Page 32 - 2018_IMC

DEFINITIONS

Vented closed system. A system in which a secondary gas compartment steamers (both pressure and atmospheric)
coolant is cooled or heated by the refrigerating system and and electric and gas cheesemelters.
then passed through a closed circuit in the air or other sub- [FG] LIMIT CONTROL. A device responsive to changes in
stance to be cooled or heated, except that the evaporator or pressure, temperature or level for turning on, shutting off or
condenser is placed in an open or appropriately vented throttling the gas supply to an appliance.
tank.
LIMITED CHARGE SYSTEM. A system in which, with
INDIRECT SOLAR SYSTEM. A solar thermal system in the compressor idle, the design pressure will not be exceeded
which the gas or liquid in the solar collector loop circulates when the refrigerant charge has completely evaporated.
between the solar collector and a heat exchanger and such gas [A] LISTED. Equipment, materials, products or services
or liquid is not drained from the system or supplied to the included in a list published by an organization acceptable to
load during normal operation.
the code official and concerned with evaluation of products or
INFILTRATION. Uncontrolled inward air leakage to condi- services that maintains periodic inspection of production of
tioned spaces through unintentional openings in ceilings, listed equipment or materials or periodic evaluation of services
floors and walls from unconditioned spaces or the outdoors and whose listing states either that the equipment, material,
caused by pressure differences across these openings result- product or service meets identified standards or has been tested
ing from wind, the stack effect created by temperature differ- and found suitable for a specified purpose.
ences between indoors and outdoors, and imbalances between LIVING SPACE. Space within a dwelling unit utilized for
supply and exhaust airflow rates. living, sleeping, eating, cooking, bathing, washing and sanita-
INTERLOCK. A device actuated by another device with tion purposes.
which it is directly associated, to govern succeeding opera- LOW-PROBABILITY PUMP. A pump that does not rely
tions of the same or allied devices. A circuit in which a given on a dynamic shaft seal as a singular means of containment to
action cannot occur until after one or more other actions have prevent atmospheric release of the pumped fluid.
taken place.
LOWER EXPLOSIVE LIMIT (LEL). See “LFL.”
JOINT, FLANGED. A joint made by bolting together a pair LOWER FLAMMABLE LIMIT (REFRIGERANT)
of flanged ends.
(LFL). The minimum concentration of refrigerant that is
JOINT, FLARED. A metal-to-metal compression joint in capable of propagating a flame through a homogeneous mix-
which a conical spread is made on the end of a tube that is ture of refrigerant and air.
compressed by a flare nut against a mating flare.
[F] LOWER FLAMMABLE LIMIT (LFL). The minimum
JOINT, PLASTIC ADHESIVE. A joint made in thermoset concentration of vapor in air at which propagation of flame
plastic piping by the use of an adhesive substance that forms will occur in the presence of an ignition source. The LFL is
a continuous bond between the mating surfaces without dis- sometimes referred to as LEL or lower explosive limit.
solving either one of them. LOW-PRESSURE HOT-WATER-HEATING BOILER.
JOINT, PLASTIC HEAT FUSION. A joint made in ther- A boiler furnishing hot water at pressures not exceeding 160
moplastic piping by heating the parts sufficiently to permit psi (1103 kPa) and at temperatures not exceeding 250ºF
fusion of the materials when the parts are pressed together. (121ºC).
JOINT, PLASTIC SOLVENT CEMENT. A joint made in LOW-PRESSURE STEAM-HEATING BOILER. A
thermoplastic piping by the use of a solvent or solvent cement boiler furnishing steam at pressures not exceeding 15 psi (103
that forms a continuous bond between the mating surfaces. kPa).
JOINT, SOLDERED. A gas-tight joint obtained by the join- LOW-PROBABILITY SYSTEMS. A refrigeration system
ing of metal parts with metallic mixtures of alloys that melt at in which the basic design or the location of components is
temperatures between 400ºF (204ºC) and 1,000ºF (538ºC). such that a leakage of refrigerant from a failed connection,
seal or component will not enter an occupancy-classified
JOINT, WELDED. A gas-tight joint obtained by the joining
of metal parts in molten state. area, other than the machinery room.
LOW-SIDE PRESSURE. The parts of a refrigerating sys-
[A] LABELED. Equipment, materials or products to which
have been affixed a label, seal, symbol or other identifying tem subject to evaporator pressure.
mark of a nationally recognized testing laboratory, approved MACHINERY ROOM. An enclosed space that is required
agency or other organization concerned with product evalua- by Chapter 11 to contain refrigeration equipment and to com-
tion that maintains periodic inspection of the production of ply with Sections 1105 and 1106.
the labeled items and whose labeling indicates either that the MECHANICAL DRAFT SYSTEM. A venting system
equipment, material or product meets identified standards or designed to remove flue or vent gases by mechanical means,
has been tested and found suitable for a specified purpose. that consists of an induced-draft portion under nonpositive
LIGHT-DUTY COOKING APPLIANCE. Light-duty static pressure or a forced-draft portion under positive static
cooking appliances include gas and electric ovens (including pressure.
standard, bake, roasting, revolving, retherm, convection, Forced-draft venting system. A portion of a venting sys-
combination convection/steamer, countertop conveyorized tem using a fan or other mechanical means to cause the
baking/finishing, deck and pastry), electric and gas steam- removal of flue or vent gases under positive static pres-
jacketed kettles, electric and gas pasta cookers, electric and sure.

2018 INTERNATIONAL MECHANICAL CODE  15
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