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Subchapter 7. General Industry Safety Orders
Group 18. Explosives and Pyrotechnics
Article 116. Handling and Use of Explosives--Blasting Operations

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§5280. Pneumatic Loading of Explosives for Blasting.

(a) Construction of Air Loaders.

(1) Blasting agents shall not be loaded into any air loader constructed of copper, copper alloys, or zinc (including galvanized metals) unless the loader is constructed so that such incompatible materials do not come in contact with blasting agents.

(2) An explosive shall not be loaded into any air loader constructed wholly or in part of ferrous metals except that stainless steel may be used.

(3) The vessel that is pressurized on an air loader shall be designed, constructed, inspected, and stamped in compliance with the Unfired Pressure Vessel Safety Orders.

(b) Air Loader Equipment.

(1) A 20-mesh screen, an air trap or a filter shall be installed in the air supply line adjacent to the loader when a pressure vessel is being used.

(2) An air pressure reducing regulator of standard manufacture shall be installed in the air supply line and be a part of the loader assembly for a pressure-type loader.

(3) An air pressure relieving safety valve of adequate capacity shall be installed in the air supply line between the air pressure reducing regulator and the pressure vessel of the air loader. There shall be no valve between the pressure vessel and the pressure relieving device.

(4) An adequate pressure gauge shall be installed in the air supply line between the air pressure reducing regulator and the air loader pressure vessel.

(c) Air Temperature and Pressure.

(1) The temperature of the air supplied to the air loader shall not exceed 150 degrees Fahrenheit.

(2) The air pressure shall not exceed 50 pounds per square inch when explosive materials are being loaded.

(3) The air pressure relieving safety valve shall be set to open at a pressure not to exceed 55 pounds per square inch, when an explosive is being loaded.

(4) When a blasting agent is being loaded, the safety valve shall be set at not more than 110% of the safe loading pressure, but in no case to exceed 110 psi.

(d) Control of Static Electricity and Stray Currents.

(1) There shall be continuous electrical path from the discharge end of the loading tube, through the loading tube, the loading line, the air loader, and to ground. The loading tube shall be static dissipating and shall be at least 2 feet longer than the deepest hole loaded.

(2) Where metal air loaders are on non-conductive rock or earth, an auxiliary ground shall be provided by metal straps or cables of at least #8 American Wire Gauge connected to ground rods. If it is necessary, the ground rods shall be driven into water-filled holes. The total resistance from the discharge end of the loading tube to ground shall not exceed two megohms.

(3) Pneumatic loading equipment shall not be grounded to water lines, airlines, rails, or other permanent electrical grounding systems.

(4) The loading tube and loading hose, if one piece, shall be either of a distinctive design or else identified at least every 18 inches that it is static dissipating.

(e) Operations and Procedures.

(1) The air supply line shall be thoroughly blown out before it is attached to the air loader.

(2) All material poured into a pressure type air loader shall be passed through a screen having openings not larger than half an inch.

(3) Air loaders when used to blow or force stemming into loaded holes shall be thoroughly cleaned before and after such use.


Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment of section heading and section and new Note filed 7-11-2003; operative 8-10-2003 (Register 2003, No. 28).

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