Hydrogen Valves
Table M . 1 from API Specification 6D Annex M : Summary of specification level requirements for hydrogen - Reproduced courtesy of the American Petroleum Institute ( QSL = quality specification level )
Item |
Sequence |
Requirement |
SLH1 |
SLH2 |
SLH3 |
SLH4 |
1 |
– |
Minimum QSL level |
a |
QSL2 |
QSL3G |
QSL4G |
2 |
– |
Validation |
5.10.4 |
5.10.4 |
M . 3.3.4 |
M . 3.3.4 |
3 |
A |
Validation : High-pressure gas shell test |
M . 3.3.2 |
M . 3.3.2 |
M . 3.3.4 |
M . 3.3.4 |
4 |
B |
Validation : High-pressure gas seat test |
M . 3.3.3 |
M . 3.3.3 |
M . 3.3.4 |
M . 3.3.4 |
5 |
C |
Validation : Dynamic gas pressure test |
N / R |
M . 3.3.5 |
M . 3.3.4 |
M . 3.3.4 |
6 |
D |
Validation : Antistatic test |
N / R |
M . 3.3.7 |
M . 3.3.7 |
M . 3.3.7 |
7 |
– |
Validation : Fugitive emission test ( ISO 15848-1 ) |
N / R |
M . 3.3.6 |
M . 3.3.6 |
M . 3.3.6 |
8 |
– |
Validation : Fire safe design |
M . 3.3.8 |
M . 3.3.8 |
M . 3.3.8 |
M . 3.3.8 |
9 |
1 |
Supplemental Acceptance Testing : Antistatic test |
M . 8.6 |
M . 8.6 |
M . 8.6 |
M . 8.6 |
10 |
2 |
Supplemental Acceptance Testing : Pressure tests with hydrostatic end load |
N / R |
N / R |
N / R |
M . 8.5 |
11 |
3 |
Supplemental Acceptance Testing : High-pressure gas shell test |
N / R |
M . 8.2 |
per QSL and M . 8.2 |
per QSL and M . 8.2 |
12 4
Supplemental Acceptance Testing : High-pressure gas seat test N / R M . 8.3 per QSL and M . 8.3 per QSL and M . 8.3
13 |
5 |
Supplemental Acceptance Testing : Fugitive emissions production test |
N / R |
N / R |
M . 8.4 |
M . 8.4 |
14 |
– |
SLH marking ( see M . 9 ) |
SLH1 |
SLH2 |
SLH3 |
SLH4 |
FOOTNOTES |
|
|
|
|
|
|
|
a
For SLH1 , the applicable quality requirements of Sections 4-14 apply .
|
N / R = no required |
Figure 2 : Samples from material coating and weld-overlay testing in high-pressure hydrogen gas performed by SLB . of various types of seals such as lip seals , V-packing , or die-formed graphite seals . The SLH level also drives quality requirements in the production of valves for hydrogen gas service . The SLH levels link directly with the “ quality specification level ” ( QSL ) as a minimum quality requirement . For SLH1 , the quality requirements of the main body of API 6D apply , which are aligned with the recent removal of QSL1 . Increasing to SLH2 leads to a minimum quality requirement of QSL2 . For SLH3 and SLH4 , the gas version of the QSLs is used , with SLH3 requiring QSL3G and SLH4 requiring QSL4G . Supplemental acceptance testing is also influenced by the SLH level , ranging from an antistatic test for SLH1 to multiple gas tests with extended durations and in alignment with the QSL level for SLH3 and SLH4 . SLH3 and SLH4 valves also require fugitive emissions production testing to ISO 15848- 2 , with options for the use of helium or forming gas ( a mixture of 95 % nitrogen and 5 % hydrogen ) as test gases . The acceptance criteria for forming gas were established based on testing done by a third-party laboratory to provide an equivalent result to tests with helium . The remainder of the requirements outlined in Annex M are independent of the SLH level and apply to all valves seeking conformance . This includes requirements related to the design , materials , welding , bolting , marking , and documentation . Design requirements are generally unaltered from
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