November 18, 2021

Mr. Thomas Van Hooser
131 NW 10th Ct.
Boca Raton, Florida 33486

Dear Mr. Van Hooser:

Thank you for your letter to the Occupational Safety and Health Administration (OSHA) regarding the use, handling and storage of acetylene cylinders in general industry and construction. This letter constitutes OSHA’s interpretation only of the requirements herein, and may not be applicable to any questions not delineated in your original correspondence.

Your letter discusses concerns with the safety of compressed gas cylinders on some types of portable carts configured for “in use” or “connected for use.” Specifically you mention that cylinders, which are top heavy and therefore can be unstable (unbalanced) are commonly found poorly secured to the cart and leaves the cylinders susceptible to toppling over when used, moved, or stored. In your letter, several pictures are provided to illustrate your point (See Pictures 1, 2, and 3) of poorly secured cylinders.

Picture 1

Picture 2

Picture 3

As an alternative you recommend the use of a “trolley,” with an example provided in your follow up email (See picture 4), as a safer solution to ensuring protection of cylinders from toppling and creating a possible fire/explosion hazard from cylinder damage.

Picture 4

You reference in your letter, an updated version of the Compressed Gas Association Standard P-1-2015, 12th edition, which allows Acetylene cylinders to be positioned with the valve end up with the container axis inclined as much as 45 degrees from vertical.

Your two questions are paraphrased below, and our responses follow:

Question 1: Are acetylene cylinders positioned at a 45 degree angle from vertical, as shown in picture 4, acceptable to OSHA while in use, moved, or stored?

Response: The following OSHA standards contain requirements for protection of compressed gas cylinders while in use, moving, or storage:

General industry under Subpart H, Compressed gases (general requirements):

§1910.101(b) “Compressed gases.” The in-plant handling, storage, and utilization of all compressed gases in cylinders, portable tanks, rail tankcars, or motor vehicle cargo tanks shall be in accordance with Compressed Gas Association Pamphlet P-1-1965, which is incorporated by reference as specified in §1910.6.

General industry requirements under Subpart H, Acetylene:

§1910.102(a) Cylinders. Employers must ensure that the in-plant transfer, handling, storage, and use of acetylene in cylinders comply with the provisions of CGA Pamphlet G-1-2009 (“Acetylene”) (Incorporated by reference, see § 1910.6).

General industry requirements under Subpart Q, Oxygen-fuel gas welding and cutting:

§1910.253(b)(3)(ii) Acetylene cylinders shall be stored valve end up.

§1910.253(b)(5)(iii)(A) Fuel-gas cylinders shall be placed with valve end up whenever they are in use. Liquefied gases shall be stored and shipped with the valve end up.

§1910.253(b)(5)(iii)(B) Cylinders shall be handled carefully. Rough handling, knocks, or falls are liable to damage the cylinder, valve or safety devices and cause leakage.

Construction requirements under Subpart J, Gas Welding and Cutting:

§1926.350(a)(7) A suitable cylinder truck, chain, or other steadying device shall be used to keep cylinders from being knocked over while in use.

§1926.350(a)(9) Compressed gas cylinders shall be secured in an upright position at all times except, if necessary, for short periods of time while cylinders are actually being hoisted or carried.

§1926.350(b)(3) Fuel gas cylinders shall be placed with valve end up whenever they are in use. They shall not be placed in a location where they would be subject to open flame, hot metal, or other sources of artificial heat.

§1926.350(j) Additional rules. For additional details not covered in this subpart, applicable technical portions of American National Standards Institute, Z49.1-1967, Safety in Welding and Cutting, shall apply.

OSHA standards require the compressed gas cylinders to be in an upright position (vertical) or valve end up position. This requirement is provided to ensure the protection of and safe access to the valve while in use, during movement, or while in storage. OSHA agrees that the use of the “trolley” shown in picture 4 can provide such protection, even at a 45 degree angle from vertical. As you noted in your letter, the twelfth addition of the Compressed Gas Association Standard P-1 (Standard for Safe Handling of Compressed Gases in Containers) allows use and storage of Acetylene cylinders at a 45 degree angle from vertical. If an employer is not in compliance with the requirements of an OSHA standard but is complying with the requirements of a current consensus standard that clearly provides equal or greater employee protection, the violation of OSHA's requirement will be treated as a de minimis condition. De minimis conditions are those having no direct or immediate relationship to safety and health and result in no citation, penalty, or requirement to abate. The use and storage of a cylinder secured to a “trolley” and reclined up to a 45 degree angle from vertical would be considered a de minimis condition, as long as all the following conditions are present:

• The “trolley” is properly designed to fully support the cylinder weight and top heaviness of the cylinder(s) to prevent falling over (toppling);
• The valve is protected from damage;
• The angle does not create a possibility of a solvent leak (fire hazard); and
• That valve access is unimpeded to ensure quick, safe operation

Question 2: Are cylinder carts subject to special design and if so please identify the standard?

Response: Design requirements for cylinder carts or “special trucks”, the term used in 29 CFR 1910.253(b)(5)(ii)(D), are described in the September 9, 1993, letter of interpretation to Mr. Kenneth Yotz.¹ The letter reads in part:

“Compressed gas cylinders with the regulators installed are considered by OSHA to be ‘connected for use.’ A ‘special truck’ is a vehicle or cart used for the specific purpose of transporting the aforementioned ‘connected for use’ compressed gas cylinders in the workplace. The ‘special truck’ must be designed so that the following conditions can be met: 1) when cylinders are on the special trucks, they must be held in an erect or nearly erect position; and 2) protection of the cylinder valves and regulators must be provided.”

The conditions of the first requirement can be met for Acetylene cylinders so long as the cylinder is held in an incline of no more than 45 degrees from vertical, as stated in response 1 above. Carts that cannot meet these two requirements and are susceptible to toppling while moving cylinders or while maintained in a standing position while in use or in storage would be considered in violation of the standards and must be evaluated on a case-by-case basis. Please refer to the standards cited above which specify requirements to prevent cylinders from being knocked over while in use, being moved, or stored.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA’s requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA’s interpretation of the requirements discussed. From time to time, such letters may be affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA’s website at http://www.osha.gov. If you have any questions, please feel free to contact the Directorate of Enforcement Programs at (202) 693-2100.

Sincerely,

Kimberly Stille, Acting Director
Directorate of Enforcement Programs

¹Found at https://www.osha.gov/laws-regs/standardinterpretations/1993-09-09-2.