I’ve been seeing this more and more lately and its time to clear the air. In the past, dry chemical fire suppression was the standard. Either Halon or FM200 dry chemical gas would suppress the fire by removing all oxygen from the space.

Nowadays, many datacenters are cutting back on dry chemical systems. Instead they advertise that they have “Dry Pipe Preaction Sprinklers”. Sounds good doesn’t it! Well its a fancy way of saying we use building code required overhead sprinklers. Preaction simply means that the sprinkler pipes dont have water pressure in them. An action has to trigger the building pumps which pressurize the pipes, i.e. smoke alarms and such. Dry pipe means that after the system is triggered (either a real alarm event or planned maintenance) it is drained.

The play on words tricks people into thinking that “Dry Pipe” makes a connection to dry chemical – of which there is none!

Sprinklers are code in all buildings… period. The sprinkler heads only open after a temperature fuse breaks – normally around 175 degrees. Well, if a datacenter gets up to 175 degrees, its all over. Thats why you use dry chemical like FM200 or Halon to kill the fire immediately before sprinklers heads open.

Point of the story is… Never point your equipment in a datacenter that does not have true dry chemical fire suppression.