Specification for Class O Armaflex
1.0 Material
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| 1.1 | Class O Armaflex pipe insulation, black in colour, having a Class 1 fire rating to BS 476: Part 7, 1987 (Surface spread of flame test) and a Fire Propagation Index to BS 476 Part 6 (1989) test with values of I less than12 and i1 less than 6, to comply with the Class O specification as defined in the » Building Regulations. |
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| 1.2 | The technical values for the thermal insulation shall be as published in current literature of Armacell UK Limited. |
2.0 Internal Pipework (concealed or exposed to view)
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| 2.1 | Temperature range -200 ºC to +105 ºC (+85 ºC on flat surfaces). For temperatures below -50 °C please consult Armacell Customer Services Deparment. |
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| 2.2 | All pipework to be insulated with Class O Armaflex pipe insulation, as defined in 1.1 and 1.2 above. |
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| 2.3 | Lengths to be close butted. All butt joins, longitudinal seams and joins at fittings shall be sealed with Armaflex 520 adhesive to provide an unbroken vapour barrier. |
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| 2.4 | The adhesive shall be used in accordance with the published Technical Information sheets. Apply a thin uniform layer to BOTH surfaces to be joined, allow an “open time” of 2-3 minutes - dependent upon ambient conditions - to allow the solvents to evaporate, press together the surfaces to be joined using firm pressure, allow to cure for 36 hours for the bond to reach maximum strength and resistance to water vapour. |
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| 2.5 | In addition, all valves and other fittings shall be insulated with purpose-made sections fabricated on site in accordance with the » Armaflex Installation Manual and other
technical literature from Armacell. Valve covers shall fully protect flanges and bonnet with only the wheel and stem exposed and shall be sealed with Armaflex adhesive to prevent ingress of water and water vapour. |
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| 2.6 | For insulation thickness refer to specification information for » Frost Protection, » Energy Conservation and » Condensation Control. |
3.0 External Pipework (exposed or in trenches)
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| 3.1 | Temperature range -200 ºC to +105 ºC (+85 ºC on flat surfaces). For temperatures below -50 °C please consult Armacell Customer Services Deparment. |
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| 3.2 | All pipework to be insulated with Class O Armaflex pipe insulation, as defined in 1.1 and 1.2 above. |
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| 3.3 | Lengths to be close butted. All butt joints, longitudinal seams and joins at fittings shall be sealed with Armaflex 520 to provide an unbroken vapour barrier. |
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| 3.4 | The adhesive shall be used in accordance with the published Technical Data Sheets. Apply a thin uniform layer to BOTH surfaces to be joined, allow an “open time” of 2-3 minutes - dependent upon ambient conditions - to allow the solvents to evaporate, press together the surfaces to be joined using firm pressure, allow to cure for 36 hours for the bond to reach maximum strength and resistance to water vapour. |
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| 3.5 | In addition, all valves and other fittings shall be insulated with purpose-made sections fabricated on site in accordance with the » Armaflex Installation Manual and other
technical literature from Armacell. Valve covers shall fully protect flanges and bonnet with only the wheel and stem exposed and shall be sealed with Armaflex adhesive to prevent ingress of water and water vapour. |
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| 3.6 | Where the surface of the Armaflex is exposed to sunlight, UV radiation or attack by aggressive chemicals it shall be protected using Armafinish FR paint applied strictly in accordance with the manufacturer’s recommendations. It is important to ensure that the recommended coverage rate is not exceeded to give the proper thickness of coating. A minimum of two coats will normally be required.
Note: HT Armaflex has very good resistance to UV radiation and needs no UV protection when installed externally under normal environmental conditions. |
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| 3.7 | Where the Armaflex is buried in trenches the insulation shall be protected by an outer rigid pipe to prevent the insulation being crushed thereby losing its effective thickness. If the Armaflex insulation is being buried where it will be in wet or moist ground for long periods then the sealed Armaflex shall be wrapped in a waterproof tape, e.g. Densotape or approved equivalent, prior to being protected by an outer rigid pipe. |
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| For insulation thickness refer to specification information for » Frost Protection, » Energy Conservation and » Condensation Control. |
4.0 Boilerhouses and Plant Rooms
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| 4.1 | Temperature range -200 ºC to +105 ºC (+85 ºC on flat surfaces). For temperatures below -50 °C please consult Armacell Customer Services Deparment. |
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| 4.2 | All pipework to be insulated with Class 0 Armaflex pipe insulation, as defined in 1.1and 1.2 above. |
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| 4.3 | Lengths to be close butted. All butt joins, longitudinal seams and joins at fittings shall be sealed with Armaflex 520 to provide an unbroken vapour barrier. |
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| 4.4 | The adhesive shall be used in accordance with the published Technical Data Sheets. Apply a thin uniform layer to BOTH surfaces to be joined, allow an “open time” of 2-3 minutes - dependent upon ambient conditions - to allow the solvents to evaporate, press together the surfaces to be joined using firm pressure, allow to cure for 36 hours for the bond to reach maximum strength and resistance to water vapour. |
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| 4.5 | In addition, all valves and other fittings shall be insulated with purpose-made sections fabricated on site in accordance with the » Armaflex Installation Manual and other technical literature from Armacell. Valve covers shall fully protect flanges and bonnet with only the wheel and stem exposed and shall be sealed with Armaflex adhesive to prevent ingress of water and water vapour. |
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| 4.6 | Where the surface of the Armaflex is exposed to sunlight, UV radiation or attack by aggressive chemicals it shall be protected using Armafinish FR paint applied strictly in accordance with the manufacturer’s recommendations. It is important to ensure that the recommended coverage rate is not exceeded to give the proper thickness of coating. A minimum of two coats will normally be required.
Note: HT Armaflex has very good resistance to sunlight and UV radiation and needs no UV protection when installed externally under normal environmental conditions. |
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| 4.7 | Where it is required to provide additional protection against mechanical damage the Armacell Arma-Chek systems are recommended. Application methods shall be strictly in
accordance with the » Arma-Chek Installation Manual. A separate » Specification is available for the Arma-Chek systems. |
5.0 Frost Protection
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| 5.1 | The minimum thickness of insulation shall meet the requirements of BS 5422 or 6700. |
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| 5.2 | Where dwellings are left unoccupied for longer periods or more severe conditions are likely then additional protection will be required. It should be noted that where prolonged cold spells are to be expected then thermal insulation by itself will not prevent pipes freezing and the system should be drained down or trace heating installed. |
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| 5.3 | Where trace heating is used as part of the frost protection system then a self-limiting trace heat shall be used having a maximum surface temperature which does not exceed the maximum line temperature of Armaflex. The thickness of insulation shall comply with BS 5422 or 6700 and where preformed pipe insulation is fitted the bore size of the insulation shall be the next larger compared with the outer diameter of the pipe. Where insulation, particularly sheet material, is being used with trace heating the material should NOT be hollowed out to accommodate the heating tape. |
6.0 Energy Conservation
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| 6.1 | The minimum thickness of insulation shall comply with the Building Regulations Approved Document L1 ( Conservation of fuel and power) dated July 1995 |
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| 6.2 | Recommended thickness of thermal insulation for hot water and heating pipework.
Pipe O.D. in mm | Thickness of Insulation in mm |
15 | 13 |
22 | 19 |
28 | 25 |
35 | 32 |
over 40 | 32 |
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| 6.3 | Where hot water and heating pipework passes through unheated areas, e.g. loft spaces, then the requirements for frost protection shall also be satisfied, as stated in section 5.1. Particularly in the case of 15 mm tube it will be necessary to use 25 mm of thermal insulation. |
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| 6.4 | The Building Regulations Approved Document L1 section 1.40 requires that; “the hot pipes connected to hot water storage vessels including the vent pipe, and the primary flow and return to the heat exchanger, where fitted, should be insulated for at least one metre from their points of connection or they should be insulated up to the point where they become concealed”. Armaflex at a thickness of 13 mm will satisfy this requirement. |
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| 6.5 | Section 0.1 a of the Approved Document states; “limit the heat loss from hot water vessels and heating and hot water pipes and ducts where such heat does not make an efficient contribution to the space heating". |
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| 6.6 | Section 1.39 of the Approved Document states; “unless the heat loss from the pipe or duct contributes to the useful heat requirement of the room or space the pipe or duct shall be insulated”. |
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| 6.7 | Section 1.38 of the Approved Document states; “For unvented hot water systems additional insulation shall be provided to control the heat losses through the safety fittings and pipework but without impeding safe operation and visibility of warning discharges”. |
7.0 Condensation Control
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| 7.1 | Recommended thickness of thermal insulation for cold water chilled water and refrigeration - See BS 5422. |
8.0 Ductwork Insulation
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| 8.1 | All ductwork to be insulated with Class O Armaflex insulation, as defined in 1.1 and 1.2 above. |
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| 8.2 | The sheet insulation shall be installed in accordance with the » Armaflex Installation Manual from Armacell and other technical literature from Armacell. |
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| 8.3 | Adhesive shall be applied with full adhesive coverage to the sheet insulation and metal surface. The adhesive shall be applied first to the Armaflex sheet and then to the metal surface. The insulation shall be applied to the metal surface once both surfaces have tack dried. |
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| 8.4 | All joins and seams shall be fitted in slight compression by overlapping the sheet by 3-5 mm and making a “wet-sealed” join. |
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| 8.5 | All raised metal seams shall be insulated to the full design thickness by using strips of Armaflex insulation, not less than 15 mm wide, on both sides of the seam until level with the metal and then over-insulating with a strip wide enough to cover the seam and side strips. Alternatively a half-round section cut from an appropriate size and thickness of Armaflex tube may be used. |
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| 8.6 | On new ductwork systems, wherever possible, Armaflex insulation shall be used in conjunction with Armafix insulated duct supports. The Armaflex sheet shall be butted in slight compression directly to both sides of the Armafix duct support using Armaflex 520 recommended adhesive. |
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| 8.7 | On existing ductwork systems, a suitable load-bearing insulant such as Armaload or other high density material shall be used to take the weight of the duct. The use of wooden duct supports or direct metal contact between the duct and support is not recommended. |
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| 8.8 | For insulation thickness, refer to Section 8.9 for chilled air ductwork and section 8.12 for warm air and dual temperature ductwork. |
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| 8.9 | Recommended thickness of insulation for condensation control on chilled air ductwork.
Ambient conditions | Insulation | Air temperature inside duct |
Temp. | Rel. humidity | | 15 °C | 10 °C | 5 °C | 0 °C |
25 ° C | 80% | Class O Armaflex | 6 mm | 13 mm | 19 mm | 25 mm |
25 ° C | 80% | NH/Armaflex | 9 mm | 19 mm | 25 mm | 25 mm |
25 ° C | 80% | HT/Armaflex | 9 mm | 19 mm | 25 mm | 25 mm |
20 ° C | 70% | Class O Armaflex | 6 mm | 6 mm | 6 mm | 13 mm |
20 ° C | 70% | NH/Armaflex | 6 mm | 6 mm | 9 mm | 13 mm |
20 ° C | 70% | HT/Armaflex | 6 mm | 6 mm | 9 mm | 13 mm |
Air temperature 25 ºC and relative humidity 80% are the ambient conditions used in the calculation of Table 16 in BS 5422 : 1990 for a material with high emissivity. |
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| 8.10 | The thickness requirement for energy conservation is stated in approved Document L1 of the Building regulations as section 1.39 b; “for pipes, and in the case of warm air ducts, insulation is provided in accordance with BS 5422: 1990”. The following thickness recommendations for Armaflex are in broad agreement with the insulated heat loss values quoted in Table 16 Economic thickness of insulation on ductwork carrying warm air. |
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| 8.11 | Recommended thickness of thermal insulation for warm air and dual temperature ductwork. |
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