(a) Thermal Insulation Performance Statement
The performance of Dimond thermal insulation systems for roofing and wall cladding is covered by the statement for uninsulated systems together with the additional criteria set out below.
The use of Dimond metal roof or wall cladding in conjunction with foil underlay, Tasman Insulation NZ Building Insulation Blanket (BIB), or Foil Faced Building Insulation Blanket (FFBIB), can achieve thermal insulation with a reasonable expectation of performance to meet NZ Building Code requirements of:
- B2 – 50 years durability
- H1 – Energy efficiency
Design considerations must include:
- Appropriate combination of foil underlay BIB and foil, or FFBIB to achieve the appropriate R value and light reflection.
- Allowance for thermal bridging
- – via purlins or girts
- – via skylights
- Use of the full thickness of insulation when laid between battens fixed onto purlins, rather than squeezing down onto purlin.
- Maintenance (and replacement if necessary) of the roof sheeting or wall cladding and fastener components.
The performance is greatly affected by the quality of the installation which requires careful attention to detail to ensure gaps and holes through the insulation are eliminated as much as practicable.
When foil underlay is used as a vapour barrier all laps must be lapped 150mm and fully taped using 3M 425 foil tape 48mm wide.
BIB and FFBIB are designed for use at ambient temperatures and should not be used in conditions where the temperature exceeds 120ºC (e.g. within 150mm of hot flues). The glass wool content of BIB and FFBIB will not burn.
Aluminium foil surfaces must not be exposed to continuous moisture contact, salt laden air, alkalines or contact with dissimilar metals, that will corrode the surface and reduce the insulation and light reflectance performance.
(b) Foil Selection
Reflective foils can be used to increase thermal insulation, reduce daytime heat gain, disperse light within the building, and provide a vapour barrier.
NZS 4200.1 Category
|Product Name||Duty||Reflective Surfaces 1||Reflective Surfaces 2||Vapour Barrier||Fire Retardant||Abrasion Resistant Surfaces 1||Abrasion Resistant Surfaces 2||Self Supporting|
|Sisalation 420 White Faced||Medium||X||W||X||X||X||X|
|Sisalation 420 White Ink||Light||X||W||X||X||X|
|Sisalation 120||Extra Light||X||X||X||X|