SEVERE SERVICE VALVES
RESPOND TO
NEW PRESSURES
Valves are getting
bigger, more
complicated and
tougher as a response
to ever more
demanding
applications.
BY PETER CLEAVELAND
For a category that has become so important in the world of valves
and piping, it’s unusual that there
doesn’t seem to be a hard-and-fast def-
inition for “severe service.”
Bill Flowers, director, Hydrocarbon
Industry, Fisher Global Industry Sales,
defines severe service valves as: “ 10
inches and larger, 500 to 600 pounds,
anything that requires a special trim to
handle the process conditions, whether
that’s anti-cavitation trim, anti-noise
trim, high-pressure drop trim.”
Yet there’s some special condi-
tions that create fuzziness around
the edges of that definition. While he
clearly would not consider a 4-inch,
300-pound carbon steel valve a
severe service valve, for example, he
says he would define a 6-inch class
1,500-pound valve with anti-cavita-
tion trim, a 12-inch, 600-pound with
anti-noise trim, or a big ball valve
with a noise attenuator part of the
category of “severe service.” The
common element, he explains, is
“basically anything that has poten-
tial to tear up the control valve …
[or those for which] a standard trim
package, standard body material
can’t handle the process flow.”
Others would define severe services
