Notice the lack of bolt holes on this valve
in a 1910 Powell advertisement.
MSS created, SP-61, “Pressure Testing
of Valves” in 1961. It has been supplanted substantially by the most widely used
testing standard in the U.S. today, API
598, “Valve Inspection and Test,” which
was first published in 1968.
During the 1960s through the 1980s,
many new valve standards were devel-
oped by API, MSS and ASME. These
new standards covered a variety of valve
types, including check, butterfly, ball and
others. Although most of the valve stan-
dards emerged from API, MSS and
ASME, other standards organizations
were also developing valve standards.
Across the pond, for example, was the
British Standards Institute, which creat-
ed several standards used in the U.S. for
many years. Also, the International
Organization for Standardization (ISO),
which published its first standard in
1947, has been very active in valve stan-
dards creation during the past 25 years.
Some of the ISO standards are used reg-
ularly in the U.S.
GREG JOHNSON is a contributing editor for Valve
Magazine and president of United Valve in Houston
( www.unitedvalve.com). Reach him at
As valve castings became more complex chemically, the need for additional casting standards became vident.
Initially, each valve manufacturer tested
valves in accordance with their own company
standards and procedures. Standardized
testing standards would not be published until