Sheriff40
Mechanical
- Jun 9, 2014
- 1
thread408-318910
I saw the original post asking why API-594 does not reference TYPE b SWING Check Valves? This is the answer no one in the thread pointed out. Swing Checks are not approved for API related services. Only use Swing checks for general water, utilites etc. where doing so will not pull a vacuum due to extreme temperature drops and pressure. Beware of specifing wafer checks for the same reason for API Services.For this reason Spring Checks that are calculated to prevent undesired closing are to be used.
Reference PIP PNC0005 ASME B31.3 Para 3.5.5.3
States: Check Valves
1. Dual- and single-plate wafer check and swing check valves shall not be used in reciprocating pump and compressor suction and discharge services or similar pulsating services.
2. In parallel pump or compressor systems, check valves installed at the discharge of pumps or compressors should be of a nonslam internal-spring-assisted type. Swing check valves should not be used in this service.
3. For parallel pump systems with individual pump discharge piping of NPS 20 and greater, a hydraulic analysis shall be conducted to verify that the selected check valves have the correct dynamic response to prevent slamming and limit pressure surge to an acceptable level. The analysis shall include consideration of the “worst case” operating mode scenario.
The Code will not allow them so API 600 does not reference them.
I hope this helps.
I saw the original post asking why API-594 does not reference TYPE b SWING Check Valves? This is the answer no one in the thread pointed out. Swing Checks are not approved for API related services. Only use Swing checks for general water, utilites etc. where doing so will not pull a vacuum due to extreme temperature drops and pressure. Beware of specifing wafer checks for the same reason for API Services.For this reason Spring Checks that are calculated to prevent undesired closing are to be used.
Reference PIP PNC0005 ASME B31.3 Para 3.5.5.3
States: Check Valves
1. Dual- and single-plate wafer check and swing check valves shall not be used in reciprocating pump and compressor suction and discharge services or similar pulsating services.
2. In parallel pump or compressor systems, check valves installed at the discharge of pumps or compressors should be of a nonslam internal-spring-assisted type. Swing check valves should not be used in this service.
3. For parallel pump systems with individual pump discharge piping of NPS 20 and greater, a hydraulic analysis shall be conducted to verify that the selected check valves have the correct dynamic response to prevent slamming and limit pressure surge to an acceptable level. The analysis shall include consideration of the “worst case” operating mode scenario.
The Code will not allow them so API 600 does not reference them.
I hope this helps.
