Cracks in the Alberni Valley Multiplex’s brand new ice refrigeration plant’s chiller likely occurred during the manufacturing process, a Technical Safety BC report has found.
The 60-page report was compiled after a small ammonia leak detected in the chiller caused a three-week shut-down of the Multiplex in peak hockey season while city staff, contractors and TSBC representatives tried to find the source of the leak.
Representatives with the City of Port Alberni met with TSBC director of risk and safety knowledge Jeff Coleman on Dec. 16 to go over the report, city CAO Tim Pley said. “The city doesn’t dispute any of the content in the report,” he said. “The city appreciates TSBC’s helping the city keep people safe from a number of hazards, including ammonia.”
The report was released to the public on Dec. 19, and a media release was distributed on Dec. 20.
READ: Ammonia leak closes Port Alberni hockey rink
Coleman was quick to say the TSBC’s investigation and incident report “isn’t fault-finding or blame oriented.” The report was compiled so people can learn from the incident, he said in an interview with the Alberni Valley News.
The ammonia leak was discovered at 6 a.m. on Nov. 3, when it activated an alarm in the ammonia detection system. The source of the leak was discovered Nov. 5 and was determined to be coming from a crack in the welding inside the chiller portion of the refrigeration plant. The brand new chiller had been installed last summer and in use for 20 weeks when the leak occurred.
The chiller installation was signed off by a TSBC representative last summer; the faulty welds were not detected at the time.
The city waited for two days after the ammonia leak was detected before an arena patron finally reported it to Technical Safety BC. In that time, city staff and a refrigeration contractor worked to find the source of the leak.
“We reported the incident to WorkSafe BC but not the TSBC,” Pley acknowledged.
The city voluntarily shut down the Multiplex before receiving a safety order from TSBC.
“We (TSBC) were made aware of the leak from a patron that contacted us and was concerned,” Coleman confirmed. “This underscores some of our messages that we’re trying to get into the refrigeration community, is even a small leak can be a concern.
“Two days is too long.”
All ammonia leaks must be reported to TSBC within 24 hours of occurrence, as per the Safety Standards Act, according to TSBC’s report.
The TSBC listed Port Alberni’s ammonia leak as “moderate” on an incident rating scale that goes from insignificant to minor, moderate, major and severe. The Multiplex leak was labeled moderate because of the time and attention it took to detect it, as well as the amount of damage to the chiller vessel, Coleman said.
While the first leak was detected and repaired, more were discovered on a second pressure test of the system.
“Eleven cracks is significant. The nine more they found (after initial testing) really underscores what was happening in the vessel that wasn’t being detected,” Coleman said.
The internal cracks were found all around the bottom half of the vessel. One of the cracks grew while the chiller was in service due to stresses from normal operation until the crack penetrated the vessel shell, releasing ammonia into the room, the report noted.
Cracks can form inside welds during manufacturing if certain precautions are not taken. Quality control test procedures such as ultrasonic testing were not included in the manufacturer’s quality control and quality assurance plans, according to the report.
The TSBC is trying to impart the seriousness of ammonia leaks in ice refrigeration plants, and Port Alberni’s incident is a classic example of how the response needs to change, Coleman said. “The predominant response by many that they look at the crack, grind it and repair and move on…that typical response wouldn’t have been sufficient in this case.
“We want to make sure people are paying attention to these leaks. Even small leaks require diligence and paying attention to the underlying causes.”
A TSBC communications spokesperson said no decision has been made on whether the City of Port Alberni will be fined over the way the ammonia leak was handled.
The report, released on Dec. 21, still needs to be forwarded to TSBC’s compliance and enforcement team for review. “Technical Safety BC will take appropriate compliance and enforcement action if warranted under legislation and by policy,” Laura McLeod said.
ALSO: Port Alberni mayor gives thanks to Campbell River after ammonia leak at Multiplex
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