Insulation
Description
Work of this Section shall conform to the requirements of the Contractor Documents.
Work Included
i. Piping Insulation
ii. Duct Insulation
iii. Equipment Insulation
Submittals
Product Data: Manufacturer’s latest published data for materials, “R” values and installation.
Shop Drawings: Submit list of insulation to be used for each service.
Quality Assurance
All insulating materials to be free of asbestos.
Comply with all requirements of ASTM or equivalent for thermal and moisture transmission.
Provide insulation (including insulation jacket of facing and adhesive used to adhere the facing or jacket to the insulation) with non-combustible material meeting Code requirements and fire and smoke hazard ratings as tested by procedure, not exceeding flame spread 25 and smoke developed 50. Adhesives, mastics, cements, etc. will not exceed the same component ratings.
Product
General
Only skilled craftsmen related to the air-conditioning industry shall carry out all the insulation work and special attention must be paid to the final coating of insulation that will be on view. All plane surfaces shall be trowelled to a truly smooth surface and all pipe insulation shall be finished using purpose made metal or hardwood formers as necessary for a clean, smooth, unlined surface to the approval of the ER.
All duct and pipe insulation materials and fire-resistant double-sided aluminium foils to be used as vapour seals for the whole installation work shall have been approved by the Chief Inspector of Fire Services, Malaysia Malaysia
Duct Insulation
The supply and return ductwork of the air-conditioning systems shall be insulated with Fibreglass insulation material as specified below.
The ductwork shall be externally insulated and vapour sealed with aluminium sisalation.
The ductwork thermal insulation shall conform to the requirements listed below:-
i. The thermal conductivity of the insulation materials shall not be greater than 0.036 watt per meter degree Kelvin at a mean temperature of 20 deg.C.
ii. The density of the insulation materials shall be 24 kg/m3 and 32 kg/m3 minimum for fibreglass thickness of 25mm and 50mm respectively.
iii. The insulation materials must be classified as non-combustible by the Fire Authority and tested in accordance to BS 476: Part 4 – 1970.
iv. The external insulation shall faced with fire resistance double sided reinforced aluminium foil.
v. The aluminium foil shall have Class I surface spread of flame and be tested in accordance to BS 476: Part 7 – 1971.
vi. The vapour permanence of the aluminium foil shall not exceed 0.01 perm. The aluminium foil shall be of 8 layer locally made Grade Sisalation 450 or approved equivalent.
vii. The thickness of the thermal insulation shall be as shown on the drawings and/or as follows:-
a. 25mm thick thermal insulation shall be used where the ductwork is located in the return-air ceiling space between two air-conditioned floors.
b. 50mm thick thermal insulation shall be used on ductwork in other areas.
Insulation shall be carried out over all flexible connections and points subject to condensation. A channel section of 1½ inches wide with ½ inch deep leg of 20 gauge galvanised iron sheet shall run along the bottom of ductwork over 2 feet in width so as to prevent sagging of insulation. The channel shall be secured to flanged connection with self-tapping screws; the head of screws shall be covered with vapour seal adhesive tape.
Piping Insulation
Factory Assembled Plant
The factory assembled plant shall be insulated as recommended by the manufacturers and as specified earlier. This insulation may be applied at the manufacturer’s work or on site during or after installation to the approval of the ER.
Refrigerated Pipework
After completion of all pressure tests and charging with refrigerant, all refrigerant suction piping and suction liquid heat exchangers shall be insulated.
Insulation shall be CFC free chemically blown PVC nitrile black coloured rubber sponge type material having a thermal conductivity factor not greater than 0.30 Btu/hr/sq ft/in°F at a mean temperature of 75°F and a thickness sufficient to prevent condensation. It shall be supplied in tubular form, preferably without longitudinal joint. All surfaces over which insulation is to be applied shall be dry and grease free. Adhesive plaster shall be applied evenly on the surface. The insulation shall then be fixed and secured by a ½ inch wide aluminium bank at not more than 1½ feet centres. Afterwards, the whole length of insulated piping shall be completely and neatly wrapped with an approved grey PVC pressure sensitive tape. The tape shall be spirally wound around the pipe insulation with a minimum of ¾ inch overlap of the successive tape runs. The visible ends of pipe insulation shall be neatly coned down to the pipe of adjacent fitting.
For refrigerant pipe exposed to view and weather, an approved vapour seal shall be used in lieu of PVC pressure sensitive tape. The insulation shall be held securely by ½ inch wide aluminium band applied not more than 1½ feet centres and vapour sealed by using the appropriate ‘Flinkote’ emulsion in two coats. The surface finish shall consist of ½ inch thick hard-setting cement applied in two coats and reinforced by using 5/8 inch galvanised wire mesh all trowelled to clean smooth finish ready for painting.
All joints shall be staggered and carefully sealed with vapour barrier.
For refrigerant pipe buried underground, the whole length of insulated piping shall be completely and neatly wrapped with 4 inch wide waterproof tape similar to proprietary. The tape shall be spirally wound around the pipe insulation with a minimum of 1 inch overlap of the successive tape runs.
Condensate Drains
The insulation to be used on all condensate drain piping shall be chemically blow PVC nitrile block-coloured rubber sponge type of material having a thermal conductivity not greater than 0.30 Btu/Hr/Sq Ft/In/°F at a mean temperature of 75°F.
It shall be supplied in tubular form, preferably without a longitudinal joint. The insulation shall be 1 inch thick unless specified otherwise.
Chilled Water Valves and Fittings
Chilled water valves, strainers, flanges, pump-volutes and other fittings shall be insulated as necessary as detailed for the chilled-water pipes insulation, and securely held in purpose-made galvanised sheet steel or aluminium splitcase boxes with non-corrodible screws. Special care shall be taken to ensure an effective and continuous vapour barrier at the outer surface of the insulation.
Chilled Water Pumps
The chilled water pump shall be insulated with 1½ thick coporite, armaflex or equivalent fixed to pump with hot bitumen and sealed externally with hot bitumen. The Contractor shall ensure that the vapour seal of bitumen is continuous.
Insulation shall be applied in a manner that will allow for the removal of the upper section of the pump on horizontally split type without destruction to the insulation.
After insulation has been applied, the pump shall be rendered with ½” thick of smooth setting cement, neatly trowelled off and finished with two coats of paint to approval.
Vapour Barrier
After faxing the insulation, all voids in the surface shall be filled with plastic filling water proofing compound.
The vapour barrier shall have a water vapour permeability of not exceeding 0.02 perm. And have one layer of aluminium, and another layer of white paper laminate reinforced with fibreglass. The vapour barrier must be factory pre-laminated all purpose type, pre-sized and suitable for printing.
a. Chilled Water Piping
Solvent shall not be applied to the gloved surface promote a Smooth finish.
b. Condensate Drains
No separate vapour barrier shall be applied over the insulation. However, care shall be taken, to ensure that all joints in the insulation are thoroughly filled with the insulation adhesive and that there are not gaps in the longitudinal seams and between the adjoining sections of the insulation.
Sealing of Joints
All segments of pipe insulation shall be firmly butted against the preceding sections and the joint shall be sealed with a butt strip. The butt strip shall be applied with aluminium pressure sensitive adhesive tape with a minimum width of 3 inch. Joint of aluminium foil vapour barrier shall be overlapped 4” minimum and sealed with an approved brand of vapour seal adhesive.
Adhesives
Execution
Installation
Support horizontal piping in accordance with the following schedule:
Pipe Size
|
Maximum Hanger Spacing
|
Minimum Rod Size
|
25mm and smaller
|
1800mm
|
10mm
|
32mm to 50mm
|
2700mm
|
10mm
|
65mm to 80mm
|
3000mm
|
15mm
|
100mm to 125mm
|
3600mm
|
15mm
|
150mm
|
3600mm
|
10mm
|
Pipe Size
|
Maximum Hanger Spacing
|
Minimum Rod Size
|
200mm to 300mm
|
3600mm
|
25mm
|
350mm to 400mm
|
3600mm
|
25mm
|
450mm
|
3600mm
|
30mm
|
500mm
|
3600mm
|
35mm
|
600mm
|
3600mm
|
40mm
|
750mm
|
3600mm
|
40mm
|
1000mm
|
3600mm
|
50mm
|
1200mm
|
3600mm
|
50mm
|
Provide hangers at each change in direction and both sides of each valve.
Provide drilled expansion type inserts to the reinforced concrete. Structural slab for pipe supports.
Regardless of the type of construction (i.e, concrete, concrete-deck-steel or other variations) take particular care to support all main lines and all large and heavy pipes in an approved manner, including the furnishing and installation of supplementary steel, if required. Supplementary steel sections are to be mill-rolled. Submit shop drawings, indicating support methods, point loading to the building structure and hanger locations for review sufficiently in advance of concrete pouring schedules to permit evaluation, critique and any necessary changes to handling and support methods.
Provide approved roller support, floor stands, wall brackets, etc, for all lines running near the floor or near walls, which can be properly supported or suspended by the floors or walls. Pipelines near walls may also be hung by hangers carried from approved wall brackets at a level higher than the pipe.
Do not hang piping from other piping. Support of hangers by means of vertical expansion bolts is not permitted.
Wherever hangers using pipe rolls are used provide approved steel pipe covering protection saddles, spot welded to the piping at each hanger location.
Anchor piping and as required to localise expansion or to prevent undue strain on piping and braches. Anchors to be entirely separate from hangers. All anchor designs to be submitted for approval and to include piping reactions which respective anchors are capable of supporting. Provide all indicated or required expansion loops.
Support all lines for copper tubing individually by approved type hangers not more than 2m apart, or as shown on the drawings. Use hangers especially designed for copper tubing and of exact outside diameter to tubing. On hangers for covered tubing, use broad straps fitting outside of covering.
Hangers used for cold piping will support the pipe without piercing the insulation. Use insulation shields to protect the insulation on cold pipes. Weld insulation protection saddles to insulated hot pipes, or any piping subject to axial movement, at roller supports. Space between pipe and saddle to be filled with insulation.
For piping 100mm and larger, support the elbows of the piping adjacent to the pumps with steel base elbow supports from the inertia base which pump is on the prevent loading heavy weights of piping on pump casing. Where inertia base is not provided, base elbows to be supports on floor with 25mm neoprene pad.
Scratches and cut ends to be field touched up with protective paint or galvanising agent.