Compressed Air Safety

General safety requirements for compressed air

The following precautions pertain to the use of compressed air in machine shops:

  1. All pipes, hoses, and fittings must have a rating of the maximum pressure of the compressor. Compressed air pipelines should be identified (psi) as to maximum working pressure.
  2. Air supply shutoff valves should be located (as near as possible) at the point-of-operation.
  3. Air hoses should be kept free of grease and oil to reduce the possibility of deterioration.
  4. Hoses should not be strung across floors or aisles where they are liable to cause personnel to trip and fall. When possible, air supply hoses should be suspended overhead, or otherwise located to afford efficient access and protection against damage.
  5. Hose ends must be secured to prevent whipping if an accidental cut or break occurs.
  6. Pneumatic impact tools, such as riveting guns, should never be pointed at a person.
  7. Before a pneumatic tool is disconnected (unless it has quick disconnect plugs), the air supply must be turned off at the control valve and the tool bled.
  8. Compressed air must not be used under any circumstances to clean dirt and dust from clothing or off a person’ s skin. Shop air used for cleaning should be regulated to 15 psi unless equipped with diffuser nozzles to provide lessor pressure.
  9. Goggles, face shields or other eye protection must be worn by personnel using compressed air for cleaning equipment.
  10. Static electricity can be generated through the use of pneumatic tools. This type of equipment must be grounded or bonded if it is used where fuel, flammable vapors or explosive atmospheres are present.

 

Safety Requirements for Operating & Maintaining Compressed Air Machinery:

All components of compressed air systems should be inspected regularly by qualified and trained employees. Maintenance superintendents should check with state and/or insurance companies to determine if they require their own inspection of this equipment. Operators need to be aware of the following:

Air receivers:

The maximum allowable working pressures of air receivers should never be exceeded except when being tested. Only hydrostatically tested and approved tanks shall be used as air receivers.

  1. Air tanks and receivers should be equipped with inspection openings, and tanks over 36 inches in diameter should have a manhole. pipelug openings should be provided on tanks with volumes of less than five cubic feet.
  2. The intake and exhaust pipes of small tanks, similar to those used in garages, should be made removable for interior inspections.
  3. No tank or receiver should be altered or modified by unauthorized persons.
  4. Air receivers should be fitted with a drain cock that is located at the bottom Of the receiver.
  5. Receivers should be drained frequently to prevent accumulation of liquid inside the unit. Receivers having automatic drain systems are exempt from this Requirement.
  6. Air tanks should be located so that the entire outside surfaces can be easily inspected. Air tanks should not be buried or placed where they cannot be seen for frequent inspection.
  7. Each air receiver shall be equipped with at least one pressure gauge and an ASME safety valve of the proper design.
  8. A safety (spring loaded) release valve shall be installed to prevent the receiver from exceeding the maximum allowable working pressure.
  9. Only qualified personnel should be permitted to repair air tanks, and all work must be done according to established safety standards.

Air Distribution Lines:

  1. Air lines should be made of high quality materials, fitted with secure connections.
  2. Only standard fittings should be used on air lines.
  3. Operators should avoid bending or kinking air hoses.
  4. Air hoses should not be placed where they will create tripping hazards.
  5. Hoses should be checked to make sure they are properly connected to pipe outlets before use.
  6. Air lines should be inspected frequently for defects, and any defective equipment repaired or replaced immediately.
  7. Compressed air lines should be identified as to maximum working pressures (psi), by tagging or marking pipeline outlets.

Pressure regulation Devices:

  1. Only qualified personnel should be allowed to repair or adjust pressure regulating equipment.
  2. Valves, gauges and other regulating devices should be installed on compressor equipment in such a way that cannot be made inoperative.
  3. Air tank safety valves should be set no less than 15 psi or 10 percent (whichever is greater) above the operating pressure of the compressor but never higher than the maximum allowable working pressure of the air receiver.
  4. Air lines between the compressor and receiver should usually not be equipped with stop valves. Where stop valves are necessary and authorized, ASME safety valves should be installed between the stop valves and the compressor.
  5. The Safety valves should be set to blow at pressures slightly above those necessary to pop the receiver safety valves.
  6. Blowoff valves should be located on the equipment and shielded so sudden blowoffs will not cause personnel injuries or equipment damage.
  7. Case iron seat or disk safety valves should be ASME approved and stamped for intended service application.
  8. If the design of a safety or a relief valve is such that liquid can collect on the discharge side of the disk, the valve should be equipped with a drain at the lowest point where liquid can collect.
  9. Safety valves exposed to freezing temperatures should be located so water cannot collect in the valves. Frozen valves must be thawed and drained before operating the compressor.

Air Compressor Operation:

  1. Air compressor equipment should be operated only by authorized and trained personnel.
  2. The air intake should be from a clean, outside, fresh air source. Screens or filters can be used to clean the air.
  3. Air compressors should Never be operated at speeds faster than the manufacturers recommendation.
  4. Equipment should not become overheated.
  5. Moving parts, such as compressor flywheels, pulleys, and belts that could be hazardous should be effectively guarded.

Compressed Air Equipment Maintenance:

  1. Only authorized and trained personnel should service and maintain air compressor equipment.
  2. Exposed, non current-carrying, metal parts of compressor should be effectively grounded.
  3. Low flash point lubricants should not be used on compressors because of its high operating temperatures that could cause a fire or explosion.
  4. Equipment should not be over lubricated.
  5. Gasoline or diesel fuel powered compressors shall not be used indoors.
  6. Equipment placed outside but near buildings should have the exhausts directed away from doors, windows and fresh air intakes.
  7. Soapy water of lye solutions can be used to clean compressor parts of carbon deposits, but kerosene or other flammable substances should not be used. Frequent cleaning is necessary to keep compressors in good working condition.
  8. The air systems should be completely purged after each cleaning.
  9. During maintenance work, the switches of electrically operated compressors should be locked open and tagged to prevent accidental starting.
  10. Portable electric compressors should be disconnected from the power supply before performing maintenance.