Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-307 - Safety standards for agriculture › SPECIALIZED OPERATIONS › Part V - Welding › Section 296-307-48037 - Installation of service piping systems

Current through Register Vol. 24-14, July 15, 2024
(1) Distribution lines must be installed and
				  maintained in a safe operating condition.
(2) Piping may be above or below ground. All
				  piping must be run as directly as practical, protected against physical damage,
				  with an allowance for expansion and contraction, jarring and vibration. Pipe
				  laid underground in earth must be below the frost line and protected against
				  corrosion. After assembly, piping must be thoroughly blown out with air or
				  nitrogen to remove foreign materials. For oxygen piping, only oil-free air,
				  oil-free nitrogen, or oil-free carbon dioxide must be used.
(3) Only piping that has been welded or
				  brazed must be installed in tunnels, trenches or ducts. Shut-off valves must be
				  located outside such conduits. Oxygen piping may be placed in the same tunnel,
				  trench or duct with fuel-gas pipelines, if there is good natural or forced
				  ventilation.
(4) Low points in
				  piping carrying moist gas must be drained into drip pots constructed to permit
				  pumping or draining out the condensate at necessary intervals. Drain valves
				  must be installed for this purpose having outlets normally closed with screw
				  caps or plugs. Open end valves or petcocks are prohibited, except that in drips
				  located outdoors, underground, and not readily accessible, valves may be used
				  at such points if they have means to secure them in the closed position. Pipes
				  leading to the surface of the ground must be cased or jacketed where necessary
				  to prevent loosening or breaking.
(5) Gas cocks or valves must be provided for
				  all buildings at points where they will be readily accessible for shutting off
				  the gas supply to these buildings in any emergency. Underground valve boxes or
				  manholes should be avoided wherever possible. There must be a shut-off valve in
				  the discharge line from the generator, gas holder, manifold or other source of
				  supply.
(6) Shut-off valves must
				  not be installed in safety-relief lines in such a manner that the safety-relief
				  device can be rendered ineffective.
(7) Fittings and lengths of pipe must be
				  examined internally before assembly and, if necessary, freed from scale or
				  dirt. Oxygen piping and fittings must be washed out with a suitable solution
				  that will effectively remove grease and dirt but will not react with oxygen.
Note:
Hot water solutions of caustic soda or trisodium
							 phosphate are effective for this purpose.
(8) Piping must be thoroughly blown out after
				  assembly to remove foreign materials. For oxygen piping, oil-free air, oil-free
				  nitrogen, or oil-free carbon dioxide must be used. For other piping, air or
				  inert gas may be used.
(9) When
				  flammable gas lines or other parts of equipment are being purged of air or gas,
				  open lights or other sources of ignition are prohibited near uncapped
				  openings.
(10) No welding or
				  cutting must be performed on an acetylene or oxygen pipeline, including the
				  attachment of hangers or supports, until the line has been purged. Only
				  oil-free air, oil-free nitrogen, or oil-free carbon dioxide must be used to
				  purge oxygen lines.
97-09-013, recodified as § 296-307-48037, filed
						4/7/97, effective 4/7/97. Statutory Authority:
						RCW
						 49.17.040,[49.17.]050 and [49.17.]060.
						96-22-048, § 296-306A-48037, filed 10/31/96, effective
						12/1/96.