Chloride Stress Corrosion Cracking

Chloride Stress Corrosion Cracking

Roof purlin was cold formed corner and sheared edge.

Type 304 stainless steel.

Indoor swimming pool.

The pool had to be closed down early due to rust falling into the pool.

Service Life
The Type 304 stainless steel roof purlins had been in service for approximately six years.


Stress corrosion cracking happened at many spots in the purlins where cold work, either by bending or punching, had been imparted into the Type 304 stainless steel. The structural designers and the persons supplying the Type 304 stainless steel purlins should have been aware that a very corrosive, high chloride environment exists at ceiling level in an indoor swimming pool. In Europe, Type 304 stainless steel structural members have been banned for approximately 20 years due to numerous cases of stress corrosion cracking in many European countries.

This investigation was featured in the Winnipeg Free Press: Portage La Prairie Suing Over Pool Roof.