OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

July 8, 1999

Steven D. High
P.O. Box 10008
1853 William Penn Way
Lancaster, PA. 17605-0008

Re: 1926.350; ANSI 01.1-1967

Dear Mr. High,

In your letter dated January 11, 1999, you ask the Occupational Safety and Health Administration (OSHA) to determine when a compressed gas cylinder has to be stored in accordance with 29 CFR 1926.350. You also ask us to comment on how the storage requirements would apply to four specific situations.

Section 1926.350(a)(10) requires that oxygen cylinders that are in storage be separated from fuel- gas cylinders and combustible materials. It specifies that the cylinders either be separated by a minimum of 20 feet or have a non-combustible fire wall (with a fire resistance rating of one half hour) at least five feet high. However, the standard does not specify when cylinders are considered to be in storage.

When a gas cylinder is considered to be "in storage"
OSHA considers a cylinder to be in storage when it is reasonably anticipated that gas will not be drawn from the cylinder within 24 hours (overnight hours included). At that point the storage requirements must be met. In contrast, if it is reasonably anticipated that gas will be drawn from the cylinder during the next 24 hours, the cylinder is not considered to be in storage and the §1926.350 (a)(10) storage requirements do not apply. "Reasonable anticipation" that gas will be drawn within 24 hours must be based on whether specific welding or cutting work is planned for that period. An assessment must also be made as to the number of gas cylinders expected to be required to do that work and only that number is considered to be out of storage. (Enclosed is a copy of a December 31, 1998, letter that addresses this issue in detail).

Question (1): A construction company removes the regulators, torch, and gauges from the compressed gas cylinders at the end of today. Valve protection caps are installed and the oxygen and fuel-gas cylinders are left secured and upright on a portable cart. The cart is stored away from sources of ignition and the cylinders will not be used until tomorrow morning, when they will be used again (welding work is planned for the morning and these tanks will be the ones used for that work). Does this violate the storage requirements of §1926.350?

The storage requirements of §1926.350 do not apply to this scenario since it is reasonably anticipated that gas will be used within a twenty four hour period from the time today's work is completed (welding work will resume within 24 hours).

Question (2): Welding work ends for the day and the regulators, torch, and gauges remain on a burning rig. At what point must you separate and store the oxygen and fuel gas cylinders?

As stated above, once the welding ends, the cylinder is considered to be in storage when it is reasonably anticipated that gas will not be drawn from it within the next 24 hours. At that point the employer must meet the storage requirements of §1926.350. However, if it is reasonably anticipated that the cylinders will be used within the next twenty four hours, the storage requirements need not be met.

3. The cylinders are brought to the work site and the valve protection caps are on. The intent is to use them but not immediately. How long can they stay there without having to be stored?

The only cylinders not in storage are those anticipated to be used within the next 24 hours. The number of cylinders anticipated to be used in that period will depend on the amount of gas the work is anticipated to require. Any cylinders in excess of that are considered to be in storage, and the storage requirements must be met for them.

4. Would the answers to any of the above questions change in a General Industry setting?

This question has been forwarded to the Directorate of Compliance Programs for further comments with respect to general industry.

Please let us know if you need any further clarification on this standard and feel free to contact us again by writing to: Directorate of Construction- Office of Construction Standards and Compliance Assistance, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210.


Russell B. Swanson
Directorate of Construction