Houston Valve and Testing Co. operates four hydrostatic testers. These machines are
designed for optimum efficiency in valve service. There are two racks manufactured by Dunn
Valve Testers, for intermediate size valves, and two of our own design, one for rapid
testing of small forged steel valves and one for testing very large valves. Glycerine
filled gauges are used on all these racks, for accuracy, and are regularly calibrated by
American Flow Measurement Co.
All valves are tested to API 598 specifications. These requirements include, but are
not limited to, a high pressure closure and shell test with water. The shell test is made
with both parts of the valve closed, the valve partially closed, and the packing gland
tight. There can be no visible leakage through the casting, body bonnert joint, or packing
for this test. The high pressure closure test is made on each side if the valve is
designed to hold pressure from both directions, or the correct side otherwise. No leakage
through the disk, behind the seat, or through structural damage is allowable.
All steel pressure containing casting can be certified using nondestructive testing
methods by our inspection contractor, Precision Inspection, Inc., when specified.
Radiographic inspections are performed to MSS SP54 standards while magnetic particle
inspection is made to MSS SP53 specification. Dye penetrant testing is done to ASTM E 165
specifications, and ultrasonic inspection is performed to ASTM SE213 standards.
- Final Preparation and Indentification and Inspection
Aluminum painting of the valve body protects the valve from external corrosion. The
valve is painted in the closed position and drain taps are fitted with thread protectors.
The end connections of each valve are fitted with flange or butt-weld end protectors.
Indentification tags may also be provided per customer's request.