120 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|
|60||Yes||Yes||SMT||SMT + 30mm of 60 kg/m³||SMT + 50mm of 60 kg/m³|
|120||Yes||Yes||SMT||SMT + 50mm of 60 kg/m³||SMT + 80mm of 140 kg/m³|