“If CEC had not intervened, it is very likely that another explosion was only a matter of time.”
A university medical center suffered three boiler explosions prior to any involvement with CEC. “Number one boiler had blown up twice and number two had blown up once” the medical center’s facility manager explained. The two Babcock & Wilcox boilers were retrofitted in 1991, as well as a controls upgrade after the first explosion in 1993. Then after the second explosion in 1997, an oxygen trim system was added. The last explosion occurred in late 2002. In all three cases, the wind box burner sections had been damaged when the boilers experienced low oxygen levels (very fuel rich conditions) at low fire.
CEC’s team of engineers, tuning and controls technicians identified the root cause of the explosions as an improperly designed boiler and inadequate repairs. Additional factors are listed below:
– Improper fuel/air ratio set up which made for very difficult and dangerous control of air fuel ratios at low fire.
– Improperly purge time prevented safe evacuation of combustibles prior to light-off.
– Poor training and lack of preventive maintenance program prevented identification and resolution of dangerous combustion issues.
– Dangerous bypassing of important safety interlocks included airflow switches, jumper wires and failed switches.
– Numerous safety shut-off valves were leaking through when in the closed position and others had inoperable and/or missing shut-off handles.
– Lacking start-up, shutdown, and emergency procedures
The CEC team brought to an end a long history of explosive “near-misses”. Based upon the recommendations, the site’s management decided to shut down Boiler # 2 after the discovery of the safety deficiencies. There were many other safety issues, which needed attention, including preventive maintenance, training of staff, emergency procedures and gap analysis. After conducting various testing, inspection and analyses throughout the facility, a comprehensive long-term recommendation plan was presented to the client.