OAR 340-232-0190
Open Top Vapor Degreasers


The owner or operator of all open top vapor degreasers must comply with the following equipment specifications:


Be equipped with a cover that may be readily opened and closed. When a degreaser is equipped with a lip exhaust, the cover must be located below the lip exhaust. The cover must move horizontally or slowly so as not to agitate and spill the solvent vapor. The degreaser must be equipped with at least the following three safety switches:


Condenser flow switch and thermostat to shut off sump heat if coolant is either not circulating or too warm;


Spray safety switch to shut off spray pump or conveyor if the vapor level drops excessively, (e.g., greater than 10 cm (4 inches));


Vapor level control thermostat to shut off sump heat when vapor level rises too high.


Intentionally left blank —Ed.


A closed design such that the cover opens only when the part enters or exits the degreaser and when the degreaser starts up, forming a vapor layer, the cover may be opened to release the displaced air, and either;


A freeboard ratio equal to or greater than 0.75; or


A freeboard, refrigerated or cold water, chiller.


Post a permanent and conspicuous pictograph or instructions clearly explaining the following work practices:


Do not degrease porous or absorbent materials such as cloth, leather, wood or rope;


The cover of the degreaser must be closed at all times except when processing workloads;


When the cover is open the lip of the degreaser must not be exposed to steady drafts greater than 15.3 meters per minute (50 feet/minute);


Rack parts so as to facilitate solvent drainage from the parts;


Workloads must not occupy more than one-half of the vapor-air interface area;


When using a powered hoist, the vertical speed of parts in and out of the vapor zone must be less than 3.35 meters per minute (11 feet/minute);


Degrease the workload in the vapor zone until condensation ceases;


Spraying operations must be done within the vapor layer;


Hold parts in the degreaser until visually dry;


When equipped with a lip exhaust, the fan must be turned off when the cover is closed;


The condenser water must be turned on before the sump heater when starting up a cold vapor degreaser. The sump heater must be turned off and the solvent vapor layer allowed to collapse before closing the condenser water when shutting down a hot vapor degreaser;


Water may not be visible in the solvent stream from the water separator.


A routine inspection and maintenance program must be implemented for the purpose of preventing and correcting solvent losses, as for example, from dripping drain taps, cracked gaskets, and malfunctioning equipment. Leaks must be repaired immediately.


Sump drainage and transfer of hot or warm solvent must be carried out using threaded or other leak-proof couplings.


Still and sump bottoms must be kept in closed containers.


Waste solvent must be stored in covered containers and returned to the supplier or a disposal firm handling solvents for final disposal, such that no greater than 20 percent of the waste (by weight) can evaporate into the atmosphere. Handling of the waste must also be done in accordance with DEQ’s Solid and Hazardous Waste Rules, OAR 340 division 100.


Exhaust ventilation may not exceed 20 cubic meters/minute per square meter (65 cubic feet per minute per square foot) of degreaser open area, unless necessary to meet OSHA requirements. Ventilation fans may not be used near the degreaser opening.
NOTE: This rule is included in the State of Oregon Clean Air Act Implementation Plan that EQC adopted under OAR 340-200-0040 (State of Oregon Clean Air Act Implementation Plan).

Source: Rule 340-232-0190 — Open Top Vapor Degreasers, https://secure.­sos.­state.­or.­us/oard/view.­action?ruleNumber=340-232-0190.

Last Updated

Jun. 8, 2021

Rule 340-232-0190’s source at or​.us