| 摘要 |
<p>Roofs have explosion passages venting vertically upwards around the edges of the roof. Pref. the design allows the room to vent sideways into overhanging passages with perforated blast-off flaps to exclude leaves etc. Any incoming rain water can be independently drained. The edges of the roof are pref. skirted and sealed against the side of the building to prevent any local down blast. The roofs may be of concrete, steel or plastic, pref. having the peripheral skirts and passage walls moulded in lightweight concrete and the central zone made of glass fibre-reinforced polyester resin. Esp. the products are lightweight prefabricated safety roofs for electric power transformer or distribution buildings.</p> |
