National Board Assistant Director of Inspections
Summary: The following article is a part of National Board
Classic Series and it was published in the National Board BULLETIN. (4 printed pages)
Saturday was cleanup day at the small drycleaner's. Every week, the horizontal
return tubular (HRT) boiler was drained, flushed and prepared for the next
week's work. This Saturday, however, the boiler operator was interrupted during
his final steps. He performed every task except refilling the boiler.
This boiler was set to start automatically early on Monday mornings. The
prescribed time arrived; the burner engaged. When the owner arrived to open the
business Monday morning, she found the local fire department at her back door
and the severely overheated remains of her boiler.
Luckily, there was no explosion, since there was no water in the boiler. Also,
firefighters on the scene knew they should never spray water on an overheated
boiler, so they closed the gas supply valve on the outside of the building and
allowed the boiler to cool gradually. They stayed on-site to prevent any
structural fires that might have developed as a result of the overheated
The low-water fuel cutoff should have prevented the burner from engaging, but
the electrician improperly wired the control into the burner circuitry. The
boiler had been operating in a potentially hazardous manner for several months.
Had the owner requested an inspection, the boiler inspector would have tested
the operation of the low-water fuel cutoff and, in this case, would have found
The uninsured boiler was a total loss. Both tube sheets had numerous cracks in
the ligaments (the tube sheet material between the tube holes) and the bottom
portion of the shell was severely deformed due to excessive heat.
This loss cost the owner of the drycleaning business several thousand dollars
for replacement of the boiler and business lost while waiting for the
replacement boiler installation. A boiler inspection and jurisdictional
certificate would have cost less than $50.
The National Board of Boiler and Pressure Vessel Inspectors has files full of
photographs, newsclippings and official reports from serious accidents.
Frequently and unfortunately, facilities that use boilers, like drycleaners,
are the subject of these accidents. Since drycleaning plants need an adequate
supply of steam, all have a boiler of some sort on the premises. Boilers are
workhorse devices that sometimes are neglected for years, possibly decades,
with no apparent maintenance. This neglect, whether intentional or due to lack
of understanding, can have terrible consequences.
Depending on the operation, a drycleaning plant will have one or more boilers
under its roof. A drycleaning plant will also contain other pressure vessels
such as a typical water heater and an air compressor tank. While these pressure
vessels are potentially hazardous and are subject to inspection in most
jurisdictions, this article focuses on the boiler.
We all know how a boiler operates. Water is contained within a vessel and is
heated by gas, electricity or some other fuel. As the water heats, it creates
pressure and steam. Boilers are equipped with devices to control operating
pressure, and safety valves that should allow pressure relief when safe
operating limits are exceeded. But lack of routine inspection and lack of
proper maintenance are widespread.
The National Board reports the following two causes at the top of the 2000 list
Prevention Through Inspection
Failure of cutoff system to operate when water gets too low.
Operator error or poor maintenance.
* At time of posting, latest year for which statistics are
In the incident described above, a boiler inspector would have seen the problem
and made recommendations to repair the boiler before that fateful morning.
Thus, a costly and potentially dangerous accident would have been prevented.
Typically, insurance companies and city, state or provincial governments
(jurisdictions) require boiler and pressure vessel inspection on some regular
interval. The National Board trains and commissions boiler inspectors who
perform both safety inspections and accident investigations. But there are many
boiler and pressure vessel system-users who have not had their systems
inspected or licensed. It's no surprise that often, the uninspected systems are
also poorly maintained.
Everyone Can Help
Perhaps the best route to ensure boiler and pressure vessel safety is to
practice installation and maintenance functions that meet both jurisdictional
requirements and national standards.
Five preventive steps can help:
Each drycleaning plant can establish a simple safety program. For example, look
for a certificate of inspection on or near each boiler. The certificate should
indicate the number of pounds of pressure under which the system can safely
operate. A quick glance at the pressure gage can instantly identify a potential
Equipment installation: Install only boiler and pressure vessel
equipment registered with the National Board. Such equipment will be
manufactured in accordance with the ASME Boiler and Pressure Vessel Code.
Most jurisdictions mandate National Board registration.
Replacement parts: Purchase first-quality replacement parts (new or
rebuilt) for any boiler or pressure vessel repair or maintenance effort.
Training: Adequately train all personnel who regularly use or maintain a
boiler or pressure vessel. Do not allow a general maintenance person to assume
the responsibilities for day-to-day operation of any boiler or pressure vessel
unless that person has had specific training.
Safety testing: Establish a regular, periodic safety-testing program for
all boilers and pressure vessels. Develop a checklist. Make sure everyone who
encounters the boiler or pressure vessel knows the danger signs and whom to
call for immediate help.
Repairs: Require that all welded repairs be performed by National Board
"R" stamp holders who are properly trained and qualified to repair boilers and
pressure vessels. Such items have very specific repair protocols that help
As part of routine maintenance, open and clean boilers. Test pressure relief
valves to make sure they are functioning properly. Move clutter, stored items
and combustible substances far away from a boiler, so that overheating of these
materials is not possible. Flammable liquids should not be stored in the same
area as a boiler. Clean and dust the room that houses the boiler, and prevent
nesting or breeding sites for pests.
Whenever you spot a potential problem, call the chief boiler inspector within
your jurisdiction. For a listing of chief boiler inspectors, consult the
page on the National Board Web site. Note the inspection certificate number and
the jurisdictional number assigned to the boiler. With these numbers, the chief
boiler inspector can determine the boiler's location and any other information
necessary to perform an inspection.
If There Is An Accident . . .
During the first minutes on an accident scene, one of the biggest risks with
boilers is the high temperatures that may exist. Water or condensate hitting
superheated metal can cause instant bursts of steam or further explosions.
Also, one breath of superheated steam can damage the lungs and cause permanent
breathing problems. If a problem does occur, local emergency personnel, such as
firefighters, are your first line of defense. A call to the chief boiler
inspector within your jurisdiction will be vital to any accident investigation.
Good preventive maintenance and periodic inspection result in cost savings.
Good safety practices make sense in a liability context. Since boilers are an
integral part of the drycleaning business, provide the routine maintenance and
obtain the periodic inspections that will prevent accidents or problems in the
Editor's note: Some ASME Boiler and Pressure Vessel Code requirements may have changed because of advances in material technology and/or actual experience. The reader is cautioned to refer to the latest edition and addenda of the ASME Boiler and Pressure Vessel Code for current requirements.