Air receiver safety requirements

This section applies to compressed air receivers and equipment used for workplace operations such as cleaning, drilling, hoisting, and chipping. See Application in 1917.155(a).

• It does not apply to equipment used to convey materials or to transportation equipment such as railways, vehicles, or cranes.
• If you are unsure whether a particular piece of equipment is being used for an excluded transportation purpose, treat the activity as outside 1917.155 unless another OSHA standard covers it.

Cited: 1917.155(a).

Air receivers must have indicating pressure gauges and spring-loaded safety valves; the safety valves must prevent receiver pressure from exceeding 110 percent of the maximum allowable working pressure (MAWP). See 1917.155(b)(1).

• "Indicating pressure gauges" means gauges that show the internal pressure so operators can monitor vessel pressure.
• "Spring-loaded safety valves" must be installed and set so they open before pressure exceeds 110% of the MAWP.

Cited: 1917.155(b)(1).

No — no other valves may be placed between air receivers and their safety valves. See 1917.155(b)(2).

• This rule prevents isolating the safety device from the receiver so the safety valve can always relieve pressure directly from the receiver.
• For maintenance or isolation, employers must use procedures that do not place a valve between the receiver and its safety valve (for example, work with the compressor and system depressurized and follow lockout/tagout practices).

Cited: 1917.155(b)(2).

A safety valve must prevent the receiver pressure from exceeding 110 percent of the MAWP, so it must be set to open at or below that 110% limit. See 1917.155(b)(1).

• Example: if MAWP = 100 psi, the safety valve must prevent pressure from rising above 110 psi (110% of MAWP).
• Employers should document calibration and testing to verify the safety valve opens at the required pressure.

Cited: 1917.155(b)(1).

1917.155(b)(1) specifically requires spring-loaded safety valves on air receivers. See 1917.155(b)(1).

• Because the regulation names spring-loaded safety valves, employers should use that type unless they have alternative authority or a documented engineering justification under another applicable standard.
• If you consider a different device, obtain a manufacturer's or qualified engineer's written justification and ensure the alternative still prevents pressure above 110% of MAWP.

Cited: 1917.155(b)(1).

Yes — 1917.155 requires spring-loaded safety valves but does not prohibit having more than one safety valve on an air receiver, so multiple safety valves are permitted if appropriate for safe relief capacity. See 1917.155(b)(1).

• Multiple valves are commonly used to provide sufficient relieving capacity and redundancy.
• Ensure each valve is installed so that no other valve is placed between the receiver and any safety valve, per 1917.155(b)(2).

Cited: 1917.155(b)(1) and 1917.155(b)(2).

Yes — every air receiver must be equipped with an indicating pressure gauge, which means a readable gauge that shows the receiver's internal pressure so operators can monitor it. See 1917.155(b)(1).

• The gauge should be positioned and maintained so it can be easily read during normal operations.
• Keep gauges calibrated and in good working order so they accurately reflect pressure in the receiver.

Cited: 1917.155(b)(1).

You may not place any valve between the receiver and its safety valve, and safety valves must remain capable of preventing pressure above 110% MAWP; temporarily inserting a valve in that location would violate 1917.155(b)(2).

• For maintenance, isolate and depressurize the system following accepted lockout/tagout and safe work procedures rather than inserting a valve between the receiver and its safety valve.
• If a safety valve must be removed for service, ensure the receiver cannot be pressurized and follow documented safe work practices.

Cited: 1917.155(b)(2).

No — 1917.155(a) explicitly excludes equipment used in transportation applications such as railways, vehicles, or cranes. See 1917.155(a).

• If the compressed air equipment is part of a transport vehicle or conveyance system, this particular marine terminals provision does not apply; other OSHA standards may apply.

Cited: 1917.155(a).

No — compressed air should not be used to clean a person's clothing or body; OSHA guidance for maritime/general industry explains compressed air for personnel cleaning is unsafe and, in maritime rules, is explicitly prohibited. See 1917.155(a) and the OSHA interpretation on compressed air cleaning, 1994-01-14.

• 1917.155 covers receivers used for operations like cleaning equipment or surfaces, but the 1994 Letter of Interpretation clarifies employers should not allow compressed air for cleaning personnel and that compressed air used for cleaning must be reduced to less than 30 psig for general industry uses with appropriate guarding and PPE.
• For maritime workplaces, consult the explicit prohibition in [1917.154] referenced by the interpretation.

Cited: 1917.155(a) and OSHA Letter of Interpretation, 1994-01-14.

Generally no — OSHA's Part 1917 requirements do not apply to certain designated waterfront facilities used solely for bulk storage, handling, and transfer of liquids or gases; see the OSHA interpretation on applicability to waterfront facilities. See 1917 and the Letter of Interpretation, 2017-05-31.

• The 2017 Letter of Interpretation explains that some facilities fitting the definition of a "designated waterfront facility" fall outside Part 1917's scope, so provisions such as 1917.155 may not apply at those locations.
• If your site is a designated waterfront facility, confirm applicability with OSHA or legal counsel and check whether other OSHA standards (e.g., general industry) apply.

Cited: 1917 and OSHA Letter of Interpretation, 2017-05-31.

It is an ongoing requirement: safety valves must be sized and set so the receiver pressure cannot rise above 110 percent of the MAWP under any foreseeable overpressure condition. See 1917.155(b)(1).

• Employers must select, install, and maintain safety valves so they reliably open at or below the 110% threshold and relieve excess pressure.
• Routine testing and maintenance help ensure valves continue to function as required.

Cited: 1917.155(b)(1).

The pressure gauge must be arranged so it accurately indicates the air receiver's internal pressure and is readable during normal operations; it should be located on the receiver or on a tapping that represents receiver pressure. See 1917.155(b)(1).

• Mount the gauge where it is protected from damage but visible to the operator; ensure piping or fittings do not isolate the gauge from the receiver pressure.
• Keep gauges maintained and calibrated so they provide reliable readings.

Cited: 1917.155(b)(1).

No — regardless of piping layout, no valves may be placed between the receiver and its safety valve; safety valves must have a direct path to relieve pressure from the receiver. See 1917.155(b)(2).

• Arrange piping so relief is direct from the receiver and ensure branch piping does not interfere with the safety valve's function.
• If piping changes are needed for operations, redesign the layout so the safety valve remains directly connected to the receiver.

Cited: 1917.155(b)(2).

No — 1917.155 requires that receivers be equipped with indicating pressure gauges and spring-loaded safety valves and that safety valves prevent pressure above 110% MAWP, but it does not specify inspection or testing intervals. See 1917.155(b)(1).

• Employers should establish and document inspection and testing schedules based on manufacturer recommendations, recognized industry practice, and the need to ensure continued valve and gauge performance.
• Maintain records of tests and maintenance to demonstrate ongoing compliance and safe operation.

Cited: 1917.155(b)(1).

You may modify outlet piping downstream of the safety valve as long as you do not place any valve between the receiver and the safety valve and the safety valve remains able to relieve to a safe location; 1917.155(b)(2) prohibits valves between the receiver and its safety valve. See 1917.155(b)(2).

• Ensure any rerouting does not impair valve operation (e.g., avoid excessive backpressure or obstructed discharge).
• Follow manufacturer guidance and good engineering practice when changing discharge piping so relief capacity and function are not reduced.

Cited: 1917.155(b)(2) and 1917.155(b)(1).

Yes — 1917.155 covers receivers used for cleaning operations of equipment or surfaces, but compressed air cleaning must be done safely: do not use high-pressure air to clean personnel and follow guarding and PPE guidance. See 1917.155(a) and the OSHA Letter of Interpretation on compressed air cleaning, 1994-01-14.

• The 1994 interpretation states compressed air for cleaning should be reduced to less than 30 psig for general industry cleaning and used only with effective chip guarding and PPE; maritime rules may be stricter.
• Never use compressed air for cleaning a person’s clothing or body (see the Letter of Interpretation 1994-01-14).

Cited: 1917.155(a) and OSHA Letter of Interpretation, 1994-01-14.

OSHA's Part 1917 scope and the 2017 Letter of Interpretation about waterfront facilities can help determine applicability: some "designated waterfront facilities" used solely for bulk storage and transfer may fall outside Part 1917. See 1917 and the Letter of Interpretation, 2017-05-31.

• Review the definitions and scope in Part 1917 and consult the 2017 LOI to see if your facility matches the described "designated waterfront facility" exclusion.
• If uncertain, contact OSHA's Office of Maritime Enforcement or legal counsel for a site-specific determination.

Cited: 1917 and Letter of Interpretation, 2017-05-31.