The Occupational Safety and Health Administration (OSHA) is responsible for promoting workplace health and safety in the United States, and it enforces standards for acceptable practices for a wide range of workplace activities. OSHA limits air pressure from open outlets because of risk of injury through dead-ending.
Dead-ending occurs when the nozzle or outlet of a hose, tube or other aperture is blocked. Blocking or "dead-ending" a high-air-pressure outlet with a hand or other body part can lead to air entering the body through the skin, causing soft tissue damage or an air bubble in the bloodstream, known as an embolism. If the air enters through a cavity such as a nostril or ear, physical injury can be serious.
High-Pressure Air in the Workplace
A threat of workplace injuries from dead-ending of high-pressure air jets arises primarily in the use of compressed air guns for cleaning purposes. Very high-pressure air is often used to drive power tools, but is also effective at removing detritus when sprayed through a nozzle or cleaning lance.
Under standard number 1910.242, regulating the use of hand and portable powered tools and equipment, OSHA has issued a directive limiting the pressure of air expelled through the nozzle of equipment used for cleaning purposes to less than 30 psi, or pounds per square inch. OSHA recommends the use of air pressure regulators, which can control the pressure of air supplied to the outlet of a cleaning tool, while allowing higher-pressure air to be driven directly to power tools.