During a January 2005 cold snap, some pipes froze in an unattended boiler room. The boiler was not damaged, but the blowdown line froze hard enough to burst a ball valve. The boiler had subsequently shut down on low water condition due to loss of water through the failed valve. A maintenance worker made a temporary repair of the blowdown line with rubber pipe and hose clamps, and put the boiler back into operation.

Four days later, while two workers from a repair company were in the boiler room to make a permanent repair to the blowdown line, the temporary repair blew apart under operating pressure filling the room with steam. The boiler had been operating at 5psi, and the temperature of steam at this pressure is 230 Degrees F. Fortunately, the two workers were able to escape the room without being injured.

The lesson is: steam can be dangerous and all repairs to steam piping must be done properly.

From ABSA "Pressure News", March 2005, visit www.absa.ca

First published in "the Operator", March 2006