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AWADUKT THERMO InsTAllATIOn gUIDElInEs

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As no British Standard for the installation of ground air heat exchangers currently exists, we recommend that BS EN 1610 (Construction and Testing of Drains and Sewers) is used for guidance on structural and installation issues.

1.1 Trench ExcavationExcavate the trench as per site requirements.The trench depth should allow for the specified thickness of soil cover (min 1.5m) above the pipe crown.

The trench base should be free of stones, flat with a 2% fall towards the condensation chambers.

1.2 Lowering pipes into trenches- Use adequate machinery in order to lower the

pipe into the trench- Lower the pipe carefully to avoid any damage- For DN/OD 200 to 500 pipes, remove the

protection cap directly before connecting the pipes to the sockets. If work is interrupted please put them on again so that any entry of foreign material is avoided

- Please ensure that the Ground-Air Heat Exchanger system is installed according to the relevant plans/designs

1.3 Systembeddingandbackfillrequirementinto trenchesFlexible pipes deform under the application of load and require support from surrounding material in order to avoid excessive deformation of the pipe (BS EN 1295-1 B.2. 12.1.4); selection of correct embedment materials is critical (refer to Table 1).

Sample Project component layout

1. AWADUKT THERMO InsTAllATIOn

Section A-A

Section B-B Section C-C

Section D-D

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Table 1 – Embedment Details

*BS EN 1295-2:2005 ** (Operating Weight ≥ 60kg)

1 Surface

2 Bottom of road, if any

3 Trench Walls

(if applicable)

4 Main backfill

5 Initial backfill

6 Sidefill

7 Upper bedding

8 Lower bedding

9 Trench bottom

10 Depth of cover

11 Depth of bedding

Embedment Level Embedment Materials Compaction

MainBackfill(4)Unless otherwise specified the material excavated from the trench may be used for the remainder of the backfill above the required top level of the selected sidefill material

The main backfill (4) should be applied in layers of 300mm and compacted with heavy vibro tampers (Operating weight <200kg)

750–1050(DN/ID)header and distribution

pipes

200–500(DN/OD)heattransfer and header

pipes

Initial Backfill (5) c = 300mm above the crown of the pipe

Initial Backfill (5) c = 300mm above the crown of the pipe

Initial backfill (5) should be compacted with a light weight vibro-tampers**

Class S1 / S2* – uniform, well compacted granular bed type and surround, 20/5 or single size stone max 20mm

Class S4* – Fine grained soil, liquid limit less than 50%, medium to no plasticity and between 25% – 65% coarse grained material (Stone size max 30mm)

Sidefill (6) should be placed evenly, either side, to the top of the pipe and compacted** in 150mm layers. Material should also be worked under the pipe haunch to eliminate voids

Lower bedding (8) a = 150mm

Lower bedding (8) a = 150mm

Lower bedding (8) should be well compacted

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1.3 InstallationofSystemAccesschamber(withManhole)If a system access (chamber ≥ DN 800) condensation chamber is required, this should be installed first, at the lowest point of the system.

Utilise slings or straps suspended from JCB/fork lift etc to lower and position the chamber and to avoid damage.

If required, the chamber can be laid with a concrete foundation.

1.4 InstallationofPipes

1.4.1 InspectionPipes and fittings should be visually checked for any damage prior to installation.

1.4.2 Handling- Utilise slings or straps suspended from JCB/fork

lift etc to lower and position the pipe and to avoid damage.

- Pipes should be suitably supported at two places at least when being lifted and nylon slings should be used. If pipes are delivered one inside the other, special care should be taken to avoid damage during unloading.

- If pipes are loaded or unloaded by mechanical means (fork lift truck, cranes etc) care should be exercised to avoid damage.

1.4.3 BeddingUnless otherwise specified, the thickness of the lower bedding a, measured under the Pipe barrel, shall not be less than 150mm.

Manhole Access Chamber

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1.5 Joining pipesi. The pipes should be jointed in the excavated area

and laid on the prepared bed so that the pipes are fully supported along their length.

ii. Small depressions should be made at proposed joint position to accommodate the pipe sockets and couplings.

IMPORTANT:Oncethejointiscomplete,thesedepressionsshouldbecarefullyinfilled,takingcare that no voids remain under or around the joint.

1.5.1Joining200–500(DN/OD)pipes- Only use the REHAU seals that are already

integrated into the sockets- Clean both the socket and the end of the pipe

and ensure that there is no damage- In order to check if the pipe has been introduced

into the socket at the defined length, mark the required insertion depth on the pipe (if not already marked) before assembly

- Lubricate the bevelled end of the pipe with REHAU lubricant

- Push the bevelled end of the pipe up to the base of the socket

- The insertion force has to be centric along the pipe axis and can be carried out by hand or with levers

- When using levers, a square timber should be laid across the pipe in order to achieve an even force distribution and avoid damage

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1.5.2Joining750–1050(DN/ID)pipes(FlexSeal) Where groundwater is present, additional sealing may be required (contact REHAU for further advice)- Clean pipe surface and apply a non-oil based lubricant to the pipe surface. Slide coupling onto pipe before placing in trench.- Place next pipe in trench, Line up step at soffit

of pipe and align pipes so that the pipe ends are butted together.

- Pull on the coupling, using the locating lines which are marked on the outside face of the pipe to locate the coupling centrally over the joint. See section 1.5.6

- Tighten all bolt tensioners evenly so that all the slack is taken up before tightening fully with the spanner provided to 20-25 Nm. The bolts on the clamping beads should be positioned so as to be accessible.

- Pack bedding materials beneath the pipe to fill the void.

- Place the required embedment materials as outlined in Table 1, leaving the end of the pipe exposed, ready to make the next connection.

- Prior to completing the backfill of the pipe, the bolts should be re-tensioned in the morning after the pipes have been laid.

1.5.3Cuttingof200–500(DN/OD)pipes- Use a jig saw, pipe cutter or an equivalent in

order to cut the pipe, ensure that a rectangular cut is achieved

- Chamfer the shortened end of the pipe with a file or with a chamfering tool

1.5.4 Usage of Lubricant Please use the following approx. amount of lubricant for 100 connections

1.5.5Furthernotesoninstallation- Pipes must be laid at a depth of at least 1.5m.- The pipes are to be laid at suitable distance away

from the building so as not to jeopardise the building stability.

- The fall of the pipes is to be approx. 2% towards the condensation collection chamber.

- The pipes should be cut using a fine toothed saw or pipe cutter. Pipes are to be cut square and the ends are to be de-burred and chamfered

DN/OD g(ca.)

110 200

125 250

160 300

200 400

250 600

315 800

400 1000

500 1300

1.5.6PipeAllignment

IDEAL ACCEPTABLE (With max. allowable deflection of 20mm)

UNACCEPTABLE

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1.6 InstallationofAirInletTower

Air Inlet Tower ( 200 – 500 ID)

Air Inlet Tower ( 800 – 1200 ID)

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1.7 Loading Evaluation The load on a pipeline depends on the diameter of the pipe, the depth at which it is laid, the trench width, and the traffic, or other superimposed loading (BS EN 1295-1 7.1 and 7.2)

Special note should be taken of the construction traffic and the loads due to the construction processes, such as compaction of trench backfill.

Traffic loads from plant machinery is only permissible on a compacted backfill of at least 0.8m in height. (For further information, please contact REHAU)

1.8 Supervision The system must be installed and supervised by suitably competent personnel. In this way careless work and the subsequent appearance of problems can be avoided.

1.9 Pump installation Small Submersible pump1 for condensation should be installed in the shaft (see sample project component layout picture), the drilled holes to the condensation shaft for the discharge pipe and power cable should be sealed airtight.

Note: Submersible pump is not supplied by REHAU.

1.AdviseonpumpselectionPump Diameter (incl. discharge pipe) ≤ 290mmFlow rate 1.5m3/Hr @ 6m headPump with integrated automatic floating switch with minimum draining level (i.e minimum standing water)

Example 1 Example 2

Climate Conditions 350C / 45% humidity 280C / 80% humidity

Temperature drop 18K 12K

Air flow rate 150m3/h 150m3/h

Condensation approx 0.4 l/h approx. 0.8 l/h

Estimation of condensationExample estimates of condensation volume according to Mollier diagram:

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2. AWADUKT THERMO COMMIssIOnIng

2.1 Processesandrequirements for checking pipelines

2.1.1 General Testing of leak tightness of pipelines, manholes and inspection chambers shall be conducted either with air (method ‘L’) or water (method ‘W’). Separate testing of pipes and fittings, manholes and inspection chambers, e.g. pipes with air and manholes with water may be undertaken. In the case of method L, the number of corrections and re-tests following failure is unrestricted. In the event of a single or continued air test failure, recourse to water test is allowed and the water test alone shall be decisive.

If the ground water level is present above the crown of the pipeline during testing, an infiltration test may be applied with individual specification.

Initial testing may be applied before any sidefill placed. For final acceptance the line shall be tested after backfilling and removal of sheeting; choice of testing by air or water may be given by the specifier.

2.1.2Testingwithair(method‘L’)The testing times for pipelines excluding manholes and inspection chambers are given in the following table in relation to pipe size and testing methods (LA; LB; LC; LD). Testing method should be given by the specifier. Suitable airtight plugs shall be used in order to avoid errors arising from the test

equipment. Special care is required when testing large diameters for safety reasons.

Air testing of manholes and inspection chambers is difficult to implement in practice.

1. Until there is sufficient experience of air testing manholes and inspection chambers testing time of half that for an equivalent diameter pipeline may be used.

An initial pressure approximately 10% in excess of the required test pressure, P

0, shall first be held

for approximately 5 min. The pressure shall then be adjusted to the test pressure shown in Table 3, related to testing to testing method LA, LB, LC or LD. If the pressure drop measured after the testing time is less than ∆p given in Table 3 then the pipeline complies.

2. The test requirements for negative air pressure testing are not given in this European Standard as there is currently insufficient experience with this method. The equipment used for measuring the pressure drop shall allow a measurement with an accuracy of 10% of ∆p. The accuracy of measurement of time shall be 5s.

- The Installed Ground Air Heat Exchanger system should be pressure tested (see pressure testing guidelines).

- The system needs to be inspected and thoroughly cleaned (see cleaning guidelines), all the water used during cleaning needs to flushed out.

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2.1.3Testingwithwater(method‘W’)

2.1.4 Test pressure The test pressure is the pressure equivalent to or resulting from filling the test section up to the ground level of the downstream or upstream manhole, as appropriate, with a maximum pressure of 50kPa and a minimum pressure of 10kPa measured at the top of the pipe.

2.1.5 Conditioning timeAfter the pipelines and/or manholes are filled and the required test pressure applied, conditioning may be necessary.

Usually 1 hour is sufficient.

2.1.6 Test timeThe testing time shall be 30± 1 min.

2.1.7TestrequirementsThe pressure shall be maintained within 1kPa of the test pressure defined in 5.4.4 by topping up with water.

The total amount of water added during the test to achieve this requirement shall be measured and recorded with the head of water at the required test pressure.

The test requirement is satisfied if the amount of water added is not greater than: - 0.15l/m² during 30 min for pipelines- 0.20 l/m² during 30 min for pipelines

including manholes- 0.40 l/m² during 30 min for manholes and

inspection chambers

M2 refers to the wetted internal surface.

Test process P0*)mbar(kPa)

∆p**mbar(kPa)

DN/OD110-200

DN/OD 250-315

Testtime(min) DN/OD 400

DN/OD 500-630

DN/OD 710-800

DN/OD 1000

LA 10 (1)

2.5 (0.25)

5 7 10 14 19 24

LB 50 (5)

10 (1)

4 6 7 11 15 19

LC 100 (10)

15 (1.5)

3 4 5 8 11 14

LD 200 (20)

15 (1.5)

1.5 2 2.5 4 5 7

*) Pressure above atmospheric pressure **) Allowed pressure drop

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2.1.8 Testing individual jointsUnless otherwise specified, testing of individual joints instead of testing the whole pipeline can be accepted for pipelines, normally larger than DN 1000.

For individual pipe joints to be tested, the surface area for test ‘W’ is taken as that represented by 1m length of pipe, if not otherwise specified. Test requirements shall be given in 5.4.7 with a test pressure of 50kPa at the top of the pipe.

The conditions for test ‘L’ shall follow the principles given in 5.4.2 and be specified individually.

Please refer to BS EN 1610 for further advice.

2.1.9Flexsealcouplingsfor750–1050 (DN/ID)pipesAir Testing Pipes Using Water in the Spiral:1. Ensure Flexseal has been fitted as recommended.2. Drill hole in outer box section at either end of

pipeline to be tested or, at either side of joint.3. Pour water into the box section through hole.4. A minimum of 1 litre will suffice for sizes up

to 900 diameters.5. The water will stop air escaping through the

spiral during testing.6. This method can also be used for Manhole stubs.

Note: High pressures are needed to drive water around the spiral.

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2.2 InspectionandCleaning2.2.1 General a. If no other technical rules are known, VDI 6022

shall apply. b. All inspection and cleaning shall be carried

out by personnel qualified for maintenance of air-conditioning systems.

2.2.2Worktobecarriedoutevery6-12months1.Airinlettowera. Remove air inlet filtersb. Clean air inlet box with a cleaning tissuec. Insert new air inlet filterd. Close / lock air inlet tower

2.Airductoutlet(intobuilding)a. Check air duct outlet for contaminationb. Remove any contamination with a cleaning

tissue (use a rod to reach into the duct up to the condensation chamber)

3. Condensation chambera. Check function of condensation submersible

pump (if installed)b. Check air ducts either side of the chamber

for contaminationc. Remove any contamination within the pipe from

the filter to the contamination chamber using high pressure water jetting equipment (max 100 bar and 60ºC). Standard disinfectant can be used.

Cleaning steps:- Close duct from the condensation chamber

to the building tight- Insert an immersion pump into the condensation

chamber in case the capacity of condensation pump does not match the water flow of the jetting equipment

- Insert the high pressure water jetting equipment through the condensation manhole into the air duct

- Activate the high pressure water jetting equipment and move it towards the filter; pump the water out through the condensation chamber

d. For the jetting, use pure potable water; the safety of any cleaning agents used has first to be verified

e. Remove the jetting equipment (and additional immersion pump)

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3. AWADUKT THERMO PIPE TRAnsPORT AnD sTORAgE

3.1 Pipetransport200–500(DN/OD)Pipes:- Treat the pipes carefully in order to avoid

any damage- The pipe has to be supported over its length

in order to avoid sagging- Loose pipes have to be secured against

movement during transport

3.1.1Delivery750-1050(DN/ID)Pipes- Pipes will be delivered on site in banded packs

for sizes up to 1350mm, or as individual pipes if larger.

- Nylon slings should be used for offloading.- The bands must be removed with care after

offloading and pipes should be stored as detailed below.

- Detailed offloading advice would be offered with each order.

3.2 Pipe storage 3.2.1200–500(DN/OD)Pipes:- Pipes are to be stored on a level base and

secured to ensure they are not damaged by rolling off

- Protect the pipes against damage and pollution- Excessive stacking heights should be avoided, so

as not to place too much load on the bottom part of the stack

- Do not store the pipes near open trenches- Protect the pipes against weather influence, e.g.

direct solar radiation, hail, ice on the ground, etc.

3.2.2PipeStorage750-1050(DN/ID)PipesThe following recommendations relate to the storage of pipes under normal climate conditions of the United Kingdom.

i. Pipes should be stacked on timber supports placed on flat ground free from sharp projections, stones and other protuberances. It is recommend that timber supports are placed at 2m centres. The top surface of the supports should be horizontal to within +/- 20mm. Maximum pipe stacks should not exceed 6 layers with a maximum height of 4m.

ii. It is recommended that pipes are not stored one inside another, but can be transported in this manner.

Pipe must be secured at all times to prevent

rolling or collapse of pipe stack. Larger diameter pipes which have been prepared with “stepped” ends should be stored on site with the “step” at top dead centre.

iii. When long term storage is envisaged, WEHOLITE pipes must be protected from direct sunlight. If protection cannot be provided then consideration must be given to the effects of daily exposure.

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www.rehau.co.uk 342683EN/DAIR/01.09

The REHAU Awadukt Thermo system is designed for use as a ground-air-heat-exchange (GAHE) device. Such devices must be properly installed and maintained to avoid microbial growth in the system. This includes installing the device in such a way that all condensate can flow to a condensate collection device. The installation of the condensate collection device shall ensure that no dirt, rain water, ground water or sewer-discharge can pollute the gahe.

The Awadukt Thermo‘s integrated anti-microbial layer is a supplemental measure in inhibiting microbial growth in the system and is not a substitute for proper installation, proper use of filtration, and proper system maintenance including but not limited to routine replacement of filters and periodic system cleaning following standard air duct cleaning procedures. The anti-microbial layer inhibits microbial growth but will not prevent such growth if the system is polluted, improperly installed or maintained.

REHAU makes no guarantees regarding the quality of air supplied by the Awadukt Thermo system. It is the responsibility of the project owner and their designates to ensure proper ventilation is supplied to each respective project. This includes but is not limited to proper placement of air-inlet towers and inclusion of proper filtration strategies.