Sml Cast Iron Fitting Application:Building install, dirty water and rain water exhausting,exchanging dirty air with pure air, facilities of hygene room and sewerage Sml Cast Iron Pipe. Cast Iron System will not deflect under loads, this makes it the ideal choice for below ground drainage installations; special bedding and over-excavation of trenches are not required to withstand damage from ground movement. This renowned strength also benefits above ground systems securing against heavy snow falls, high winds and the weight of ladders. Cast iron is non-combustible and in the event of a fire will not contribute to spread or burn away to allow the transfer of flames, emit toxic fumes or melt and drip. Building regulations do not require intumescent fire collars to be fitted to Cast Iron System.