MESC SPE 77-307
Valves shall have successfully passed the normal production tests as per the applicable design standard and specification.
PRODUCTION TESTING OF VALVES IN VACUUM SERVICE
1.
INTRODUCTION
1.1 SCOPE
This specification covers the requirements and procedures for the acceptance testing of valves in vacuum service down to 10 Pa (0.1 mbar).
This specification shall apply in addition to the applicable MESC buying descriptions and referenced external standards. 1.2. The applicable valve type and design standard are specified in the relevant MESC description and/or requisition.
2.
REFERENCES
In this specification, reference is made to the following publications:
NOTE:
Unless specifically designated by date, the latest edition of each publication shall be used, together with any amendments/supplements/revisions thereto.
SPE 77 / 302 Materials, examination and certification requirements for valves in general services.
SPE 77 / 312 Fugitive emission leak detection of valves.
3. GENERAL INFORMATION AND PRE-REQUISITES
3.1 Test valves shall be selected at random from the total lot of valves, taking into account the requirements of SPE 77/302 sections
4.2.1 through 4.2.4. 3.2 Total number of samples shall be 10%, but with a minimum of one per type. 3.3 Valves shall be tested at the manufacturer's works or an independent testing facility. 3.4 3.5 The operational test at ambient temperature, as per section 7, is an optional test and shall be specified by the Principal.
3.6 For a sample of the test record/certificate, see Appendix A.
3.7 If the test equipment fails or a shortage of gas (bottle/supply) occurs, the test shall be aborted and the valve shall be submitted to a re-test.
4. TEST RIG AND INSTRUMENTS (VACUUM TEST) 4.1 A sketch of a suitable test rig is shown in appendix B. 4.2 The test medium shall be helium.
4.3
Leakage into the valve and test equipment shall be detected by means of a mass spectrometer or other method suitable for helium leak detection. Other detection methods are subject to approval by the Principal.
4.4
All measuring equipment and instruments shall have a valid calibration certificate.
5. PREPARATIONS PRIOR TO TESTING
5.1 The test equipment and valve shall be dry and free of oil and dust.
5.2 The valve shall be visually inspected for any damage, defects etc.
5.3 The valve shall not have any protective coating on the valve body and internals which
may hide any porosity. If a protective coating has to be removed, the valve shall be
disassembled and the valve body and internals shall be thoroughly cleaned and
degreased with inhibited methylene-chloride or tri-chlor-ethylene. After re-assembly,
the valve shall be re-qualified to the requirements of the applicable design standard
and specification.
5.4 The valve ends shall be equipped with end covers, capable for testing in both
directions. Both covers shall be provided with a pressure/vent connection.
5.5 Brackets to support the valve in the test rig shall be fixed to the end covers or
alternatively clamped to the body. There shall be no support mounted to the bonnet of
the valve.
6. TEST PROCEDURES AND REQUIREMENTS
6.1 The tests shall be carried out in the sequence as stated in sections 7 and 8.
6.2 All observations, obtained test data and findings shall be recorded (see appendix A)
and submitted to the Principal.
6.3 Bi-directional valves shall be tested in both directions.
Uni directional valves shall be tested in one direction only.
6.4 Full operation of the valve (from open to close) shall not take more than the maximum
time specified by the manufacturer or as otherwise specified by the Principal.
6.5 Manually operated valves shall be operated without the use of spanners.
6.6 The maximum force and torque for operation of the valve during the maximum
differential test pressure, shall not exceed the value as per the applicable design
standard / MESC additional requirement.
6.7 Check valves need not to be opened and closed.
7. OPERATIONAL TEST AT AMBIENT TEMPERATURE - OPTIONAL
7.1 The test pressure shall be equal to the allowable (rated) cold working seat pressure of the valve. The pressure shall be established in steps of 5 equal increments.
7.2 The test pressure may be applied either hydrostatic or pneumatic.
7.3 The valve shall be in the closed position and subjected to the test pressure. The
downstream system of the valve shall be de-pressurised at the beginning of each
pressure increment.
7.4 After the first, third and fifth pressure increment the valve shall be fully opened and
closed five times. The pressure shall be stable at the beginning of each first
operation.
7.5 The opening force, closing force and torque of each first operation shall be recorded.
8. VACUUM TEST AT AMBIENT TEMPERATURE
8.1 The valve shall be in the half open position and subjected to a vacuum of 10 Pa (0.1 mbar). The vacuum shall remain stable throughout the test duration. 8.2 The test duration shall be as follows:
Test duration in minutes
Nominal size
Pressure class
150/300 600 800/900 1500 2500
Up to and
including DN 50 DN 80 up to and including DN 150 DN 200 up to and including DN 400 DN 450 up to and including DN 600
3 6 9 9
6 9 9 12
9 12 12 15
12 15 15 18
12 18 18 21
8.3
The measured emission performance class (i.e. tightness class, endurance class and temperature class) shall comply with the acceptance criteria specified in the purchase order (i.e. the MESC buying description) and SPE 77/312.
9. POST-TEST EXAMINATION 9.1 The valve shall be visually inspected for any damage, etc.
APPENDIX A
PRODUCTION VALVE TEST RECORD/CERTIFICATE
Inspection authority Report reference no. Valve manufacturer Purchaser
Purchase order no. Valve identification Design standard
:
: : : : : :
Date of test Type of valve Size
Class rating Seat material Body material
: : : : : :
Test 1) Requirements and limits Actual results
(7) Increment
: Operational test at
ambient temperature
test medium:
Operate valve 5 times
fully open/close
1. Pressure bar Leakage cm3/5 min. cm3/5 min.
2. Pressure bar
Operational
force and torque
Max.
Max. 350 N
Nm
O =
C =
N
N
Nm
3. Pressure bar
Operational
force and torque
Max.
Max. 350 N
Nm
O =
C =
N
N
Nm
4. Pressure bar
Operational
force and torque
Max.
Max. 350 N
Nm
O =
C =
N
N
Nm
5. Pressure bar
Operational
force and torque
Max.
Max. 350 N
Nm
O =
C =
N
N
Nm
(8.1) (8.2) Shell (vacuum) test
at ambient
temperature test
medium:
Pressure:
10 Pa (0.1 mbar)
Leakage
through the
valve:
Test duration as per
SPE 77/307 section 8.2.
Leakage criteria as per
buying description and
SPE 77/312 cm3/5 min.
(9) Valve examination Observations and findings.
Inspection authority signature: Date:
Witness
signature: Date:
1) Numbers between brackets refer to paragraphs in this specification.
Appendix B, Schematic arrangement of test rig :