NFPA 86-1999 Standard for Ovens and Furnaces

NFPA 86-1999 Standard for Ovens and Furnaces. Separator, Oil. An oil reservoir with baffles used to mini- mize the discharge of oil mist from the exhaust of a rotary mechanical vacuum pump. Shall. Indicates a mandatory requirement. Should. Indicates a recommendation or that which is advised but not required. Special Atmosphere. Prepared gas or gas mixtures that are introduced into the work chamber of a furnace to replace air, generally to protect or intentionally change the surface of the material undergoing heat processing (heat treatment). Special Atmosphere, Carrier Gas. Any gas or liquid compo- nent of the special atmosphere that represents a sufficient portion of the special atmosphere gas volume in the furnace so that, if the flow of this component gas or liquid ceases, the total flow of the special atmosphere in the furnace is not sufficient to maintain a positive pressure in that furnace. Special Atmosphere, Flammable. Gases that are known to be flammable and predictably ignitable where mixed with air. Special Atmosphere, Generated. Atmospheres created in an ammonia dissociator, exothermic generator, or endother- mic generator by dissociation or chemical reaction of reaction air and reaction gas. Special Atmosphere, Indeterminate. Atmospheres that con- tain components that, in their pure state, are flammable but that, in the mixtures used (diluted with nonflammable gases), are not reliably and predictably flammable. Special Atmosphere, Inert (Purge Gas). Nonflammable gases that contain less than 1 percent oxygen. Special Atmosphere, Nonflammable. Gases that are known to be nonflammable at any temperature. Special Atmosphere, Synthetic. Those atmospheres such as anhydrous ammonia, hydrogen, nitrogen, or inert gases obtained from compressed gas cylinders or bulk storage tanks and those derived by chemical dissociation or mixing of hydrocarbon fluids. Synthetic atmospheres include mixtures of synthetic and generated atmospheres. Switch, Differential Flow. A switch that is activated by the flow of a gaseous or liquid fluid. This flow is detected by mea- suring pressure at two different points to produce a pressure differential across the sensor. Switch, Flow. A switch that is activated by the flow of a fluid in a duct or piping system. Switch, High Fuel Pressure. A pressure-activated device arranged to effect a safety shutdown of the burner system in the event of abnormally high fuel pressure. Switch, Limit. A switching device that actuates when an operating limit has been reached. Switch, Low Fuel Pressure. A pressure-activated device arranged to effect a safety shutdown of the...