Interpretation Response #18-0010
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Easytek Engineering Services Co. Ltd.
Individual Name: Mr. Stephen Burton
Location State: Chonburi Country: TH
View the Interpretation Document
Response text:
August 3, 2018
Mr. Stephen Burton
Easytek Engineering Services Co. Ltd.
62/277-278 Moo 12, Soi Thepprasit 6, Thepprasit Rd.
Nongprue, Banglamung
Chonburi 20150
Thailand
Reference No. 18-0010
Dear Mr. Burton:
This letter is in response to your January 13, 2018, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the qualification and testing of cylinders. Specifically, you ask whether the elastic expansion (EE) and permanent expansion (PE) percentage ratio pass/fail limits are per test or cumulative. In your email, you provide the following example—
A cylinder is presented for inspection that has a 5-year requalification period and a maximum 5% PE-to-EE ratio, as illustrated in the following table:
| Inspection Timeline | Per Test PE/EE | Cumulative PE/EE | Per Test Pass/Fail Decision | Cumulative Pass/ Fail Decision |
|---|---|---|---|---|
| First Inspection | 1.5% | 1.5% | PASS | PASS |
| 5-year inspection | 1.1% | 2.6% | PASS | PASS |
| 10-year inspection | 1.8% | 4.4% | PASS | PASS |
| 15-year inspection | 1.4% | 5.8% | PASS | FAIL |
| 20-year inpsection | 1.2% | 7.0% | PASS | FAIL |
To answer your question, the EE and PE percentage ratio pass/fail limits are per test and not cumulative. Therefore, the cylinder in your example would also pass the 15-year and 20-year tests.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division