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SIZING OF

REMI PLANTS

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PROCEDURE "SIZING OF REMI PLANTS"

1) FOREWORD (SCOPE - OBJECTIVES - LIMITS)

The sizing engineering, functional and resistance standards of a natural gas receiving, reduction and measurement plant, set by the Transporter as minimum requirements, are described in this procedure. This procedure has been drawn up in accordance with the principles set forth in current national and international technical standards and law and on the basis of the specific experience of the Transporter in the field in question: current law provisions must be observed in all cases as regards the safety, engineering, construction and maintenance of measurement instruments. The main sizing criteria for natural gas receiving, reduction and measurement plants illustrated in this procedure: provide the minimum technical-construction sizing criteria for REMI plants

without ruling out the adoption, by the owner, of upgrading solutions agreed on by the parties;

define pressure, temperature and flow rate parameters needed for engineering purposes;

classify REMI plants according to public or non public utility and interruptibility and, on the basis of this classification, define the sizing criteria of the regulation and measurement units; said destinations are selected under the full and sole responsibility of the owner of the plant;

indicate the charatersitics of materials and instruments; indicate the formulae and parameters required to calculate plant sizing; indicate the utilisation fields of the primary measurement system (volume and

venturimeter measurement) and the standardised engineering configurations in accordance with national and international standards;

prescribe the use of suitable equipment for automatic collection and processing of measurement data and relative remote transmission.

1.1)Plant with adjusted pressure and temperature

The “building blocks” of REMI plants are the following, described in the order in which the gas flows:

a) Upstream section, including the pipeline section between the delivery point and the

upstream filter manifold, the on-off valves, the insulating joint and emergency valve (optional)

b) Filtering unit (to split liquids and/or solid particles that may be in the gas) c) Preheating unit (optional) d) pressure regulation plant, including service regulators, control and emergency

regulators ("monitor"), shutdown device (optional), blowdown valve e) metering plant and associated by-pass f) exit section, including downstream emergency valve, the on-off valves and the

insulating joint.

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In addition, the following elements are also components of the REMI plant :

g) fuel system for the preheating unit (optional) h) odorization plant (optional)

(The odorization of the gas for domestic and related use in the distribution networks is requested by the law N.1083 of 6-12-1971. The odorization plants are regulated by the rule UNI-CIG 9463 and must be installed downstream of the gas measurement. The schemes contained in this procedure do not cover the odorization plant).

To assure continuity of operations the units b) c) d) are usually installed in series in two parallel lines. These lines are usually called “regulation lines”. Solutions different from those presented in this procedure may be adopted if equivalent or if they provide improvements from the functional point of view: the technical assessment will be carried out on a case by case basis.

1.2)Plant with pipeline pressure and temperature

Measurement plant with variable pressure and temperature, in the case of particular operational conditions, can be installed, after agreement between the parties, upstream of the pressure regulation. In any event, the measurement plant will be installed immediately downstream of the filtering unit. The scope in this case only covers the measurement plant or the installation of all the plant parts described in points 1.1c – 1.1d – 1.1g – 1.1h.

1.3)REMI plant with max upstream p ≤ 5 bar

These types of plant, consistent the other sizing criteria described below, must be developed in accordance with the criteria contained in Attachment 7. The main difference with plants where max upstream p > 5 bar is that plants ≤5 are allowed a filtering unit with lower performance, but this must still assure the normal functioning of the downstream plant. If these plants are "Gas pressure reduction plants” according to the rule UNI-CIG 8827, their development should be consistent with this rule. Attachment 7 contains its main features. In the Attachment 7 there are also some schemes valid for REMI plant with max upstream P ≤ 5 bar, not reduction plant, with Qimp. < 300 m3/h and with fiscal measurement of the volumes only.

1.4)Functional types of the plants

Plants have different characteristics according to the following types of customer supplied:

a) Non-Interruptible and Public Utility (Households, Hospitals, Schools, Nursing Homes, etc. for which unplanned supply interruptions will have serious impacts and may give rise to safety issues).

b) Non-interruptible and not Public Utility (Industrial customers, etc. for which unplanned supply cut in the gas supply may have significant impact).

c) Interruptible at any time (customers for which unplanned supply interruptions have minimal impact). These categories are assigned by the owner of the metering plant and documented as such.

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1.5)Accessory REMI plants It may be necessary, for fiscal reasons and in order to ensure correct measurement, to have an accessory measurement plant parallel to the main one. In this case the minimum configuration (concerning an interruptible plant with supplied flow rate < 300 m3/h) is contained in the scheme FA of Attachment 7. If the plant is not interruptible or with a supplied flow rate > 300 m3/h, the same approach should be used, consistent with this procedure and attachments, and considering the possible installation of other equipment (e.g. filters or regulators). The accessory REMI plants will normally be located downstream of the main measurement plant.

1.6)Law and standard references

The structure of the regulation and measurement plant described in this procedure, as far as the safety and the functional aspects are considered, complies with the rule UNI-CIG-9167 and with the rules EN 12186 (pressure regulation plant-functional requirements) EN 1776 (measurement plant-functional requirements). The solutions to be implemented for cases not covered by this procedure, or not specified in detail, should be agreed in advance with Snam Rete Gas. In designing the plant, in addition to the criteria contained in this procedure, the following rules should be taken into consideration:

EC laws and Directives in force at the time of the design standards (UNI-EN-ISO) in force at the time of the design legal metrology standards possible additional requirements for particular operational cases, such as, for

instance: minimum external temperature lower than –10 °C, two or more REMI plants supplying the same distribution network.

1.7)Pressure equipment (Pressure Equipment Directive 97/23 CE)

This Directive, applied by D.Lgs. n° 93 of 25.02.2000 for REMI plants includes the following equipments:

Primary measurement elements (meters, orifice-fitting) On-off valves Pressure regulators Safety and shotdown valve filters, exchangers and other containers.

Therefore in the design, building and testing of these equipments one has to comply with the dispositions of the Decree mentioned above.

2) FLOW RATE, PRESSURES AND TEMPERATURES

2.1)Flow rate

The flow rates, if not stated otherwise, are always expressed in m3/h at the standard conditions, i.e. in m3/h at 15 °C and 1,01325 absolute bar.

2.1.1) Delivered flow rate (Qero)

This is the max actual flow rate that the system can deliver.

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2.1.2) Minimum flow rate (Qmin) This is the minimum flow rate actually required by the plant.

2.1.3) Plant flow rate (Qimp) Plant flow rate is defined as the maximum flow rate for which the size of the plant has to be determined. It is appropriate to also consider potential future enhancements. At the time of construction or reconstruction of the plant Qimp should not be lower than 125% of Qero. The maximum value of Qimp must allow normal operation of the REMI plant at Qmin.

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Regulation line flow rate (Qlin) This is the flow rate which regulates the sizing of the regulation line according to the following scheme:

PLANTS

N.LINES

PARAMETERS TO DEFINE Qlin VALUE

CLEARLY INTERRUPTIBLE

1

LINE : Qlin = Qimp

NOT INTERRUPTIBLE TO SUPPLY PUBLIC UTILITY CUSTOMERS

2

LINE : Qlin = Qimp

3

CHOICE BETWEEN: a – FOR EACH LINE : Qlin ≥ 0,5 Qimp b - Σ 3 LINES : Qtot ≥ 1,5 Qimp

with always 2 lines able to supply

Q ≥ 2/3 Qimp.

> 3

TO BE ASSESSED EVERY TIME

NOT INTERRUPTIBLE TO SUPPLY NON PUBLIC UTILITY CUSTOMERS

2

LINE : Qlin ≥ Qimp/2

≥ 3

TO BE ASSESSED EVERY TIME

2.1.4) Flow rate off the end of the reading scale of the measurement plant (Qf.s.) This is the maximum flow rate which can be measured at the top end of the reading scale of the measuring plant, whose value must be increased by a certain % in relation to the flow rate delivered, to allow the correct determination of the volumes actually offtaken.

2.1.5) Emergency flow rate (Qemergenza) The emergency flow rate is the flow rate delivered in case of emergency by temporary equipment, and the upstream and downstream emergency valves, if present on the plant.

2.2)Pressure Where not otherwise stated, the pressure values are indicated in relative bar (o mbar). The meanings of the most useful pressure concepts are described below.

2.2.1) Maximum operational pressure (p max es)

The maximum pressure the system may sustain during normal running conditions.

2.2.2) Project pressure (p pro) or (Ps) The pressure on which the design calculations are based. This pressure must be higher or equal to the maximum calibration pressure of the release device whose values are defined in the same decree referred to in the following point 2.2.5.

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2.2.3) Minimum operational pressure (p min) The minimum pressure the system may sustain during normal running conditions.

2.2.4) Testing pressure (p col) The pressure used for the mechanical resistance test of the “Main Circuit”. Acceptable values are those defined by: MINISTERIAL DECREE 24 NOVEMBER 1984, titled "FIRE PREVENTION RULES

FOR THE TRANSPORTATION, DISTRIBUTION, STORAGE AND UTILIZATION OF NATURAL GAS WITH DENSITY NOT HIGHER THAN 0,8"

LAW DECREE 25.02.2000 N° 93 IMPLEMENTATION OF THE DIRECTIVE 97/23/CE CONCERNING PRESSURE EQUIPMENTS (P.E.D.).

2.2.5) Pressure for field pneumatic tightness test

The pressure used to test the tightness of the pipes and plants. It is equal to the maximum available operational pressure.

2.2.6) Upstream pressure (p mon) The pressure at the entry of any REMI. Usually the following values are identified: The maximum value (p mon max), communicated by the Transporter when

defining the connection; The value for preheating sizing (p mon pre) The values of minimum contractual pressure as defined in paragraph 2 of the

chapter “Entry and redelivery points pressure” (long period minimum contractual pressure “p min L”, minimum contractual pressure published yearly “p min A”).

2.2.7) Minimum pressure to size piping (p min P)

The minimum pressure for the geometric sizing of the pipe. This value must be equal or lower than “p min A” and will be chosen by the designer considering the provisions of paragraph 2 of the chapter “Entry and redelivery points pressure”.

2.2.8) Adjusted pressure (p reg) The pressure at the exit of the pressure regulation unit. It may be changed according to the management needs of the plant. Its maximum value (p reg max) can be equal to the minimum pressure to size piping and affects the sizing in terms of mechanical resistance of the relevant part of the plant. The minimum value of the adjusted pressure (p reg min) experienced for the operations at the Qimp shall be used for the geometric sizing.

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2.2.9) Minimum pressure to size the measurement (p min M)

The minimum pressure to size the measurement main device and the pipes connected to it. This value will be defined according to the following table:

P min M p mon pre ≥ 24 bar The minimum value between “p min A * 1,4”

and 35 bar 12 ≤ p mon pre < 24 bar The minimum value between “p min A * 1,4”

and 20 bar p mon pre < 12 bar Equal to p min A

2.2.10) Measurement pressure (p mis)

The pressure used to measure gas.

2.2.11) Downstream pressure The pressure at the exit of the REMI plant.

2.2.12) Differential pressure The pressure difference between the upstream and downstream intake of a measurement diaphragm.

2.2.13) Vent pressure The pressure for the opening of a vent valve, which is higher than the regulated pressure.

2.2.14) Locking pressure The pressure to close the stop valve. In the case of interruption as a result of exceeding the regulated pressure, the locking pressure is higher than the vent pressure.

2.2.15) Nominal pressure The nominal pressure is the conventional indication of the rel. max. pressure beyond which the mechanical stability is no longer guaranteed. Based on this, dimensions of pipe elements are set such as flanges, valves, faucets. The coupling nominal pressure – project pressure should be set on the basis of the current rules related to the nominal pressure. As an example the schemes of the nominal pressures are provided.

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SCHEME PN (UNI-EN-1333)

(Valid for operational temperature up to 120 °C) PN1

Maximum project pressure in

bar 2 PN Maximum project pressure in

bar 6 5 50 49 10 9 64 62 16 15 100 98 20 19 150 147 25 24 160 156 40 39

SCHEME ANSI (B.16.34 – 1996)

CLASS Maximum project pressure in bar ANSI For operational

temperature up to 50 °C For operational temperature up to

100 °C 150 19 17 300 50 46 400 66 61 600 100 92 900 150 139

N.B. In cases where PN and the associated ANSI are not easily found in the market, the coupling should be done at the higher commercial PN or ANSI.

2.2.16) Seal pressure for the preheater and the filter The following scheme indicates, for the most frequent max operational pressures, the minimum seal pressures required by this procedure.

Maximum operational pressure

Bar

Minimum seal pressure

bar 1,5 2 5 6 12 15 24 30 60 85 64 85 70 85 75 85

On the containers it is not necessary to install safety devices (blowout disk, safety valves); unless the competent authorities expressely require it in particular cases. It is not necessary to check the sizing of such devices eventually installed.

1 I valori di PN indicati sono solo quelli per i quali le Norme UNI hanno previsto l'unificazione dei vari elementi di tubazione (flange, valvole, rubinetti, ecc.) 2 I valori sono arrotondati per difetto

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2.3)Temperature 2.3.1) Project temperature

The project temperature to be considered for the sizing of the plant in terms of mechanical resistance, are: -10 ÷ +95 °C for the part of the plant between the upstream flange of the filter and the downstream flange of the preheater, inclusive of the possible transit pipe between the two devices. -10 ÷ +50 °C for the rest of the plant. In case of external temperature lower than –10 °C the manufacturer must define the value of the minimum project temperature.

2.3.2) Temperature of the gas in entry A value of +5°C is normally assumed if not otherwise stated.

3) GENERAL PROVISIONS

The plant has to assure regular running at different operational conditions, as follows:

The plant is not subjected to significant stresses other than those associated with the gas pressure

The external conditions are: temperature –10 ÷ +40 °C humidity up to 95 % The noise level during the normal operation conditions should not be higher than the

limit set at the plant’s location

The charts to be used within this procedure are contained in attachment 10. The REMI plant has to be built and run according to the laws and rules issued by the appropriate bodies and authorities. In addition, for the preheating plants and the pressure containers and for the electric devices, the rules issued by the competent bodies should be followed. The electric devices in places with fire and explosion danger should be reported to the appropriate local health authority (ASL) by the plant manager.

3.1)Application of the Directive 97/23/CE (P.E.D.)

With reference to the content of point 1.6 all the relevant devices must comply with EC regulations and bear the EC mark as described in the same document. The article 22 (Final and temporary dispositions) of the DLgs. n° 93 of 25.02.2000 defines the application of the Directive in the case of building new plants. In addition, as far as “safety devices” are concerned (safety valves, monitor, blocks), the essential requirements defined in the attachment 1° point 2.11 of this Decree must be satisfied.

3.2)Detail of the general dispositions The general provisions for the sizing are the following:

a) It should be possible to run the measurement plant with flow rate equal to Qimp.

and upstream pressure values equal to its minimum value.

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By this principle and considering that in some cases it is convenient to have the highest downstream pressure as possible, the sizing criteria should aim to minimize the pressure losses and to assure the normal running of the plant in all the operational conditions.

b) The plant by pass, in relation to point a), should not represent a bottleneck which increases the pressure losses creating utilisation problems.

c) Low speed allows better regulation, lower noise and pressure losses. d) To assure an appropriate filtering (separation of the liquid and/or solid particles

present in the gas) for the safe and regular running of the operations, the separating filters must be physically separated by the preheaters.

e) The measuring plant is made up of a main measuring system complying with the

legal metrology regulations and, if requested, by a backup system (or equipment) to be used in case of failure of the main system or as control. The main measuring system must provide in an automatic and continuous way the values of the volumes and of the calculated flow rates needed to carry out the measurement, save the data on gas quantities, the diagnostic and the operational data. These data should be readable directly at the site or transferable by tele-reading. The plant can be made up of one or more measuring units in parallel, so that, considering the nature of the operation (wide seasonal variation in the flow rate or specific types of offtake) and the Qimp of the plant, the flow rate offtaken always lies within the valid range to correctly determine the measured quantity.

f) The pressure regulation plant should not cause oscillations and pulses which may determine measurement errors. It is preferable to insert the possible flow rate regulation downstream of the measuring plant.

g) The downstream on-off valves of the regulation lines, if present, divide the plant in

two parts: (based on the connection of the taps of the safety devices upstream of the on-off valve under discussion)

The part upstream of the downstream on-off valves (inclusive), which must

sustain the maximum upstream pressure

The part downstream of the downstream on-off valves, which must sustain the expected max. regulated pressure.

For the cases where these valves are not considered, the plant must sustain the upstream pressure up to the regulator (inclusive).

h) Usually the removable connections must be flanged (for the valves also

connections of the type welded – flanged are accepted and for DN ≤ 4" also loose flanges are accepted). Threaded connections are accepted provided they assure the seal and the safety and resistance requirements required by the present rules. They should also assure, in the case of maintenance and substitution, the functionality

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and practicability at least equal to the flanged connections and comply with the current rules.

i) In general the devices should be located in a building; the standard solution

anticipates: a room for the reduction and measurement devices, a room for the possible heating system and a room for the electrical equipment which cannot be installed in “dangerous area”. If the cabin is not built, the measurement devices should be anyway protected, therefore: The measurement devices have to be located in appropriate rooms which

allow people to be present An appropriate shield for the meters has to be considered. In all cases the enclosure is necessary.

4) PARAMETERS AND FORMULAS OF COMMON USE

Due to the fact that natural gas is variable in its composition and that it is not necessary to obtain absolute accuracy of the parameters commonly in use to size the plants, average indicative parameters are acceptable for this procedure and, where possible, simplified formulae. The formulae and parameters in the calculation for plant sizing are:

4.1)Parameters

ρs gas volumic mass at 15 °C and 1,01325 bar = 0,70 kg/m3

Mm gas molecular mass = 16,57 g/mol Vm gas molecular volume at 15 °C and 1,01325 bar = 23,64 dm3/mol σ isoentropic index = 1,31 ρsA air volumic mass at 15 °C and 1,01325 abs.bar = 1,22541 kg/m3

µ gas average dynamic viscosity = 10,8 mPa.s Pb average barometric pressure = 1 bar P absolute pressure (bar) = p + 1, where p = relative pressure in bar K deviation coefficient from the law of perfect gas compared to the conditions of

ρs; K = 1 - 0,002 p H enthalpic overflows which can be obtained, in kj/kg or in kcal/kg, from the diagram Pressure/Enthalpy for the pure gas (see attachment 1)

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t gas temperature = 5 °C, if not otherwise specified.

4.2)Formulae 4.2.1) Calculation of the pipe diameter

Assuming the gas temperature equal to 5 °C, the simplified formula is:

)1(*)*002,01(**92,345

pvpQDteo +

−= where:

v = speed in m/s 345,92= numeric constant Q= flow rate in standard conditions in m3/h p = relative pressure in bar, at the entry of the pipe The theoretical diameter obtained by the above calculation must always be rounded to the normalized diameter defined at point 5.1 applying the following rule:

DN ≥ 0,95 Dteo

4.2.2) Calculation of the pressure loss in the pipe

To calculate the pressure losses the following simplified Renouard formula valid for high and medium pressures and for values of Q/D < 150 should be used:

( )dp P P L Q D= − − −1000 25 242 1,82 4 82* , * * * , where: dp = pressure loss in mbar 1000 = numeric constant P = absolute pressure in bar, at the beginning of the pipe 25,24 = numeric constant L = length of the pipe in m Q = flow rate in standard conditions in m3/h D = internal diameter of the pipe in mm

5) NOMINAL DIAMETERS TO USE - MATERIALS

5.1)Nominal diameters (DN) The most used DN are the following:

20 - 25 - 32 - 40 - 50 - 65 - 80 - 100 - 125 - 150 - 175 - 200 - 225 - 250 - 300 - etc. with increase of 50 mm.

5.2)Materials

D.M. 24.11.84 definitions apply.

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6) TYPES OF ON-OFF VALVES TO BE USED

The different types of valves, according to their location, are: a) From the delivery point to the valves upstream of the filtering unit ball valves or

conic plug valves must be installed. Ball valves can also have venturi passage with ratio between the passage diameter (d) and the diameter (DN) of the valve ≥ 60%.

b) Upstream and downstream valves for the preheating unit and/or of the regulation

unit should be as indicated in a). c) The on-off valve of the blowdown valve must be a ball valve with full passage. d) The on-off valves of the measuring plant and of its by-pass must be ball valves

(with full or venturi passage as in a) or butterfly valves, with the exception of the valve upstream of the venturimetric section which has to be a ball valve with full passage.

e) Exit valves should be as indicated in d). f) For all other possible valves, the type will be defined on the basis of their function,

consistent with the above criteria.

7) SIZING AND MAIN FUNCTIONAL INDICATIONS

The plants will be designed following the flow schemes contained in Attachment 3. The quantity and location of the valves, of the equipment and pressure and temperature intakes must be, in their minimum configuration, that described in those schemes. They may be increased in number only to improve the plant functionality. To simplify the check and design operations, the sizing criteria described do not take into account the pressure losses through the plant, assuming that in most cases this omission is acceptable. For the plant resistance, the principles defined in the chapter “General Criteria” and the information supplied in the chapter “Pressures” apply, except for what is specified in the following points.

7.1)Diameters and maximum operational pressures of the valves, of the pipes (including

the manifolds) and of connected equipments The valves must have the same DN of the pipe where they are inserted. Every section of pipe must have uniform diameter. The DN must be calculated from the theorical diameter according to the rule in point 4.2.1. The theoretical diameter must be calculated in such a way that the speeds indicated in the following scheme should be respected with the specified flow rate and minimum pressure values. In the following scheme the maximum operational pressure values are indicated to define the project pressure relevant for the mechanical resistance of each component of the plant.

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The details in the following points apply to the geometric sizing and in terms of mechanical resistance. For the parts of the plant not included in the scheme, the general criteria already defined apply. Regarding the number and the location of the insulating joints the present procedure assumes that REMI entry and exit sections are not underground, while the upstream and downstream pipes of such sections are underground.

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SECTION

PARAMETERS TO SIZE THE DIAMETERS

V

max m/s

Flow rate Q

SIZING PRESSURE

NOTE Measure with regulated p.

Measure with var. p.and t.

1 Upstream section 30 Imp p min P p min P Complying with point 7.2 2 Pipes, valv. filter FILTER 30 Lin p min P p min P DN filter ≥ DN pipe

3 Pipes, valv. Preheat. PREHEATER 30 Lin p min P p min P DN preheat.. ≥ DN pipe

4 Pipes, valves upstream 1° regulator

REGULATOR

30

Lin

p min P p min P DN ≥ upstream regulator

DN

5 Pipes and valv. Downstream regulators

25 Lin < p min P < p min P See point 2.2.8

6 Manifold downstream regulators 25 Imp < p min P < p min P See point 2.2.8

7 Valv. feed. And exit measure. lines 25 Imp < p min P p min P See point 2.2.8

8 Pipes downstream and upstream entry and exit valves

measure. lines

25

30

Imp

Imp < p min P p min P

See point 2.2.8

9 By-pass pipes and valves

measure lines

30

Imp

< p min P

p min P

See point 2.2.8

10 Pipes and valves series parallel 25 Imp < p min P p min P See point 2.2.8

11 Pipes. Meter lines METERS

25

Ero

p mis (≤ p min P) p min M Complying with 8.2

12 Pipe venturimetr. line 25 Ero p mis (≤ p min P) p min M Complying with 8.3

13 Manifold downstream filters 30 Imp p min P p min P

14 Manifold upstream preheating 30 Imp p min P p min P

15 Manifold upstream regulators 30 Imp p min P p min P

16 Exit section 25 Imp < p min P < p min P See point 2.2.8 Pressures: p min P minimum pressure to size piping p min M minimum pressure to size measure p mis measure pressure

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SECTION

PRESSURE TO SIZE THE MECHANICAL ENDURANCE

Measure with regulated p.

Measure with var. p.and. NOTE

1 Upstream section p mon max p mon max 2

Pipes, valv. filter FILTER p mon max p mon max For the pressure containers,

see point 2.2.15 3

Pipes, valv. Preheat. PREHEATER. p mon max p mon max For the pressure containers,

see point 2.2.15

4

Pipes, valves upstream 1° regulator

REGULATOR

p mon max p mon max

5

Pipes and valv. Downstream regulators

p mon max p min P

p mon max p min P

Up to the 1st valve in the gas direction

After the 1st valve in the gas direction

6

Manifold downstream regulators

p mon max p min P p mon max

Up to the 1st valve in the gas direction

After the 1st valve in the gas direction

7

Valv. feed. And exit measure. lines p min P p mon max

8

Pipes downstream and upstream entry and exit valves measure. lines

p min P p mon max

9

By-pass pipes and Valves measure lines

p min P p mon max

10

Pipes and valves series parallel p min P p mon max

11

Pipes. Meter lines METERS p min P p mon max

12 Pipe venturimetr. line p min P p mon max

13 Manifold downstream filters p mon max p mon max

14 Manifold upstream preheating. p mon max p mon max

15

Manifold upstream regulators p mon max p mon max

16 Exit section p min P p min P Pressures: p min P minimum pressure to size piping p mon max maximum entry pressure

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7.2)Upstream section

This is the section between the delivery point and the upstream filter manifold, the latter and possible upstream emergency valve included. The general upstream on-off valve of the REMI plant (1st valve in the direction of the gas downstream of the delivery point) must be located as close as possible downstream of the delivery point. The pipes must have uniform diameter and such dimension as to satisfy the following condition:

a) gas speed must be ≤ 30 m/s. To calculate the speeds the formula at point 4.2. can be used, where: Q = Q plant in m3/h P = Minimum pressure to size piping (p min P)

The (optional) upstream emergency valve must be installed outside the room in the section between the general on-off valve and the next on-off valve/s. Usually it is located downstream of the upstream insulating joint and must be electrically isolated if it is by-passed from underground pipe protected by current. The valve and the connected pipes must be sized to allow the supply of the flow rate in case of emergency.

7.3)Filtering unit

The filters must be efficient enough to hold both the liquid and solid particles present in the gas. In addition the filters must have such a filtering capacity as to assure the normal operations of specific equipment downstream of the same filter (es. regulator, meters, etc.) with Qimp.

7.3.1) Filter with condensate separator

The filter can be made up by two separate stages (solid and liquid particles). The filtering element must be changeable. The minimum filtering capacity must be equal to: 98% of the solid particles ≥ 5 micron 100% of the solid particles ≥ 10 micron 95% of the weight of the carried liquid particles. The collection capacity should be no lower than 12% of the total capacity of the

filter and shouldn’t impact the gas flowing zone to avoid obstruction. The pressure loss through the clean filter should not be higher than 0,1 bar with

flow rate equal to Qlin, with pressure equal to a “p min P”. The manufacturer must declare this deltapi

The filter must be equipped with an indicator of the pressure loss between entry and exit (dpI), with on-off valves and possible by-pass.

The DN at the entry and exit of the filter should not be lower than the DN of the pipes connected to it.

A “full size” quick closing is recommended to substitute the filtering element in short time.

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For the project and building criteria, the rules in force on this subject apply. In particular the provisions of point 2.2.15 appy.

7.3.2) Additional filter ustream of the meters

In order to avoid damage to the meters in the starting phase of the plant, additional filters can be installed upstream of the meters, and they should be removed after 2 months to avoid pressure losses or functional defects.

7.4)Heating plant and preheating unit (See note at point 7.4.1.) The temperature of the gas after the reduction must be regulated at an average value of 5 °C and in any case cannot be lower than 0 °C: this must be assured by the preheating plant for the Qimp with an upstream pressure higher or equal to that of the sizing of the preheating. The preheating plant must assure regulation of the gas temperature with variations, between minimum and maximum value, lower than 8 °C (on average ± 4 °C versus the regulated value). Insulation of the preheating circuit is recommended. The connection between preheaters downstream of the same preheaters is allowed by inserting an on-off valve. When the sizing pressure for the preheating is ≤ 12 bar, or the pressure overfall is ≤ 12 bar the gas preheating is optional.

7.4.1) Hot water preheater (Note)

The main characteristics are: The DN at the entry and at the exit cannot be lower than the DN of the pipes

connected to it. It is advisable to inspect the tube bundle, where the heat exchange takes place. The speed of the gas in the tube bundle, at the minimum operational pressure,

should be ≤ 40 m/s The pressure loss at the gas side between entry and exit, in the worst operational

conditions, must be ≤ 0,2 bar at the “p min P”. The manufacturer must declare this deltapi. The preheater must be provided with: On or more vent valves on the gas side An air vent valve at the side of heating fluid A vent valve for the heating fluid. For the project and building criteria, the rules in force on this subject apply. In particular the provisions in point 2.2.15 apply. The capacity in kcal/h is obtained by the formula:

Ch Q

prerh Qs= =

* *, * *

ρη

0 78

where:

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ρs = gas volumic mass at 15 °C and 1,01325 bar ≈ 0,7 kg/m3 η prer = preheater efficiency ≈ 0,9 Q = maximum line flow rate in m3/h in standard conditions h = enthalpic overfall in kcal/kg equal to the difference between gas

enthalpy at Pv - tv conditions and gas enthalpy at Pm - Tm conditions (to be obtained on the basis of the scheme in attachment 1).

Pm = absolute upstream pressure to size the preheating tm = 5 °C (average value) = delivery temperature Pv = minimum absolute pressure foreseen downstream of the

regulator (p reg min) tv = temperature downstream of the pressure regulator. If the capacity C is expressed in kw and the entalphic overfall h is expressed in kj/kg, the previous formula becomes:

QhC **000216,0= NOTE: This procedure deals specifically only with the cases of hot water preheating

plants, since they are the most frequently used. Operational temperatures even higher than those indicated may be reached if

using different preheating plants (which may be used, if complying with the rules in force). In this case, the sizing in terms of mechanical resistance should take into account the necessary correlation between temperature and pressure.

7.4.2) Thermal capacity

The total capacity of the thermal plant in kcal/h is obtained by the formula:

Mh Qrisc prer

h Qs= =* *

*, * *

ρη η

0 86

where: Q = max plant flow rate in m3/h = Qimp η risc = coeff. rid. efficiency boiler ≈ 0,9 Other symbols = same meaning as in 7.4.1. If the capacity M is expressed in kw and the enthalpic overfall h in kj/kg, the previous formula becomes:

M h Q= 0 00024, * * It is advisable, for safety and operational continuity reasons, that the total thermal capacity should not be provided by just one boiler, but should be distributed at least between two boilers working in parallel.

7.4.3) Reduction unit feeding the heating system The unit has to be installed in the room or the area of the reduction (and measurement) equipment.

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The feed must be shunted downstream of the measure, with steel valve, able to sustain the maximum operational pressure (usually the measurement pressure). The reduction unit has to be made up of: A pressure reducer A safety valve which avoids, in case of failure of the reducer, the maximum

pressure defined downstream being exceeded. The two elements, which may be integrated in just one device, may have the casing in spheroidal iron or other suitable materials if the maximum operational pressure is ≤ 5 bar. In all other cases the casing should be made of steel. It is advisable that a backup unit is installed; in this case on the main unit, a stop valve can be inserted in the regulator, as an alternative to the safety valve. In this case on the emergency line the monitor (incorporated or not) may be installed, instead of the safety valve.

7.5)Regulation plant The regulation plant is made up by the ensemble of valves (monitor, regulator, block) and possible additional equipment such as pilots, pressure taps, service regulators, connection small pipes, safety and relief valves. The sizing criteria for the valves are provided. The calibration value has to be chosen considering the maximum acceptable pressure value in the downstream network. The pressure regulation plant should allow a regulated pressure to be obtained with a maximum variation versus the calibration value equal to 10%. If the measuring plant is not automated this variation is limited to ± 2,5%. For each regulation line the pressure reducing valve and the monitor can be two different valves, in series on the same pipe axis and with the same size characteristics (the connection between the two valves will be that provided by the manufacturer), or a single valve with the two functions. The use of “fail to open” regulating valves with monitor function is not allowed. The monitor has to be marked EC as safety device complying with D.Lgs. n° 93 of 25.02.2000.

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7.5.1) Design Formula

With (P1 - P2) < 0,456 P1 (not in critical overfall)

gradi

PPP

CPCgQ

−=

121*

13417sen*1**55,0

With (P1 - P2) ≥ 0,456 P1 Q Cg P= 0 55 1, * * where: Q = flow rate of the valve m3/h Cg = characteristic coefficient of the valve P1 = upstream absolute pressure of the valve bar P2 = downstream absolute pressure of the valve bar C1 = ratio between Cg/Cv coefficients, where Cv is the

liquid coefficient of the valve. If the value of Cg is unknown, but Cv is known, assumptions will be C1 = 30 and therefore Cg = 30 Cv.

7.5.2) Values of Cg and C1

The values have to be officially declared by the manufacturer and usually are published in the technical specification of the manufacturer. In particular cases if the Cg and C1 values are not available, the following values may be used for an indicative calculation: C1 = 30

2*6540.0 DNCg = for DN up to 150 included

CgDN

DN=+

−

0 654

1150

250

2, * for DN higher than 150

If the regulator is provided with a muffler and the manufacturer doesn’t define clearly the resulting Q reduction, the known Cg is multiplied by 0,9.

7.5.3) Values of P1ande (P1 - P2) The P1 value to insert in the formulae is usually the project minimum absolute value (p min P + 1). The value of (P1 - P2) will be equal to (P1 - P reg min), with (P1 - P reg min) higher or equal to the minimum dp established by the manufacturer and lower than 0,456 P1 (in the particular cases with minimum upstream pressure equal to 0,15 relative bar, il dp will be set equal to a 40 mbar). With (P1 - P reg min) ≥ 0,456 P1, the calculation formulas don’t require the value (P1-P reg min).

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P reg min is the minimum regulated pressure value foreseen for the operations at Qimp.

7.5.4) Choice of the regulator The regulator to be chosen is the one – as results from the calculation - able to provide a flow rate ≥ Qlin. The calculation should be performed using the formulas A or B, the Cg and C1 values described at 7.5.2. and P1 and (P1 - P2) values described at 7.5.3.

7.5.5) Choice of the monitor (if separate) The monitor should have the same dimension characteristics of the regulator described at 7.5.4.

7.6)Relief valve The aim of the relief valve is to avoid the increase in the regulated pressure which can happen in case of closing failure both of the regulators and monitors. As an alternative, a valve can be installed on each regulation line, or a single valve can be installed downstream of the manifold. In the case where the relief valve is installed downstream of the downstream on-off valve, it is mandatory to install, downstream the relief valve, a spherical on-off valve with full passage, sealed with lead in opening position, with DN and PN equal to those of the relief valve. The relief valves must be marked EC as safety devices complying with D.Lgs. n° 93 of 25.02.2000. In the cases where this D.Lgs. allows the installation of “qualified valves”, in accordance with ISPESL rules, these should have the value of the coefficient of efflux K experimentally determined according to predefined criteria. In the description of the device must be included:

The net area "A" of the orifice of the valve cm2 the coefficient of efflux K resulting from the ISPESL qualification tests.

The theoretical diameter "dteo" must be equal to 1/10 of the diameter of the pipe from which it is shunted the pipe on which the same is installed. The formulas to be used are:

dteoA k

=4 * *

π

( )A

dteok

=π *

*

2

4

Based on the calculated value of A, the equal or immediately higher value, available in the market, is to be found.

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8) MEASUREMENT PLANT

The measurement plant is made up of the ensemble of devices and tools installed as measurement, backup and/or control as well as the piping needed to by-pass the gas flow. The primary element has to be designed to allow a valid measurement within the range Qero ÷ Qmin. The measurement plants have to be realized in accordance with the general criteria previously defined, as indicated at point 7.1., and complying with the technical attachments to the present procedure.

8.1)Allowed equipment and type of piping

The equipment and type of piping allowed for the measurement plants are indicated for flow rate ranges Qero in the attached table (attach. 2). The standard schemes, as indicated in attach. 3b, are defined in accordance with these tables. The flow rate ranges under consideration in m3/h based on the type of the measurement primary element are the following:

MEASUREMENT WITH METER MEASUREMENT WITH VENT.

DIAPHRAGM Qero < 4000 12000 ≤ Qero < 30000

4000 ≤ “ < 30000 30000 ≤ “ < 60000 30000 ≤ “ 60000 ≤ “

The main criteria to define the characteristics of the metering plant are the following:

a) The main measuring system must be automated with electronic data processing

devices (flow computer). The m3/h and m3/d data needed for fiscal reasons must be saved (current and previous month) and transferred by telereading (switched network or GSM) according to the standards defined by the transporter. Besides, in some cases, the back-up and control equipment are required to determine, in a non automatic way, the gas quantities.

b) The electronic data processing devices (flow-computers, calibrators, PTZ) must

comply with:

Legal metrology provisions in force on the subject issued by EEC Directive and national laws

CEN rules specific for this product, currently only the EN 12405 “Electronic volume conversion device associated with gas meters”

ISO international rules concerning the formulae to calculate the flow rates and quantities in volume and energy.

c) For values of Qero < 12000 m3/h the measurement by venturimetric diaphragm is

not allowed. d) The measurement by meters is allowed for every value of Qero.

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e) If the meter with a Qmax designed on the basis of Qimp is not able to measure the minimum flow rate offtaken (e.g.: seasonal variations) it is necessary to install a meter with lower Qmax , indipendent and in parallel with the 1° meter.

f) For Qero ≥ 4000 and < di 30000 m3/h a second meter equal to the first one has to

be installed as back-up. The second meter, if the case e) applies, can be of a lower class provided a by-pass common to the two meters be installed.

g) For Qero ≥ 30000 m3/h the piping of the plant with meters, of the same gauge,

must allow connection in series. h) For Qero ≥ 30000 m3/h in the plants with two or more meters (of the same gauge)

every meter has to be connected with an automated measurement chain (flow rate calculator and transmitters).

i) For Qero ≥ 60000 m3/h in the venturimetric plants the automated measurement

chain (transmitters, flow rate calculator) must be duplicated (see attach. 2).

8.2)Measurement with meters The volumetric meters (with expandable walls, rolling pistons, turbine) must comply with the legal requirements, the performance and the functional characteristics defined in the following documents:

National metric rules EEC Directives concerning the gas meters:

DPR n° 857 of 23 August 1982 (71/318, 74/331, 78/365) Decree 9 September 1983 and subsequent modifications

UNI-CIG 7987/7988 provisions ISO 9951 provision EN 12480 – EN 12261 provisions.

In accordance with what the above laws and rules define, the meter should be equipped with metric seals, plate with all the data (Qmax, Qmin, pmax, impulses/m3, ecc.) and the certificate with the calibration curve. The meters made in other EEC Countries must show on the plate the EEC mark with the approval number of the model. The meters should be equipped with two pulses emitters with characteristics complying with the above rules.

8.2.1) Choice of a meter

a) The meters that can be installed should comply with the above requirements, and assure as minimum value a measurement range with ratio Qmax/Qmin not lower than 20:1.

b) The maximum operational and measurement pressure connot be higher than the

meter’s Pmax .

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c) The meters with casing made up by material different from steel (spheroidal cast iron, aluminium) may be used with the limits defined by DM 24.11.84 as far as the maximum operational pressure and nominal diameter are concerned.

d) To define the Qmax of the meter to be installed, the following steps should be

followed:

d1) Calculate the maximum theoretical flow rate with the following conventional formula:

( )1*05,1max

+=

pQerotQ

where: Qmaxt = theoretical maximum flow rate m3/h Qero = flow rate delivered (max effective flow rate that the plant must

deliver) 1,05 = increase coefficient equivalent to approx 5% compared to Qero p = relative measurement pressure in bar, according to the cases p reg for the plants at regulated p and t

p min M for the measurement plants at pipeline p and t

d2) Identify the meter with Qmax, based on the following table, equal or immediately higher than Qmaxt calculated as above. The Qmax values are unified, however the manufacturers may provide different DN for the same Qmax, or provide no meter with particular Qmax value. This last case may reduce the choice. Qmax m3/h

DN mm

V m/s

Qmax m3/h

DN mm

V m/s

Qmax m3/h

DN mm

V m/s

25 40 50

6 4

400 80 100 150

22 14 6

6500 300 400 500

26 14 9

40 40 50

9 6

650 100 150 200

23 10 6

10000 400 500 600

22 14 10

65 40 50

14 9

1000 150 200

16 9

16000 500 600

23 16

100 40 50

22 14

1600 150 200 250

25 14 9

25000 600 25

160 50 80

23 9

2500 200 250 300

22 14 10

250 80 100

14 9

4000 250 300 400

23 16 9

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e) The pulse emitters may be low frequency if Qmax is ≤ 400 m3/h. For higher flow rate at least one should be high frequency. If a signal (4÷20 mA) is needed of the instantaneous flow rate a high frequency emitter should be preferred independently of Qmax.

NOTE The ratio Qmax/Qmin of the turbine meters is variable, because, remaining constant Qmax, Qmin changes in function of the square root of the gas density at the line conditions. The minimum flow rate in m3/h at the operational conditions is approximately given by the following formula:

Q pQ

pmin( )

, * min=

+1 32

1

Qmin(p) = Minimum flow rate m3/h at the operational pressure "p". Qmin= Minimum flow rate reported in the meter plate (metrologically

approved)

1,32= d1

where d = relative density (0,57392).

8.2.2) Diameter of the rectilinear sections directly connected to the meters

The DN of the pipe of the rectilinear sections (excluding the valves) upstream and downstream the meter, must be equal to the meter DN.

8.2.3) Lengths of the rectilinear sections directly connected to the meters Assuming as DN that of the meter needed to calculate a Qero = Qimp, the minimum lengths to be complied with are: a) Upstream section

a1) For turbine meters: 10 DN1

The length can be reduced to a 5 DN if a meter with integrated flow rectifier is installed, in this case the manufacturer should document the result of the tests carried out in the ways defined in EN 12261 (Annex B) rule.

a2) For meters with expandable walls, with rolling pistons: 5 DN1 b) downstream section

for all types of meter: 2 DN It necessary to provide after the 2 DN enough room to insert the two thermometer pockets, to measure and control.

1 Per i contatori a parete deformabile od a turbina radiale non risulta necessario alcun tratto rettilineo. Per cui se il contatore installato è quello relativo a Qimp i tratti rettilinei non sono necessari.

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8.2.4) By-pass of the on-off valve upstream of the meter On the measurement line with meters with DN ≥ 150 it is advisable to install a by-pass (DN 25 ÷ 50) to use in the starting operations, avoiding to damage the meter.

8.3)Measurement with venturimetric diaphragm This measure can be performed if the following 3 conditions occur at the same time:

Value of Qero ≥ 12000 m3/h DN of the measurement section ≥ 100 Measurement section ≥ 2 bar

The plant must be carried out in accordance with UNI EN ISO 5167-1/A1 rules, the provisions hereunder indicated and possible rules defined by following legal metrology regulations. The gauging certificate of the measurement diaphragm should comply with attach. 5. and the dimension check in accordance with these rules should be carried out by an appropriate Institute. The exact dimension of the inside diameter of the pipe should be reported with the gauging report as defined in attach. It is advisable for accuracy reasons, both for equipment reasons and for the limits set by Reynolds number, that the minimum flow rate ‘Qmin’ offtaken should be lower than approximately 5 % of the F.S. Q. In fact, at that Qmin value corresponds a differential pressure value equal to 1,25 mbar (measured by the low deltapi transmitter with f.s. 100 mbar). If the plant Qmin is lower than these percentages, better solutions should be identified to measure the low flow rate, for instance by installing more measurement lines with automated insertion.

8.3.1) Measurement line

Information relating to the whole measurement line is: a) Throttling devices

Primary elements made up by diaphragm-holder of the type "Orifice Fittings" with “pressure taps on the flanges” are allowed.

These devices allow:

A better functionality and operational easiness which reduce significantly the

time needed to substitute or check the diaphragm Improved ease to center the diaphragm and therefore greater guarantees of

better measurements. b) Lengths of the rectilinear sections of the venturimetric section

b1) Upstream section

For Qimp < 30000 m3/h L ≥ 30 DN For Qimp ≥ 30000 m3/h L ≥ 50 DN

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b2) Downstream section In all cases L ≥ 8 DN The DN to consider, to define lengths, is the one that, in accordance with the table at the following point, allows the measurement of a Q = Qimp with speed ≤ 25 m/s and with: Measurement p = p reg min (always < p min P) for plant at regulated p and t Measurement p = p min P for the measurement plant at pipe p and t. The values indicated are valid until new legal metrology criteria are introduced. c) Pipes allowed for measurement line

c1) Type of pipes according to the manufacturing process Obtained by weldless cold-drawing (preferred) Obtained by weldless hot-drawing By longitudinal welding.

Different types should be analyzed case by case.

c2) Inside wall condition Inside walls must be clean, without corrosion and scaling, even if localized in few points. The presence of a slight rust film is allowed.

d) DN of the pipe to be installed and value of the ratio between diameters

The DN project calculation is carried out according to point 7.1, complying with the ß limit hereunder indicated and applying the flow rate calculation formula indicated in UNI EN ISO 5167-1/A1 rule.

ß value(ratio between diameters d/D): with DN ≥ 100 mm: 0,10 ≤ ß ≤ 0,7 if the lenght of the upstream section is > 40 DN, a value of ß up to a maximum

of 0,75 is allowed.

8.3.2) Lay-out of pipes and devices in thel "entry section" A plant section defined as “entry section” is a plant section upstream of the rectilinear section upstream of the metering line. It should be realized in accordance with the following points: a) Once defined a reference plan (horizontal or vertical) along the axis of the

measurement section, the “entry section”, located in the reference plan for a total length ≥ 10 DN (point 8.3.1.c), can be made up by a single pipe, or a pipe, elbows and/or valves and/or other devices in accordance with the following points.

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b) The gas flow in the "entry section" must always remain, even changing direction, in the same reference plan defined in a). Therefore it shouldn’t be installed in the entry section:

Elbows and T part on plan different from the reference one Any other device which causes a plan change,

compared to the reference plan, in the gas flow. c) In the "entry section it is forbidden to install:

Any regulation valve Any expansion in the diameter with ratio higher than 0,5 to 1 of the DN of the

measurement section (the expansions must have length ≥ DN of the measurement section).

d) The on-off valves in the "entry section" should be of the type described in point 6d. e) If the upstream rectilinear section has a length ≥ 50 DN the limits set in c) and d)

do not hold and besides the rectilinear sections mentioned in a) may be on different plans and of the total length strictly necessary to connect the devices or special parts or elbows.

f) The cases clearly different from those here described should be analyzed case by

case.

8.3.3) Measurement equipment and devices The equipment and devices necessary in relation to Qero are defined in attachment 2. The ends of the reading scale of the differential pressure are:

High deltapi 500 mbar

Low deltapi 100 mbar It should be foreseen pressure taps, deltapi (on the diaphragm) and thermometer pocket to carry out checks in the field. All the thermometer pockets should be inserted downstream, after the gli 8 DN, on the upper generatrix of the pipe.

9) EXIT SECTION 9.1)Exit valve

The last downstream valve, in the gas direction, is described in attach. 3b and 3c. Practically this may not occur. Therefore the conditions defined in 9.2 and 9.3 should be satisfied, remaining valid the design criteria above defined until the exit valve.

9.2)DN of the pipe

The pipe of the exit section should have a DN to assure a speed ≤ 25 m/s.

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9.3)Downstream emergency valve (optional) This valve should be installed outside the room, at the exit section, upstream or downstream of the exit valve. It may be located upstream or downstream of the downstream insulating joint and should be electrically isolated if shunted by underground pipe shielded by current. The emergency valve should be sized in order to be able to easily supply the emergency flow rate.

9.4)Check valve

If the plant configuration or the system operations cause possible gas backflows, it is necessary to install in the exit section a check valve.

10) PERFORMANCE CRITERIA

10.1)Foreword In this chapter the main criteria to follow in assembling and installing the receiving and first gas reduction plants are described. The assembling and installing of the pre-heating plant (boiler, pipes), not considered in this chapter, should be carried out in accordance with the building and installation rules of the heating plants, applying for the boiler the safety requirements foreseen by the laws in force.

10.2)General priciples 10.2.1) Safety and easy of access

The design should consider in particular the safety factor. The accessibility to all the equipment of the plant should be assured and any point should be reachable by the relevant tools. An easy exit from the plant should be assured in case of emergency.

10.2.2) Assembling and installing The assembling and installing should not cause additional mechanical stresses besides those produced by the gas pressure. The special parts, the equipment and the pipe sections should be manufactured and installed in such a way as to comply with the criteria of verticality, horizontality and parallelism.

10.2.3) Cabin building The walled cabin should be built and tested in accordance with the rules issued by the competent authorities regarding the buildings as well complying with D.M. 24 November 1984 "SAFETY RULES FOR THE TRANSPORTATION, DISTRIBUTION, STORAGE AND UTILIZATION OF NATURAL GAS WITH DENSITY LOWER THAN 0,8".

10.2.4) Materials The provisions of the same D.M. apply also to the materials. The pneumatic joints for the devices, impulse taps and relief of the regulating tools must be made by stainless steel. For inside diameters not greater than 10 mm, they can be also made of copper.

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10.3)Pipes, flanged connections, special parts, releases As a rule pipes should be layed above ground or should in any case be inspectable. Underground laying is only allowed for the pipes connecting the general on-off valves and the plant. At the installation the pipes, the connections and the special parts must be perfectly internally clean. In building the piping it should be used only special parts such as: elbows, tees, weldolets, flanges, made by materials and dimensions complying with appropriate standards (ASTM, ANSI, API, MSS, etc.). The gaskets should be made in material resistant to effect of gas and to possible odorizing substances. In accordance with D.M of 24.11.84, for the safety valves and the release devices in the atmosphere appropriate vent pipes should be prepared to let gas in the air at appropriate height (not < to 3 m from the field), not affecting the openings of the possible boiler room. In particular the end part of the releases should be made in such a way as to let the gas vent bottom-up and to prevent rain infiltration.

10.4)Welding

Welding should be carried out by qualified welders and with processes qualified by appropriate and officially recognized institutions. Contiguous weldings between pipes along the axis with distance lower than 1,5 D (with a minimum limit of 60 mm) should be avoided.

10.5)Installation of the devices

For the installation of the devices and possible pneumatic joints the indications of the manufacturers should be respected as well as these criteria. Easy control and calibration should also be assured.

10.5.1) Separating filters and preheaters

Between lines should be left enough room to let the maintenance operations to be performed. If the inspection and maintenance of the filters is not allowed by the free space, a service platform should be considered. The drainage of the devices should be separately carried outside of the possible cabin and in such a position as to assure the maximum safety and the easy collection of possible inpurities.

10.5.2) Regulation plants Between lines should be left enough room to let the maintenance operations to be performed. The appropriate actions should be taken in order to assure in any moment the continuity and regularity of the operations (e.g. pre-heating or tretment of the gas feeding possible additional devices such as service regulators and pilots). Devices by-passing the regulators are not allowed.

10.5.3) Measuring devices General principles The measurement devices and the primary elements should be installed in such a position as to assure an easy access and to easily allow the data collection, the control and calibration operations.

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If, for specific reasons, it is necessary to install measurement devices in the open air (transmitters, recorders, calibrators, etc.) they should be shielded within appropriate protections such as: boxes, cabinets, containers. These protections should be made by appropriate materials, with such dimensions and in such a way as to avoid temperature variations outside the limits defined by the manufacturer. Measurement venturimetric section The measurement venturimetric section should be installed in accessible position, if possible at a height from the field not higher than 1 ÷ 1,20 m . Meters The meter has to be installed in such a way as to avoid any mechanical stress caused by the upstream and downstream piping and according to the manufacturer’s instructions. If requested, the lubricating oil must reach the set level, and be verified by suitable lamp. The meausrement pressure has to be taken by the appropriate tap “Pr” present on the meter. In the case of meters with expandable walls and rolling pistons even if provided with tap Pr, the operational pressure can be measured upstream of the upstream rectilinear section of the meter.

10.6)Painting and insulation The piping and all the devices should be protected against corrosion by an appropriate painting cycle. Insulation is recommended on the heat exchangers, on the water circuit and on the measurement section.

10.7)Electrical systems

The gas reduction and measurement plants are locations with the potential for explosions due to the presence of inflammable gas where the electrical systems (from the 1st of July 2003, also other systems which can represent primer source) must comply with particular safety requirements.

The definition of the area with explosion danger should be made in accordance with the criteria set in the CEI EN 60079-10 (CEI 31-30) rule and in the 1999/92/CE directive. To design the electrical system, the installation and choice of the protection according to the three types of area (0,1,2), should comply with CEI EN 60079-14 (CEI 31-33) rule and 94/9/CE directive.

Regarding the electrical material to be used, in 1994 the CEE 94/9 directive has been issued, received by D.P.R. n°126/98, aiming to define for all products, electrical and non electrical, to be installed in the EU Countries, the essential requirements for the utilizazion zone. This directive will substitute the previous ones (76/117/CE; 79/196/CE) starting from the 1st of July 2003. The electrical devices with compliance certifications issued on the basis of old directives may be installed until and no later than the 30th of June 2003.

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According to the law n.46/90, such electrical systems should be designed by a professional belonging to the register within his competencies, and the works of installation, transformation, expansion and extraordinary maintenance should be carried out by qualified companies, or in the case of non installing companies, by the internal technical departments which at the end of the works issue appropriate statement of compliance of the system to the standards. Such electrical systems, the grounding system, and possible devices against atmospheric discharges have to be set at work, approved and verified in accordance with D.P.R. 22 October 2001, n° 462. The check of the need of a device against atmospheric discharges has to be carried out in accordance with CEI 81-4 rule or, where applicable, CEI 81-1 rule. If the protection system has to be provided, the provisions contained in CEI 81-1 apply and, where foreseen by D.P.R. 26.5.59 N.689, it has to be communicated to ISPESL.

10.8)Protection of the undergroung pipes against corrosion

The metallic pipes should be coated against damage caused by the ground where the pipes are laid and the corrosion caused by possible natural or leaked electric currents. In presence of natural or leaked electric currents, besides an efficient coating, a cathodic protection is recommended. These systems should comply with the legal provisions (D.M. 24/11/1984) and with the technical rules in force.

10.9)Criteria for the pneumatic connections of the measuring devices

See attachment 8. 10.10)Criteria to install computerized measurement systems

See attachment 9.

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INDEX OF THE ATTACHMENTS

Attach. 1 DIAGRAM PRESSURE – ENTHALPY FOR THE NATURAL GAS (2

pages) “ 2 MEASUREMENT PLANT WITH FISCAL VALUE (1 page) “ 3 STANDARD SCHEMES FOR "REMI PLANTS" AND DESCRIPTION

OF THE DEVICES 3a - regulation plant (5 pages) 3b - measurement plant with fiscal value (9 pages)

3c - REMI plants with variable pressure and temperature (4 pages)

“ 4 MAXIMUM ALLOWED ERRORS IN THE MEASUREMENT SYSTEMS

(1 page) “ 5 DIAPHRAGM GAUGING CERTIFICATE (1 page) “ 6 GAUGING OF THE MEASUREMENT SECTION (1 page) “ 7 REMI PLANT WITH UPSTREAM P max ≤ 5 bar (6 pages) “ 8 CRITERIA TO CARRY OUT THE PNEUMATIC CONNECTIONS (6

pages) “ 9 CRITERIA TO INSTALL COMPUTERIZED MEASUREMENT

SYSTEMS (5 pages) “ 10 CARTHOGRAPHIC DOCUMENTATION FOR PIPELINES (15 pages)

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ATTACH. 1 - DIAGRAM PRESSURE – ENTHALPY FOR THE NATURAL GAS

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Example on how to use the diagram NOTE: The diagram is taken by "THERMO PROPERTIES OF HYDROCARBONS", published on “Hydrocarbon Processing and Petroleum Rafiner”, September 1962. Let’s consider: the following conditions, upstream of the heating plant and the pressure regulator: P1 = upstream absolute pressure = 50 bar T1 = upstream relative temperature = +5 °C The following conditions, downstream of the pressure regulator: P2 = downstream absolute pressure = 11 bar T2 = downstream relative temperature = +10 °C. The heat quantity supplied to each gas kg to increase the temperature from T1 +5 °C to T2 +10 °C has to be determined. On the diagram (see the explaining lines) starting from the point corresponding to 50 bar and +5 °C, draw a vertical line (isoenthalpic) up to the 11 bar straight line; in this point run the temperature curve which the gas will take after the decompression, if not preheated. From this point draw a horizontal line (isobar) up to the +10 °C temperature curve: the length of the segment indicates the heat quantity supplied at each gas kg , in preheating phase (31 - 17,7 = 13,3 kcal/kg) or (129,8 - 74,1 = 55,7 kJ/kg). To determine the gas temperature at the exit of the preheating and at the entry of the pressure regulator, from the point where the segment and the +10 °C curve meet follow the vertical line up to 50 bar: in that point the +26,5 °C curve runs and this is the temperature we were looking for.

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ATTACH. 2 - MEASUREMENT PLANT WITH FISCAL VALUE

SYMBOLS: V = provides a final value for flow rate and/or vol. M = belongs to the measurement chain R = back-up and control C = control

Vol Qero < 4000 X Vol. 4000 ≤ Qero < 30000 X Vol. 30000 ≤ Qero X Vent.12000 ≤ Qero < 30000 X Vent.30000 ≤ Qero < 60000 X Vent.60000 ≤ Qero X

DEVICES TYPE OF MEASUR.PLANT DESCRIPTION ABBR. 10 30 40 60 61 62

1 Meter FT M M M 2 P and T indicators PI,TI R C C C C C 3 Manotermograph PR,TR R R 4 II° Meter Series/Parallel II°FT R R 5 Venturimetric section FE M M M 6 Type 1 calculator RK V 7 Type 2 calculator FF+FP V V V V V 8 2° Type 2 calculator FF+FP R V 9 Telereading module TEL V V V V V V

10 P Transmittiter PT M M M M M 11 T Trasmittiter TT M M M M M 12 High dp transmitter HdpT M M M 13 Low dp transmitter LdpT M M M 14 Gaschromatograph or RHOS transmitter GC o GT M M 15 E lectric recorder of RHOS and/or Q eGR/eFR R R 16 Multivariable transmitter (Q-dp-p-t) (5) MT R R

NOTE 1 4 2 2 3 2 3 4

NOTES: A type of plant with higher performance is always allowed. 1) For Qero < 4000 the installation of back-up and control measurement is

recommended. 2) For Qero ≥ 30000 a gas chromatograph (or in alternative the densimeter

RHOS) has to be installed. This device is recommended for Qero between 12000 and 30000. The gas chromatograph should be installed as indicated in the Attachment 11/B of the chapter “Gas quality” of the Network Code. If permitted by the legal metrology, the direct connection between the gas chromatograph and the computer is possible.

3) The signal (4 ÷ 20 mA) of Q must be recorded when the measurement pressure is, or may be, variable. The signal 4÷20 mA of Rhos must always be recorded.

4) The devices from pos. 10 to pos. 16 must be duplicated in function of the 2nd calculator.

5) Device substituting the deltapi indicator and the 3 peen mechanical recorder. This transmitter calculates Q; it displays the values Q-dp-p-t-; it stores the same values with hourly frequency for 45 days.

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ATTACH. 3 - STANDARD SCHEMES FOR "REMI PLANTS" AND DESCRIPTION OF THE DEVICES

ATTACH. 3A – REGULATION PLANT

SUMMARY SCHEME

TYPE OF CUSTOMER

PRESS. PREHEA

T. TYPE CHARACTERISTICS

REGULATION LINES

NOT INTERRUPTIBLE

Pubblic Utility > 12 A Min. 2 lines (F,P,M,R) Qlin ≥ Qimp Pubblic Utility ≤ 12 B Min. 2 lines (F,M,R) Qlin ≥ Qimp Not Pubblic Utility > 12 A Min. 2 lines (F,P,M,R) Qlin ≥ 0,5 Qimp Not Pubblic Utility ≤ 12 B Min. 2 lines (F,M,R) Qlin ≥ 0,5 Qimp

INTERRUPTIBLE > 12 C LINE (F,P,M,R) Qlin ≥ Qimp ≤ 12 D LINE (F,M,R) Qlin ≥ Qimp

As an alternative to the monitor it may be installed: block valve (upstream of the regulator) or block valve incorporated in the regulator. The choice of these alternatives will be made by the designer assessing the operational conditions foreseen in the downstream network, especially in particular cases (e.g. more remi plants connected in parallel. F = SEPARATING FILTER P = PREHEATER (heat

exchanger) M = MONITOR R = REGULATOR

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REGULATION PLANT – NOT INTERRUPTIBLE

p mon pre. > 12 BAR

TYPE A

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc Insulating Joint 12 Pressure indicator 2 On-off valve 13 On-off valve 3 On-off valve 14 On-off valve full passage 4 Blind flange 15 Direct-acting Relief valve 5 Gauge tap 16 On-off valve 6 On-off valve 17 Filter with condensate separator 7 Filter with condensate separator 18 Hot water heat exchanger 8 Hot water heat exchanger 19 Pressure regulator – MONITOR 9 Pressure indicator 20 Pressure regulator – REGULATOR

10 Pressure regulator – MONITOR 21 On-off valve 11 Pressure regulator – REGULATOR 22 Boiler to heat water

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REGULATION PLANT - NOT INTERRUPTIBLE

p mon pre. ≤ 12 BAR

TYPE B

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc Insulating Joint 11 Pressure indicator 2 On-off valve 12 On-off valve 3 On-off valve 13 On-off valve full passage 4 Blind flange 14 Direct-acting Relief valve 5 Gauge tap 15 On-off valve 6 On-off valve 16 Filter with condensate separator 7 Filter with condensate separator 17 Pressure regulator – MONITOR 8 Pressure indicator 18 Pressure regulator – REGULATOR 9 Pressure regulator – MONITOR 19 On-off valve

10 Pressure regulator – REGULATOR

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REGULATION PLANT - INTERRUPTIBLE

p mon pre. > 12 BAR

TYPE C

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc Insulating Joint 9 Pressure indicator 2 On-off valve 10 Pressure regulator – MONITOR 3 On-off valve 11 Pressure regulator – REGULATOR 4 Blind flange 12 Pressure indicator 5 Gauge tap 13 On-off valve 6 On-off valve 14 On-off valve full passage 7 Filter with condensate separator 15 Direct-acting Relief valve 8 Hot water heat exchanger 16 Boiler to heat water

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REGULATION PLANT - INTERRUPTIBLE

p mon pre. ≤ 12 BAR

TYPE D

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc Insulating Joint 8 Pressure indicator 2 On-off valve 9 Pressure regulator – MONITOR 3 On-off valve 10 Pressure regulator – REGULATOR 4 Blind flange 11 Pressure indicator 5 Gauge tap 12 On-off valve 6 On-off valve 13 On-off valve full passage 7 Filter with condensate separator 14 Direct-acting Relief valve

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ATTACH. 3B – MEASUREMENT PLANT WITH FISCAL VALUE

MEASUREMENT PLANT WITH FISCAL VALUE

Qero < 4000

TYPE 10

POS. DESCRIPTION POS. DESCRIPTION 30 Thermometer pocket 39 Telereading module 31 Temperature indicator 40 On-off valve 32 Pressure indicator 41 On-off valve 33 Gauge tap 42 On-off valve 34 On-off valve 43 Blind flange 35 Meter 44 On-off valve 36 Thermoresistance 45 Enbloc Insulating Joint 37 Straingauge pressure transmitter 46 Blind disc 38 Type 1 Calculator

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MEASUREMENT PLANT WITH FISCAL VALUE

4000 ≤ Qero < 30000

TYPE 30

With meters of the same class the elements 46 and 48 are optional.

POS. DESCRIPTION POS. DESCRIPTION 30 Thermometer pocket 40 Type 2 Calculator 31 Temperature indicator 41 Telereading module 32 Pressure indicator 42 On-off valve 33 Gauge tap 43 On-off valve 34 On-off valve 44 Blind flange 35 Meter 45 On-off valve 36 Meter 46 On-off valve 37 Pressure and temperature recorder 47 Enbloc Insulating Joint 38 Pressure transmitter 48 Blind disc 39 Thermoresistance

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MEASUREMENT PLANT WITH FISCAL VALUE

Qero ≥ 30000

TYPE 40

The meters are deemed of the same gauge. POS. DESCRIPTION POS. DESCRIPTION

30 Thermometer pocket 39 Thermoresistance 31 Temperature indicator 40 Type 2 calculator 32 Pressure indicator 41 Telereading module 33 Gauge tap 42 On-off valve 34 On-off valve 43 On-off valve 35 Meter 44 Blind flange 36 Meter 45 On-off valve 37 Pressure and temperature recorder 46 Enbloc Insulating Joint 38 Pressure transmitter 47 Seal on closed valve

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MEASUREMENT PLANT WITH FISCAL VALUE

12000 ≤ Qero < 30000

TYPE 60

POS. DESCRIPTION POS. DESCRIPTION 30 Thermometer pocket 40 Blind flange 31 Temperature indicator 41 On-off valve 32 Pressure indicator 42 Enbloc Insulating Joint 33 Gauge tap 43 Low dp transmitter 34 On-off valve 44 High dp transmitter 35 Diaphragm-holder 45 Pressure transmitter 36 On-off valve 46 Thermoresistance 37 Multivariable transmitter 47 Type 2 Calculator 38 On-off valve 48 Telereading module 39 On-off valve 49 Blind disc

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MEASUREMENT PLANT WITH FISCAL VALUE

30000 ≤ Qero < 60000

TYPE 61

POS. DESCRIPTION POS. DESCRIPTION 30 Thermometer pocket 42 Enbloc Insulating Joint 31 Temperature indicator 43 Low dp transmitter 32 Pressure indicator 44 High dp transmitter 33 Gauge tap 45 Pressure transmitter 34 On-off valve 46 Thermoresistance 35 Diaphragm-holder 47 Sampling system 36 On-off valve 48 Volumic mass transmitter 37 Multivariable transmitter 49 Type 2 Calculator 38 On-off valve 50 Electric recorder 39 On-off valve 51 Telereading module 40 Blind flange 52 Blind disc 41 On-off valve

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MEASUREMENT PLANT WITH FISCAL VALUE

Qero ≥ 60000

TYPE 62

POS. DESCRIPTION POS. DESCRIPTION 30 Thermometer pocket 42 Low dp transmitter 31 Temperature indicator 43 High dp transmitter 32 Pressure indicator 44 Pressure transmitter 33 Gauge tap 45 Thermoresistance 34 On-off valve 46 Sampling system 35 Diaphragm-holder 47 Volumic mass transmitter 36 On-off valve 48 Type 2 calculator 37 On-off valve 49 Electric recorder 38 On-off valve 50 Telereading module 39 Blind flange 51 Blind disk

40 On-off valve 52 Supply unit with back-up with autonomy ≥ 24 ore

41 Enbloc Insulating Joint

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EQUIPMENT CHARACTERISTIC The characteristics to be supplied during the plant Approval or Modification phases are the following:

INSULATING JOINT Manufacturer Type Nominal Diameter Nominal Pressure

ON-OFF VALVE Manufacturer Type Nominal Diameter Nominal Pressure Material

GAUGE TAP Nominal Diameter Nominal Pressure

THERMOMETER POCKET Nominal Diameter Nominal Pressure

FILTER Manufacturer Type Nominal Diameter Nominal Pressure Filtering element Capacity Seal pressure

HEAT EXCHANGER Manufacturer Type Nominal Diameter Nominal Pressure Gas capacity Seal pressure Thermal capacity

PRESSURE REGULATOR Manufacturer Type Nominal diameter Nominal pressure Cg valve coefficient Calibration pressure

RELIEF VALVE Manufacturer Type Nominal diameter Nominal pressure Useful passage section K discharge coefficient Calibration pressure

BOILER Manufacturer Thermal capacity

PRESSURE INDICATOR Manufacturer Type Scale

TEMPERATURE INDICATOR Manufacturer Type Scale

METER Manufacturer Type Nominal diameter Nominal pressure Max flow rate Qmax Min flow rate Qmin

DIAPHRAGM-HOLDER Manufacturer Type Nominal diameter Nominal pressure Inside diameter Design rule Tap type

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PRESSURE RESISTANCE Manufacturer Type Scale

THERMORESISTANCE Manufacturer Type Scale

LOW DP TRANSMITTER Manufacturer Type Scale

HIGH DP TRANSMITTER Manufacturer Type Scale

VOLUMIC MASS TRANSMITTER Manufacturer Type

MULTIVARIABLE TRANSMITTER Manufacturer Type

METER Manufacturer Type Homologation

BLIND FLANGE Nominal diameter Nominal pressure

BLIND DISC Nominal diameter Nominal pressure

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ATTACH. 3C – REMI PLANT WITH VARIABLE PRESSURE AND TEMPERATURE

REMI PLANT WITH PIPE P AND T

TYPE OF CUSTOMER CHARACTERISTICS FILTERING LINES NON Public Utility Min. 2 lines - (F) ≥ Qimp INTER. Not Public Utility Min. 2 lines - (F) ≥ 0.5 Qimp INTER. 1 line - (F) ≥ Qimp

F = SEPARATING FILTER

MEASUREMENT PLANT CHARACTERISTICS

Diagrams of acceptable plant structures and explaining notes are included in attach. 2

IN THE FOLLOWING PAGES THE FOLLOWING 3 SCHEMES ARE DESCRIBED: - SCHEME WITH VOLUMETRIC MEASURE (4000 ≤ Qero < 30000 m3/h) - SCHEME WITH VENTURIMETRIC MEASURE (12000 ≤ Qero < 30000 m3/h) - SCHEME FOR MOTOR TRANSPORT PLANT (300 ≤ Qero < 4000 m3/h)

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PIPE P AND T : VOLUMETRIC

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc insulating joint 10 Meter 2 On-off valve 11 Pressure transmitter 3 Gauge tap 12 Thermoresistance 4 On-off valve 13 Type 2 calculator

5 Filter with condensate separator 15 Telereading module

6 Themometer pocket 16 P and T recorder 7 Temperature indicator 17 On-off valve 8 Pressure indicator 18 Enbloc insulating joint 9 On-off valve

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PIPE P and T : VENTURIMETRIC

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc insulating joint 11 Multivariable transmitter 2 On-off valve 12 Low dp transmitter 3 Gauge tap 13 High dp transmitter 4 On-off valve 14 Pressure transmitter 5 Filter with condensate

separator 15 Thermoresistance

6 Thermometer pocket 16 Type 2 Calculator 7 Temperature indicator 17 Electric recorder 8 Pressure indicator 18 Telereading module 9 On-off valve 19 On-off valve

10 Diaphragm-holder 20 Enbloc insulating joint

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PIPE P and T : MOTOR TRANSPORT

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc insulating joint 9 Meter 2 On-off valve 10 Pressure transmitter 3 Gauge tap 11 Thermoresistance 4 On-off valve 12 Type 1 Calculator

5 Filter with condensate separator 13 Telelereading module

6 Thermometer pocket 14 Pressure and temperature recorder 7 Temperature indicator 15 On-off valve 8 Pressure indicator 16 Enbloc insulating joint

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ATTACH. 4 - MAXIMUM ALLOWABLE ERRORS IN MEASUREMENT SYSTEMS

Criteria to assure correct measurement The maximum allowable errors shown in the following table are defined by legal metrology regulations with two different levels relating to the “first check” in the plant and to the “periodic check” in the field. However, to assure correct measurement the interested parties should not limit themselves to comply with the maximum allowable error, but should strive for a better result adopting the following criteria. During the periodic check, calibration operations should be carried out to bring the total error, or the error of the single equipment, as close to zero as possible, even if the observed error does not exceed the maximum value. For Type 2 equipment this action should be taken independently from the periodic check due date if the check indicates a total error [C calculation] or [Q calculation] greater than or equal to 0,8%. However the interested party may agree stricter limits to increase the equipment accuracy.

Table of the maximum allowable errors in the metric checks

PRIMARY INSTRUMENTS BACK-UP

Pos. Type of check

Measurement system

Bar Pressure

Temperature °C

Deltapi mbar

C calculat

ion

Q calculati

on 1 First Volumetric Type 1 ≤ 0,6% 2 Periodic Volumetric Type 1 ≤ 1,2% 3 First Volumetric Type 2 ≤ 0,3% ± 0,4 ≤ 0,6% 4 Periodic Volumetric Type 2 ≤ 0,5% ± 0,6 ≤ 1,2%

5 First Venturimetric Type 2 ≤ 0,3% ± 0,4 ≤ 0,3% ≤ 0,6%

6 Periodic Venturimetric Type 2 ≤ 0,5% ± 0,6 ≤ 0,4% ≤ 1,2%

Note: C calculation = calculation of the total conversion coefficient (includes variables P, T, Z) Q calculation = calculation of the instantaneous flow rate in m3/h (includes variables ∆P, P, T, Z) All % values refers to the measured value except the ∆P value which refers to the calibration end of scale. Allowable errors for measurement devices (Back-up and Control)

Table of the maximum allowed errors

Pos. Device Maximum error in the condition of: Note Calibration Operation

1

Mechanic recorder - pressure - temperature - flow rate √dp

0,5% 0,5% 0,5%

1% 1% 1%

% referred to e.s. “

2 Multivariable Transmitter P – T – deltapi 0,2% 0,5% “

3 Electric recorder 0,3% 0,5% “

4 Densimeter 0,2% 0,5% 0,5% limit referred to analysis calculation

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ATTACH. 5 - DIAPHRAGM CALIBRATION CERTIFICATE CERTIFICATE n° _____________________________

DATE _____________________________

RIF. _____________ PAGE __________ of ________

Check and gauging according to UNI EN ISO 5167-1 rule: diaphragm n° ____________________________________ REQUESTED BY ________________________________________________________________ ADDRESSEE ________________________________________________________________ PLANT LOCATION ________________________________________________________________

MEASURED VALUES LIMIT CONDITIONS d1 ................ mm d max. = 1,0005 d = ................ mm

d2 ................ mm d min. = 0,9995 d = ................ mm d3 ................ mm 0,2 D ≤ d ≤ 0,75 D d4 ................ mm

-------------------------------------------- d ≥ 12,5 mm Average value d ................

mm 0,005 D < e < 0,020 D

-------------------------------------------- e max – e min. ≤ 0,001 D e ................ mm E max – E min. ≤ 0,001 D E ................ mm e ≤ E < 0,05 D F ............…….. ° 30° ≤ F ≤ 60°

No bur or other elements visible at first sight at the Entry and Exit edges. The upstream sharp edge complies with the regulations. The checks have been performed at the temperature of .................. °C for the following equipment: _______________________________________________________________________________________________

WRITTEN BY VERIFIED BY APPROVED BY

__________________________ __________________________ __________________________

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ATTACH. 6 - GAUGING OF THE MEASUREMENT SECTION

IDENTIFICATION DATA Manufacturer Fabrication year DN Pipe Number

Installed on REMI plant Manufacturer Location

D measured values in mm (to 2 decimal places) D in mm.

Value average Sez. a, b, c

D1 D2 D3 D4 Sez. a

Sez. b

Sez. c

Dmax = 1,003 D = Dmin = 0,997 D =

Sez. d D measured in

mm

Sez. e Dmax= 1,03 D= Dmin= 0,97 D= Check date At the temperature of °C. Measurement device used NOTE:

WRITTEN BY VERIFIED BY APPROVED BY

__________________________ __________________________ __________________________

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ATTACH. 7 - REMI PLANT WITH UPSTREAM P MAX ≤ 5 BAR

EXPLANATORY NOTES

a) Foreword The design and implementation of REMI plants should comply with D.M. 24 November 1984 "Fire prevention Dispositions for the transportation, distribution, storage and utilization of natural gas with density lower than 0,8", published in the supplement of the “Gazzetta ufficiale” n° 12 - 15 January 1985. Also the provisions contained in the UNI-CIG 8827 Rule should apply in particular as far as final reduction plants are concerned. Final reduction plants are defined as those reducing pressure for pipeline gas, operating with relative entry pressure in the range 0,04 < P max es. ≤ 5 bar and exit pressue not higher than 0,04 bar used to supply a distribution network or households directly.

b) Sizing and number of regulation lines The design of the regulation lines should be based on the flow rate of the regulation line (Qlin). This flow rate is defined in the following table, on the basis of the n° of lines and the plant flow rate (Qimp = maximum flow rate to size the plant, given the forecasts).

PLANTS N.LINES PARAMETERS TO DEFINE Qlin VALUES CLEARLY INTERRUPTIBLE 1 LINE: Qlin = Qimp NOT INTERRUPTIBLE supplying Public Utility customers

2 MAIN LINE. : Qlin = Qimp

3

CHOICE BETWEEN: a – FOR EACH LINE: Qlin ≥ 0,5 Qimp b - Σ 3 LINES: Qtot ≥ 1,5 Qimp with always 2 lines able to supply Q ≥ 2/3 Qimp.

> 3 CASE BY CASE VALUATION NOT INTERRUPTIBLE supplying customers not Public Utility

2 LINE : Qlin ≥ Qimp/2

≥ 3 CASE BY CASE VALUATION

c) In the case of filters, separation of liquid particles is not mandatory. In this case, if necessary, the control operations should be intensified. The minimum filtering capacity of the whole functioning range should be equal to 100% of the solid particles ≥ 50 micron and not higher than that defined by the manufacturers for the regular running of specific equipment (e.g. meters, regulators, etc.).

d) As a partial modification to the specification contained in the Procedure “Main criteria to size REMI Plants" the valve installed downstream of the pressure regulator can also be a butterfly valve.

e) Thermometers should only be used where good technical standards allow this.

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f) The meter should be installed in accordance with the manufacturer’s instruction and

with the rectilinear upstream and downstream distance indicated in the “Procedure to size Remi plants".

g) The equipment should be installed in housings allowed by the D.M. and by the UNI-CIG rules described above. If metallic boxes are used, they should be equipped with appropriate grounding.

h) The schemes mentioned at point 2 refers to minimum REMI plant configurations with the following characteristics: P mon max ≤ 5 bar not final reduction plant Qimp < 300 m3/h Fiscal measurement in accordance with attach. 2 Automated system. In particular, the FA scheme refers to the minimum configuration for interruptible accessory measurement plant. This type of plant may be required for fiscal, contractual, accuracy reasons or for any other reason; it will be usually shunted downstream of the main pressure regulation. For cases other than those described, the following points should be taken into account. h1) For REMI plants with P mon max > 5 attach. 7 is not applicable. h2) In the case of a final reduction plant, Qero > 120 m3/h and P mon max between

1,5 and 5 bar, it is necessary that, both on the main line and on the possible emergency line, a second emergency device be installed; in this case one of the emergency devices should be made up of a stop valve to be installed upstream of the monitor or incorporated in it.

h3) For every reduction plant (final and not final) if Qero ≤ 120 m3/h and P mon max

≤ 1,5 bar, the installation of only one emergency device is allowable made up of a double pressure reduction-regulation overfall incorporated in the reducer, provided it is in accordance with the above UNI-CIG rule.

h4) For plants with Qimp ≥ 300 m3/h the measuring plants should also comply, in

relation to the piping, with attach. 2 and 3b. h5) If the ancillary measurement plant is not interruptible, it must comply with the

other schemes shown in the following table, where relevant (e.g. filters or regulators may not be relevant).

SUMMARY TABLE AND SCHEMES

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TYPE OF CUSTOMER TYPE REGULATION LINE CHARACTERISTICS NOT INTERRUPTIBLE Public Utility NF Min. 2 lines (f,M,R) Qlin ≥ Qimp Not Public Utility NF Min. 2 lines (f,M,R) Qlin ≥ 0,5 Qimp INTERRUPTIBLE F LINE (f,M,R) Qlin ≥ Qimp ANCILLARY FA LINE (M,R) Qlin ≥ Qimp As an alternative to the monitor, stop valves (upstream of the regulator) or stop valve incorporated in the regulator, can be installed. The choice between these alternatives will be defined by the designer globally assessing the operational conditions expected in the downstream network, according to specific cases (e.g. more remi plants connected in parallel). M = MONITOR R = REGULATOR Bi = BLOCK (incorporated in the regulator) f = FILTER

(with reduced performance)

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REGULATION PLANT – NOT INTERRUPTIBLE

TYPE NF

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc insulating joint 12 Meter 2 On-off valve 13 Straingauge pressure transmitter 3 Gauge tap 14 Thermoresistance 4 On-off valve 15 Type 1 calculator 5 Filter 16 Telereading module 6 Pressure regulator – MONITOR 17 On-off valve full passagge 7 Pressure regulator – REGULATOR 18 Direct-acting Relief valve 8 On-off valve 19 Enbloc insulating joint 9 Thermometer pocket 20 On-off valve 10 Temperature indicator 21 On-off valve 11 Pressure indicator

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REGULATION PLANT - INTERRUPTIBLE

TYPE F

POS. DESCRIPTION POS. DESCRIPTION

1 Enbloc insulating joint 11 Meter 2 On-off valve 12 Straingauge pressure transmitter 3 Gauge tap 13 Thermoresistance 4 On-off valve 14 Type 1 Calculator 5 Filter 15 Telereading module 6 Pressure regulator – MONITOR 16 On-off valve full passage 7 Pressure regulator – REGULATOR 17 Direct-acting Relief valve 8 Thermometer pocket 18 On-off valve 9 Temperature Indicator 19 Enbloc insulating joint 10 Pressure indicator

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REGULATION PLANT - ANCILLARY

TYPE FA

POS. DESCRIPTION POS. DESCRIPTION 1 Enbloc insulating joint 9 Straingauge pressure transmitter 2 Gauge tap 10 Thermoresistance 3 Pressure regulator – MONITOR 11 Type 1 calculator 4 Pressure regulator – REGULATOR 12 Telereading module 5 Thermometer pocket 13 On-off valve full passage 6 Temperature indicator 14 Direct-acting Relief valve 7 Pressure indicator 15 On-off valve 8 Meter 16 Enbloc insulating joint

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ATTACH. 8 - CRITERIA FOR PERFORMING PNEUMATIC CONNECTIONS

GENERAL PRINCIPLES The pneumatic connections of the measurement equipment should be acrried out in accordance with the following principles. a) The length of the pipes must be as short as possible; the maximum total length

allowed (for single connection) is 45 m. b) The connecting pipes should be laid above ground and should be easily

inspectable. If the distance requires it, appropriate bearings should be considered and gangways are permitted at a minimum height of 2 m so as not to obstruct the passage. Underground passages are not allowed.

c) The pneumatic connection pipes at any point of the passage should always have a

8% minimum slope towards the condensate separating kegs, or towards the manifolds or towards the connection point on the main line when these latter do not exist.

d) Usually all measurement, control or back-up equipment should be connected

separately and directly to the connection point on the main line. If this is technically not possible (e.g. taps on the orifice fitting or taps on the meter or to avoid interfering with the inferior semicircumference of the throttling device) a mainfold should be installed close to the connection point with as many taps as there are instruments to connect. (See the schemes where the position and the quantity of stop cocks are indicated). The manifold should be installed in vertical position and with the drain cock top-down. The section of the connecting pipe between the entry tap and the manifold must be as short as possible.

e) At each connection in advance of the instrument a condensate separating keg

should be installed with capacity not lower than than 500 cm3, fixed below the instrument. The connection manifold/instrument should be vertical or with equivalent slope. On the pressure and differential pressure transmitter connections the condesate separating keg may be eliminated, if the manifolds and a continuous slope towards it exist.

MATERIALS AND DIMENSION a) Pipes

The following materials should be employed in order of preference:

Stainless steel copper steel API 5L Gr B

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In the last case the connections should be of pocket-type to be welded. Inside diameter value Φ = 8 mm (Φ external 10mm) for connection total length ≤ 15 m Φ = 10 mm (Φ inside 12 mm) for total length > 15 m. connection 15 ÷ 45 m b) Pipe fittings for connection pipes Φ 6 mm, 10 mm and 12 mm (stainless steel and

copper) The use of compression pipe fittings of universal type with countersunk pipe at 37° in stainless steel is recommended for the connections on devices, valves, manifold etc. When the connection lengths are such that a single pipe cannot be used, a welded connection is recommended as a alternative.

c) Stop cocks and manifold (zero setting units)

The following materials should be employed in order of preference : Stainless steel Carbon steel Nonferrous metallic materials only for max. operational pressure ≤ 5 bar. Type of shutter: Needle valve type or not lubricated ball valve type are permitted. The connections should always have DN ≥ 3/8" with threaded ends, according to ANSI B.2.1. NPT. In any event the inside passage should have a diameter smaller than 6 mm. In cases where the connections are made by steel pipes API 5L Gr B ≥ DN 1/2", given the rigidity of such connections and the seal of pipe fittings, more taps or manifolds should be installed to allow the calibration without disconnecting the instruments. The use of manifolds is always recommended since they allow calibration and control operations to be performed easily and safely, and without any disconnections (always to be avoided). Type of manifold: For devices measuring the differential pressure: 3-valve or 5-valve manifold. For devices measuring the pressure: 2-valve manifold. The taps and the manifolds should have high quality performance, such as: Perfect seals on the stem and the shutter seat Seals to be obtained without excessive stress on the taps Easy maneuverability of the taps without excessive stress, to get the closing

seal.

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MEASUREMENT DEVICE PNEUMATIC CONNECTIONS

Trasmitters and recorders for plant Qero < 60000 m3/h

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KEY 1 - High delta P transmitter 2 - Low delta P transmitter 3 - Pressure transmitter 4 - Multivariable (Q-dp-p-t) transmitter 5 - 3-valve or 5-valve (suggested) Manifold with connections ½" 6 - Water trap 7 - Manifold 8 - pin or ball Cutoff cock ½" 9 - Connection pipes 10- Drain cock with tap 11- pin or ball Cutoff cock ½" or (suggested) 2-valve Manifold connections ½" 12- Pressure recorder. 13- Taps with connections ½" for control taps. NOTE In the case of two meters running alternate or in series, the same water trap can be used interposing a 3-valve or (recommended) 5-valve manifold between the pipe entering the water trap and the pipes coming from the meters. N.B. The valves and the taps not used will be sealed in closing.

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MEASUREMENT DEVICE PNEUMATIC CONNECTIONS

Trasmitters and recorders for plant Qero ≥ 60000 m3/h

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KEY 1 - High delta P transmitter 2 - Low delta P transmitter 3 - Pressure transmitter 4 - 3-valve or 5-valve (suggested) Manifold with connections ½" 5 - Water trap 6 - Manifold 7 - pin or ball Cutoff cock ½" 8 - Connection pipes 9 - Drain cock with tap 10- pin or ball Cutoff cock ½" or (suggested) 2-valve Manifold connections ½ 11- Taps with connections ½" for control taps N.B. The valves and the taps not used will be sealed in closing.

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ATTACH. 9 - CRITERIA TO INSTALL COMPUTERIZED MEASUREMENT SYSTEMS

SCOPE This document defines the general criteria for the development and installation of automated systems for the fiscal measurement of gas supplied by REMI plants. Systems considered The measurement systems considered include: a) Processing devices (calculators, manothermocalibrator, thermocalibrator) b) transmitters and/or sensors connected to the processing devices c) electric connections d) pneumatic connections e) accessories and components necessary for the installation and to assure appropriate

running (boards, boxes,shields, etc..). For the main components, indicated in points a) and b), these devices should be subject to the statutory metric tests; these devices, according to the definition of the Central Metric Bureau, are classified as: "Type 1", an electronic device converting the gas volume, associated to the meter,

where the (temperature and pressure) sensors are an integral part of the meter. "Type 2", an electronic device converting or processing the gas volume, where the

temperature, pressure (and possibly differential pressure) sensors are separate (and interchangeable) components.

GENERAL PRINCIPLES The choice of the type of electric safety device to be used to install converters must be done in accordance with CEI EN rules in force. The converters should not be installed in places under the direct action of solar rays, of rain, or in places where dust or corrosive acids are present in the atmosphere. Installation should also not take place close to sources of electromagnetic disturbances such as electric cabins, inverters, high tension lines, etc. The "type 2" converters can be contained in boards installed both on the floor and on the wall, provided its internal components can be easily accessed. In both cases it should be possible to access the internal connections from just one side (front or back) by specific door which can be sealed to prevent unauthorized acts. The "type 1" converters can be installed both on the wall and directly on the meter, provided the maximum access to their internal components is assured. For particular weather conditions, a condensate resistance and/or aeration fan should be installed, to allow correct operation of the converter given the expected maximum and minimum temperature and humidity level in the room where it is installed. Other equipment (e.g. Q regulators, additional recorders, commutators, controls etc.), provided the size and number allow, can be installed on the board provided they are fitted in specific space totally closed on all sides by welded plate and independent access door.

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ELECTRIC CONNECTIONS Specified below are type of cables, how they should be laid and connected to the equipment, the power supply line and grounding. a) General principles

All the electric cable should preferably be of the type “NOT FIRE PROPAGATING” in line with CEI 20-22 rule. The wires should be of flexible type, made of copper and spiral. The R-value can be > 1,5 (Uo/U = 230/300 V) for plants in Ex-i execution while it should be > 3 (Uo/U = 450/750 V) for the type of plants using other protection methods. The feeding or signal cables, in addition to the primary insulation of each conductor, should have secondary insulation by appropriate material, containing all the conductors and should be in the form of a cylindrical shape. The terminals of the conductors should be clearly marked in the same way as that indicated in the functional electrical scheme, a copy of which should be available on the plant. In the AD-PE plants the terminal connection on the transmitter side, or thermoresistance side, should be made by flexible cable-holding pipe in Ex-d execution. In the Ex-i plant the Zener barriers shoul be of the passive type in for safety reasons.

b) Equipment connections

b1) Cable Characteristics A multicore cable with PVC abrasion proof coating (minimum size 0,8 mm) should be used to carry out the lines for the entry/exit signals and every conductor should have a minimum section of 1,5 mm2. This section, only for plants in Ex-i execution, can be ≤ 1,0 mm2 if the length is < 100 m. Where the colour of the sheath is used to identy the circuits, the light blue color should be reserved for the Ex-i circuit cable. The cable should be provided with a total electric shielding (with 100% coverage) made by (Mylar) aluminium tape with 0,05 mm minimum thickness and flexible drainage conductor by tinned copper minimum section 0,5 mm2; or by copper plait. One end of the cable shielding should be connected to the ground at only one point which in the Ex-i circuits, if not otherwise indicated, should be on the same ground bar of the passive barriers. The number of wires should be defined on the basis of the device to be connected. To connect theromoresistance cables at least 4 wires should be used. The colours used for the measurement signal cables should be different, for + and – signs.

b2) Cable laying The cable path to connect the measurement equipment can be above ground or underground provided an easy inspection can be assured and it should be defined in such a way as to minimize the connection length. Permitted above ground locations include gangways, channels or directly fixed on the wall. Underground laying should be carried out in accordance

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with the appropriate building criteria, such as the use of inspection and threading traps, connected by PVC pipe sections with length < 20 m. The cable housings should be defined along the whole path in such a way as to keep separate the different circuit types (e.g. power, signal and communication cables) - therefore signal cables should not be laid in the same passages, gangways, channels or pipes used for laying power cables. Parallel paths are allowed for signal and power cables only if they are laid at a distance apart greater than 0,80 m. This spacing is not required for short parallel sections (around a few metres). Ex-i circuit cables should not be inserted in pipes containing non Ex-i circuit cables or not belonging to the measurement system. Non armoured cables without protecting pipes should be protected against mechanical damage along the whole path. Each category of laying should be undertaken, in terms of the quantity and size of cable, consistent with the expected load and other stresses. The path of the cable must be chosen in such a way that its distance and orientation do not lead to induced overvoltage, that is they should be laid without producing induction loops.

b3) Connections

The connections to entry and exit signals should be linked to terminal boards, located within the box containing the converter, appropriately grouped according to the functions. Where Zener barriers are required for saftey reasons, they will replace the terminals and will be the only point of interconnection between the measurement equipment and computer. Independently from the type of safety plant, the electric connections of the equipment (Dp, P, T, ρ., etc.) should be made up by a single cable for each device without intermediate junctions between the terminals of the same device and those on the device to which the signal is directed. To fix the conductors to the terminal boards terminals with insulated prod should be used. The shunts from computer exit signals with additional or different functions from fiscal measurement (e.g. flow rate regulation, remote transmitting) must always be carried out by interposing an appropriate galvanic separator between the terminal board and the converter.

c) Network supply

If the equipment is supplied by the network voltage, they should be supplied by an untinterruptible power supply with batteries sized to assure the normal running of the measurement system, during a power failure on the main network, for a 6 hour period. Every device directly supplied by the power supply must be individually connected to it, isolated by appropriate switch. The supply line upstream of the uninterruptible power supply, which must use a multipolar cable with a minimum of 3 wires of section 1,5 mm2 with PVC sheath and coating, must be shunted by the main supply line by interposing a magnetothermal differential switch with high sensitivity (Id=300 mA), sensitive to alternate and unidirectional pulsating currents (class A), with breaking capacity 6kA and adequate uninominal current; this switch should be dedicated - that is it should not cross the supply line dedicated to other devices.

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The provisions contained in 3.2.2. (connection of the measurement equipment) apply for the laying of cables.

d) Earthing

The recommendations described here should be considered as an addition to those contained in CEI 64-12, 64-8 e 81- 1 rules. As a general earth plate it is advisable to use a meshed earth net spread all over the plant area, thickening it in the most critical zones, connected to which at a single point, should be an equipotential bar, the cable shields, the functioning and protection earth wires. The earth wires of the accessible metallic parts of the devices (e.g. the box) should be installed so as to minimize the impedance and to limit to the minimum the area subtended by the turns made up with the other supply and signal cables. For the earthing of intrinsically safe plants AD-I, the solutions suggested by the manufacturers of the relevant equipments (transmitters, converters, etc.) should be followed together with the provisions contained in the Certificate of Compliance (Ex-i) of such devices. In the intrinsically safe circuits (barriers, separators and transmission cables marked by the transmitters) earthing should be carried out by a conductor insulated by every other earth of the plant and connected to the earth system in just one point (all the passive barries, fixed on just one earth bar, must be connected to the equipotential earth system by a single conductor with section 6 mm2.) The resistance between the earth terminal and the equipotential earth point must be less than 1 Ω. The passive barriers, in any operational condition, should never be subjected to a voltage higher than 250 V a.c.; it is therefore a prerequisite that the earthing of the intrinsically safe circuits and the earthing of the network supply at 230 V a.c. be equipotential. d1) Check of the efficiency of the earthing

Following installation of new plant, or modification of the same, an efficiency check should be performed of the earthing of the whole measurement system (transmitters, cables, barriers, boards, boxes, supply, etc..) using the methods defined by the CEI 64-8 e 64-12 rule, and summarizing the outcome in a report.

PROTECTION AGAINST ELECTRICITY SUPPLY VARIATIONS To be reliable, the measurement system must be provided with the necessary protection against electricity supply variations, both on the entry and exit circuits. The main recommended solutions, which can be improved by adopting new available technologies, are: Overvoltage discharger

The installation of dischargers assures the protection against overvoltage due to lightning discharges which hit overhead lines, supply lines or areas close to the cabin. They provide protection also against overvoltage due to commutations in ENEL stations and against the MT or HT line short circuits. This does not always assure that the voltage will not exceed the maximum values; in any event, for the

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dischargers which do not allow automatic restart, continuous checks are needed to control the situation.

Network filters

The network filters should be able to limit symmetrical and asymmetrical interferences. Filters with double absorption cells are preferred since they are more effective.

TVSS

The TVSS (Transient Voltage Surge Suppressor) are hybrid devices, made up of filters and resistors, able to absorb very high quantities of energy and are characterized by a high operating speed to take account of the rapid growth of the impulse. This aspect is very important since it protects the device from damaging events and lengthens its operational life. To protect telephone lines it is advisable to use hybrid protection made up of dischargers and resistors, to provide protection for lines subject to frequent overvoltage. It is also advisable (if feasible), to increase the electromagnetic conditions within a REMI cabin, to interconnect all the metallic parts of the structure with significant dimensions (metallic coverings, reinforcement bars, etc..), as well as to connect it to the lightning protection system (LPS), creating an effective shield (Faraday cage) of the structure. CEI 81-1 and CEI 81-4 rules contain the assessment of the risk to decide whether to install a lightning protection systems (LPS) and the criteria to use in their installation.

INSTALLATION OF THE TRANSMITTERS (DELTAPI - PRESS. – TEMP.) The transmitters must be installed on appropriate supports with no vibrations appropriately fixed on the ground and/or on the wall (a distance from the ground between 1 and 1,5 m is recommended). The position should allow easy access to carry out maintenance and calibration operations. The thermoresistance (PT100) to measure the temperature should be inserted in a thermometer pocket, full of mineral oil. The insertion depth of the pocket within the tube must be as a minimum 1/3 of the “DN”, in pipes with DN ≥ 300 the depth can be reduced at a minimum of 100 mm. The thermometer pocket must be made of stainless steel; with max operational pressure ≤ 5 bar the pocket may be provided by pipe. The pocket should be installed along the superior generatrix of the pipe in vertical postion, for pipes with small diameter (DN ≤ 100) a 45° slope with respect to the pipe axis is allowed.

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ATTACH. 10 - CARTHOGRAPHIC DOCUMENTATION FOR PIPELINES 1) SCOPE The scope of this annex is to provide a mechanism to identify the devices of the functional diagrams of gas reception and reduction plants. In this system equipment is identified by a graphic symbol and a literal abbreviation, those relating to the instruments also by a literal sign, and are described either in the list of instruments on in appropriate specification. (See point 5) 2) GRAPHIC SYMBOLS The graphical representation of the symbols does not require any particular scale. The dimensions of the symbols will be chosen according to the complexity of the system concerned. The symbols should be set out in the design according to the most logical sequence and in the direction of the gas flow, avoiding line intersections, as far as possible. To increase the understanding of the direction of the process flows, direction arrows may be inserted on the lines representing the pipes. All heights should be in mm. 3) NUMERICAL ABBREVIATIONS In the functional plant diagrams, numerical abbreviations and graphical symbols are used to identify devices in the diagram. The numerical abbreviation is followed by a number if the device is unique and by a number followed by a dot and by another progressive number if there is more than one instance of the same equipment. In the list of equipment only the first number is shown. If the device is multi-functional (e.g. manothermograph) the numeric abbreviation will always be the same and it will be repeated, for each function, near the graphic symbol on the diagram.

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4) LITERAL ABBREVIATIONS The literal abbreviations, used for the equipment, identify their function. The construction and interpretation of the literal abbreviations use the following table:

ABBR. POSITION LETTER MEANING OF

THE LETTERS

EQUIPMENT DESCRIPTION

aFR Prefix a Average Average 1a position F Flow Rate Flow rate 2a position R Recorder Recorder

FR 1a position F Flow Rate Flow Rate 2a position R Recorder Recorder

PI 1a position P Pressure Pressure 2a position I Indicator Indicator

TI 1a position T Temperature Temperature 2a position I Indicator Indicator

In the construction of the abbreviation the position of the letter has a fundamental importance. In fact, the identification abbreviation is generally made up by different letters with the following positions: - a) prefix - b) 1a position - c) 2a position - d) 3a position - e) 4a position - f) suffix The prefixes (4.4.a.), precede the first positions, are in lower case letters and are identified on the previous table in the second column. The positions 1a, 2a, 3a, 4a, (4.4.b,c,d,e) are in upper case and are identified in the following table in the third, fourth,fifth and sixth colums respectively. The suffixes (4.4.f) occupy the last position, divided by a hyphen and are in upper case. In the table they are identified in the seventh column. The prefixes (4.4.1.) and the letters indicated in points 4.4.2. represent the function of the base equipment. The suffix indicated in point 4.4.3. identifies the equipment upstream or downstream of the base equipment to which it sends or from which it receives the signal.

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FUNCTION OF THE LETTERS IN EACH POSITION OF THE ABBREVIATION

LETTER 1

PREFIX

Lower case

letter 2

1a POSITION

Upper case

letter 3

2a POSITION

Upper case

letter 4

3a POSITION

Upper case

letter 5

4a POSITION

Upper case

letter 6

SUFFIXES

Upper case

letter 7

A Absolute average analysis Alarm alarm alarm B flame C By programme conductivity Regulator regulator regulator D Differential delta. Operational Volu.

mass Blowout disc

E electric Primary element Primary element

F Flow rate Computer Flow rate G reference vol. mass Glass pilot lamp H high manual I Indicator K time Calibrator calibrator L low level M humidity Electric engine P pressure Printer Piston Q board R ratio pressure

temperature Recording.

S speed safety - block

block block

T turbine temperature transmit.

transmit.

transmit.

transmit.

V venturimetric viscosity valve autoact.

valve

W weight Sump dp Differential

pressure

XX Generic equipment

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5) LIST OF EQUIPMENT The list of equipment is made up by seven colums with the following headings: First column "POSIT." = first number of the numeric abbrev. Second column "QUANT." = N° of identical equipments Third column "BRAND" = name of the manufacturer Fourth column "TYPE” = abbrev. identifying the equip. Fifth column "DESCRIPTION" = short description of the equip. And

technical characteristics needed to identify it.

Sixth column "DN" = equip. Nominal diameter Seventh column "PN/ANSI" = equip. Resiatnce class. The list of equipment should be made on UNI A4 format paper. 6) USE OF THE SYMBOLS The graphic symbol will only appear on the diagram according to the point 2 clarifications. The numeric abbreviation will appear both on the diagram and in the list of equipment, according to the point 3 clarifications. The literal abbreviation, if relevant, will appear on the diagram, located within the graphic symbol of the equipment, according to the point 4 clarifications. The functional diagram must be designed on UNI A4 or UNI A3 papers. 7) DESIGN OF THE PLANTS When designing plant, and for those equipment for which a specification description is required, their number of specifications may be added to the list of equipment, in addition to a short description of the equipment. 8) TABLES OF THE GRAPHICAL SYMBOLS AND OF THE LITERAL

ABBREVIATIONS The following tables contain the graphical symbols in current use (including the additional literal abbreviations if appropriate).

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Pipes - Connections – Electric Transmission

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Elbow- Tees - Reductions - Bottoms- Flanges – Thermometric pockets – Dielectric Disks – Dielectric Joints- Demounting Joints – Valves with special functions

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Valves – Servo controlled Valves – Blowout Discs – Hydraulic guides - Safety devices with blowout discs – Stop Valves - Valves with special functions

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Pressure Regulators

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Pressure containers - Separators - Filters – Heating Filters - Exchangers

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Odorizers – Expansion tank - Boilers - Punps - Compressors

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Meters – Throttling devices – Venturimetric Sections – Flow Rectifiers

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Instruments- Indicators – Indicators and Recorders

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Recording instruments – Regulating Recording instruments – Average Flow Rate Recorders

Totalling instruments

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Recording instruments with more pens - Printers - Computers

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Converters - Transmitters – Ancillary Devices

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