to all valves. The pressure relief system
for all four boilers now meets the needs
of the system.
LESSONS LEARNED
These case studies clearly show how the
improper design, installation and maintenance of safety valves within pressure
relief systems can lead to system malfunctions and hazardous conditions that
put equipment, facilities and personnel at
risk. When combined, mistakes and compromises made at various stages in a
PRV’s lifecycle can add up with disastrous results.
By following three simple principles,
plant personnel can avoid this situation.
First, design work must be done diligently. It is essential to consider not only
the pressure relieving devices or safety-related systems, but also the complete
pressure relief system so as not to reduce
the relieving capacity or adversely affect
the proper and expected operation of the
safety devices. 2
Second, valve manufacturers’ guide-
“YELLOW JACKET” WEATHER
CAPS EXTEND THE LIFE OF
YO UR PRESSURE RELIEF VALVE S
A well-maintained and monitored PRV system
will be reliable, efficient and safe.
lines must be followed in valve selection,
installation and maintenance.
Finally, maintenance personnel must
be given the proper training. Personnel
who do not understand a valve’s function
cannot be expected to make valves operate consistently at peak performance.
Most, if not all, safety valve manufacturers offer comprehensive training courses
that provide instruction in basic valve
maintenance and are designed to support
regulatory standards. Plant, OEM and
EPC engineers can also benefit from
attending training courses.
Maintenance personnel must have
the skills and ability needed to look
past a malfunctioning safety valve and
consider the entire pressure relief system to make an accurate diagnosis.
Identifying the potential hazards during operation must be done from a
wide-angle approach; dangerous situations can occur due to many root cause
situations. 2
A pressurized system is a complex
combination of components. Each contributing component must be properly
designed, installed and maintained in
order to ensure the integrity of the system. When valves fail or do not perform
correctly, the entire system must be
assessed before making a final diagnosis.
A valve that is not operating properly
may not be the cause of a problem; it
may only be a symptom.
By following these guidelines, engineers and maintenance personnel can
help ensure a positive outcome for the
process plant, including improved equipment reliability, more consistent product
quality, lower operating costs and, most
important, the safety of the facility,
equipment, products and personnel. VM
SUBSTANTIALLY REDUCES
MAINTENANCE COST
WEATHERCAPS MEET ALL
ENVIRONMENTAL REGULATIONS
ImNpe ov& rwov& I ed
FIVE YEAR WARRANTY
NO TOOLS TO INSTALL, SIZES 0.5
UP TO 24”
HIGHLY VISIBLE (CHROME
YELLOW) PROVIDING VISUA
EVIDENCE OF VALVE ACTIV
SCIENTIFIC LININGS AND COATINGS
888 8&" 5)& 3$" 1 $0. t
FIND YOUR LOCAL DISTRIBUTOR ON OUR WEBSITE
CIRCLE READER RESPONSE #139
DAVID MELCHER is senior product manager, aftermarket for Dresser Consolidated Pressure Relief
Valves in Alexandria, LA ( www.dresser.com).
Reach him at 318.640.6424 or david.melcher@
dresser.com. WILLIAM TRAVIS is product service
training manager for Dresser Consolidated Pressure Relief Valves in Alexandria, LA. Reach him at
318.640.6054 or william.travis@dresser.com.
Based on a paper first presented at the Valve
World Asia 2007 Conference & Expo, organized by KCI Publishing, Jacob Damsingel 17,
NL-7201 AN Zutphen, The Netherlands.
REFERENCES
1. Williams M., Dresser Flow Solutions. “Curb
Your Valve Costs,” Plant Services, December
2002. Accessed at www.plantservices.com on
May 3, 2007.
2. Bours, R. Fike Europe Bvba. “Incorporating
safety design considerations in design of
pressure relief systems.” Engineer Live,
www.engineerlive.com. Accessed May 3,
2007.
