4
All Valves
1. With the valve in the open position, verify that
flow passes through the valve.
2. With the valve in the closed position, verify
that no flow passes through the valve.
3. Test the diaphragm seal and the seat seal for
leakage by performing an inboard helium leak
test to a rate of 1 10–9 std cm3/s.
4. Test the seat seal for leakage at the
application pressure.
Manually Actuated (Round Handle) Valves
1. Turn the handle to the open position, then
the closed position to test for proper three-
quarters turn operation.
Manually Actuated (Integral
Lockout Handle) Valves
1. Turn the handle to the open, then the closed
position to test for proper three-quarters turn
operation.
2. With the valve in the closed position, pull
up on the handle to test for proper locking
function.
Welding
location
Purge Gas Flow
Welding
location
Purge Gas Flow
Testing
Welding (All Valve Types)
CAUTION
Disassembly of the valve is not required
for inline welding if proper precautions are
taken. If the valve is disassembled, cover
the sealing surfaces to protect them from
nicks and weld spatter.
WARNING
Welding should be done by qualified
personnel as outlined in Section IX of the
ASME Boiler Code.
1. If necessary, use a heat sink to prevent
excessive heating of internal components.
2. Actuate the valve to the OPEN position.
3. Connect the purge gas supply so that the gas
exits out of the valve port being welded.
CAUTION
Use a high quality purge gas to maintain
cleanliness and reduce welding
discoloration.
4. Perform the weld.
5. With the valve in the open position, purge the
valve and system of contamination.
6. Test the valve for proper operation and
leak-tight integrity. See Testing.
