240 Minute Durasteel Fire Rated Ductwork
The SMT system is formed by fixing 9.5mm, DURASTEEL® sheets on to a welded or cleated, prefabricated steel skeletal framework, minimum 3mm thick. The sheets are fixed using self-drilling self-tapping screws, with PROMASEAL® mastic applied before fixing to the frame. Flanged lengths of ductwork are bolted together trapping the PROMASEAL® mastic between the mating flanges. The SMT system can be constructed in 1, 2, 3 or 4 sided configurations.
Ductwork Insulation Matrix
| Natural Ventilation / Powered Ventilation / Smoke extract | |||||
| Minutes | Stability | Integrity | Rock Wool Insulation | ||
| Type A or B duct – 300°C smoke temperature | Type A duct – 1000°C+ | Type B duct -1000°C | |||
| 180 | Yes | Yes | SMT | SMT + 50mm of 140 kg/m³ | SMT + 100mm of 140 kg/m³ |
| 240 | Yes | Yes | SMT | SMT + 90mm of 165 kg/m³ | SMT + 120mm of 140 kg/m³ |
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