Definitions.
40 C.F.R. § 60.391
in effect(a) All terms used in this subpart that are not defined below have the meaning given to them in the Act and in subpart A of this part.
Applied coating solids means the volume of dried or cured coating solids which is deposited and remains on the surface of the automobile or light-duty truck body.
Automobile means a motor vehicle capable of carrying no more than 12 passengers.
Automobile and light-duty truck body means the exterior surface of an automobile or light-duty truck including hoods, fenders, cargo boxes, doors, and grill opening panels.
Bake oven means a device that uses heat to dry or cure coatings.
Electrodeposition (EDP) means a method of applying a prime coat by which the automobile or light-duty truck body is submerged in a tank filled with coating material and an electrical field is used to effect the deposition of the coating material on the body.
Electrostatic spray application means a spray application method that uses an electrical potential to increase the transfer efficiency of the coating solids. Electrostatic spray application can be used for prime coat, guide coat, or topcoat operations.
Flash-off area means the structure on automobile and light-duty truck assembly lines between the coating application system (dip tank or spray booth) and the bake oven. Flash-off area also means the structure between spray booths in a wet-on-wet coating process in which some of the solvent evaporates before the next spray booth; the flash off area may be ambient temperature or heated to accelerate evaporation.
Guide coat operation means the guide coat spray booth, flash-off area and bake oven(s) which are used to apply and dry or cure a surface coating between the prime coat and topcoat operation on the components of automobile and light-duty truck bodies.
Light-duty truck means any motor vehicle rated at 3,850 kilograms gross vehicle weight or less, designed mainly to transport property.
Plastic body means an automobile or light-duty truck body constructed of synthetic organic material.
Plastic body component means any component of an automobile or light-duty truck exterior surface constructed of synthetic organic material.
Prime coat operation means the prime coat spray booth or dip tank, flash-off area, and bake oven(s) which are used to apply and dry or cure the initial coating on components of automobile or light-duty truck bodies.
Purge or line purge means the coating material expelled from the spray system when clearing it.
Solids Turnover Ratio (RT) means the ratio of total volume of coating solids that is added to the EDP system in a calendar month divided by the total volume design capacity of the EDP system.
Solvent-borne means a coating which contains five percent or less water by weight in its volatile fraction.
Spray application means a method of applying coatings by atomizing the coating material and directing the atomized material toward the part to be coated. Spray applications can be used for prime coat, guide coat, and topcoat operations.
Spray booth means a structure housing automatic or manual spray application equipment where prime coat, guide coat, or topcoat is applied to components of automobile or light-duty truck bodies.
Surface coating operation means any prime coat, guide coat, or topcoat operation on an automobile or light-duty truck surface coating line.
Topcoat operation means the topcoat spray booth, flash-off area, and bake oven(s) which are used to apply and dry or cure the final coating(s) on components of automobile and light-duty truck bodies.
Transfer efficiency means the ratio of the amount of coating solids transferred onto the surface of a part or product to the total amount of coating solids used.
VOC content means all volatile organic compounds that are in a coating expressed as kilograms of VOC per liter of coating solids.
Volume Design Capacity of EDP System (LE) means the total liquid volume that is contained in the EDP system (tank, pumps, recirculating lines, filters, etc.) at its designed liquid operating level.
Waterborne or water reducible means a coating which contains more than five weight percent water in its volatile fraction.
(b) The nomenclature used in this subpart has the following meanings:
Caj = concentration of VOC (as carbon) in the effluent gas flowing through stack (j) leaving the control device (parts per million by volume),
Cbi = concentration of VOC (as carbon) in the effluent gas flowing through stack (i) entering the control device (parts per million by volume),
Cfk = concentration of VOC (as carbon) in the effluent gas flowing through exhaust stack (k) not entering the control device (parts per million by volume),
Dci = density of each coating (i) as received (kilograms per liter),
Ddj = density of each type VOC dilution solvent (j) added to the coatings, as received (kilograms per liter),
Dr = density of VOC recovered from an affected facility (kilograms per liter),
E = VOC destruction or removal efficiency of the control device,
F = fraction of total VOC which is emitted by an affected facility that enters the control device,
G = volume weighted average mass of VOC per volume of applied solids (kilograms per liter),
Lci = volume of each coating (i) consumed, as received (liters),
Lcil = Volume of each coating (i) consumed by each application method (l), as received (liters),
Ldj = volume of each type VOC dilution solvent (j) added to the coatings, as received (liters),
Lr = volume of VOC recovered from an affected facility (liters),
Ls = volume of solids in coatings consumed (liters),
LE = the total volume of the EDP system (liters),
Md = total mass of VOC in dilution solvent (kilograms),
M0 = total mass of VOC in coatings as received (kilograms),
Mr = total mass of VOC recovered from an affected facility (kilograms),
N = volume weighted average mass of VOC per volume of applied coating solids after the control device
Qaj = volumetric flow rate of the effluent gas flowing through stack (j) leaving the control device (dry standard cubic meters per hour),
Qbi = volumetric flow rate of the effluent gas flowing through stack (i) entering the control device (dry standard cubic meters per hour),
Qfk = volumetric flow rate of the effluent gas flowing through exhaust stack (k) not entering the control device (dry standard cubic meters per hour),
T = overall transfer efficiency,
Tl = transfer efficiency for application method (l),
Vsi = proportion of solids by volume in each coating (i) as received
Woi = proportion of VOC by weight in each coating (i), as received
Source: ecfr_bulkFetched: 7/26/2026
Source: eCFR APIURL: https://www.ecfr.gov/api/versioner/v1/full/2024-07-01/title-40.xml?part=60Fetched: 5/31/2026