GAIL (India) Limited

12D) THERMAL/ACOUSTIC INSULATION. GENERAL:Scope of this specification comprises of supplying, installing, testing and commissioningof insulation on duct, pumps, chilled water piping, chillers, expansion tank, AHU roomand duct lining.1.0 DUCT INSULATION:Resin bonded, glass wool, prelaminated with aluminium foil. The thermal conductivityof glass wool shall not exceed 0.024 Kcal/hr sqm deg C (0.19 BTU in/Hr Sq ft deg F at10 deg C - mean temperature and density shall not be less than 48 kg/m3.1.1 Thickness of Insulation:a. For Duct passing through return air areas = 25mmb. For Duct passing through non air conditioned space = 50mmc. Treated fresh air duct = 50mmd. For exposed duct = 50mm1 2 Application: (For unexposed duct)- Clean the surface of duct and apply coal of Black Japan paint of approvedmake applied @ 7 Sq mt./Kg.- Fix the insulation material of required thickness before adhesive dries up. Alllongitudinal joint will have an over lap of minimum 50 mm followed bycovering firmly by 75 mm width aluminium sticking tape to seal all transverse& longitudinal joints.Where the duct is exposed to atmosphere material shall be same as for ducts not exposed toatmosphere but without aluminium foilApplication: (For exposed duct)a. Cleaning the surface of ducts with wire brush to remove dirt, rust etc.b. Applying a coat of adhesive.c. Fixing the glass wool insulation and tied with PVC strap of 25mm widthd. Cover the insulation with fire retardant quality polythene lined hessian of 500gand seal the joint with black Japane. Fixing 24 x 3/4" Hexagonal wire netting tied with G.I. wire.f Finally applying sand cement plaster in ratio 1:3 in two layers each 10mmthick.g. Paint it to required colour with brush.