Q. Show drain systems used in plant?

Process/power plants usually have a variety of different drain systems to collect the different types of liquid effluent. One of these is usually designed to collect contaminated stormwater and aqueous plant effluent (e.g. boiler blowdown water). This can present hazards through the accumulation of flammable vapors or mixing of incompatible chemicals to generate noxious gases. Liquid seals should be used in collection sumps to prevent the transmission of gases and vapors. Sumps should also have sealed lids vented to a safe place.

Equipment connections into this drain sometimes utilize a tundish, which needs to be considered as potential sources of vapor leaks.

Water-immiscible flammable liquids should not be allowed to enter drains, where they create fire or explosion hazards. In particular, open drains with solvent floating on the water may transmit fires over long distances. All waste water should be routed to interceptors to prevent such liquids from entering the drain system.

If at all possible, catch basins, floor drains, and other flammable fluid spill collection points should not be located under fixed ladders, stairways, low platforms, or flammable/heat-sensitive fluid storage equipment or close to egress points.