:blink: :blink: ;)
OK I done a bit of research and this is what I came up with from the PHMSA Pipeline and Hazardous Materials Safetly Administration Site (I have extracted the main heading and the last paragraph is the regulation which is -10% to 0% - if you want to read the complete paper I have pasted a link at the bottom. My initial research also sent my to Dive Rite Express (link
http://www.diveriteexpress.com/library/valves.shtml this was written in 2006 so should - in theory - be correct.)
[Federal Register: August 8, 2002 (Volume 67, Number 153)]
[Rules and Regulations]
[Page 51625-51668]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08au02-9]
[[Page 51625]]
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Part II
Department of Transportation
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Research and Special Programs Administration
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49 CFR Part 107 et al.
Hazardous Materials: Requirements for Maintenance, Requalification,
Repair and Use of DOT Specification Cylinders; Final Rule
[[Page 51626]]
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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
49 CFR Parts 107, 171, 172, 173, 177, 178, 179, and 180
[Docket No. RSPA-01-10373 (HM-220D)]
RIN 2137-AD58
Hazardous Materials: Requirements for Maintenance,
Requalification, Repair and Use of DOT Specification Cylinders
AGENCY: Research and Special Programs Administration (RSPA), DOT.
ACTION: Final rule.
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SUMMARY: In this final rule, RSPA is amending the requirements of the
Hazardous Materials Regulations applicable to the maintenance,
requalification, repair, and use of DOT specification cylinders. In
addition, RSPA is adopting changes to revise the requirements for
approval of cylinder requalifiers, independent inspection agencies, and
non-domestic chemical analysis and tests. Further, RSPA is removing
authorization for the manufacture of DOT specification cylinders made
with aluminum alloy 6351-T6. This action is being taken to simplify the
regulations, respond to petitions for rulemaking, address
recommendations of the National Transportation Safety Board, and
enhance the safe transportation of hazardous materials in cylinders.
DATES: Effective Date: October 1, 2002.
Incorporation by Reference Date: The incorporation by reference of
publications listed in this final rule has been approved by the
Director of the Federal Register as of October 1, 2002.
FOR FURTHER INFORMATION CONTACT: Cheryl Freeman or Mark Toughiry, (202)
366-4545, Office of Hazardous Materials Technology, Research and
Special Programs Administration.
(7) Require pressure relief devices on all DOT-3 series
specification cylinders to be set at test pressure with a tolerance of
-10% to +0 beginning at the first requalification due on or after the
effective date of this final rule.http://hazmat.dot.gov/regs/rules/final/67fr/67fr-51625.htm