Airgas, Inc. — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Research and NOV - 5 2003 400 Seventh St., S.W. Washington, D.C. 20590 Administration Spacidi Programs Mr. John Anderson Director of DOT Operations Ref No: 03-0159 Airgas, Inc. P.O. Box 20067 Cheyenne, WY 82003 Dear Mr. Anderson: This is in response to your telephone conversation with Sandra Webb of this office and subsequent letter, requesting a clarification of the requirements for filling DOT specification Regulations (HMR; 49 CFR Parts 171-180). cylinders with non-liquefied (permanent) compressed gases under the Hazardous Materials You stated that it is industry practice to add approximately 50 psi to 100 psi to the target fill pressure so that, once the cylinder has cooled, the pressure in the cylinder at 70 °F. will be as cylinder, such as a DOT 3A, 3AA or 3AL cylinder, may be filled in excess of its marked service close as possible to its marked service pressure. Specifically, you ask whether a high-pressure pressure. A cylinder may be filled to a pressure in excess of the marked service pressure to compehsate for certain factors, such as heat of compression, high ambient temperature or changes in elevation. cylinder at 21 °C. (70 °F.) must not exceed the service pressure for which the cylinder is marked However, § 173.301a(c) specifically states that when offered for transportation, the pressure in a or designated, except as provided in § 173.302a(b) of the HMR. This requirement has been in industry. effect for many years, and it is based on standards and recommendations of the compressed gas In your letter, you imply there is an inconsistency between fill limit requirements of the HMR (FDA). We disagree. FDA concurs with RSPA that the internal pressure at 21 °C. and those of the U.S. Department of Health and Human Services' Food and Drug Administration (70 °F.) must not exceed the cylinder's service pressure. Therefore, your operating procedures must ensure that the marked service pressure is not exceeded when the cylinder is offered for transportation. I hope this information is helpful. If we can be of further assistance, feel free to contact us. Sincerely, Salual 7. Mazzallo Edward T. Mazzullo Director, Office of Hazardous Materials Standards 113.302 TELLINE HIMANI 030159#

Page 2Airgas. Director of DOT Operations John Anderson Airgas, Inc. Cheyenno, WY 82003 PO Box 20067 http://www.airgas.com (307) 778-8809 Fax: (307) 778-7497 john.anderson@airgas.com June 25, 2003 Sandra Webb DOT/RSPA 400 Seventh St. SW Washington, DC 20590 Dear Ms. Webb: Per our conversation today, please provide Airgas with guidance on how to comply with the following. The compressed gas industry fills high-pressure cylinders (such as 3A, 3AA and 3AL) allow for the filling of these cylinders at different pressures and temperatures to obtain by pressure and temperature, per 49 CFR 173.301a. Charts have been developed that the correct service pressure/product.content. The gauges and thermometers that are used are calibrated, but the manufacturer of the gauge states the gauge is accurate to 1.5%, and the thermometer is accurate to 0.5%. Even when working within this range, it is almost impossible to obtain a 100% accurate service pressure. A 2% variance on a cylinder rated at 2,015 psi is a 40-psi difference. As a cylinder is being filled, the temperature of the compressed gas raises the temperature of the cylinder. The compressed gas inside the cylinder is getting hotter (due to compression), and it takes a while for the increased heat to penetrate the wall of the cylinder. It is difficult to obtain a 100% accurate temperature reading on the outside cylinder wall. The filling process becomes more difficult because the DOT states the cylinder cannot be over-filled, and the FDA states the cylinder cannot be under-filled. The FDA requires that the cylinder have the correct amount of product since the product is dispensed as a medical gas. The industry practice is to add approximately 50 to 100 psi to the target fill pressure so that once the cylinder is allowed to cool to the room temperature, the cylinder will be as close as possible to the correct service pressure when the settle pressure check is performed. As you know, the DOT removed the requirement to perform a settle pressure check (on high pressure cylinders), and the requirement to maintain a settle pressure log (on high pressure cylinders) in the October 1, 2002 update to 49 CFR. Recently, Christopher Michalski, an inspector from the RSPA office in NJ performed an audit at one of our locations. Mr. Michalski reviewed our FDA cylinder filling records. He noted that our FDA cylinder filling record recorded a settle pressure in excess of the cylinders service pressure. Example, if the cylinder was a 3AA 2015, the cylinder might have a settle pressure of 2,055 psi at 70 degrees.#

Page 3Mr. Michalski noted on the exit briefing, "173.302 & 173.301(c) Shipping oxygen, unauthorized package". compressed, 2.2, UN 1072 in a cylinder filled above the service pressure, therefore As noted above, we follow the standard industry practice that has been used safely for am improve our in or are and please provide Are and dancer me almost 100 years. filling high-pressure cylinders. John Anderson Director of DOT Operations Airgas, Inc.#