You must:
(1) Provide an automatic fire extinguishing system or an automatic dip tank cover for any hardening and tempering tank that uses flammable or combustible liquids and:
– Holds five hundred gallons (1893 L) or more of liquid
or
– Has twenty-five square feet (2.37 m2) or more of liquid surface area.
(2) Prevent fires.
• Make sure hardening and tempering tanks are:
– Not located on or near combustible flooring
– Located as far away as practical from furnaces
– Equipped with noncombustible hoods and vents (or equally effective devices) for venting to the outside.
• Treat vent ducts as flues and keep them away from combustible material, particularly roofs.
(3) Make sure air under pressure is not used to:
• Fill the tank
or
• Agitate the liquid in the tank.
(4) Equip each tank with an alarm that will sound when the temperature is within 50°F (10°C) of the liquid's flashpoint (alarm set point).
(5) Make sure a limit switch shuts down conveyors supplying work to the tank when the temperature reaches the alarm setpoint, if operationally practical.
(6) Have a circulating cooling system if the temperature of the liquid can exceed the alarm set point.
Note: | The bottom drain of the tank may be combined with the oil circulating system if the requirements for bottom drains in WAC 296-307-45515 are satisfied. |