Boiler System Safety
Boiler System Safety
|Use of working boiler controls and adherence to proven ASME code maintenance standards are absolutely essential to ensure the safe, reliable operation of both steam and hot water boilers.According to the National Board of Boiler and Vessel Inspectors’ 1995 Boiler Incident Report, boiler accidents are on the rise. The report also indicates that 81 percent of boiler incidents are caused by low water conditions, operator error, or poor maintenance. This means they are preventable.
“Boiler systems require ongoing maintenance,” said John Cecilia, marketing manager of ITT McDonnell & Miller. “However, if operators pay attention to and follow ASME recommendations, they should have trouble-free performance.”
When we’ve investigated incidents, we invariably find that ASME recommended maintenance standards have not always been followed,” added Cecilia, who was interviewed on the subject for an article that was published in the Spring 1996 edition of the National Board Bulletin of the National Board of Boiler and Vessel Inspectors. “Either maintenance has slipped or components and adjustments have been tinkered with or reset, creating a hazard.”
In some cases, boiler system failure results from a deliberate bypass of boiler controls. All steam boilers must operate withlow-water cutoffs and so should hot water boilers. Law requires that all steam boilers, hot water boilers and direct-fired storage water heaters have code relief valves.
Low volume finned copper tube boilers (not designed for steam operation) usually have no provision for a low-water cutoff, so they usually rely on a flow switch. The boiler can’t be fired unless there is flow through – and water in – the boiler.
All steam boilers must have some make-up water. With this water comes new dissolved solids and oxygen. If the precipitated solids and the oxidized metal sludge is not removed, these substances will clog operating and boiler controls. The more make-up water is used, the more often the control must be blown down or taken apart and cleaned.
Hot water boilers can be operated with little or no make-up water. This greatly reduces potential clogging, but the boiler controls still should be inspected and tested periodically. ITT McDonnell & Miller recently published recommended inspection and replacement interval guidelines.