Installation

(1) All Air Tanks shall be available for complete External Inspection, and shall be so installed that there will be not less than 12 inches between the Air Tank and any floor, wall, ceiling or other obstruction, except where an Air Tank is attached to a portable compressor by means of straps and is removable for complete inspection. The 12-inch clearance may be waived by the District Engineering Inspector who shall document in their report that there was not a clearance of 12 inches, but that a complete External and Internal Inspection was made. The name plate, safety valve, drain, pressure gauge, tank bottom, and inspection openings shall be readily visible and accessible if the clearance requirement is to be waived. (Mass. Register #1539, 1/17/2025) (2) In case of vertical Air Tanks, the bottom head if dished shall have the pressure on the concave side to ensure complete drainage. (3) Vertical Air Tanks with a base ring shall have unobstructed access to the Air Tank bottom for inspection. (4) Air Tanks in a fixed installation shall be secured to prevent movement. (5) Steel or another metallic piping and fittings shall be used from the Air Tank outlet to the first block valve and on all vessel penetrations and nozzles. (6) Air Tanks that can be isolated with block valves shall have a pressure relief valve attached to the Pressure Vessel. (7) Air Tanks that can be isolated with block valves shall have a pressure gage attached to the Pressure Vessel per 522 CMR 7.00. (8) The connection to the pressure relief valve shall be as short as possible and not reduced. (9) The pressure relief valve shall discharge to a safe location. (10) The pressure relief valve shall be sized to relieve the capacity of all compressors which may operate at one time. (11) In systems with multiple Air Tanks, all Air Tanks shall have a safety relief valve which lifts at the pressure of that Air Tank with the lowest MAWP or other means shall be provided to prevent pressurizing any Air Tank to a pressure greater than that Air Tank’s MAWP. (12) Air Tanks shall be protected from external corrosion. (13) Automatic drains may be used in addition to the drain required by 522 CMR 7.00, provided that there is a manual by-pass valve around the automatic drain so that verification of the automatic drain’s operation can be made. (14) All Air Tanks shall be protected by such safety valves and indicating and controlling devices as will ensure their safe operation. These devices shall be so constructed, located, and installed that they cannot readily be rendered inoperative.