An OSHA inspector walks into a shop. Before they look at a single machine guard, they look at the blow gun hanging off the bench, and they check what pressure it makes when you dead-end it against your palm.
That is not a guess about inspector behaviour. The 30 psi cleaning limit is the most-cited compressed air rule there is, and it is cited so often because almost every shop has at least one tool that fails it.
Here is what the rules actually say, in the order you are most likely to get written up for them. Compressed air safety is a short list, it is all checkable in an afternoon, and none of it is expensive to fix.
1. The 30 PSI Rule, 1910.242(b)
The regulation reads that compressed air shall not be used for cleaning purposes except where reduced to less than 30 psi, and then only with effective chip guarding and personal protective equipment.
Three parts, and shops usually satisfy one and miss the other two.
- Under 30 psi. This is measured at dead-end, meaning the pressure the nozzle produces when the outlet is blocked, which is what happens when it contacts skin. Line pressure can be higher. A properly designed safety nozzle relieves through side ports so dead-end pressure stays below the limit even on a 100 psi line.
- Effective chip guarding. Something that stops the chip coming back at the operator or at the person at the next bench.
- PPE. Eye protection, in practice, under 1910.133.
The common failure is a plain open-end tube or an old gun with no relief ports, fed from a 90 psi drop. That dead-ends at 90 psi and is a citation whatever the regulator says. Swapping to proper safety nozzles costs very little. Our blow gun buyer's guide covers what to look for.
Worth being clear on the thing this rule does not say: it does not ban compressed air for actual work. Blowing a part off at a machine, drying a surface in a process, operating a tool, none of that is cleaning in the sense the rule means. The rule is about using air as a broom.
2. Never Use Air on a Person
Not for cleaning clothing, not for cooling off, not as a joke.
Air forced through skin or a body opening can enter the bloodstream, and air embolism is fatal. It does not take much pressure. This is the one item on this page where the consequence is not a fine, and it is worth saying out loud in a toolbox talk rather than assuming everyone knows.
3. Air Receivers, 1910.169
This is the quiet one. Nobody thinks about the tank until an inspector asks, and the requirements are specific.
| Requirement | What to check |
|---|---|
| Drain at the lowest point | A drain pipe and valve installed at the lowest point, and actually opened often enough to stop liquid accumulating |
| Indicating pressure gauge | Fitted and readily visible, not buried behind the machine |
| Spring-loaded safety valve | One or more, sized so tank pressure cannot rise more than 10 percent above the maximum allowable working pressure |
| Nothing between tank and relief | No valve of any type may be placed between the air receiver and its safety valve or valves |
That last row is the one that catches people. Somebody adds an isolation valve during a repair so the relief can be changed without draining the tank, and it never comes out. It is a clear violation and it defeats the only thing standing between a runaway pressure switch and a tank rupture.
Two related checks while you are there. Confirm the relief valve is rated at or below the tank's stamped MAWP, and look at the tank itself. A relief valve painted over or weeping, or a tank with rust scale around the bottom seam, is a bigger problem than a citation. Our pieces on safety relief valves and tank rust cover both.
4. Stored Energy and Lockout, 1910.147
Compressed air is stored energy, and lockout tagout requires stored energy to be relieved or restrained before work begins.
In practice that means locking out the electrical disconnect is not enough. A tank at 150 psi is still dangerous with the power off, and so is a cylinder holding a load or an accumulator in a machine.
- Isolate the air supply with a lockable valve, not just a ball valve somebody could turn back.
- Bleed the downstream side and confirm zero at a gauge, rather than assuming.
- Check for trapped air between check valves, which is where people get surprised.
- Remember that some actuators hold a load with air, so bleeding can drop something. Know which ones before you bleed.
5. Noise, 1910.95
Compressors and air exhaust are frequently the loudest things in a small shop, and the obligation is a measurement rather than an opinion.
The permissible exposure limit is 90 dBA as an eight hour time weighted average, and a hearing conservation program is required at an action level of 85 dBA. If people raise their voices to talk at normal distance, you are in the range where measuring is worth doing.
Compressed air itself is often the cheapest fix. Engineered nozzles and mufflers on actuator exhausts cut noise substantially while also using less air, which is an unusual case of the safety fix and the energy fix being the same purchase.
6. Piping Material
Do not use PVC above ground for compressed air. OSHA has warned against it since a 1988 hazard bulletin, and ASME B31.3 and B31.9 both exclude it.
The reason is the failure mode rather than the pressure rating. PVC degrades with compressor oil and UV, becomes brittle, and when it fails it shatters into fragments instead of splitting. Our PVC for compressed air piece has the detail, and pipe materials compared covers what to use instead.
7. Hoses, Couplers and Whip
A hose that separates under pressure whips, and a hose end at 100 psi does real damage.
- Whipcheck cables across every hose-to-hose and hose-to-tool connection on larger hose. On construction work, 1926.302(b)(7) requires a safety device at the source of supply or branch line to reduce pressure on hose failure for hose exceeding half an inch inside diameter, and that is good practice everywhere.
- Retainers on pneumatic tools. Tool retainers stop a chisel or bit leaving the tool.
- Do not use a coupler that does not properly seat. Mixed interchanges are a safety issue as well as a leak. See our coupler guide.
- Inspect whips at the ferrule. That is where they crack.
A Walk-Around You Can Do This Week
| Check | Pass looks like |
|---|---|
| Every blow gun | Relieving safety nozzle, dead-ends under 30 psi |
| Receiver drain | At the lowest point, opens, actually used |
| Receiver gauge | Present, readable, visible without moving anything |
| Relief valve | Correct rating, not painted over, nothing valved between it and the tank |
| Lockout points | Lockable air isolation plus a bleed and a gauge |
| Piping | No PVC anywhere above ground |
| Hoses | Whipchecks fitted, whips sound at the ferrule, tool retainers in place |
| Noise | Measured, not guessed, if people raise their voices |
That is a one person, one afternoon exercise, and the parts to fix most of it cost less than an hour of a safety consultant.
What We Are Not
We sell nozzles, relief valves, piping and tools, and we will help you pick compliant parts. We are not your safety consultant and this page is not a compliance program. Standards get amended, state plans add requirements, and your specific operation may trigger rules that are not on this list. Read the current text of anything here before you rely on it, and if you are unsure, get somebody qualified to walk your plant.
Frequently Asked Questions
What is the OSHA limit for compressed air used for cleaning?
Under 1910.242(b), compressed air used for cleaning must be reduced to less than 30 psi, and even then it requires effective chip guarding and personal protective equipment. The 30 psi figure refers to dead-end pressure, meaning what the nozzle produces when the outlet is blocked, so a proper relieving safety nozzle can run on a higher line pressure and still comply.
Can I use compressed air to blow dust off my clothes?
No, and this is the one item here where the risk is not regulatory. Air forced through skin or a body opening can enter the bloodstream and cause a fatal embolism. Never direct compressed air at yourself or anyone else, at any pressure, for any reason.
Can I put a shutoff valve between my air tank and its relief valve?
No. 1910.169 is explicit that no valve of any type may be placed between the air receiver and its safety valve or valves. This gets installed during repairs so the relief can be swapped without draining the tank, and then never removed. It is a clear violation and it disables the only protection against overpressure.
Does lockout tagout apply to compressed air?
Yes. Compressed air is stored energy, and 1910.147 requires stored energy to be relieved or restrained before work. Locking the electrical disconnect is not sufficient on its own. Isolate the air with a lockable valve, bleed the downstream side, and confirm zero pressure at a gauge, keeping in mind that some actuators hold a load with air.
Is PVC pipe allowed for compressed air?
Not above ground. OSHA has warned against it since a 1988 hazard bulletin and ASME B31.3 and B31.9 both exclude it. The problem is that PVC becomes brittle with age, oil exposure and UV, and then shatters rather than splitting when it fails. Use steel, copper, stainless or a properly rated aluminum system instead.
Where to Start
Walk the shop with the table above on a clipboard. The blow guns and the valve between the tank and the relief are the two findings we see most, and both are cheap parts and a few minutes each. Fix those two and you have addressed the most-cited compressed air rule and the most consequential one in the same afternoon.
Browse air tools and safety nozzles, or the safety relief valves if your walk-around turned one up. Tell us what you found and we will help you match the right parts.
