Condensation Control & Insulation
Condensation can occur on the underside of Natural Lighting sheet when the building is not sufficiently ventilated or moisture is generated within the building space. The following three methods are recommended options to help reduce the effect of condensation that may form on Natural Lighting.
- Install a system that incorporates Dimond Skylight film as a translucent underlay. Refer 2.4.1.1.10 Detailed Drawings Fig. 1. of the Dimond Roofing & Cladding Technical Manual. This is a low performance system which in the extreme cases of low exterior temperatures, condensation may still form on the underside of the skylight film. Otherwise the skylight film is intended to carry condensation moisture dripping from the underside of the Natural Lighting sheet to the outside of the building, similar to building paper.
- Install a system that incorporates a double skin of Natural Lighting sheeting with an air gap between. In colder climates the air gap provides additional insulation and reduces the likelihood of condensation forming on the underside of the inner surface.
- For additional design considerations relating to condensation control by ventilation, refer to Section 2.4.4 of the Dimond Roofing & Cladding Technical Manual
Fire Resistance
The fire resistance properties of the Natural Lighting products have been evaluated by recognised Fire Safety Consultants, resulting in the opinion that Webglass can be used within the New Zealand Building Code requirements for fire safety given the following guidelines.
- Webglass FireGuard 2 (FG2) and Webglass FireGuard 3 (FG3) are manufactured with fire retardant polyester resin and have been tested by BRANZ. Webglass FG3 uses a bromine free formulation.
- Webglass FG2 achieves a Group 2 Number classification to the NZBC verification method C/VM2 appendix A.
- Webglass FG3 achieves a Group 3 Number classification to the NZBC verification method C/VM2 appendix A.
- BRANZ Test Report FH 5552-TT for FG2 and BRANZ Test Report FH 5553-TT for FG3 are available upon request.
- Webglass FG2 and FG3 are available in all profiles and standard colour tint options, e.g. HG4.
Safety
Impact tests carried out to AS/NZS 4040-4:1996 on Dimond Natural Lighting sheets supported by metal roofing sheets on either side, have shown that sufficient impact resistance to meet safety requirements without the installation of safety mesh can be achieved if the Natural Lighting sheet thickness is at least 1.7 mm. The maximum span for each profile to pass the safety impact test is given in the following table.
| Profile | Sheet Thickness (mm) | Maximum Span (mm) to meet Impact Safety |
| Corrugate | 1.7 | 1500 |
| Styleline/Veedek | 1.7 | 1800 |
| V-Rib | 1.7 | 1800 |
| LT7 | 1.7 | 2000 |
| BB900 & DP955 | 1.7 | 2200 |
| SS900 / Topspan | 1.7 | 2400 |
| Super Six | 1.7 | 1800 |
Safety
Dimond Webglass may be used, which is manufactured to a thicker sheet weight of 2.2 mm and reinforced with a heavy woven glass mat which provides continuous reinforcement both across and up the profiled sheet. This reinforcement gives the sheet enough strength under an impact load such that safety mesh is not required under the webglass sheet.
