VALVE TYPE ACCEPTANCE TEST EXPERIENCES

API Meeting - SCOPV

Los Angeles, California

November 15, 2011

What is Shell’s Type Acceptance Testing (TAT)?

Testing of a valve to its design limits on temperature and pressure

Seat testing with nitrogen and fugitive emission testing with heliumAmbient temperature

Maximum advertised temperature

Minimum advertised temperature

Ambient temperature

200 mechanical cycles including opening and closing torques

Acceptance criteria is based upon ISO 5208 (seat leakage) and ISO 15848 (FE)

TAT is part of a total valve qualification program complemented by:

Technical documentation review

Valve manufacturer technical audit (ISO 9001 methodology)

Valve design validation and verification

TAT EXPERIENCES

TAT EXPERIENCES--2” 1500# SOFT-SEATED TRUNNION MOUNTED BALL VALVE

Unacceptable seat leakage due to o-ring/seat failure

TAT EXPERIENCES--10” 1500# BOLTED BONNET GATE VALVE

Jammed wedge resulted in elongation of the stem. Instead of 4

threads per inch some parts of the stem only had 3 threads per inch.

TAT EXPERIENCES--1” PN10 PLASTIC LINED PISTON CHECK VALVE

During high temperature seat testing the valve failed due to the wings of

the piston being deformed and the piston being hung in the seat guide.

TAT EXPERIENCES--20” 600# EXPANDING GATE VALVE

During teardown of the valve it was discovered that the top part of

expanding gate wedge was deformed and pressed into top plate

TAT EXPERIENCES--3” 300# GATE VALVE

Valve failed seat testing and during teardown it was discovered that

the stem threads were deformed after only 100 cycles

TAT EXPERIENCES--8” 150# METAL SEATED BALL VALVE

During cycling of the valve, the opening/closing torque became very

high. During teardown it was discovered that the hard face overlay

was damaged and ball was scratched.

TAT EXPERIENCES--4” & 10” 2500# TMBV

Excessive seat leakage was experienced during testing at ambient

temperature, due to lip seal damage. Valve design didn't give sufficient lip

seal housing clearance.

TAT EXPERIENCES--10” 2500# TMBV

Actuator failure due to excessive valve torque at ambient temperature

due to bearing seizure & poor bearing design.

TAT EXPERIENCES--10” 2500# TMBV

Excessive seat leakage at ambient temperature due to failure of metal

coating on ball and seat.

TAT EXPERIENCES--10“ 600# BOLTED BONNET GATE VALVE

Damaged stem threads due to failure of the drive nut. The drive nut material was incorrect.

TAT EXPERIENCES--6” 1500# PRESSURE SEALED GATE VALVE

Stem seal failure due to incorrect packing

TAT EXPERIENCES--4” 150# TMBV

Valve had passed the testing portion of the TAT but during teardown it was found that their was interference between the ball and end pieces. The parts were within design tolerance, but the design had to be revised.

TAT EXPERIENCES

Triple offset BF valve leaked at elevated temperature due to gasket

degradation. Gasket was only rated for 650°F while valve was advertised as

good to 800°F.

18” 600# ball valve wouldn’t open during final ambient test due sticking of

stem and galling from too tight of tolerances. Design had changed earlier to

open tolerance range, but drawings were not updated.

TAT EXPERIENCES

Severe damage to stem and nut threads caused by galling between

316 SS stem & ductile iron nut.

TAT EXPERIENCES

Explosive decompression during TAT.

TAT EXPERIENCES

Stem stretched approximately 3.5” during mechanical cycling. Thread

external diameter was reduced from 2.4835” to 2.3755”.

TAT EXPERIENCES--24“ 1500# BALL VALVEPEEK lip seal & spacer rings shrank during the low temperature testing (-58°F) which allowed the lip seal

to fall out into the valve bore. The lip seal and the spacer rings became trapped between the ball and

seats during the operation of valve creating seat sealing failure. Manufacturer changed lip seal spacer

ring material from PEEK to alloy 625.

TAT EXPERIENCES

Severe cracking of high pressure steam non-return valve body

TAT EXPERIENCES--10” 1500# METAL-SEATED TMBV

Excessive seat leakage after cycling at 575°F due to failure of tungsten

carbide coatings due to spring force being too high for 575°F

TAT EXPERIENCES

Questions?

Thank you!