When selecting insulation for a Pre Engineered Building, the following criteria should be considered:
- High thermal resistance or R value, for effective thermal insulation.
- Ease of application
- Lightweight material to avoid need for support from expensive metal skin or welded mesh
- Variety of aesthetic options / finishes
- Cost effective (total installed cost)
- High NRC for effective acoustic insulation
- Fire safe properties.
- Non-corrosive to steel.
Now we discuss how Fiberglass Wool meets the above requirements.
High Thermal Resistance (R value)
- Recommended thermal resistance is R > 1.25 sq.m. oC/W to get effective temperature drop across the wall and the roof.
- The final roof or wall composite should have thermal conductance value, U as low as 0.35 to 0.7 W/m2.oC.
- 50mm Fiberglass wool technically and economically satisfies these requirements as evident from the tested values of fiberglass wool given below.
Note: Thermal Resistance = Insulation thickness/Thermal conductivity.
Fiberglass wool insulation with a minimum density 16 kg/m3 and 50 mm thickness is recommended for PEB insulation. The most widely specified density for metal roof insulation is 24kg/m3 in 50mm thickness.
Ease of Application
- Fiber glass wool being soft, resilient and non sticky, can be unrolled easily over the purlins.
- Flanges are provided for easy stapling to make an uninterrupted layer of glass wool.
- High variety of roll lengths can be provided (from 7.5 m to 30 m) to match building design and to minimize number of joins.
- Can be easily cut and fold to accommodate openings through insulation.
- Don’t have any shot content which can be awkward during installation.
- Fiberglass wool is available with various factory laminated and fire rated facing options, like Reinforced Aluminium Foil, High Strength Aluminium Foil or White Metallized Polypropylene (WMP-VR).
- All the facings used by Twiga have undergone extensive testing across many different criteria (fire safety, bursting strength, tensile & transverse strength, ageing analysis etc) prior to being approved for use.
- High Strength Alumiunium Foil and WMP-VR can be installed without the need for wire mesh or weld mesh support, thereby saving money and improving the finished look. Please note that this is only recommended when distance between purlins is less than 1.5M.
- Since Fiberglass wool is lightweight, it does not require a costly second metal roofing skin for support. It can simply be installed under the metal roof or inside the side cladding, with or without weld mesh support (depending on the type of facing used).
- Fiber glass wool being compressed, cost of inventory and transport are less.
- Require less packaging – less scrap.
- Cost of wire mesh can be eliminated by selecting right facing.
Glasswool being fibrous and having an open air cell structure, is always preferred for its good noise reduction property and is almost exclusively used for acoustic insulation of multiplexes and sound studios. Its average range of NRC is 0.75 to 1.24. Glasswool can be used in internal partitions in addition to roof or wall.
Fire Safe Properties :
Fiberglass Wool has the following fire ratings which are critical for PEB application.
- Not easily ignitable: conforms to Class P as per BS 476 part 5.
- Non-combustible: as per BS 476 part 4.
- Fire retardant – Class 1 as per BS 476 part 7/Class O as per BS 476 part 6 and 7.
Non Corrosive to Metal :
Fiber glass wool being chemically very stable does not react with metal or any other matter under normal condition. Its pH value is very near to seven, so it is neither acidic nor basic in nature. Moreover it is free from shots, sulphur and chlorides. It is non hygroscopic, too. So the structural members are completely safe from corrosion.
Contact details :
Mr. Bineet Tewari (M : 09987785941), UP Twiga Fiberglass Limited, Ahmedabad