§ 431.302 Definitions concerning walk-in coolers and walk-in freezers. *Adaptive defrost* means a factory-installed defrost control system that reduces defrost frequency by initiating defrosts or adjusting the number of defrosts per day in response to operating conditions (*e.g.,* moisture levels in the refrigerated space, measurements that represent coil frost load) rather than initiating defrost strictly based on compressor run time or clock time.
*Attached split system* means a matched pair refrigeration system which is designed to be installed with the evaporator entirely inside the walk-in enclosure and the condenser entirely outside the walk-in enclosure, and the evaporator and condenser are permanently connected with structural members extending through the walk-in wall.
*Basic model* means all components of a given type of walk-in cooler or walk-in freezer (or class thereof) manufactured by one manufacturer, having the same primary energy source, and which have essentially identical electrical, physical, and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water consumption, or water efficiency; and ( 1 ) With respect to panels, which do not have any differing features or characteristics that affect U-factor.
( 2 ) [Reserved]
CO 2 unit cooler means a unit cooler that includes a nameplate listing only CO2 as an approved refrigerant.
*Dedicated condensing unit* means a positive displacement condensing unit that is part of a refrigeration system (as defined in this section) and is an assembly that ( 1 ) Includes 1 or more compressors, a condenser, and one refrigeration circuit; and
( 2 ) Is designed to serve one refrigerated load.
*Dedicated condensing refrigeration system* means one of the following: ( 1 ) A dedicated condensing unit;
( 2 ) A single-package dedicated system; or
( 3 ) A matched refrigeration system.
*Detachable single-packaged dedicated system* means a system consisting of a dedicated condensing unit and an insulated evaporator section in which the evaporator section is designed to be installed external to the walk-in enclosure and circulating air through the enclosure wall, and the condensing unit is designed to be installed either attached to the evaporator section or mounted remotely with a set of refrigerant lines connecting the two components.
*Display door* means a door that: ( 1 ) Is designed for product display; or
( 2 ) Has 75 percent or more of its surface area composed of glass or another transparent material.
*Display panel* means a panel that is entirely or partially comprised of glass, a transparent material, or both and is used for display purposes.
*Door* means an assembly installed in an opening on an interior or exterior wall that is used to allow access or close off the opening and that is movable in a sliding, pivoting, hinged, or revolving manner of movement. For walk-in coolers and walk-in freezers, a door includes the frame (including mullions), the door leaf or multiple leaves (including glass) within the frame, and any other elements that form the assembly or part of its connection to the wall.
*Door leaf* means the pivoting, rolling, sliding, or swinging portion of a door.
*Door surface area* means the product of the height and width of a walk-in door measured external to the walk-in. The height and width dimensions shall be perpendicular to each other and parallel to the wall or panel of the walk-in to which the door is affixed. The height and width measurements shall extend to the edge of the frame and frame flange (as applicable) to which the door is affixed. For sliding doors, the height and width measurements shall include the track; however, the width (for horizontal sliding doors) or the height (for vertical sliding doors) shall be truncated to the external width or height of the door leaf or leaves and its frame or casings. The surface area of a display door is represented as *A* *dd* and the surface area of a non-display door is represented as *A* *nd*.
*Ducted fan coil unit* means an assembly, including means for forced air circulation capable of moving air against both internal and non-zero external flow resistance, and elements by which heat is transferred from air to refrigerant to cool the air, with provision for ducted installation.
*Ducted multi-circuit single-packaged dedicated system* means a ducted single-packaged dedicated system or a ducted single-packaged dedicated system (as defined in this section) that contains two or more refrigeration circuits that refrigerate a single stream of circulated air.
*Ducted single-packaged dedicated system* means a refrigeration system (as defined in this section) that is a single-packaged assembly designed for use with ducts, that includes one or more compressors, a condenser, a means for forced circulation of refrigerated air, and elements by which heat is transferred from air to refrigerant.
*Envelope* means— ( 1 ) The portion of a walk-in cooler or walk-in freezer that isolates the interior, refrigerated environment from the ambient, external environment; and
( 2 ) All energy-consuming components of the walk-in cooler or walk-in freezer that are not part of its refrigeration system.
*Freight door* means a door that is not a display door and is equal to or larger than 4 feet wide and 8 feet tall.
*High-temperature refrigeration system* means a refrigeration system which is not designed to operate below 45 °F.
*Indoor dedicated condensing refrigeration system* means a dedicated condensing refrigeration system designated by the manufacturer for indoor use or for which there is no designation regarding the use location.
*K-factor* means the thermal conductivity of a material.
*Manufacturer of a walk-in cooler or walk-in freezer* means any person who: ( 1 ) Manufactures a component of a walk-in cooler or walk-in freezer that affects energy consumption, including, but not limited to, refrigeration, doors, lights, windows, or walls; or
( 2 ) Manufactures or assembles the complete walk-in cooler or walk-in freezer.
*Matched condensing unit* means a dedicated condensing unit that is distributed in commerce with one or more unit cooler(s) specified by the condensing unit manufacturer.
*Matched refrigeration system* (also called “matched-pair”) means a refrigeration system including the matched condensing unit and the one or more unit coolers with which it is distributed in commerce.
*Multi-circuit single-packaged dedicated system* means a single-packaged dedicated system or a ducted single-packaged dedicated system (as defined in this section) that contains two or more refrigeration circuits that refrigerate a single stream of circulated air.
*Non-display door* means a door that is not a display door.
*Outdoor dedicated condensing refrigeration system* means a dedicated condensing refrigeration system designated by the manufacturer for outdoor use.
*Panel* means a construction component that is not a door and is used to construct the envelope of the walk-in, i.e., elements that separate the interior refrigerated environment of the walk-in from the exterior.
*Passage door* means a door that is not a freight or display door.
*Refrigerated* means held at a temperature at or below 55 degrees Fahrenheit using a refrigeration system.
*Refrigerated storage space* means a space held at refrigerated (as defined in this section) temperatures.
*Refrigeration system* means the mechanism (including all controls and other components integral to the system's operation) used to create the refrigerated environment in the interior of a walk-in cooler or walk-in freezer, consisting of: ( 1 ) A dedicated condensing refrigeration system (as defined in this section); or
( 2 ) A unit cooler.
*Single-packaged dedicated system* means a refrigeration system (as defined in this section) that is a single-package assembly that includes one or more compressors, a condenser, a means for forced circulation of refrigerated air, and elements by which heat is transferred from air to refrigerant, without any element external to the system imposing resistance to flow of the refrigerated air.
*U-factor* means the heat transmission in a unit time through a unit area of a specimen or product and its boundary air films, induced by a unit temperature difference between the environments on each side.
*Unit cooler* means an assembly, including means for forced air circulation and elements by which heat is transferred from air to refrigerant, thus cooling the air, without any element external to the cooler imposing air resistance.
*Walk-in cooler and walk-in freezer* means an enclosed storage space including, but not limited to, panels, doors, and refrigeration system, refrigerated to temperatures, respectively, above, and at or below 32 degrees Fahrenheit that can be walked into, and has a total chilled storage area of less than 3,000 square feet; however, the terms do not include products designed and marketed exclusively for medical, scientific, or research purposes.
*Walk-in process cooling refrigeration system* means a refrigeration system that is capable of rapidly cooling food or other substances from one temperature to another. The basic model of such a system must satisfy one of the following three conditions: ( 1 ) Be distributed in commerce with an insulated enclosure consisting of panels and door(s) such that the assembled product has a refrigerating capacity of at least 100 Btu/h per cubic foot of enclosed internal volume;
( 2 ) Be a unit cooler having an evaporator coil that is at least four-and-one-half (4.5) feet in height and whose height is at least one-and-one-half (1.5) times the width. The height of the evaporator coil is measured perpendicular to the tubes and is also the fin height, while its width is the finned length parallel to the tubes, as illustrated in Figure 1; or
( 3 ) Be a dedicated condensing unit that is distributed in commerce exclusively with a unit cooler meeting description (2) or with an evaporator that is not a unit cooler, *i.e.,* an evaporator that is not distributed or installed as part of a package including one or more fans.
[74 FR 12074, Mar. 23, 2009, as amended at 76 FR 12504, Mar. 7, 2011; 76 FR 21604, Apr. 15, 2011; 76 FR 33631, June 9, 2011; 79 FR 32123, June 3, 2014; 81 FR 95801, Dec. 28, 2016; 88 FR 28838, May 4, 2023]