1910.253(e): Oxygen-Fuel Gas Piping Protective Equipment
Oxygen-fuel gas equipment must be installed and used only for its approved service and as the manufacturer recommends. Service piping must have pressure relief devices set no higher than design pressure and venting upward to a safe place, and fuel-gas piping must have approved protective equipment to prevent oxygen backflow, flashback, and excessive oxygen back pressure.
Key takeaways
- 1910.253(e) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart Q).
- OSHA cited it 54 times in the last 3 years, in 54 inspections, with $144,848 in current penalties.
- 1 death is linked to inspections that cited this rule.
- Most citations: NJ (21), TN (16), IL (2).
- Related part: 1910.253(e)(3)(ii) (25 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.253(e) ("Protective equipment, hose, and regulators") is one requirement inside 1910.253 Oxygen-fuel gas welding and cutting, an OSHA general industry standard (Part 1910, Subpart Q). It includes 30 sub-paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(e) Protective equipment, hose, and regulators — 54 citations
(1) General. Equipment shall be installed and used only in the service for which it is approved and as recommended by the manufacturer.
(2) Pressure relief devices. Service piping systems shall be protected by pressure relief devices set to function at not more than the design pressure of the systems and discharging upwards to a safe location.
(3) Piping protective equipment. Open (e)(3) 25 citations
(i) The fuel-gas and oxygen piping systems, including portable outlet headers shall incorporate the protective equipment shown in Figures Q-1, Q-2, and Q-3. When only a portion of a fuel-gas system is to be used with oxygen, only that portion need comply with this paragraph (e)(3)(i).
(ii) Approved protective equipment (designated PF in Figures Q-1, Q-2, and Q-3) shall be installed in fuel-gas piping to prevent: Open (e)(3)(ii) 25 citations
(A) Backflow of oxygen into the fuel-gas supply system;
(B) Passage of a flash back into the fuel-gas supply system; and
(C) Excessive back pressure of oxygen in the fuel-gas supply system. The three functions of the protective equipment may be combined in one device or may be provided by separate devices. Open (e)(3)(ii)(c) 24 citations
(1) The protective equipment shall be located in the main supply line, as in Figure Q-1 or at the head of each branch line, as in Figure Q-2 or at each location where fuel-gas is withdrawn, as in Figure Q-3. Where branch lines are of 2-inch pipe size or larger or of substantial length, protective equipment (designated as PF) shall be located as shown in either Q-2 and Q-3.
(2) Backflow protection shall be provided by an approved device that will prevent oxygen from flowing into the fuel-gas system or fuel from flowing into the oxygen system (see SF, Figures Q-1 and Q-2).
(3) Flash-back protection shall be provided by an approved device that will prevent flame from passing into the fuel-gas system.
(4) Back-pressure protection shall be provided by an approved pressure-relief device set at a pressure not greater than the pressure rating of the backflow or the flashback protection device, whichever is lower. The pressure-relief device shall be located on the downstream side of the backflow and flashback protection devices. The vent from the pressure-relief device shall be at least as large as the relief device inlet and shall be installed without low points that may collect moisture. If low points are unavoidable, drip pots with drains closed with screw plugs or caps shall be installed at the low points. The vent terminus shall not endanger personnel or property through gas discharge; shall be located away from ignition sources; and shall terminate in a hood or bend.
(iii) If pipeline protective equipment incorporates a liquid, the liquid level shall be maintained, and a suitable antifreeze may be used to prevent freezing.
(iv) Fuel gas for use with equipment not requiring oxygen shall be withdrawn upstream of the piping protective devices.
(4) Station outlet protective equipment. 1 citations
(i) A check valve, pressure regulator, hydraulic seal, or combination of these devices shall be provided at each station outlet, including those on portable headers, to prevent backflow, as shown in Figures Q-1, Q-2, and Q-3 and designated as SF and SO.
(ii) When approved pipeline protective equipment (designated PF) is located at the station outlet as in Figure Q-3, no additional check valve, pressure regulator, or hydraulic seal is required.
(iii) A shutoff valve (designated VF and VO) shall be installed at each station outlet and shall be located on the upstream side of other station outlet equipment.
(iv) If the station outlet is equipped with a detachable regulator, the outlet shall terminate in a union connection that complies with the Regulator Connection Standards, 1958, Compressed Gas Association, which is incorporated by reference as specified in § 1910.6.
(v) If the station outlet is connected directly to a hose, the outlet shall terminate in a union connection complying with the Standard Hose Connection Specifications, 1957, Compressed Gas Association, which is incorporated by reference as specified in § 1910.6.
(vi) Station outlets may terminate in pipe threads to which permanent connections are to be made, such as to a machine.
(vii) Station outlets shall be equipped with a detachable outlet seal cap secured in place. This cap shall be used to seal the outlet except when a hose, a regulator, or piping is attached. 1 citations
(viii) Where station outlets are equipped with approved backflow and flashback protective devices, as many as four torches may be supplied from one station outlet through rigid piping, provided each outlet from such piping is equipped with a shutoff valve and provided the fuel-gas capacity of any one torch does not exceed 15 cubic feet (0.42 m3) per hour. This paragraph (e)(4)(viii) does not apply to machines.
(5) Hose and hose connections. 8 citations
(i) Hose for oxy-fuel gas service shall comply with the Specification for Rubber Welding Hose, 1958, Compressed Gas Association and Rubber Manufacturers Association, which is incorporated by reference as specified in § 1910.6.
(ii) When parallel lengths of oxygen and acetylene hose are taped together for convenience and to prevent tangling, not more than 4 inches (10.2 cm) out of 12 inches (30.5 cm) shall be covered by tape.
(iii) Hose connections shall comply with the Standard Hose Connection Specifications, 1957, Compressed Gas Association.
(iv) Hose connections shall be clamped or otherwise securely fastened in a manner that will withstand, without leakage, twice the pressure to which they are normally subjected in service, but in no case less than a pressure of 300 psi (2.04 MPa). Oil-free air or an oil-free inert gas shall be used for the test.
(v) Hose showing leaks, burns, worn places, or other defects rendering it unfit for service shall be repaired or replaced. 8 citations
(6) Pressure-reducing regulators. Open (e)(6) 20 citations
(i) Pressure-reducing regulators shall be used only for the gas and pressures for which they are intended. The regulator inlet connections shall comply with Regulator Connection Standards, 1958, Compressed Gas Association. 1 citations
(ii) When regulators or parts of regulators, including gages, need repair, the work shall be performed by skilled mechanics who have been properly instructed. Open (e)(6)(ii) 19 citations
(iii) Gages on oxygen regulators shall be marked “USE NO OIL.”
(iv) Union nuts and connections on regulators shall be inspected before use to detect faulty seats which may cause leakage of gas when the regulators are attached to the cylinder valves.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.253.
Injuries linked to this rule
1 death is linked to inspections where OSHA cited 1910.253(e).
At 4:00 p.m. on October 22, 2024, an employee working as a machine maintenance technician was on an inclined conveyor preparing to maintain its gearbox. The employee was on top of the "naturals" conveyor (#C8) associated with the Colorbiotics mulch dye machine while a coworker…
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 4 |
| 2024 | 19 |
| 2025 | 15 |
| 2026 | 16 |
Top states: NJ (21), TN (16), IL (2), MA (2), PA (2)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| RESOURCE RECYCLING, INC. | LIMA, OH | $11,585 |
| HACKETTSTOWN PUBLIC SCHOOLS | HACKETTSTOWN, NJ | $7,000 |
| NJ DEPARTMENT OF ENVIRONMENTAL PROTECTION | COLUMBIA, NJ | $7,000 |
| NEW JERSEY TURNPIKE AUTHORITY | MULLICA HILL, NJ | $7,000 |
| BOROUGH OF GLASSBORO PUBLIC SCHOOL DISTRICT | GLASSBORO, NJ | $7,000 |
Free toolbox talk
A 5-minute crew talk on 1910.253(e), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.253(e).
Related parts of this rule
- 1910.253(e)(3)(ii) 25 citations
- 1910.253(e)(3) Piping protective equipment 25 citations
- 1910.253(e)(3)(ii)(C) 24 citations
- 1910.253(e)(6) Pressure-reducing regulators 20 citations
- 1910.253(e)(6)(ii) 19 citations
Get your crew competent
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Frequently asked questions
What must the protective equipment in fuel-gas piping prevent?
Backflow of oxygen into the fuel-gas supply, passage of a flashback into it, and excessive oxygen back pressure.
Where must relief devices discharge?
Upwards to a safe location, set at not more than the design pressure.
Can equipment be used for other gases?
Equipment must be used only in the service for which it is approved and as recommended by the manufacturer.
About this page
Sources
- 29 CFR 1910.253 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-25
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.