Compressed Air and Hoses

Shop air runs at around 100 psi. That is enough to drive air through skin, into the bloodstream, and kill somebody — and enough to turn a loose hose into something that breaks bones.

Cleaning with air

1926.302(b)(4) sets the limit: compressed air shall not be used for cleaning except where reduced to less than 30 psi, and then only with effective chip guarding and PPE. The 30 psi limit does not apply to concrete form, mill scale and similar cleaning.

That means a blow gun with a pressure-relieving tip, safety glasses at minimum, and a face shield when the debris warrants it. A bare open-ended pipe on shop air is not a blow gun.

Never at a person

Not as a joke, not to knock dust off somebody's clothes, not at your own hand.

• Air blown at skin can enter through a small cut and cause an air embolism — a bubble in the bloodstream that reaches the heart or brain.
• Air directed at the body, even through clothing, can be forced into the abdomen or the rectum with fatal results. This has killed people on horseplay.
• Air into an ear can rupture the eardrum; at an eye it can blind.
• 1926.353(a)(6): oxygen is never used for blowing dust off clothing or cleaning. Oxygen-soaked clothing ignites from a spark.

The hose

• Whip checks on every coupling. A hose that separates under pressure flails hard enough to break a jaw, and the coupling on the end is the part that hits.
• Bleed the pressure before you break a connection. Every time.
• Close the valve at the supply when you finish, not just at the tool.
• Inspect before use — cuts, bulges, worn couplings, missing retaining pins. A bulge is a rupture that has not happened yet.
• Never kink a hose to stop the flow.
• Keep hoses out of walkways or cover them. Air hose is the most tripped-over thing on any site.
• 1926.302(b)(7): hoses over half an inch inside diameter need a safety device at the supply to shut off the air if the hose fails.
• Never hoist or lower tools on the hose.

Pneumatic tools

Tools are secured to the hose so they cannot come off. Nail guns get triggered by the sequential trip, not the bump trip, wherever the work allows — bump firing is how somebody ends up with a nail in a hand. And a pneumatic tool gets disconnected before you change a bit, clear a jam, or set it down for a break.