Electrofusion There is less variation in electrofusion procedures. The barcodes on the fittings cause the electrofusion controller unit to be programmed with the necessary time and temperature cycle for that fitting. What training is necessary for operatives to assemble PE pipe networks?

A fusion operator badge is required for all personnel involved in fusion techniques during the construction of PE gas networks. This badge must conform with ISO 12176 Part 3, and is granted after completing a training course and passing a qualification exam. In most countries the badge has a validation period of 1 to 2 years after which it must be renewed by repeating the examination.

A typical badge is shown on the right, click the image to enlarge. Every fusion operator must carry his badge at all times when undertaking fusion work.

References

ISO 12176-3:2001 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 3: Operator's badge

02 - Traceability

PE100+ Home page -> PE Pipe Model -> Construction -> Assembly -> 02 - Traceability

How can I verify that the correct assembly procedures have been followed? Traceability is an integral part of modern, sophisticated, Quality Assurance systems used for PE pipe networks. The systems available, and mandatory at many end-users, enable tracing through the whole process, from the resin batch at the PE producer, through pipe extrusion, the utility company and the installation contractor‘s operations. All installations can be traced back to the resin batch from which they were produced, with full data on the history of the pipe or fitting at any location.

The most up-to-date traceability systems are based on the use of barcodes. The barcodes can record data covering:

fusion-jointing equipment data

fusion-jointing equipment operator data

site data (geographical location)

data on fittings and pipes

fusion-jointing parameters

installation dates

assembly procedures

This information on the barcodes can be affixed to the pipes and fittings insitu, and recorded in a database, ideally linked to a Geographical Information System (GIS). At any subsequent excavation or operation the barcode can be read and all data on the pipes and fittings concerned can be accessed. Similarly in planning operations and works the data is readily accessible from the GIS or database.

ISO 12176 Part 4 defines a traceability system for encoding the characteristics of the pipes, fittings, fusion-jointing equipment, fusion-jointing equipment operators and fusion-jointing protocols. It is applicable to PE pipes, fittings and valves conforming to ISO standards for gas supply piping systems and also to the assembly operation utilising methods such butt, socket and saddle fusion, electrofusion, induction fusion and mechanical jointing.

Traccoding, a database which supports ISO 12176 Part 4, has been established at www.traccoding.com

It is up to the user to create the link between the various elements in order to provide a complete traceability system. Care is necessary when determining which data are to be downloaded into the

traceability system database and the minimum information to be stored in the database for later retrieval. The choice and the amount of data will strongly influence the performance of the database when it is used later.

Note that in a full traceability system fittings will have two barcodes; one for traceability and one for the fusion parameters. These are based on different barcode protocols so cannot be confused by the barcode reading equipment.

References

ISO 12176-4:2003 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 4: Traceability coding

Gueugnaut, D. Mise en place de la traçabilité; l‘exemple des conduites de gas en polyéthylène à Gaz de France. Gas, Wasser, Abwasser (GWA); SVGW Zürich, October 2003.

03 - Testing

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What procedures are used for testing the assembly? Different methods of testing finished fusion joints in PE pipes have been developed in different European countries. They vary in their fundamental approach to the question of how a joint should be tested. At present work is proceeding among the relevant experts to establish a harmonised European method under a CEN standard. As soon as this is publicly available a summary of the approach will be added to this Paper.

01 - Trenching

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Are there any special trenching requirements advised by our customers for PE pipe?

No special trenching requirements are normally needed for PE compared to other materials and the preparation of trenches should follow national or local practices.

Sharp stones should be removed from the base of the trench and where laying the pipe across rock or granular soil of angular consistency, such as gravel or cobbles, the trench should be excavated below the required depth to allow the pipe to be laid on imported compacted backfill.

It is advisable that PE pipe be surrounded by good quality compacted backfill which may need to be imported. Local codes of practice normally advise the nature of pipe bedding material required.

The ability of PE pipe to be joined above ground and snaked into the trench allows for the use of narrow trenches. The trench width can be kept to a minimum but should still allow for good compaction during backfilling. Again it is important to consult local and national practices.

Are there any limitations on the depth at which PE pipe can be laid?

There are normally no depth limitations related to PE pipe material.

The depth limitation to which PE pipe can be laid is not governed by the material properties but by the site conditions, soil type, level of water table, etc. This is no different from other pipe materials. The pipe should be designed to resist any additional forces from soil loading associated with deep excavations.

Suitable precautions should be taken to prevent collapse of the trench walls for deep excavations and consideration should also be given to trench drainage if the pipe is to be laid below the water table.

Reference should be made to health and safety legislation relating to deep excavations to prevent potential injury to operators.

PE pipe can be assembled at the surface and placed into a deep trench without site personnel being in the trench for long periods, or possibly not at all. This is a considerable safety benefit where stability of the trench may be a concern.

Is trench alignment critical when laying PE pipe?

No. The flexibility of PE allows it to be placed with some variations in alignment to suit local terrain if necessary.

The alignment of the trench in the vertical plane is dependant on the application for which the pipe is being used. For example, gas and water PE distribution mains can be laid to follow the contours of the ground beneath which the pipe is being laid. PE gravity sewers, however, should be laid to the specified gradient to ensure their correct hydraulic function.

In the horizontal plane the pipe can be laid to follow, for example, the alignment of a road or footpath. However there is a limit to the bending of PE pipes. The minimum advisable bend radius at which PE pipe can be laid is:

15 x nominal. pipe diameter

Example ; the minimum radius of bend for placing a 500mm pipe is

(15 x 500) mm = 7.5m

Can PE pipe normally be installed by trenchless methods or methods using minimum excavation?

Yes. PE pipe is ideally suited to installation by trenchless or minimum excavation techniques and many of the common methods were initially developed for PE. The techniques used by installers that routinely use PE are:

Pipe Bursting or Pipe Splitting ; This technique involves using a device which passes through the existing pipe and breaks it, forcing the fragments into the surrounding soil. The replacement PE pipe is pulled through behind the pipe bursting device. For the replacement of brittle materials such as concrete, cast iron, clay etc, the term pipe bursting is used.

For the replacement of more ductile materials, steel or ductile iron, the device splits the existing pipe and hence the term pipe splitting is used. The techniques allow for replacement with pipe of the same diameter, or the void can be expanded to allow a larger size PE pipe to be inserted.

Several research projects and a great deal of experience has shown that the PE pipe is seldom damaged during pipe bursting or pipe splitting works when these are undertaken following the correct procedures.

Directional Drilling or Guided Boring ; This technique is ideally suited for crossings under roads, railways, rivers, airport runways, etc. A pilot hole is initially drilled using a steerable drill head and drilling fluid, with an electronic transmitter attached behind the drill head to ensure the correct path is maintained. Further drilling and reaming achieves the required diameter.

The PE pipe can then be assembled at the surface to the required length and pulled into the hole. Equipment is available to measure and record the axial force applied to the pipe during installation to ensure that it is not over-stressed.

If required the annulus between the PE pipe and the surrounding soil can be grouted to provide greater stability if this is necessary, but this must be done in a controlled manner to ensure that the pipe is not overloaded leading to its collapse.

Slip Lining ; Slip lining is the simplest form of pipeline renovation using PE. The replacement PE pipe is simply pulled through the existing pipe. The length of the section depends on the route of the existing pipe and the location of tees and bends. The replacement PE pipe should be designed to be fully structural

and acts as an independent liner. The loose fit of the PE liner pipe in the existing pipe results in a loss of hydraulic capacity.

The void between the existing pipe and the PE liner can be grouted to provide greater stability if this is necessary, but this must be done in a controlled manner to ensure that the pipe is not overloaded leading to its collapse.

Close fit lining : The PE liner is manufactured to a slightly larger diameter than the bore of the existing pipe. The liner is pulled through a tapered die (Swageline) or through tapered rollers (Rolldown) to temporally reduce the diameter and is then inserted into the existing pipe. The liner pipe is then reverted back to its original diameter by pressure or a combination of pressure and temperature to provide a close fit liner, maximising hydraulic capacity.

The PE liner can be designed to be fully structural, acting as an independent liner or can rely on the structure of the existing pipe to act as a dependant liner. The resulting liner is often of a non-standard diameter.

Folded liners ; Close fit liners are similar to the above but the diameter of the liner is reduced by folding it into a geometrical shape, typically a ‗C‘ or ‗U‘ shape. This reduces its effective circumference and allows for ease of insertion. The liner pipe is then reverted back to its original diameter by pressure or a combination of pressure and temperature to provide a close fit liner.

Folded and reformed liners are better suited to installation in deeper pipes as they can be inserted through existing manholes.

02 - Laying

PE100+ Home page -> PE Pipe Model -> Construction -> 02 - Laying

Is PE pipe suitable for new supply or collection networks?

Yes. PE pipe is ideally suited for new supply networks. Applications in which PE pipe is widely used by our customers include:

Gas mains distribution networks

Gas service supply pipes

Water mains distribution systems

Water service supply pipes

Gravity sewer and drain networks

Pumped sewer mains

Irrigation systems

Industrial and process pipework

Below Ground For below ground applications, for example gas and water distribution mains and gravity and pumped sewer mains, the use of PE has encouraged significant improvements by our customers in the design and performance of the equipment used for laying PE, particularly in congested urban environments. Techniques that have been developed include narrow trenching and directional drilling or guided boring which are particularly suitable for road, rail, river and similar crossings.

Above Ground Where the pipe is laid above ground by our customers and the installers, for example industrial and process pipework, the relatively light weight of PE compared with other pipe materials minimises the amount of handling equipment required. Above ground pipes need to be suitably protected against mechanical damage and UV degradation.

Can PE pipe be used for replacement or rehabilitation of existing pipe networks?

Yes, The strength and flexibility of PE make it the preferred material by our customers for replacement and rehabilitation of existing pipe networks. Replacement of existing pipe networks in open trench can be carried out in a similar manner to the installation of new networks.

There is a wide range oftrenchless or minimum excavation techniques that can be employed that are suitable for the rehabilitation of existing networks. Some of the techniques that can be employed are:

Pipe bursting or pipe splitting

Directional drilling or guided boring

Slip lining

Close fit lining

Folded liners

The use of trenchless techniques can significantly reduce the cost of pipe replacement or rehabilitation, as there are minimal excavation and reinstatement costs. The choice of the trenchless technique employed by our customers or the installer depends upon a number of factors, including:

Hydraulic capacity requirements

Soil type

Location of other underground utilities and plant

Sufficient clearance under roads, footpaths etc. to avoid damage

Condition of host pipe

External loading characteristics

Network operating needs: can pipe be taken out of service or is a live insertion technique necessary?

Is any special equipment needed to lay PE pipe?

No special equipment is required by our customers for the laying of PE pipe when compared with other pipeline materials.

Pipe diameters up to 200mm can generally be laid using manual techniques, depending on pipe lengths, so it is possible that some lifting plant may be eliminated from site operations.

Pipe supplied incoils is installed directly from the coil and where possible coil dispensers should be used. Care should be taken when cutting the bands securing PE coils and reference should be made to manufacturers‘ instructions or national or international codes of practice.

Larger diameters or longer lengths of pipe will require mechanical handling equipment. Reference again should be made to manufacturers‘ instructions Generally however it is recommended that non metallic slings are used. The use of pipe rollers is recommended when laying long pipe string lengths to prevent the pipe being dragged over stones and other sharp objects which could damage the pipe.

What are the bedding requirements for PE pipe?

Customers normally advise that trench bottoms should be excavated to provide a reasonably even bed along the pipe length and free of sharp stones or other objects that could damage the pipe. Sand for pipe bedding should be used where possible and soil containing sharp, angular gravel or cobbles should not be used for bedding of PE pipe. The depth of the trench should be suitable to provide the required cover when reinstated.

PE pipes having a protective outer sheath (multi-layer) may be laid in heterogeneous ground without sand bedding thus allowing a wide range of excavated materials to be re-used.

Where the pipe is to be laid through rock or ground of variable consistency, customers normally advise that the trench should be excavated approx. 75mm below its normal depth, and a bedding material placed before the pipe to provide a bed of suitable consistency.

Where the pipe is to be laid through contaminated ground then the soil should be checked to determine if it would bechemically aggressive to PE. If necessary the aggressive material should be removed and imported bedding and backfill should be used.

What levels of productivity can be achieved in PE pipe installation?

PE can normally be installed much more quickly than most other pipe materials.

The productivity of laying PE, from excavation to reinstatement and commissioning, depends on a number of factors; environment (urban or rural), ground type and condition, surface reinstatement (road or unpaved), etc. The most important influence is the installation technique employed;trenchless techniques and chain trenching in particular can increase productivity significantly.

Factors that improve productivity are:

Ease of site handling of PE pipe due to its flexibility and low weight

Use ofcoils andlong lengths of pipe, minimising the number of joints

Ease of jointing bybutt fusion or electrofusion

Ability of pipe to be jointed above ground to provide long pipe strings

Use of narrow trench techniques

Use of trenchless or minimum excavation techniques

In urban environments using conventional open cut techniques, laying rates (excavation to reinstatement and commissioning) are typically in the following ranges:

100m per week per installation team for larger diameters

200m per week per installation team for smaller diameters.

The equivalent rate for Ductile Iron or Steel in similar circumstances is typically 60m per week per installation team. Generally for open cut installation there is at least a 50% increase in installation productivity for PE compared with Ductile iron or Steel for the equivalent pipe sizes and environments.

Using alternative installation techniques, for example trenchless techniques and chain trenching, which are ideally suited to PE pipes, the laying rates can be significantly increased with up to 500m per week per installation team easily achievable in certain conditions.

The increased productivity also leads to lower cost of installation. This cost advantage of PE is more significant at smaller diameters.

What are the bedding requirements for PE pipe?

Customers normally advise that trench bottoms should be excavated to provide a reasonably even bed along the pipe length and free of sharp stones or other objects that could damage the pipe. Sand for pipe bedding should be used where possible and soil containing sharp, angular gravel or cobbles should not be used for bedding of PE pipe. The depth of the trench should be suitable to provide the required cover when reinstated.

PE pipes having a protective outer sheath (multi-layer) may be laid in heterogeneous ground without sand bedding thus allowing a wide range of excavated materials to be re-used.

Where the pipe is to be laid through rock or ground of variable consistency, customers normally advise that the trench should be excavated approx. 75mm below its normal depth, and a bedding material placed before the pipe to provide a bed of suitable consistency.

Where the pipe is to be laid through contaminated ground then the soil should be checked to determine if it would bechemically aggressive to PE. If necessary the aggressive material should be removed and imported bedding and backfill should be used.

What levels of productivity can be achieved in PE pipe installation?

PE can normally be installed much more quickly than most other pipe materials.

The productivity of laying PE, from excavation to reinstatement and commissioning, depends on a number of factors; environment (urban or rural), ground type and condition, surface reinstatement (road or unpaved), etc. The most important influence is the installation technique employed;trenchless techniques and chain trenching in particular can increase productivity significantly.

Factors that improve productivity are:

Ease of site handling of PE pipe due to its flexibility and low weight

Use ofcoils andlong lengths of pipe, minimising the number of joints

Ease of jointing bybutt fusion or electrofusion

Ability of pipe to be jointed above ground to provide long pipe strings

Use of narrow trench techniques

Use of trenchless or minimum excavation techniques

In urban environments using conventional open cut techniques, laying rates (excavation to reinstatement and commissioning) are typically in the following ranges:

100m per week per installation team for larger diameters

200m per week per installation team for smaller diameters.

The equivalent rate for Ductile Iron or Steel in similar circumstances is typically 60m per week per installation team. Generally for open cut installation there is at least a 50% increase in installation productivity for PE compared with Ductile iron or Steel for the equivalent pipe sizes and environments.

Using alternative installation techniques, for example trenchless techniques and chain trenching, which are ideally suited to PE pipes, the laying rates can be significantly increased with up to 500m per week per installation team easily achievable in certain conditions.

The increased productivity also leads to lower cost of installation. This cost advantage of PE is more significant at smaller diameters.

How can I verify details of the pipes and fittings that have been installed?

Good Quality Assurance by the contractor is necessary to achieve this.

The contractor should record location of pipes to provide suitable location in the future and this should be carried out in accordance with the operator‘s or contractor‘s QA system. Normal practice is to record the location on maps and this is now made easier with GPS systems.

Although it may not be necessary to record details of individual pipe lengths, other thandiameter and PN rating, it may be beneficial to record joint and fitting locations. The record of the joint and fitting location can be used in conjunction with jointing data logging facilities to provide a cross-reference with the pipe and fittings installed.

Traceability is an integral part of modern, sophisticated, Quality Assurance systems used for PE pipe networks. The systems available, and mandatory at many end-users, enable tracing through the whole process, from the resin batch at the PE producer, through pipe extrusion, the utility company and the installation contractor‘s operations. All installations can be traced back to the resin batch from which they were produced, with full data on the history of the pipe or fitting at any location.

The most up-to-date traceability systems are based on the use of barcodes. The barcodes can record data covering:

fusion-jointing equipment data

fusion-jointing equipment operator data

site data (geographical location)

data on fittings and pipes

fusion-jointing parameters

installation dates

assembly procedures

This information on the barcodes can be affixed to the pipes and fittings insitu, and recorded in a database, ideally linked to a Geographical Information System (GIS). At any subsequent excavation or operation the barcode can be read and all data on the pipes and fittings concerned can be accessed. Similarly in planning operations and works the data is readily accessible from the GIS or database.

ISO 12176 Part 4 defines a traceability system for encoding the characteristics of the pipes, fittings, fusion-jointing equipment, fusion-jointing equipment operators and fusion-jointing protocols. It is applicable to PE pipes, fittings and valves conforming to ISO standards for gas supply piping systems and also to the assembly operation utilising methods such butt, socket and saddle fusion, electrofusion, induction fusion and mechanical jointing.

Traccoding, a database which supports ISO 12176 Part 4, has been established at www.traccoding.com

It is up to the user to create the link between the various elements in order to provide a complete traceability system. Care is necessary when determining which data are to be downloaded into the traceability system database and the minimum information to be stored in the database for later retrieval. The choice and the amount of data will strongly influence the performance of the database when it is used later.

Most available fusion boxes and butt fusion machines are equipped with the necessary hardware to collect the necessary data automatically.

References

ISO 12176-4:2003 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 4: Traceability coding http://www.traccoding.com Gueugnaut, D. Mise en place de la traçabilité; l‘exemple des conduites de gas en polyéthylène à Gaz de France. Gas, Wasser, Abwasser (GWA); SVGW Zürich, October 2003.

03 - Commissioning

PE100+ Home page -> PE Pipe Model -> Construction -> 03 - Commissioning

Are there any special factors that affect the testing procedures when commissioning PE pipe? Yes. It is important to follow the correct commissioning procedures in order to avoid false conclusions on the performance of the pipeline.

Factors that affect the testing of PE pipe during commissioning procedures are: temperature variations; the amount of trapped air in the pipeline and the creep characteristic of PE pipe. Failure to take these into account can lead to false test results.

Due to the relatively high co-efficient of thermal expansion of PE pipe it is essential that variations in temperature be minimised during the commissioning procedure. It is recommended, both for safety and to minimise temperature variation, that the trench is backfilled prior to testing. It may be allowable to leave critical joints open to allow for inspection during commissioning.

When carrying out hydrostatic testing it is essential that all air is removed from the pipeline prior to testing. The pipe can be filled using either pigging or gravity fed techniques. If gravity filling is to be used it may be necessary to install tapping's at high points to vent trapped air and at low points to enable all the water to be removed.

As the test pressure is applied to a PE pipeline, the pipe will expand due to the creep characteristics of the material. This will result in a drop of pressure or require the system to be ‗topped up‘ to maintain the required pressure. The test procedure for PE pipe must include a period of time to allow the pipe to stabilise or should include a method whereby the pressure drop due to pipe expansion is calculated to discriminate from the pressure drop from leakage. If this is not done false test results will be obtained because it will not be possible to determine whether any loss of pressure is due to the expansion of the pipe or to real leakage.

This expansion of the pipe when load is applied is normal behaviour for a plastic material and is not an indication of failure.

Are there any standard procedures or codes of practice that cover testing and commissioning of PE pipe? There are many national standards and codes of practice relating to testing and commissioning of PE pipe. The more recent ones take into account the creep characteristics of the material.

The choice of test method depends on the application for which the pipe is to be used. Methods can differ between gas and water applications, for example.

UK

Gas: Institution of Gas Engineers, Recommendations on Transmission and Distribution, IGE/TD/3 Edition 4 ―Steel and PE Pipelines for Gas Distribution‖ Water: WRc. A Guide to the Pressure testing of Water Supply Pipelines and Sewer Rising Mains. 1st edition, June 1999.

Construction: Commissioning: Purging Are there any special factors that affect the testing procedures when commissioning PE pipe? The only special requirements for purging PE pipes is the need to take into account discharges due tostatic electricity.

As with other materials care should be taken to protect the environment when purging or discharging following pressure testing.

Construction: Commissioning: Static Electricity

What precautions do customers and installers generally advise against discharge of static electricity? PE pipe has a high electrical resistivity and static charge can accumulate on the surface of the PE pipe. Normal handling from pipe slings, cloths, etc generates the static charge, particularly in dry conditions.

Static occurs inside PE pipe in gas distribution systems because gas is electrically resistive. That means that electrons that have been scraped off gas molecules by friction as they flow against the PE pipe surface are resisted from reinserting themselves into gas molecules that have lost electrons. Instead, the free electrons build up on the interior PE pipe surface creating a negative charge with the ever-present possibility of arcing and igniting the gas any time the pipe is breached. Dust particles in gas also generate tension which needs to be discharged.

High static electric charges can develop on PE pipes during squeeze-off, when repairing a leak, purging, making a connection, etc. Safety procedures have been developed by the major gas utilities to prevent static electricity igniting the flammable gas-air mixture.

Ensuring good contact with the ground can easily dissipate the static charge, effectively ‗earthing‘ the PE pipe. This is achieved during normal backfilling operations or by wrapping a damp cotton cloth around the pipe and ensuring it is in contact with the ground.

The following precautions may be taken to ensure safe working where there is a risk of static discharge:

Use an earthed wet tape conductor wound around, or laid in contact with, the entire section of the exposed piping.

If gas is already present, wet the pipe starting from the ground end with a very dilute water and detergent solution. Apply tape immediately and leave it in place.

Wet the tape occasionally with water. Where temperatures are below 0°C add glycol to the water to maintain tape flexibility. Earth the tape with a metal pin driven into the ground.

Do not vent gas using an unearthed plastic pipe or tubing. Even with earthed metal piping, venting gas with high scale or dust content could generate an electric charge in the gas resulting in an arc from the dusty gas cloud back to the pipe which could ignite the gas. Vent gas only at a downwind location remote from people or flammable material.

Dissipating the static charge build-up with wet rags, a bare copper wire, or other similar techniques may not be as effective as the above procedure.

In all cases, use appropriate safety equipment such as flame resistant and static free clothing, breathing apparatus, etc

Construction: Commissioning: Chlorination

Is PE resistant to the chemicals commonly used for disinfection, e.g. chlorine? PE pipe is resistant to the chemicals commonly used for water treatment and disinfection.

Disinfection of water mains is a frequent operation. Disinfection takes place when commissioning newly constructed potable water mains; mains that have been removed from service for planned repairs or for maintenance that exposes them to contamination; mains that have undergone emergency repairs due to physical failure; and mains that, under normal operation, continue to show the presence of coliform organisms. The chlorine disinfection process puts pipe in contact with a strong oxidising agent.

Several studies have been conducted to verify the effects of chlorine disinfection on the performance of PE pipes. A study by the US Plastic Pipe Institute included pre- and post-exposure testing of several characteristics of PE pipes, including resistance to slow crack growth. The testing performed in this study indicated that chlorine disinfection, when conducted within the guidelines of AWWA-C651, did not have a significant adverse affect on the subsequent performance of PE pipe.

This is supported by many years of extensive trouble free use in potable water applications. However due to the variety of chemicals, concentrations and practices in various countries if there is any doubt, advice can be sought from the polymer or pipe manufacturer.

References Disinfection of Newly Constructed Polyethylene Water Mains TR-34/2001. The Plastics Pipe Institute, Washington DC, USA. 2001

01 - Detection

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 01 - Detection

How can I verify the location of underground PE pipes? As for any underground pipeline, reference should first be made to the Construction Records held by the pipeline operator. The construction records should contain details of pipe location, depth of burial, location of other underground plant and any other relevant information.

The information shown on the construction records should be verified on site. Survey of appurtenances at the surface, such as chamber covers, as well as limited potholing to verify depth, may be necessary.

Remote pipe detection from the surface can also be used. Electromagnetic methods as used to detect buried cables and metallic pipes are not suitable for detecting PE pipes.

Is it possible to detect buried PE pipes from the surface?

Yes. Methods have been developed for detecting buried PE pipes from the surface but each has its limitations which need to be understood when deciding which to use.

The simplest method of detecting PE pipe is when laying the pipe to provide a tracer wire along the pipe route. The tracer wire can also be incorporated into marker tape, which is laid above the pipeline during construction. The tracer wire can then be detected above ground by conventional electromagnetic pipe detection equipment.

A range of more sophisticated geophysical detection techniques has been developed or adapted from other applications. Many of these are better suited to detection of large underground discontinuities than to finding small pipes, even at shallow depths.

Ground probing radar (GPR) is the most widely used of these methods and this has been developed specifically for locating small objects at relatively shallow depths. Used properly in the right circumstances GPR can be effective in detecting buried PE pipes. GPR nevertheless cannot detect all underground

objects, especially in saturated clays which attenuate the signals rapidly. GPR also requires a skilled operator so that misinterpretation of the information is minimised.

02 - Inspection

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 02 - Inspection

Is it necessary to inspect periodically the PE pipe? Periodic inspection of PE pipe is not normally required, but reference should be made to national or local codes of practice and preventative maintenance programmes. In critical locations, e.g. above ground installations, it may be necessary to implement a periodic inspection programme to determine the condition of the pipe, pipe supports and other associated structures. The frequency of the inspection should be set by a risk-based approach.

03 - Water Jetting

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 03 - Water Jetting

Can water jetting be used to clean PE pipe and are any special precautions necessary? Water jetting can be used for both routine cleaning of debris and also clearance of blockages. The normal practice would be to use low pressure/high volume for cleaning of debris and high pressure/low volume for clearing blockages. Operational conditions for water jetting depend largely on pipe diameter andSDR and reference should be made to national or local codes of practice.

04 - Flow Stopping

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 04 - Flow Stopping

What techniques are available for isolating sections of PE pipe for maintenance? The design of PE pipe networks should follow conventional network practices with the installation of valves at convenient or critical locations. The valves can then be operated to isolate sections of the pipe network for maintenance.

Additionally however PE pipe networks have the advantage that more localised isolation can be implemented by the use of pipe ‗squeeze-off‘. Squeeze-off is used in routine and emergency situations to stop or nearly stop flow in PE pipe by flattening the pipe between parallel bars. PE pipe squeeze-off utilises the ductility of PE by allowing the pipe to be squeezed together using relatively simple but specially designed squeeze-off tools thus preventing the flow of fluid and isolating the pipe section. It is important that only specifically designed tools are used and that the squeeze-off controls are set for the specific diameter and SDR of the pipe in order to control the degree of compression of the PE pipe and prevent any damage.

The squeeze off tools are generally mechanically operated up to about 125mm diameter and hydraulically operated for larger diameters. However squeeze-off equipment is not readily available for the largest diameters of PE pipe. It is important to follow the manufacturers instructions when using these tools and to use tools appropriate for the pipe diameter andSDR. Also the tools need to be capable of resisting the operating pressure of the pipe, and there are limits to the pressures that they can sustain.

Properly implemented squeeze-off, using the correct tools, is not expected to cause damage to the PE pipe, which regains its circular cross-section after the tool is released. However squeeze-off is not recommended to be done more than once at any location. If repeated flow control is required a valve or an appropriate flow control device should be installed in the system.

Squeeze-off is not intended as a means to throttle or partially restrict flow. Complete flow stoppage may not occur in all cases. When squeezing larger pipes, particularly at higher pressures, some seepage is likely. When seepage is not acceptable, it may be necessary to vent the pipe in-between two squeeze-offs. Any work performed must be downstream of the second squeeze-off.

Inflatable bag flow stopping equipment can also be used for PE pipes. A saddle fitting needs to be fixed to the pipe, through which the inflatable bags are inserted. It is important that the correct saddle fitting is used compatible with the equipment being used. Reference should be made to the manufacturers instructions.

05 - Repairs

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 05 - Repairs

The method of repairing damaged PE pipe depends upon the degree of damage sustained. Localised damage may be repaired by use of an electrofusion saddle or clamp fixed around the damaged area. Such a repair may not be suitable where gas or other flammable fluid is present in the pipe, due to the heat generated in the fusion process. PE encapsulation techniques have recently been developed and may be suitable for localised repairs. Information on these techniques can be obtained from the pipe manufacturers.

More extensive damage will require the section of pipe to be cut out and replaced. This is a relatively simple process, firstly isolating the damaged section by the use of squeeze-off tools, cutting out the section and replacing with new pipe using electrofusion couplers to tie-in the sections. It is important that the replacement section is of suitable diameter and pressure rating to maintain the integrity of the pipeline.

In all cases reference should be made to local or national codes of practice and all health and safety procedures should be closely followed.

06 - Leaks

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 06 - Leaks

What is the typical expected frequency of leaks in a PE pipe network? The frequency of repair to PE pipe depends upon a number of factors: above or below ground installation; direct burial or sliplined; location of other utility plant and pipework, etc. Studies of leakage in Belgium and the Netherlands show that PE has a frequency of leaks as follows:

In mains: 0.0156 leaks/km/year

In services 0.071 leaks/km/year

This is comparable with steel and significantly lower than the data for iron pipes.

References

"Ductile PVC Leads the Way", Professor Mannes Wolters, Gastec. International Gas Engineering and Management Journal, May 2001. Institute of Gas Engineers, London

07 - Damage

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 07 - Damage

Is PE more easily damaged than other pipe materials? PE pipe is open to many of the same risks as pipelines of other materials. The type of damage sustained by PE pipe is different compared with steel and iron pipes. Damage to PE pipe most commonly arises from external impact on the wall of the pipeline.

The degree of damage depends on the nature and the force of the impact. If through-wall impact is sustained this results in immediate fluid loss and immediate repair needs to be carried out. However damage to steel and iron pipes tends to damage the external pipe coating and only in extreme circumstances results in through-wall penetration. In such cases damage may not be apparent and the pipeline can remain in operation until failure occurs from pipeline corrosion at some point in the future. Such failures are both difficult to detect and expensive to repair.

During routine handling operations, due to its light weight, PE suffers little damage and where potential damage has occurred, for instance from scratches and scoring, guidelines are available from manufacturers to determine its fitness for purpose. PE pipe does not have any coating that can be easily damaged leading to future corrosion.

During construction and operation most pipeline damage occurs from third party interference while operations are being carried out on other nearby utility pipework and plant, for instance from a mechanical digger. In such cases damage to PE pipe is immediately apparent and can be immediately repaired. However third party damage to steel and iron pipes, in particularly the external coatings, cannot be immediately identified. The pipe can subsequently fail and need repairing at some point in the future incurring higher costs and disruption with little chance of identifying the third party offender with the costs being borne by the pipeline operator.

08 - Static Electricity

PE100+ Home page -> PE Pipe Model -> Operation and Maintenance -> 08 - Static Electricity

Are any special precautions suggested by customers and installers against the discharge of static electricity during maintenance works? PE pipe has a high electrical resistivity and static charge can accumulate on the surface of the PE pipe. Normal handling from pipe slings, cloths, etc generates the static charge, particularly in dry conditions.

Static occurs inside PE pipe in gas distribution systems because gas is electrically resistive. That means that electrons that have been scraped off gas molecules by friction as they flow against the PE pipe surface are resisted from reinserting themselves into gas molecules that have lost electrons. Instead, the free electrons build up on the interior PE pipe surface creating a negative charge with the ever-present possibility of arcing and igniting the gas any time the pipe is breached. Dust particles in gas also generate tension which needs to be discharged.

High static electric charges can develop on PE pipes during squeeze-off, when repairing a leak, purging, making a connection, etc. Safety procedures have been developed by the major gas utilities to prevent static electricity igniting the flammable gas-air mixture.

Ensuring good contact with the ground can easily dissipate the static charge, effectively earthing the PE pipe. This is achieved during normal backfilling operations or by wrapping a damp cotton cloth around the pipe and ensuring it is in contact with the ground.

The following precautions are often suggested to increase safe working where there is a risk of static discharge:

Use an earthed wet tape conductor wound around, or laid in contact with, the entire section of the exposed piping.

If gas is already present, wet the pipe starting from the ground end with a very dilute water and detergent solution. Apply tape immediately and leave it in place.

Wet the tape occasionally with water. Where temperatures are below 0°C add glycol to the water to maintain tape flexibility. Earth the tape with a metal pin driven into the ground.

Do not vent gas using an unearthed plastic pipe or tubing. Even with earthed metal piping, venting gas with high scale or dust content could generate an electric charge in the gas resulting in an arc from the dusty gas cloud back to the pipe which could ignite the gas. Vent gas only at a downwind location remote from people or flammable material.

Dissipating the static charge build-up with wet rags, a bare copper wire, or other similar techniques may not be as effective as the above procedure.

In all cases, use appropriate safety equipment such as flame resistant and static free clothing, breathing apparatus, etc, and follow instructions from installers and our customers.

01 - Energy

PE100+ Home page -> PE Pipe Model -> Environmental -> 01 - Energy

How much energy is consumed in the manufacture of PE pipe? Environmental Life Cycle Analysis (LCA), also referred to as life cycle inventory or cradle-to-grave study, has been carried out on PE manufactured and used for pipe applications. The Life Cycle Analysis for PE pipe estimates that the total energy consumption from extraction to installation is approximately 95 MJ per kg. of pipe (approx. 26 kWh per kg. of pipe).

Full life cycle analysis, which takes into account not only energy consumption but also effects from emissions etc., indicate that PE pipe has 10 times less environmental impact than the equivalent diameter of ductile iron pipe.

The life from "cradle to grave" of every industrial product has environmental impacts that originate from the extraction of raw materials, processing, distribution, use and finally disposal. The Life Cycle Assessment (LCA) is a method to evaluate these environmental impacts. Emissions that are released into air, soil and water from all the processes including those from energy production, wastewater treatment and disposal are determined and weighted. The purpose of these studies is to understand the total energy consumption and other environmental impact in the manufacture and installation of products.

This method, which is prescribed by ISO 14040 and subsequent international standards, is applied by experienced experts.

Such analysis relies on data not only from the plastics manufacturers (polymer and pipe manufacturers) but also from published data from other associated industries (energy, transport and contractors, etc.). This however may be an overestimation as no account has been made of recent initiatives in recycling.

A critical review and evaluation of nine European LCA concluded that from an environmental point of view plastic pipe products are of the same level as, and in many aspects preferable to, those made from other materials. This conclusion does not consider all the secondary positive aspects of plastic pipes that are generally not modelled in an LCA such as duration of life, tightness, flexibility, corrosion resistance and light weight.

References

Investigation of European life cycle assessment studies of pipes made of different materials for water supply and sewer systems – a critical comparison. Windsperger, A., Steinlechner, S., Schneider, F.. Institut für Industrielle Ökologie, St.Pölten, Austria. December 1999.

02 - Recycling

PE100+ Home page -> PE Pipe Model -> Environmental -> 02 - Recycling

Can PE pipe be recycled? PE pipe can easily be recycled; the end product depends on the condition of the pipe.

As there is minimal material degradation during the pipe manufacturing process, rejected pipe material, for example from start up or errors in processing, can be 100% recycled back into pipe and can meet all the required performance parameters. The level of material waste in manufacturing is therefore very low.

PE pipe reclaimed after use is unlikely to have the required characteristics for reuse in the same application, i.e. as PE pressure pipe. It can be recycled into other plastics products that are less mechanically demanding. These initiatives are organised by either the pipeline operator, the pipe suppliers or third party plastics reclamation companies.

03 - Leakage & Exfiltration

PE100+ Home page -> PE Pipe Model -> Environmental -> 03 - Leakage and Exfiltration

What is the environmental impact of PE pipe? The environmental impact of a pipe in service is a function of the leakage of transported material that it permits to the surrounding environment.

The environmental impact from leakage of PE pipe is less than that from the equivalent iron or steel pipe due to the lower frequency of leakage. However consideration should be given to the nature of the fluid being transported and the potential effect on the environment should third party damage occur.

Exfiltration occurs from the permeation of the fluid, particularly gas, from within the pipe through the pipe wall to the external environment. The level of permeation depends upon the type of fluid being carried, the internal pressure and the wall thickness of the pipe. National and international standards set the maximum allowable level of permeation, for example the transmission rate per millimetre of pipe thickness for methane may not exceed 75 cm3/m3/24h/bar.

Where particularly hazardous fluids are being transported then sensible precautions should be taken on the location of such pipelines near to potable water pipes, aquifers or watercourses. This is true for all pipe materials.

ISO Standards

PE100+ Home page -> PE Pipe Model -> ISO Standards

Standards referred to in the PE Pipe Model

ISO 1167:1996/EN 921:1995

Plastic piping systems - Thermoplastics pipes - Determination of resistance to internal pressure at constant temperature.

ISO 3663:1976 Polyethylene (PE) pressure pipes and fittings, metric series - Dimensions of flanges

ISO 4433:1997 Thermoplastics pipes - Resistance to chemical fluids - Classification: Part 1: Immersion test method; Part 2: Polyolefin pipes

ISO 4437:1997 Buried polyethylene (PE) pipes for the supply of gaseous fuels - Metric series - Specifications

ISO 9080:2003 Plastics piping and ducting systems – determination of long term hydrostatic strength of thermoplastics materials in pipe form by extrapolation

ISO 9623:1997 PE/metal and PP/metal adapter fittings for pipes for fluids under pressure - Design lengths and size of threads - Metric series

ISO 9624:1997 Thermoplastics pipes for fluids under pressure - Mating dimensions of flange adapters and loose backing flanges

ISO 12162:1995 Thermoplastics materials for pipes and fittings for pressure applications – Classification and designation – overall Service (Design) coefficient

ISO 12176-1:1998 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 1: Butt fusion

ISO 12176-2:2000 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 2: Electrofusion

ISO 12176-3:2001 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 3: Operator's badge

ISO 12176-4:2003 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 4: Traceability coding

ISO 13477:1997 Thermoplastics pipes for the conveyance of fluids — Determination of resistance to rapid crack propagation (RCP) — Small-scale steady-state test (S4 test)

ISO 13478:1997 Thermoplastics pipes for the conveyance of fluids — Determination of resistance to rapid crack propagation (RCP) — Full-scale test (FST)

ISO 13479:1997 Polyolefin pipes for the conveyance of fluids — Determination of the resistance to crack propagation — Test method for slow crack growth on notched pipes (notch test).

ISO 13480:1997 Polyethylene pipes — Resistance to slow crack growth — Cone test method

ISO 13761:1996 Plastics pipes and fittings - Pressure reduction factors for polyethylene pipeline systems for use at temperatures above 20° C

ISO 14236:2000 Plastics pipes and fittings - Mechanical-joint compression fittings for use with polyethylene pressure pipes in water supply systems

ISO/TR10358:1993 Plastics pipes and fittings – Combined chemical resistance classification table

IS0/TR11647:1996 Fusion compatibility of polyethylene (PE) pipes and fittings

ISO/TS 10839:2000 Polyethylene pipes and fittings for the supply of gaseous fuels - Code of practice for design, handling and installation

EN 1555:2002 Plastics piping systems for the supply of gaseous fuels. Polyethylene (PE).

ISO - International Organization for Standardization

Anna Wroblewska - Wavin

PE100+ Home page -> PE100+ Association -> PE100+ Eye-Witness

Anna Wroblewska - Wavin European Sales Manager Renovation

―For Wavin company – the leading producer of plastic pipes - the highest quality of products offered to the customers is a matter of the highest importance. The necessary condition for manufacturing the high-quality pipes is the high-quality raw material. For many years Wavin has produced PE100 pipes by using raw materials placed on the PE100+ Associations list of ―PE100+ Quality Materials‖. The quality of raw material is continuously controlled by independent research institutes and by Wavin quality control systems. Thanks that buying our products customers receive certainty that Wavin pipes’ quality is higher than required standards. The results from our laboratory tests and opinion of the end-users (waterworks and gasworks) confirm firmly the fact.‖

Mike Shepherd - Thames Water plc

PE100+ Home page -> PE100+ Association -> PE100+ Eye-Witness

Mike Shepherd - Thames Water plc

―High performance polyethylene is now, almost exclusively, the material of choice in the UK water industry for distribution size (90mm to 315mm) pipe systems and is increasingly being used for larger diameter trunk mains. As an end user, it is of utmost importance that these installations provide long and maintenance free service lives. The work of the PE100+ Association, by setting the standards for high quality materials and constantly working to improve best practice in manufacture, design and installation of PE pipe systems, provides confidence that these end user requirements will be met."

Robin Bresser - President of the PE100+ Association

PE100+ Home page -> PE100+ Association -> PE100+ Eye-Witness

Robin Bresser - President of the PE100+ Association "The PE 100+ Association is an industry association that welcomes all PE100 pipe material producers, who fulfill the strict quality requirements of the association. The Association promotes, in close co-operation with other organizations, the usage of all plastic pipes for example by educating and training decision makers, designers and installers. The PE100+ Association also responds to and takes leading role in common technical industry issues. The industry appreciates the broad technical and promotion work of the PE100+ Association which aims to create trust in high quality PE pipes—globally."

Dr. Elmar Loeckenhoff - Kunststoffrohrverband KRV

PE100+ Home page -> PE100+ Association -> PE100+ Eye-Witness

Dr. Elmar Loeckenhoff - Kunststoffrohrverband - KRV

"Kunststoffrohrverband e.V. (KRV), an association of the plastics pipe industry, is a speaking partner for all applications of the German plastic pipes industries. The target of the KRV and its members is to offer high quality and reliable products.

Polyethylene has been established as an important plastic pipe material already since 50 years and has steadily improved in its performance. Nowadays high quality pipes made of PE100 are used in many different application areas.

Thanks to the active education work of the PE100+ Association many pipe users and decision makers are today well informed on the benefits of PE100 material. The highest quality PE100 materials end up into both KRV and PE100+ Association Quality Materials lists. These materials exceed the requirements of the standard regulations."

01 - Why PE100+ Association

PE100+ Home page -> PE100+ Association

The PE 100+ Association ensures the very highest quality of PE 100 by continuously

monitoring three fundamental properties. Network engineers also rely on these for increasing the use of PE in gas and water distribution networks.

The PE 100+ Association aims to set higher performance standards than those founded in

CEN/ISO.

Durability under pressure is determined by both the creep rupture strength and stress crack

resistance.

PE 100 demonstrates significant improvement in the creep rupture strength, which is an

important factor in ultimately determining the lifetime of a material. Stress crack resistance

of PE 100 is also clearly improved. This ensures a longer, safer operational life for the pipe.

Notched pipe testing is an accelerated method of assessing high stress crack resistance.

As in all materials for pressure applications, including steel, engineers want to minimise the

risk of rapid crack propagation. As PE 100 is a highly ductile material, this risk is very low.

The internationally-standardised S4 test is used to assess the material’s performance, and it

shows PE 100’s performance well beyond its operational pressure.

By measuring all three properties on the same pipe at a higher level and on a regular basis,

the pipe materials listed by the PE 100+ Association deliver continuous, outstanding

performance.

01 - About Polyethylene Pipes

PE100+ Home page -> Polyethylene Pipes

About Polyethylene Pipes Plastics and performance excellence The plastics industry continues to innovate. Tailor-made solutions must always be a combination of functional excellence, long life and technological advancement. Plastics play an important role in the pursuit of sustainable development, a vital challenge for society at the dawn of the new millennium. Plastics in a challenging environment The supply of water and energy are crucial for humanity in the 21st century. Millions of people throughout the world already suffer from drinking water shortages, and the global population keeps growing. The highest quality in pressure piping material is critical for ensuring the safe transport of not only drinking water, but also natural gas and industrial fluids. PE pipe - an excellent choice The construction industry is increasingly turning to novel materials which are waterproof, stable, weather-resistant, light and easy to handle. Polyethylene (PE) was introduced in the late 1950s and has undergone tremendous development to reach the world-wide position it enjoys today. Compared to traditional materials, PE pipe installations are the most competitive by combining key advantages:

Ease of handling due to flexibility and light weight

Leak-tight installation due to excellent fusion-welding possibilities

Long life with low operational costs

Capability for relining existing pipelines

Possibility for on-site extrusion, alternative installations

Chemical resistance

The outstanding quality of PE pipe is documented by international standardisation bodies. PE has a long, proven track record for water and gas distribution, and the introduction of PE 100 material has broadened the range of pipe applications even further. PE 100 pipe sets new standards in three fundamental properties:

Creep rupture strength

Stress crack resistance

Resistance to rapid crack propagation

03 - The PE100+ Association testing schedule

PE100+ Home page -> Polyethylene Pipes

The PE100+ Association testing schedule All procedures and administration before and after testing are handled by Kiwa, who is heading the technical committee. The tests are performed at 3 different testing institutes on behalf of Kiwa. The PE 100 product manufacturers send 30 (15 for testing, 15 back-up) extruded 110 mm, SDR 11 pipes to Kiwa. Each testing institute performs a different type of testing. Kiwa forwards PIN-coded samples to those institutes and collects the results. This testing schedule, which is repeated every seventh month, builds the base for the "PE100+ Quality Materials", which is issued by the Association. This list shows those products, which successfully met the PE100+ Associations requirements and has passed 2 test rounds.

04 - Testing Institutes

PE100+ Home page -> Polyethylene Pipes

Testing Institutes Testing coordinating of test rounds and the test institutes > Kiwa N.V. in The Netherlands Kiwa works for industries in the entire gas and water chain and its products and services offer successful solutions for companies operating in gas and water exploration, production, treatment, transmission and distribution, storage, and trade as well as for installation firms and manufacturers of gas and water applications such as appliances and components. It is as well operating succesfully in the market for training employees of companies in the area's of gas and water distribution, installation, maintenance etc., and organizing of seminairs. Kiwa N.V. corporate headquarter is located in Rijswijk with subsidiaries in the Netherlands in Apeldoorn, Goes and Nieuwegein, foreign offices in the UK, Italy, Germany, Belgium and Sweden, and agencies in Japan , Turkey, Korea, China, Greece, Spain and the USA. One of the companies in the KIWA group , Kiwa Gastec Certification, .is Europe's market leader in the field of certification of products suitable for gas and water . Kiwa Gastec Certification offers pipe grade evaluations and SEM-analyses in accordance with ISO-9080, Notch testing, RCP-S4 testing, Fracture mechanics, mechanical testing like Tensile tests, Cone-tests, FNC-tests, Condensate tests, as well as physical analyses such as: DSC, DSC/SIS, FTIR, O.I.T., Density, M.F.R, Carbon Black Content and Pigment dispersion measurements etc., and offers as well Welding Technologies on various plastics applied in the gas and water industries. Kiwa Gastec Certification is accredited by the Dutch Council of Accreditation (RVA) in the Netherlands in accordance with NEN-EN 45011, NEN-EN 45012 and NEN-EN-ISO /IEC 17025. The RVA is member of EA, the European Cooperation for Accreditation. More info: www.kiwa.nl > Bodycote Bodycote Polymer is an independent testing laboratory in Nykoping, Sweden. Bodycote Polymer focuses on the lifetime performance and lifetime expectancy of polymer materials and components. With more than 30 years of experience, Bodycote Polymer is a well recognized company throughout the world. Bodycote offers a complete range of testing in the field of plastic pipes and fittings, e.g. determination of regression curves according to ISO 9080, ASTM etc., fracture mechanics tests (such as S4-test, Rapid Crack Propagation, and notch pipe testing, Slow Crack growth, chlorine and other chemicals as well as testing of pipes in circulation systems with high flow rates. With over 4 800 positions for hydrostatic pressure testing, Bodycote Polymer is today one of the largest independent accredited pipe testing laboratories in the world. Bodycote Polymer is accredited by Swedac according to ISO/IEC 17025. SWEDAC is a member of EA (European Cooperation for Accreditation). More info: www.bodycotepolymer.com > Becetel VZW Becetel vzw, the Belgian Research Centre for Pipes and Fittings, is specialised in testing plastics pipes and accessories for utilisation in gas-, water- and drain pipe systems. In order to fulful its tasks and to guarantee a high quality of it services, Becetel disposes of a plastics research centre in Melle (B) and a RCP research centre in Evergem (B). Becetel is offering a complete range of testing services in the field of plastics pipes and fittings, e.g. determination of regression curves following the SEM analysis of ISO 9080, experimental fracture mechanics tests (like S4, Full scale and Slow crack growth testing), mechanical testing, physical testing. Becetel participates in international conferences and promotes standardisation and regulation through active participation in international standardisation commissions. Becetel is accredited by Beltest in according with NBN EN ISO/IEC 17025. More info: www.becetel.be

05 - Testing methods

PE100+ Home page -> Polyethylene Pipes

Creep rupture strength - Internal pressure test The internal pressure test is standardised in ISO 1167 and EN 921 "Thermoplastic pipes for the conveyance of fluids - Resistance to internal pressure - Test method". The test specifies a method for determination of the resistance to constant] internal pressure at constant temperature. The test samples are kept in an environment at a specific constant temperature, which can be either water ("water-in-water" test), another liquid ("water-in-liquid") or air ("water-in-air" test). The tests for the PE100+ Association are performed on 110 mm SDR 11 pipes as "water-in-water" test. In terms of lengths of the pipe, the standard requires at least three times the outside diameter. For pipes bigger that 315 mm outer diameter, a minimum length 1.000 mm shall be used. Stress crack resistance - Pipe notch test The Pipe notch test is standardised in ISO 13479 "Polyolefin pipes for the conveyance of fluids - Determination of resistance to crack propagation - Test method for slow crack growth on notched pipes (notch test)". The test simulates slow crack growth and record time to failure on notched pipes. The testing environment accords to ISO 1167 and EN 921 in terms of temperature and specified constant internal pressure. PE pipes are tested at 80ºC under certain pressure levels, depending on the SDR (Standard Dimension Ratio). All tests for the PE100+ Association are carried out on 110 mm SDR 11 pipes, which leads to an internal test pressure of 9.20 bar. The CEN/ISO standard refers to a testing time of =165h at 80C at 9.20 bar for PE 100 materials. The PE100+ Associations requirement is enlarged by three times up to =500h using the same testing conditions.

Resistance to Rapid Crack Propagation - S4 Test The small-scale steady-state test (S4 test) is standardised in ISO 13477 "Thermoplastics pipes for the conveyance of fluids - Determination of resistance to rapid crack propagation (RCP)." The test simulates the phenomenon of RCP in plastic pipes and measure the determination of arrest or propagation of an initiated crack. In pipelines RCP, caused by a brittle crack, could undergo the length of several hundred meters almost at the sound of speed. This requires even more awareness about RCP. The current EN/ISO standards provide a maximum of 10 bar for natural gas and 25 bar for potable water pipelines as operating pressure. The determination of the required testing pressure is based on the MOP (maximum operation pressure) and would result in a testing pressure of only 4.2 bar for a MOP of 10 bar. The PE100+ Association takes that into consideration and raises it's requirement in terms of the testing pressure in the S4 test up to minimum 10 bars. Straight test pipe samples are used with square ends with a specified length of seven times external diameter of the pipe. All tests within the PE100+ Association are specified with 110 mm SDR 11 pipes with 800 mm length. The test is carried out by a conditioning temperature of 0? C using nitrogen or air to pressurise up the pipe. The pipes are prepared with leaktight endcaps, which are fitted over each end. The test apparatus is designed to simulate a fast-running longitudinal crack following a small notch inside the pipe. The energy obtained during an impact on a pipe sample, caused by a falling weight including a striker blade, might assure a fast running crack if the resistance to RCP is below a certain level. The required crack arrest is defined, when the crack does not exceeds or equal 4.7 times the outer

diameter of the pipe. Research work to determine the correlation factor between of the S4 and the full-scale test is ongoing.

The CEN/ISO standard requires a critical pressure Pc,S4 with the displayed formula above at a testing temperature of 0_C.

The PE100+ Association takes that into consideration and raises it‘s requirement in terms of the testing pressure in the S4 test up to minimum 10 bars.

Creep rupture strength - Internal pressure test The internal pressure test is standardised in ISO 1167 and prEN 921 ‖Thermoplastic pipes for the conveyance of fluids‖ – Resistance to internal pressure – Test method. The test specifies a method for determination of the resistance to constant internal pressure at constant temperature. The test samples are kept in an environment at a specific constant temperature, which can be either water (‖water-in-water‖ test), another liquid (‖water-in-liquid‖) or air (‖water-in-air‖ test). The tests for the PE100+ Association are performed on 110 mm SDR 11 pipes as ‖water-in-water‖ test. In terms of lengths of the pipe, the standard requires at least three times the outside diameter. For pipes bigger that 315 mm outer diameter, a minimum length 1.000 mm shall be used.

The CEN/ISO standard refers to a testing time of > 100h at 20C at 12.4 MPa for PE 100 materials. The PE100+ Association requirement is enlarged by two times up to > 200h using the same testing conditions

06 - Reference Installations

PE100+ Home page -> Polyethylene Pipes

Reference Installations The PE100+ Reference Installations feature different pipe installations, where PE 100 pipes were chosen. The pipes are made of a PE 100 material, which is listed on the Associations' Quality Materials.

The following installations are available:

"1400 mm PE 100 pipe installed in Shetland Islands‖, 2001

"710 mm wastewater pressure pipe made of PE 100‖, 1999

"Alpine village Grindelwald - 25 bar PE 100 drinking water distribution‖,1998

"First natural gas distribution made of PE 100 pipes for 12 bar‖, 1998

"1000 km of PE100 pipes to reconstruct Palermo water network‖, 1998

"The biggest underwater PE 100 pipe disposing of treated municipal effluent in Greece‖, 1996

"The first 10 bar PE gas pipeline in Germany‖, 1996

"The biggest PE gas pipeline: 630 mm diameter; Reconstruction of the gas pipeline to supply gas for the heating plant in Brno‖, 1995

Questions and answers

PE100+ Home page

Frequent questions and answers What is the objective of the PE 100+ Association? The Association‘s objective is to guarantee consistent quality at the highest level in both the production and the usage of PE 100 pipe material. The association aims also to create a marketing platform to promote the use of Polyethylene piping in general. What is the Association's Quality Materials? In the name of the PE 100+ Association, Gastec issues a PE 100+ Association Quality Materials. This list shows materials, which passed the requirements of the PE 100+ Association. How to become a member? The PE 100+ Association is open to any raw material manufacturer whose materials comply with its enhanced requirements. For further information about joining the Association, please contact the PE 100+ Association at GASTEC, Wilmersdorf 50, NL-7327 AC Apeldoorn, The Netherlands

Asociación Española de Fabricantes de Tubos y Accesorios Plásticos (AseTUB ) Es una entidad con las puertas abiertas, y en ella encontrará los instrumentos necesarios para saberse y sentirse mejor representado, con absoluta imparcialidad y con la mayor fuerza que genera la unión. Desde su fundación, en 1978, ha expresado su clara vocación de servicio a la Industria de Tuberías Plásticas. http://www.asetub.es/

Other Associations 25/02/2005

Basell Basell is the world^^s largest producer of polypropylene and advanced polyolefins products, a leading supplier of polyethylene and catalysts, and a global leader in the development and licensing of polypropylene and polyethylene processes. http://www.basell.com

PE100+ Members 25/02/2005

Becetel Becetel carries out scientific research on plastics, pipes and fittings for water and gas supply, develops new testing methods for plastics, supplies information through participation in international conferences. http://www.becetel.be/

Testing Institutions 25/02/2005

Bodycote Bodycote Polymer focuses on the lifetime performance and lifetime expectancy of polymer materials. After more than 30 years of experience Bodycote Polymer is the world leader in the lifetime evaluation of plastic pipes. http://www.bodycotepolymer.com/

Testing Institutions 25/02/2005

Borealis Borealis is a leading, innovative provider of plastics solutions with more than 40 years of experience in polyethylene (PE) and polypropylene (PP). http://www.borealisgroup.com

PE100+ Members 25/02/2005

Borouge Borouge is a leading supplier of environmentally superior polyolefin plastics -polyethylene and polypropylene. We focus on differentiated high end applications in the Middle East and Asia Pacific with Borstar Enhanced Polyethylene produced in Abu Dhabi, UAE and the full range of Borealis specialities. http://www.borouge.com/

PE100+ Members //

Der Kunststoffrohrverband e.V. (KRV ) Der Kunststoffrohrverband e.V. (KRV), im Juli 1957 gegründet, ist der Fachverband der Kunststoffrohr-Industrie mit Sitz in Bonn. Ihm gehören viele namhafte Hersteller von Kunststoffrohren und -formstücken in Deutschland an. http://www.krv.de/

Other Associations 25/02/2005

Ineos Polyolefin (Formerly Innovene) INEOS has acquired end 2005 the petrochemical and chemical activity of BP (previously called Innovene) and has become the third largest independent chemical company in the world, with 68 manufacturing sites and a turnover in excess of 30 bn USD per annum. INEOS is placed among the top 3 producers in Polypropylene and Polyethylene both in Europe and worldwide. http://www.eltex-pipe.com

PE100+ Members 25/02/2005

Kiwa Group Kiwa wishes to be a ‖Partner for progress‖ based on an acknowledged leadership in the areas of certification and research, supported by inspection, training and consultancy. The various activities of Kiwa have been grouped into several market-oriented business units. They operate independently of each other in the market and mutually exchange expertise, wherever possible. http://www.kiwa.nl

Testing Institutions 25/02/2005

Plastic pipes The European Plastics Raw Material Producers Association, PlasticsEurope and the European Plastic Pipes and Fittings Association, Teppfa, have jointly decided to support and promote the economic and environmental benefits of plastic pipes for the advantage of the European citizens. http://www.plastic-pipes.com

Industry Associations //

PlasticsEurope PlasticsEurope represents the plastics manufacturers in Europe. The association has more than 60 member companies, producing over 90% of polymers across Europe^^s 25 member states plus Norway, Switzerland and Turkey. PlasticsEurope operates from six decentralised offices: one in Brussels and five regional centres (Central, Iberia, Mediterranean, North and West) located in France, Germany, Italy, Spain and the UK. http://www.plasticseurope.org

Industry Associations //

Prime Polymer Prime Polymer Co., Ltd. was established as part of a comprehensive tie-up linking Mitsui Chemicals, Inc. and Idemitsu Kosan Co., Ltd. With a total PO capacity of 2.1 million ton, Prime Polymer is No.1 in Japan, and No.3 in Asia. We maximize the strong points of both parent companies and are determined to further expand the polyolefin business they promoted globally. By integrating the technical leadership both companies showed in the polyolefin industry, we are able to provide innovative solutions for customers worldwide. http://www.primepolymer.co.jp/

PE100+ Members //

Sabic SABIC was established in 1976 to add value to Saudi Arabia^^s natural hydrocarbon resources. Today, SABIC is among the leading petrochemical companies in terms of sales and product diversity. Headquartered in Riyadh, we are also one of the Middle East^^s largest non-oil industrial companies. http://polymers.sabic-europe.com

PE100+ Members 25/02/2005

The European Plastic Pipe and Fittings Association (TEPPFA) TEPPFA is a non profit organisation founded in Belgium in 1992 and subsequently registered by Royal Decree to actively work for and represent the interests of European manufacturers of plastic pipes and fittings and their respective national trade associations. http://www.teppfa.org/

Industry Associations 25/02/2005

Total (Formely ATOFINA) Total is a multinational energy company committed to leveraging innovation and initiative to provide a sustainable response to

PE100+ Members 25/02/2005

humankind‘s energy requirements. The world‘s fourth-largest oil and gas company and a world-class chemicals manufacturer, Total operates in more than 130 countries and has over 111,000 employees. http://www.total.com

Pipe Flow 3D Software

Pressure Drop Theory

This page describes in detail which factors need to be considered when calculating pressure drops through pipe systems, their effects on fluid flow and conditions at the pump inlet, and how Pipe Flow 3D can help with the calculations. Resistance to fluid flow Fluids in motion are subjected to various resistances, which are due to friction.

Friction may occur between the fluid & the pipe work, but friction also occurs within the fluid as sliding between adjacent layers of fluid takes place. The friction within the fluid is due to the fluid’s viscosity.

When fluids have a high viscosity, the speed of flow tends to be low, and resistance to flow becomes almost totally dependant on the viscosity of the fluid, this condition is known as ‘Laminar flow’. How do you establish the pipework resistance losses? Before the pipework losses can be established, the friction factor must be calculated. The friction factor will be dependant on the pipe size, inner roughness of the pipe, flow velocity and fluid viscosity. The flow condition, whether ‘Turbulent’ or not, will determine the method used to calculate the friction factor. The starting point must be to find the fluid’s viscosity. This will be the factor that has most effect on the pipework

losses.

Understanding viscosity units (dynamic viscosity)

Many terms can be used to describe a fluid's viscosity (its resistance to flow): Centipoise, Poise, Saybolt Universal (SSU), Saybolt Furol, Ford Cup No. 3, Ford Cup No.4, Redwood No.1, Degrees Engler, Zahn No.1, Zahn No.2 and Zahn No. 3 are some of the scales that have been used in the immediate past. All of these scales have differing upper and lower values and are usually not directly related to each other. Some references may be found in text books which attempt to list equivalent values for these different methods of measuring viscosity. Pipe Flow 3D provides a means of calculating the equivalent centistokes viscosity from some other known viscosity scales.

Kinematic viscosity and Reynold’s numbers Dynamic viscosity must be converted to its Kinematic viscosity equivalent before the viscosity value can be used to calculate Reynold’s numbers and hence friction factors.

It is very common today to express dynamic viscosity in centipoise. one Centipoise = 1 mPa.s or 0.001 (kg/m) x s

The units of centipoise are: Force per unit area x Time

It is very common today to express kinematic viscosity in centistokes.

one Centistoke = 1 mm²/s or 0.000001 m²/s

The units of centistokes are: Length²

Time

Kinematic viscosity is simply: Dynamic viscosity

Mass density

Reynold’s numbers Reynold’s numbers (Re) describe the relationship between a fluid’s velocity, the pipe size and the fluid’s

kinematic viscosity.

Reynold’s number = Fluid velocity x Internal pipe diameter

Kinematic viscosity

Effect of the inner roughness of the pipe The inner roughness of the pipe can create eddy currents. This increases the friction between the pipe wall and the fluid. The relative roughness of the inside of the pipe is used in determining the friction factor to be used.

Relative roughness = Inside pipe roughness

Inside pipe diameter

The average inner roughness of commercial pipes:

Steel tube Copper tubing Glass tubing

Polythene Flexible P.V.C. Rigid P.V.C. Cast iron tube Concrete tube

0.0460 mm 0.0015 mm 0.0001 mm

0.0010 mm 0.2000 mm 0.0050 mm 0.2600 mm 2.0000 mm

Friction factor chart

The chart above shows the relationship between Reynold’s number and pipe friction. Calculation of friction factors is dependant on the type of flow that will be encountered. For Re numbers <2300 the fluid flow is Laminar, when Re number is >2300 the fluid flow is Turbulent.

Laminar flow (Re < 2300) f = 64/Re Turbulent flow (Re > 2300) 1/sqrt(f) = -1.8 log [ (6.9/Re) + ((k/3.7)^1.11 ] (where k = inner pipe roughness / inner pipe diameter) Most commercial applications involve Turbulent flow. In these cases the inner roughness of the pipework can have a significant effect on the Friction factor. The Relative roughness is the inner roughness divided by the internal diameter of the pipe work. The Friction factor is found by plotting the intersection of Re and Relative roughness, and reading the friction factor on the left hand axis of the chart.

The Fluid head loss can be calculated once the friction factor is known. The Pressure drop in pipe work can be calculated from fluid head loss, the density of fluid and the acceleration due to gravity. Calculating the fluid head resistance Fluid head resistance can be calculated from h = f (L/d) x (v ²/2g) where h = head loss (m)

f = friction factor L = length of pipe work (m) d = inner dia of pipe work (m) v = velocity of fluid (m/s) g = acceleration due to gravity (m/s ²) Calculating the losses through pipe work fittings The fluid head resistance through various pipe work fittings can be calculated when the 'K' factor of the fitting is known. Manufacturers of pipe work fittings & valves publish 'K' factors for their products.

Usually a particular type of fitting from various manufacturers have similar 'K' factors, therefore this computer program tends to use average 'K' factor values. Fluid head loss of these fitting can be calculated from h = total 'K' x v ² / 2g

where h = head loss (m) total 'K' = total of 'K' factors for each fitting v = velocity of fluid (m/s) g = acceleration due to gravity (m/s ²) Note: If the pipework involves different pipe sizes, this calculation must be carried out separately for each pipe size, using the appropriate velocity within that pipe section. The 'K' value of entry & exit points can be taken as 0.8 and 1.0 respectively to calculate the head loss attributable to these features.

Calculating the total pressure drop The total fluid head resistance may be used to calculate the pressure required to overcome the resistance to fluid flow. Pd = h x p x g / 100000 where Pd = pressure drop (bar) h = head loss (m)

p = fluid density (kg/m3) g = acceleration due to gravity (m/s ²) Finally, the fluid is most likely to exit into atmospheric pressure. The difference between the pressure on the fluid surface during storage & the atmospheric pressure must be taken into account in determining the pressure drop to be overcome by the pump. This difference in pressure may be positive (assisting fluid flow) or negative (resisting fluid flow). Summarising the steps to be considered

Factors that affect fluid flow Fluid flow in pipes is affected by many different factors:

The viscosity, density, and velocity of the fluid.

Changes in the fluid temperature will change the viscosity & density of the fluid.

The length, inner diameter, and in the case of turbulent flow, the internal roughness of the pipe.

The position of the supply and discharge containers relative to the pump position.

The addition of rises & falls within the pipe layout.

The number & types of bends in the pipe layout.

The number & types of valves, & other fittings, in the pipe layout.

Entrance & exit conditions of the pipe work.

Calculating the fluid head

When all of the above information is known, the following steps must be carried out to determine the fluid head necessary to overcome the flow of the fluid through the pipe work layout:

Calculate the Reynolds number

Determine if the flow is Laminar or Turbulent

Calculate the friction factor for either Laminar flow or Turbulent flow

Calculate the fluid head resistance to overcome the flow through the pipe work

Determine the ‘K’ factors for the fittings within the pipe work layout

Calculate the fluid head resistance to overcome the flow through the fittings

Determine which lengths & components within the pipe work layout are significant in establishing the maximum fluid head to be considered (branch lines may be important).

The effect of fluid density & gravity must be applied to the maximum fluid head to calculate the pressure required to overcome the resistance to fluid flow.

Fluid Flow Factors

Summary of the items to consider when calculating pressure drops. Factors that affect fluid flow Fluid flow in pipes is affected by many different factors:

The viscosity, density, and velocity of the fluid.

Changes in the fluid temperature will change the viscosity & density of the

fluid.

The length, inner diameter, and in the case of turbulent flow, the internal

roughness of the pipe.

The position of the supply and discharge containers relative to the pump position.

The addition of rises & falls within the pipe layout.

The number & types of bends in the pipe layout.

The number & types of valves, & other fittings, in the pipe layout.

Entrance & exit conditions of the pipe work.

Calculating the fluid head When all of the above information is known, the following steps must be carried out to determine the fluid head necessary to overcome the flow of the fluid through the pipe work layout:

Calculate the Reynolds number

Determine if the flow is Laminar or Turbulent

Calculate the friction factor for either Laminar flow or Turbulent flow

Calculate the fluid head resistance to overcome the flow through the pipe work

Determine the ‘K’ factors for the fittings within the pipe work layout

Calculate the fluid head resistance to overcome the flow through the fittings

Determine which lengths & components within the pipe work layout are significant in establishing the maximum fluid head to be considered (branch lines may be important).

The effect of fluid density & gravity must be applied to the maximum fluid head to calculate the pressure required to overcome the resistance to fluid flow.

Pumping the fluid - Can you pump the fluid?

Will the pressure on the fluid surface & the effect of any positive or negative fluid head be sufficient to ensure that the full flow rate required will reach the pump inlet? Will the lowest fluid pressure, which occurs in the pump inlet, fall below the fluid vapour pressure, and hence cause cavitation to occur? You will needs to establish the inlet condition to the pump

and establish the discharge pressure that the pump must overcome. Getting Fluid to the Pump?

What about pump suction? Pumps do not suck! It is a common belief that pumps provide the energy to lift fluid to the pump inlet. This is not true. The pump simply moves fluid from the immediate inlet pipework and discharges this fluid against the outlet pressure in the discharge system. This action creates a local suction effect, which allows the external forces acting on the fluid intake system to push the remaining fluid in the intake system towards the pump inlet. This alternative (actual) view of what is happening within the pipework system leading to the pump inlet will help in understanding the limitations introduced by bad pipework system design.

If the inlet system arrangement does not provide enough energy to move the required flow rate to the pump

inlet, the pump will be starved of fluid and the required flow rate

will not be delivered.

Getting fluid to the pump The air pressure on the fluid surface is the usual energy source used to push the fluid into the pump. A supply container positioned above the pump inlet will increase the available energy. A supply container positioned below the pump inlet will reduce the available energy.

Resistance to fluid flow Fluids in motion are subjected to various resistances, which are due to friction. Friction may occur between the fluid & the pipe work, but friction also occurs within the fluid as sliding between adjacent layers of fluid takes place. The friction within the fluid is due to the fluid’s viscosity. When fluids have a high viscosity, the speed of flow tends to be low, and resistance to flow becomes almost totally dependant on the viscosity of the fluid. This condition is known as ‘Laminar flow’. Will the required flow rate actually reach the pump inlet?

The energy losses in the pipework system must be calculated. This energy loss must be subtracted from the available energy to obtain the condition at the entrance to a pump. The inlet condition is commonly referred to as the ‘suction condition’ - Leading to the idea that pumps suck. If the theoretical pump inlet pressure is too low the system will operate at some lower flow rate or the pump may not operate at all.

Boiling fluid (Cavitation)

Many fluids will boil at ambient temperature if the pressure is reduced below a particular level. This pressure is referred to as the ‘Vapour pressure’ of the fluid. If the pump inlet pressure falls below the vapour pressure of the fluid, gas bubbles will form in the fluid. These bubbles will be moved through the pump. The bubbles will collapse when the fluid pressure is raised on the discharge side of the pump. The effect of this is to reduce the flow of delivered fluid. In some systems the effect can cause

dramatic vibrations, and may result in damage to the system and the pump. Increasing the pressure at the pump inlet

Small pipe sizes will result in high pipework energy losses. Increasing the pipework size will help to reduce this energy loss. In the case of high viscosity fluids, increasing the pipework size may not have the desired result. Also, commercial considerations may limit the size of the pipe that can be used. Under these circumstances, the easiest solution is to raise the position of the supply container, to increase the positive head available, thus more force will be available to push the fluid through the pipework.

If is not practical to raise the supply container, it may be necessary to enclose the supply and introduce some positive pressure above atmospheric onto the fluid surface. Look out for sealed supply containers where the force moving the fluid will reduce as the container is emptied. Suction units Suction conditions can be described in many different ways.

Normal atmospheric pressure (about 1000 mBar, 14.5 psi.g) will support a water column of 10.2 metres

(33.45 ft) high. If the fluid column was Mercury the column height would be 750 mm (29.52 inches)

Net Positive Suction Head Check Pump inlet loss N.P.S.H.r An energy loss occurs during

fluid entry into most pumps. This loss is described as N.P.S.H.r (Net Positive Suction Head requirement). The N.P.S.H.r is determined

by the pump manufacturer. The N.P.S.H.r is usually plotted on pump performance curves. The N.P.S.H.r is expressed in metres head ( or ft head) of fluid. The value of N.P.S.H.r will be dependent on many factors including flow rate, Impellor design, inlet type,

pump speed etc. Boiling fluid (Cavitation) (repeated from last section) Many fluids will boil at ambient temperature if the pressure is reduced below a particular level. This pressure is referred to as the ‘Vapour pressure’ of the fluid. If the pump inlet pressure falls below the vapour pressure of the fluid, gas bubbles will form in the fluid. These bubbles will be moved through the pump. The bubbles will collapse when the fluid pressure is raised on the discharge side of the pump. The effect of this is to reduce the flow of delivered fluid. In some systems the effect can cause dramatic vibrations, and may result in damage to the system and the pump.

Minimum pressure at the pump inlet and N.P.S.H.a The minimum pressure at the pump inlet minus the ‘Vapour pressure’ of the fluid is usually known as the Net Positive Suction Head available (N.P.S.H.a) This must not be confused with the N.P.S.H.r published by the pump manufacturer. Net Positive Suction Head Check

The NPSH calculations featured in Pipe Flow 3D will display the N.P.S.H.a The example graphic here shows how the calculation is performed. The N.P.S.H.a must be greater than the pump manufacturer’s N.P.S.H.r to avoid the fluid pressure falling below the point at which ‘Boiling of the fluid’ will occur.

Pipe Flow 3D - Fluid Database

PipeFlow 3D comes with its own Fluid Database and Fluid Data Editor. PipeFlow comes

with a default set of data for well known fluids. The fluid entries can be amended

by using the new entry, edit entry and delete entry options.

Note: The fluid data listing contains viscosity information in Centistokes. This is a common method of expressing viscosity. Usually the Centistokes value has been converted from some timed test methods of establishing viscosity, such as Redwood 1 (Britain), Saybolt Seconds Universal SSU (U.S.A.) or degree Engler (Germany).

The S.I. units for Centistokes are: 1 Centistoke = 1 mm² /s = 10-6 m² /s This is known as Kinematic Viscosity.

Centipoise is an another method of expressing viscosity. The S.I. units for Centipoise are: 1 Centipoise = 1 mPa s = 10-3 Pa s This is known as Absolute Viscosity. Care must be taken to enter the viscosity in the appropriate Viscosity Units when entering new fluid data.

Viscosity Relationship Kinematic Viscosity = Absolute Viscosity / Fluid density Where the fluid density is Relative Density (to Water) = 1000 kg / m3 = 1 kg / litre = g / cm3 Approximate viscosity equivalents A listing of some approximate viscosity equivalents is included to assist the user in converting from various viscosity scales to Centistokes.

Pipe Flow Wizard Software

"What if?" calculations for Liquids and Gases

Pipe Flow Wizard is able to perform four different calculations depending on the known information. It can calculate:

Pressure Drops

Flow Rates

Size of Internal Diameters

Pipe Lengths

Pipe Flow Wizard will calculate results for LIQUIDS or COMPRESSED GASES. A comprehensive Fluid Database is included with viscosity and density of

common fluids.

PRESSURE DROP CALCULATION When internal roughness, internal diameter, length, fittings, elevation change, and flow rate applicable to a pipe are known the PRESSURE DROP through the pipe can be calculated. The type of flow, Reynold's number, friction factor, and fluid velocity are also displayed.

FLOW RATE CALCULATION When internal roughness, internal diameter, length, fittings, elevation change, and available pressure applicable to a pipe are known the FLOW RATE through the pipe can be calculated. The type of flow, Reynold's number, friction factor, and fluid velocity are also displayed.

INTERNAL DIAMETER CALCULATION When internal roughness, length, fittings, elevation change, available pressure, and flow rate applicable to a pipe are known the MINIMUM INTERNAL DIAMETER of the pipe can be calculated.

The type of flow, Reynold's number, friction factor, and fluid velocity are also displayed.

PIPE LENGTH CALCULATION When internal roughness, internal diameter, fittings, elevation change, available pressure, and flow rate applicable to a pipe are known the MAXIMUM LENGTH of the pipe can be calculated. The type of flow, Reynold's number, friction factor, and fluid velocity are also displayed.

Pipe Flow Wizard - Pressure Drop Calculations

Set the following values : 1*. Internal roughness of the pipe. 2*. Internal diameter of the pipe. 3 . Length of the pipe. 4*. Valves, bends, and other fittings in the pipe.

5 . Elevation change of the pipe (Rise or fall). 6 . Flow through the pipe. 7 . Select flow rate units from drop down list. 8 . Select pressure units from drop down list. 9 . Change the fluid data : Name, viscosity, density The fluid data can only be changed if the Pipe Flow Wizard program has been registered.

Click 'Calculate pressure drop' to display : Flow type. Reynold's number. Friction factor. Fluid velocity. Pressure drop. (Change units if required).

NOTES:

1*. Select a pipe material from the drop down list to set a common value for internal roughness.

2*. Use 'diam?' button to assist in setting the internal diameter of the pipe, or enter your own value.

4*. Click the 'Valve' button to show the pipe fittings entry screen.

A comprehensive Fluid Database is included with viscosity and density of common fluids.

Pipe Flow Wizard - Flow Rate Calculations

Set the following values : 1*. Internal roughness of the pipe. 2*. Internal diameter of the pipe. 3 . Length of the pipe. 4*. Valves, bends, and other fittings in the pipe. 5 . Elevation change of the pipe (Rise or fall). 6 . Available pressure at inlet of the pipe. 7 . Select pressure units from drop down list. 8 . Select flow rate units from drop down list. 9 . Change the fluid data : Name, viscosity, density

The fluid data can only be changed if the Pipe Flow Wizard program has been registered.

Click 'Calculate flow' to display: Flow type. Reynold's number. Friction factor. Fluid velocity. Flow rate. (Change units if required).

NOTES:

1*. Select a pipe material from the drop down list to set a common value for internal roughness.

2*. Use 'diam?' button to assist in setting the internal diameter of the pipe, or enter your own value.

4*. Click the 'Valve' button to show the pipe fittings entry screen.

A comprehensive Fluid Database is included with viscosity and density of common fluids.

Pipe Flow Wizard - Internal Diameter Calculations

Set the following values :

1*. Internal roughness of the pipe. 2 . Length of the pipe. 3*. Valves, bends, and other fittings in the pipe. 4 . Elevation change of the pipe (Rise or fall). 5 . Available pressure at inlet of the pipe. 6 . Select pressure units from drop down list. 7 . Flow through the pipe. 8 . Select flow rate units from drop down list. 9 . Change the fluid data : Name, viscosity, density The fluid data can only be changed if the Pipe Flow Wizard program has been

registered.

Click 'Calculate pipe diameter' to display: Flow type. Reynold's number. Friction factor. Fluid velocity. Minimum internal pipe diameter.

NOTES:

1*. Select a pipe material from the drop down list to set a common value for internal roughness.

3*. Click the 'Valve' button to show the pipe fittings entry screen.

A comprehensive Fluid Database is included with viscosity and density of common fluids.

Pipe Flow Wizard - Pipe Length Calculations

Set the following values : 1*. Internal roughness of the pipe. 2*. Internal diameter of the pipe. 3*. Valves, bends, and other fittings in the pipe. 4 . Elevation change of the pipe (Rise or fall). 5 . Available pressure at inlet of the pipe. 6 . Select pressure units from drop down list. 7 . Flow through the pipe.

8 . Select flow rate units from drop down list. 9 . Change the fluid data : Name, viscosity, density The fluid data can only be changed if the Pipe Flow Wizard program has been registered.

Click 'Calculate pipe length' to display : Flow type. Reynold's number. Friction factor. Fluid velocity.

Max. pipe length. NOTES:

1*. Select a pipe material from the drop down list to set a common value for internal roughness.

2*. Use 'diam?' button to assist in setting the internal diameter of the pipe, or enter your own value.

3*. Click the 'Valve' button to show the pipe fittings entry screen.

A comprehensive Fluid Database is included with viscosity and density of common fluids.

Pipe Flow Wizard - Pipe Fittings

The type and quantity of various valves and fittings associated with the pipe can be set by amending the values on the 'Pipe fittings' screen. Click the 'Valve' button to display the 'Pipe fittings' screen. Enter the quantity of bends, fittings, valves etc. in the appropriate input boxes, click 'OK' to return to the calculation screen. The total quantity of fittings will be displayed on the 'Valve' button, on the appropriate calculation screen.

If the fitting type required is not displayed an appropriate entry in the other 'K' factor input box can be used to include the pressure drop of the fitting in the calculation.

Where two or more of these fittings are required the 'K' factor for each fitting should be added together and the total 'K' value should be entered. When a 'Find diameter' calculation is carried out, it may be necessary to first estimate the pipe diameter to allow the 'K' factor to be established (perform the calculation without the 'K' factor data

to estimate the pipe diameter). Generally the effect of pipe fittings are considered as minor losses. The pressure loss of a fitting (m hd or ft.hd) is calculated using the 'K' factor as shown here where: hd loss = v^2 / 2g v = fluid velocity (m/s or ft/s) g = 9.806 m/s^2 or 32.174 ft/s^2

On occasion the pressure loss of a fitting is expressed as an 'Equivalent length' of pipe.

Pipe Flow Wizard does not allow the use of equivalent length of pipe. The 'K' factor of a fitting may be calculated from the 'Equivalent length' (Eq.) (in m or ft.) if the friction factor (ff) and the Internal diameter (i.d.) (in m or ft.) is known. The 'Equivalent length' and 'Internal diameter' must be in the same units to calculate the 'K' factor. K = (Eq. * ff) / i.d.

Pipe Flow Wizard - Fluid Database

The fluid data may be changed by clicking the 'Change fluid' button to display the Fluid data base screen. Select an item from the 'Fluid data listing' to copy the data to transfer boxes at the top of the screen. Click 'Use this data' to transfer the data to the appropriate calculation screen. New entries may be added to the 'Fluid data listing': Amend the data in the 4 transfer boxes at the top of the screen and click 'Add this

data to list', the new data will be added to the 'Fluid data listing', the new list will be sorted in to alphabetical order.

The 'Liquids' or 'Gases' radio buttons may be used to display either Liquid or Gas data listings (Selecting 'Gases' will change the nature of the calculation, and you may need to re-assess the flow rate value to be used). User entries may be removed, select the appropriate entry and click 'Remove user entry'. The LIQUID database includes 'Kinematic viscosities' in Centistokes and

Density in kg / m^3 x 10^-3 The density value is also known as RELATIVE DENSITY (formerly this value was known as Specific Gravity).

The fluid data can only be changed if the Pipe Flow Wizard program has been registered. Olive oil is the only fluid which may be used in an un-registered version of Pipe Flow Wizard.

Flow Advisor Software

for Channels and Tanks

Flow Advisor may be used to estimate water flow rate from various shaped channels and tanks. It can calculate:

Open Channel Flow

Water Flow Rates

Time taken to empty tanks

Volume, Capacity, Weight and Expansion

Flow Advisor's Materials Database is included with density and coefficient of

expansion of many common materials.. A Fluid Database is included with density of common fluids.

OPEN CHANNEL FLOW Open-channel flow occurs when a liquid flows due to gravity. Usually the flowing liquid has a free surface, as in a channel, flume or partially full pipe. The liquid is not under pressure, other than atmospheric pressure. Many formulae have been developed to estimate the flow rate in open-channels, the Manning formula has become widely accepted as the usual method of estimating flow rate.

WATER FLOW RATE CALCULATION The Manning formula uses a coefficient to correct for the type of channel in use. The cross-sectional area of the flow, the wetted perimeter of the flow and the slope ratio must be calculated. The results are more accurate if the

flow cross-section, velocity, depth and slope are constant (steady flow). The flow rate estimates are applicable to water or fluids similar to water.

TIME TAKEN TO EMPTY TANKS The flow rate from a tank outlet will be dependant on the orifice size, orifice type and the head of fluid above the outlet position. The additon of an oulet pipe may restrict the oulet flow rate unless the outlet pipe is relatively short. As the tank empties the fluid head will reduce progressively, reducing the outlet flow rate. The shape of the tank will also affect the time taken to empty, as changes in shape will affect the rate of change of the fluid head available.

VOLUME, CAPACITY, WEIGHT & EXPANSION The inner volume, fluid capacity, weight and expansion of various pipes, sections, channels and tanks can be calculated. The weight of a pipe, channel or tank in various material constructions (steel, wood, aluminium,

brass etc.) and the fluid contents may be displayed by entering the appropriate dimensions and choosing the material and fluid type.

Choose from Pipes, Channels, Weirs and Tanks. Select a calculation screen to suit your application, by clicking an approriate tab.

Flow Advisor - Channel Types

Channel Types Open Channels appear in many arrangements:

Part full pipes.

Part full rectangular sections.

Rectangular channels.

Flate bottomed channels (with sloping sides).

Vee channels.

Each type of 'Open Channel' has an appropriate calculation screen. Choose the type of calculation required: Water flow rate, water depth, or volume & weight. Enter the data for your application. Click the 'Calculate button' and the answer appears.

Flow Advisor - Channel Calculations

Channel Calculations Flow Advisor may be used to calculate water flow rate, water depth, volume and weight, and length expansion. The calculations can be performed on:

Part full pipes.

Part full rectangular sections.

Rectangular channels.

Flate bottomed channels (with sloping sides).

Vee channels.

Examples from the pipe calculation screen are shown below.

WATER FLOW RATE Click the 'Water flow rate' radio button. Choose an appropriate Manning's coefficient for the type of pipe material. Enter the appropriate data (length, internal diameter, fluid depth, drop) for the pipe arrangement. Choose the flow rate units required. Click the 'Calculate water flow rate' button.

WATER DEPTH Click the 'Water Depth' radio button. Choose an appropriate Manning's coefficient for the type of pipe material. Enter the appropriate data (length, internal diameter, water flow rate, drop) for the pipe arrangement. Click the 'Calculate water depth' button. The maximum flow rate for a circular section occurs when the water depth is approximately 93.8% of the internal diameter.

Click 'Max Flow' button to display the maximum flow possible.

VOLUME AND WEIGHT Click the 'Volume and Weight' radio button. Enter the internal diameter, external diameter, length of the pipe, and the depth of fluid. Choose the pipe material to set the material density (or enter your own value). Choose the fluid to set the fluid density (or enter your own value). Click the 'Calculate Volume & weight' button.

LENGTH EXPANSION Click the 'Length Expansion' radio button. Choose the temperature change from the drop down listing. Click the 'Calculate expansion' button.

Flow Advisor - Weir Flow

Flow from Weirs Flow from Weirs may be used to estimate the water flow rate discharged. The calculations can be performed on different types of weir:

Rectangular weir with end contractions.

Trapezoidal weir with sloping end contactions.

Triangular weir with end contractions.

Smooth channel (horizontal) without contactions.

Weir Calculations Each design needs a different calculation method to estimate the flow rate. All four calculations methods use the weir dimensions, the water head (raised to some power - different for each design), and a constant factor (again different for each design.) Each type of 'Weir' has an appropriate calculation screen. Select a calculation screen by choosing a weir type. Enter the data for your application. Click the 'Calculate button'.

Flow Advisor - Tank Types

Tank Types Fluid Tanks can be found in many arrangements:

Rectangular

Circular

Cylindrical

Spherical

Cone or Frustrum

Hopper or Pryamid

Each type of 'Tank' has an appropriate calculation screen. Choose the type of calculation required (Time to empty, or volume & weight). Enter the data for your appplication. Click the 'Calculate button' and the results are shown.

Flow Advisor - Tank Empty Times

Time to empty a Tank The discharge from an orifice is dependant on various factors:

The discharge coefficient (varies with the type of outlet fitting).

The cross-sectional area of the orifice.

The 'Head' of water above the orifice outlet.

The Flow Advisor program offers a choice of outlet types:

Rounded outlet - discharge coefficient 0.98

Square edge outlet - discharge coefficient 0.80

Sharp edge outlet - discharge coefficient 0.61

Borda outlet (projecting inside) - discharge coefficient 0.51

Discharge Flow Rate The discharge flow rate from an orifice is calculated as follows: Flow rate = Orifice discharge coefficient x Orifice cross-sectional area x square root (2gH)

Where g = acceleration due to gravity Where H = head of fluid about outlet

As the tank empties the fluid head will reduce and the discharge flow from the orifice will reduce.

Fluid Surface Area If the fluid surface area within the tank is not constant, the rate of change in the fluid head will not be constant. Initially the change in fluid head may be slow, but as the tank empties the fluid head will change more quickly. The example shows that the time to reduce the fluid level by 300 mm (12 inch) is initially 3m - 37s, where as the final 300 mm of fluid will empty in 1m - 33 s.

Effect of Discharge Pipe

When a pipe is used to feed the tank discharge to some other point the pipe may restrict the discharge flow rate. When a 4 metre (13 ft) length of pipe is used, in this example, the time to empty is increased by almost 8 minutes.