# Weatherford International — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 11-0311
- **title:** Weatherford International — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2012-02-10
- **effective on:** Not available
- **summary:** 11-0311 response to Weatherford International concerning 173.306.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-11-0311.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-11-0311.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-11-0311
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2011/110311.pdf
**body:**

<<<PAGE 1>>>

U.S. Department 1200 New Jersey Avenue SE
of Transportation Washington. DC 20590
Pipeline and Hazardous
Materials Safety
Administration
fEB 1 0 1012
Mr. Tim Redwine
Weatherford International
495 Winscott Road
Fort Worth, Texas 761256
Reference No.: 11-0311
Dear Mr. Redwine:
This responds to your letter requesting clarification of Hazardous Materials Regulations
(HMR; 49 CFR Parts 171-180) applicable to limited quantities of compressed gases. In
your incoming letter, you describe an accumulator system that functions as part of a natural
gas or oil drilling rig. You also include a picture of this accumulator system. You ask
whether this accumulator system, as shown in the picture, is excepted from the HMR as
specified in § 173.306(f).
The answer is yes. In accordance with § 173.306(f)(1), provided the accumulator system is
installed in either a motor vehicle, construction equipment, or assembled machinery and is
designed and fabricated with a burst pressure of not less than five times their charged
pressure at 70 oF., the accumulator system would not be subject to any other requirements
of the HMR. As described in your incoming letter and shown in the accompanying
picture, this accumulator system meets the requirements specified in § 173.306(f)(1) and is
excepted from the HMR.
I trust this satisfies your inquiry. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

<<<PAGE 2>>>

September I, 2011
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11-03//
Mr. Charles E. Betts
Director, Office of Hazardous Materi als Standards
U.S. DOT/PHMSA (PHH- I O)
1200 New Jersey Avenue, SE East Buildi ng, 2nd Floor
Washington, DC 20590
Dear Mr. Betts:
This letter is written requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR
Pa rts 171- 180) applicable to limited quantities of com pressed gases. Will the accumulator system
pictured below be excepted from regulat ion under § 173 .306(f) ( 1). This type of equipment is to be
transported to an oil or natural gas site drilling rig and is used to " shut in" a well bore . Each cylinder
has a burst pressure 5 times greater than t he charged pressure @ 70 degrees. The five accumulators
pictured are plumbed into a manifold system with each cylinder pre-charged to 1000 psig.
Sincerely,
Tim Redwine
US DOT Compliance Coordinator
Weatherford I nternational
495 Winscott Rd
Fort Worth, Texas 761256
Telephone: 817.249.7861
Email: tim.redwine@weatherford.com
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