Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-307 - Safety standards for agriculture › SPECIALIZED OPERATIONS › Part U-2 - Hazardous Materials - Liquified Petroleum Gas › Section 296-307-41031 - Construction and installation of direct gas-fired vaporizers

Current through Register Vol. 24-14, July 15, 2024
Direct gas-fired vaporizers must be constructed, marked,
					 and installed as follows:
(1)
				  According to the requirements of the
American Society of Mechanical
				  Engineers Boiler and Pressure Vessel Code
, 1968, that apply to the
				  maximum working conditions for which the vaporizer is designed.
(2) With the name of the manufacturer; rated
				  Btu input to the burner; the area of the heat exchange surface in square feet;
				  the outside surface of the vaporizer in square feet; and the maximum vaporizing
				  capacity in gallons per hour.
(3)
				  Vaporizers may be connected to the liquid section or the gas section of the
				  storage container, or both. The container must have a manually operated valve
				  in each connection that completely shuts off when desired, all flow of gas or
				  liquid from container to vaporizer.
(4) Vaporizers with a maximum capacity of 35
				  gallons per hour must be located at least 5 feet from container shut-off
				  valves. Vaporizers more than 35 gallon capacity but a maximum of 100 gallons
				  per hour must be located at least 10 feet from the container shut-off valves.
				  Vaporizers having a capacity greater than 100 gallons per hour must be located
				  at least 15 feet from container shut-off valves.
(5) Vaporizers may be installed in buildings,
				  rooms, housings, sheds, or lean-tos used exclusively for vaporizing or mixing
				  of LP-gas. Vaporizing housing structures must be noncombustible, and well
				  ventilated near the floorline and the highest point of the roof. When vaporizer
				  and/or mixing equipment is located in a structure or room attached to or within
				  a building, such structure or room must be separated from the remainder of the
				  building by a wall designed to withstand a static pressure of at least 100
				  pounds per square foot. This wall must have no openings or pipes or conduit
				  passing through it. The structure or room must have adequate ventilation, and a
				  roof or at least one exterior wall of lightweight construction.
(6) Vaporizers must have at or near the
				  discharge, a safety-relief valve providing an effective rate of discharge
				  according to WAC
				  296-307-41025.
				  The relief valve must be located where it is not subjected to temperatures over
				  140°F.
(7) Vaporizers must have
				  suitable automatic means to prevent liquid passing from the vaporizer to the
				  gas discharge piping of the vaporizer.
(8) Vaporizers must have means for manually
				  turning off the gas to the main burner and pilot.
(9) Vaporizers must have automatic safety
				  devices to shut off the flow of gas to main burners if the pilot light should
				  fail. When the flow through the pilot exceeds 2,000 Btu per hour, the pilot
				  also must have an automatic safety device to shut off the flow of gas to the
				  pilot should the pilot flame be extinguished.
(10) Pressure regulating and pressure
				  reducing equipment located within 10 feet of a direct fired vaporizer must be
				  separated from the open flame by an airtight noncombustible
				  partition.
(11) Except as provided
				  in subsection (5) of this section, the following minimum distances must be
				  maintained between direct fired vaporizers and the nearest important building,
				  group of buildings, or line of adjoining property that may be built on:
(a) Ten feet for vaporizers with a vaporizing
				  capacity of 15 gallons per hour or less;
(b) Twenty-five feet for vaporizers with a
				  vaporizing capacity of 16-100 gallons per hour;
(c) Fifty feet for vaporizers with a
				  vaporizing capacity over 100 gallons per hour.