It depends. Cal/OSHA requires a permit if the air compressor tank is 1.5 cubic feet in volume or larger, OR when the safety valve is set greater than 150 pounds per square inch (psi).
Tanks with less than 1.5 cubic feet of air AND less than 150 psi ARE EXEMPT.
However, ALL air compressor tanks (whether over or under the 1.5 cubic feet volume and 150 psi) have to be inspected before they are put into service, to ensure they comply with Cal/OSHA regulations on proper tank material, design, and construction.
ALL air compressor tanks should have a nameplate with the ASME code symbol (a clover leaf with a “U” or “UM”) on the tank to indicate it is in compliance with ASME Code and meets all safety and construction regulations.
Cal/OSHA’s Pressure Vessel Unit is responsible for all air compressor tank inspections and permits. For more information or to schedule an inspection, they can be contacted either online at firstname.lastname@example.org, or by phone at (510) 622-3066 for the Oakland Office or (714) 567-7208 for the Santa Ana Office.