By: Thomas H. Welby Published: July 2012

Safety Policy: OSHA Citation Upheld for Inadequate Firewall Separating Oxygen and Acetylene Cylinders

It's important to be familiar with OSHA standards governing the use and storage of compressed gas cylinders, even if your own employees do not themselves engage in cutting and welding operations. Since the risks include explosions and fire, general knowledge of the Subpart J (Welding and Cutting) standards is essential, as a matter of protecting your employees. Obviously, if your company doesperform cutting and welding, your knowledge must be thorough. If you are a general contractor, you will probably be responsible for your subcontractors' OSHA violations under the "Multi-Employer Doctrine," which implies the need to know these standards well.

In Secretary v. National Steel Erection, Inc., the respondent was a subcontractor engaged in fabricating holding tanks for a wastewater treatment system in Tennessee. It was issued a single-item "Serious" citation by OSHA for having oxygen, acetylene and propane cylinders on a storage rack, without a sufficient firewall. The cylinders were separated by a noncombustible barrier 5 feet in height, and 1/4" thick, but with a 1" gap between the barrier and the frame on the frame's right and left sides. At the time of the OSHA inspection, National Steel had not done any cutting or welding for one week; and, as it was finishing up and had only one employee remaining onsite, had no plans to use the cylinders again on the project. (The importance of the last-mentioned fact is that, generally, OSHA is less strict in citing violations of the "storage" standards, if the cylinders are expected to be in use within 24 hours, and are connected to a properly-functioning regulator).

National Steel was cited for violating 29 C.F.R. $ 1926.350(a)(10), which provides:

Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.

National Steel contested the citation. At the time of the inspection, four or five employees of another contractor were painting and sandblasting the tanks, about 30 feet distant from the storage rack. Another contractor's job trailer was about 50 feet away. Employee exposure to the condition was thereby established.

The element of actual knowledge was established by admissions by National Steel's superintendent that he knew that the cylinders were in storage, and that the barrier had not been tested. The ALJ found "constructive knowledge" as well, as the storage rack and cylinders were in plain view at the time of the inspection.

Apart from the amount of the proposed penalty, there was only one issue for the ALJ to decide: the sufficiency of the barrier on the storage rack to comply with the standard.

The exact composition of the barrier was uncertain. While it was shown to have been made only of metal (and not metal combined with cement plaster or mineral wool fillers) it was not shown to be 100% steel. While neither National Steel nor the Secretary had actually had the barrier tested to establish its fire rating, the ALJ found convincing the Secretary's argument, based on a 2006 "Memorandum on Interpretation for Fire Resistance Ratings for Metal." That Memorandum found, essentially, that 1/2" thick steel would not meet the necessary 1/2-hour fire resistance rating. Steel plate barriers combined with plaster (cement, lime and perlite) fillers, or mineral wool fillers, provide a higher protection factor. Since National Steel's barrier was only 1/4" thick, even if it were assumed to be solid steel, it would not meet the fire rating required.

Also, the ALJ found, even if the partition had been thicker and combined with concrete plaster, it would still be insufficient, because of the 1" gap between the barrier and the frame, which would permit fire to circumvent the barrier.

Although the ALJ reduced the monetary penalty, she affirmed the firewall violation as "Serious."

OSHA issued a new final rule regarding acetylene, under the Part 1910 general industry standards, which became effective on November 9, 2009. The Part 1926 construction standards have not been amended correspondingly.

An innovation, which while spurred by the amendment to the general industry guidelines has spread into the construction domain, is the replacement of many old-style two-wheeled "tip-back" carts (having two gas cylinders chained to the deck) which had been the standard since the early 1900s.

Naturally, a primary safety feature on the newer welding carts is an OSHA-compliant firewall between the gas cylinders. One design has a partition consisting of three separate baffles, to create two exhaust vents at the top, and two intakes at the bottom. This allows heat from the fuel-gas flame of one cylinder to draw in ambient air from below, with the heated air escaping through the top vents. This minimizes heat transfer to the oxygen cylinder.

The newer carts have a number of additional safety-related features. Among them are: a four-wheel base; steel enclosures to protect the cylinders from being punctured or otherwise damaged by falling objects; mechanical devices, rather than loose-fitting chains, to secure the cylinders; a separate, vented container for the regulators, a torch cradle, a surface for parts, supplies, and manuals, and a self-recoiling hose reel.

Down the road, I expect, OSHA will update the Part 1926 construction standards regarding the storage and use of compressed gases in cutting and welding operations.

In the meantime, it's a good idea to become familiar with existing Subpart J standards. (All OSHA standards can be found online at www.osha.gov). In addition, and in advance of necessity, you should consider adopting some of the practices required or commended under the amended general construction standards.

One frequently-found practice to be avoided is storing acetylene cylinders in confined spaces, such as unventilated cabinets, closets, and drawers. It is recommended, also, that cylinders not be transported in automobiles, and that the valves on acetylene cylinders not be opened without a regulator and flow restrictor attached.

There are thousands of welding-related injuries annually, and statistically a high fatality rate amongst workers in this trade. Many of the rules are matters of common sense, such as keeping hoses and cables clear of passageways, ladders and stairs, inspecting torches at the beginning of each shift for leaking shutoff valves, hose couplings, and tip connections, and not taking acetylene or oxygen cylinders into confined spaces.

By taking advantage of improved technology and attention to the welding and cutting standards, this is one construction hazard that can be significantly reduced.

Thomas H. Welby is a licensed professional engineer, as well as an attorney and managing partner of Welby, Brady & Greenblatt, LLP, a construction law firm with its main office in White Plains. Geoffrey S. Pope, counsel to the firm, assists in the preparation of this series. Articles in this series are for general guidance only, and should not be relied upon as providing all information necessary for compliance with OSHA and other legal requirements.

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