“Winter is here,” Bresland said. “As temperatures continue to drop, it's important for process plants to be prepared for the unique safety challenges of subfreezing weather.”
Bresland cited two serious accidents investigated by CSB where water froze inside piping or equipment, causing it to rupture and release flammable liquids that ignited.
At a refinery near Dumas, Texas, in February 2007, a water-containing pipe froze and cracked, releasing high-pressure liquid propane; the resulting fire burned three workers and caused more than $50 million in property damage. In January 2001, two workers burned to death at a large Indiana steel mill after they were sprayed with flammable gas condensate, which ignited. The accident occurred after ice had cracked and damaged a valve in the mill's coke oven gas distribution system.
“These two serious accidents illustrate the importance of establishing effective winterization programs at refineries, chemical plants, and other facilities that handle hazardous materials,” Bresland said. “Companies should establish formal, written winterization programs, and they should apply appropriate management of change techniques when piping or equipment is taken out of service.”
The accidents in 2001 and 2007 involved what are known as dead legs, or sections of piping that do not have any flow of liquid. The safety message noted that dead legs are particularly susceptible to freezing hazards and should be surveyed and then removed, isolated or properly winterized.
The safety message can be viewed on CSB’s safety message channel and can be read on http://safetymessages.blogspot.com. Viewers also can download video files for all safety messages and safety videos from a page within the CSB Video Room.