213.0 No definitions.

Labeled. 214.0 Equipment or materials bearing a label of a listing– L agency (accredited conformity assessment body). See Listed (Third Party Certified). [HCD 1 & HCD 2] “Labeled” means equipment or materials to which has been attached a label, symbol or other identifying mark of an organization, approved by the Department, that maintains a periodic inspection program of production of labeled products, instal- lations, equipment, or materials and by whose labeling the manufacturer indicates compliance with appropriate stan- dards or performance in a specified manner. LEL (Lower Explosive Limit). See LFL. mability). LFL (Lower Flammable Limit or Lower Limit of Flam- The minimum concentration of a substance that

propagates a flame through a homogeneous mixture of the substance and air under the specified test conditions. The LFL is sometimes referred to as LEL (Lower Explosive Limit). For the purposes of this definition, LFL and LEL are identical. Limited-Combustible Material. Refers to a building construction material that does not comply with the definition of noncombustible material that, in the form in which it is used, has a potential heat value not exceeding 3500 British thermal units per pound-force (Btu/lb) (8141 kJ/kg), where tested in accordance with NFPA 259, and includes either of the following: (1) Materials having a structural base of noncombustible

material, with a surfacing not exceeding a thickness of

(2) Materials, in the form and thickness used, having neither

a flame-spread index greater than 25 nor evidence of continued progressive combustion, and of such composition that surfaces that would be exposed by cutting through the material on any plane would have neither a flame-spread index greater than 25 nor evidence of continued progressive combustion, where tested in accordance with ASTM E84. Line Contact Installation. An installation in which a furnace is installed so that building joists, studs, or framing are contacted by the furnace jacket upon the lines formed by the intersection of the jacket sides with the top surface. Lineset. A set of two refrigerant pipes that extends from the condenser to the evaporator (cooling coil) in direct systems, consisting of a suction line and a liquid line. Liquefied Petroleum Gas (LP-Gas). Means and includes a material composed predominantly of any of the following hydrocarbons or mixtures of them: propane, propylene, butanes (normal butane or isobutane), and butylenes. When reference is made to liquefied petroleum gas in this code, it shall refer to liquefied petroleum gases in either the liquid or gaseous state. Liquefied Petroleum Gas (LP-Gas) Facilities. Liquefied petroleum gas (LP-Gas) facilities include tanks, containers, container valves, regulating equipment, meters, appurtenances, or any combination thereof for the storage and supply of liquefied petroleum gas for a building, structure, or premises. Liquid-Tight. Constructed and performing in such a manner as not to permit the passage of liquid at any temperature.

s (LP-Gas) Facilities.** Liquefied petroleum gas (LP-Gas) facilities include tanks, containers, container valves, regulating equipment, meters, appurtenances, or any combination thereof for the storage and supply of liquefied petroleum gas for a building, structure, or premises. Liquid-Tight. Constructed and performing in such a manner as not to permit the passage of liquid at any temperature.

[NFPA 96:3.3.35] Listed (Third Party Certified). Equipment or materials included in a list published by a listing agency (accredited conformity assessment body) that maintains periodic inspection of current production of listed equipment or materials and whose listing states either that the equipment or material complies with approved standards or has been tested and found suitable for use in a specified manner. [HCD 1 & HCD 2] “Listed” means all products that appear in a list published by an approved testing or listing agency. For additional informa- tion, see Health and Safety Code Section 17920(h).

(1) Materials having a structural base of noncombustible

material, with a surfacing not exceeding a thickness of 1⁄8 of an inch (3.2 mm), that has a flame-spread index not greater than 50. (2) Materials, in the form and thickness used, having neither

a flame-spread index greater than 25 nor evidence of

2019 CALIFORNIA MECHANICAL CODE 37

DEFINITIONS any other purpose or distributed to any other persons or parti es.

Listed and Listing. [SFM] “Listed” and “Listing” are terms referring to equipment or materials included in a list published by an approved testing laboratory, inspection agency, or other organization concerned with product evalu- ation that maintains periodic inspection of current produc- tions of listed equipment or materials and which listing states that the material or equipment complies with approved nationally recognized codes, standards, or tests and has been tested or evaluated and found suitable for use in a specific manner. These terms shall also mean equipment or materials accepted by the State Fire Marshal as conforming to the pro- visions of these regulations and which are included in a list published by the State Fire Marshal. Listing Agency. An agency accredited by an independent and authoritative conformity assessment body to operate a material and product listing and labeling (certification) system and that are accepted by the Authority Having Jurisdiction, which is in the business of listing or labeling. The system includes initial and ongoing product testing, a periodic inspection on current production of listed (certified) products, and that makes available a published report of such listing in which specific information is included that the material or product is in accordance with applicable standards and found safe for use in a specific manner. [HCD 1 & HCD 2] “List- ing Agency” means an agency approved by the Department that is in the business of listing and labeling products, materials, equipment, and installations tested by an approved testing agency, and that maintains a periodic inspection program on current production of listed products, equipment, and installa- tions, and that at least annually makes available a published report of these listings. For additional information, see Health and Safety Code Section 17920(i). Low-Pressure Hot-Water-Heating Boiler. A boiler furnishing hot water at pressures not exceeding 160 psi (1103 kPa) and at temperatures not exceeding 250°F (121°C). Low-Pressure Steam-Heating Boiler. A boiler furnishing steam at pressures not exceeding 15 psi (103 kPa). Lowside. Refers to the parts of a refrigeration system subjected to approximate evaporator pressure.

215.0Machinery. The refrigeration equipment forming a part of – M – the refrigeration system, including, but not limited to, the following: compressors, condensers, liquid receivers, evaporators, and connecting piping. Machinery Room. [SFM] Machinery Room is a room in which a refrigeration system is permanently installed and operated but not including evaporators located in a cold stor- age room, refrigerator box, air-cooled space or other enclosed space. Closets solely contained within, and opening only into, a room shall not be considered machinery rooms, but shall be considered a part of the machinery rooms in which they are contained or open into. It is not the intent of this definition to cause the space in which unit or self-con- tained systems of Group I refrigerants are locate to be clas- sified as machinery rooms.

losed space. Closets solely contained within, and opening_ only into, a room shall not be considered machinery rooms, but shall be considered a part of the machinery rooms in which they are contained or open into. It is not the intent of this definition to cause the space in which unit or self-con- tained systems of Group I refrigerants are locate to be clas- sified as machinery rooms.

Mechanical Ventilation. Ventilation provided by mechanically powered equipment, such as motor-driven fans and blowers, but not by devices such as wind-driven turbine ventilators and mechanically operated windows. [ASHRAE 62.1:3] Miniature Boiler. A power boiler having an internal shell diameter of 16 inches (406 mm) or less, a gross volume of 5 cubic feet (0.14 m ³ ) or less, a heating surface of 20 square feet (1.86 m ² ) or less (not applicable to electric boilers), and not exceeding 100 psi (689 kPa).

216.0Natural Ventilation. Ventilation provided by thermal, wind,– N or diffusion effects through doors, windows, or other intentional openings in the building. [ASHRAE 62.1:3] Noncombustible Material. As applied to building construction material, means a material that in the form in which it is used is either one of the following: (1) A material that, in the form in which it is used and under

the conditions anticipated, will not ignite, burn, support

(1) A material that, in the form in which it is used and under

the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Materials that are reported as passing ASTM E136 are considered noncombustible material. (2) Material having a structural base of noncombustible

material as defined in item 1 above, with a surfacing

(2) Material having a structural base of noncombustible

material as defined in item 1 above, with a surfacing material not over ¹ ⁄8 of an inch (3.2 mm) thick that has a flame-spread index not higher than 50. Noncombustible does not apply to surface finish materials. Material required to be noncombustible for reduced clearances to flues, heating appliances, or other sources of high temperature shall refer to material in accordance with item 1 above. No material shall be classed as noncombustible that is subject to increase in combustibility or flame-spread index beyond the limits herein established, through the effects of age, moisture, or other atmospheric condition. Nonhazardous Process Piping (NPP). Production material piping or tubing conveying a liquid or gas that is not classified as hazardous production material piping. Nuisance. [HCD 1 & HCD 2] “Nuisance” shall mean any nuisance as defined in Health and Safety Code Section 17920(l). Notes: 1. For applications subject to the Mobilehome Parks Act as referenced in Section 1.8.3.2.2 of this code, refer to Cal- ifornia Code of Regulations, Title 25, Division 1, Chap- ter 2 for the definition of “Nuisance”. 2. For applications subject to the Special Occupancy Parks Act as referenced in Section 1.8.3.2.3 of this code, refer to California Code of Regulations, Title 25, Division 1, Chapter 2.2 for the definition of “Nuisance”.

217.0Occupancy. The purpose for which a building or part – O – thereof is used or intended to be used.

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DEFINITIONS

Occupancy Classification. Classifications are defined in the building code. [HCD 1, HCD 2 & SFM] Whenever the term “Building Code” is used in this code, it shall mean the California Building Code, Title 24, Part 2. Occupational Exposure Limit (OEL). The timeweighted average (TWA) concentration for a normal 8-hour workday and a 40-hour workweek to which nearly all workers can be repeatedly exposed without adverse effect, based on the OSHA PEL, ACGIH TLV-TWA, TERA OARSWEEL, or consistent value. [ASHRAE 34:3] Occupiable Space. An enclosed space intended for human activities excluding those spaces intended primarily for other purposes such as storage rooms and equipment rooms that are only occupied occasionally and for short periods of time.

[ASHRAE 62.1:3] Open Combustible Construction. Combustible building construction, including wall, structural framing, roof, roof ceiling, floor, and floor-ceiling assemblies, adjacent to a grease duct on three or fewer sides where one or more sides require protection in accordance with Section 507.4.

Package Boiler.218.0 A class of boiler defined herein and shall – P – be a boiler equipped and shipped complete with fuel-burning equipment, automatic controls and accessories, and mechanical draft equipment. PE. Polyethylene. PE-AL-PE. Polyethylene-aluminum-polyethylene. PE-RT. Polyethylene of raised temperature. PEL (Permissible Exposure Limit). The time-weighted average concentration [set by the U.S. Occupational Safety and Health Administration (OSHA)] for a normal 8-hour workday and a 40-hour workweek to which nearly all workers can be repeatedly exposed without adverse effect. Chemical manufacturers publish similar recommendations [e.g., acceptable exposure level (AEL), industrial exposure limit (IEL), or occupational exposure limit (OEL), depending on the company], generally for substances for which PEL has not been established. [ASHRAE 34:3] The maximum permitted time-weighted average exposures to be utilized are those published in 29 CFR 1910.1000. PEX. Cross-linked polyethylene. PEX-AL-PEX. Cross-linked polyethylene-aluminum-crosslinked polyethylene. Pilot. A burner smaller than the main burner that is ignited by a spark or other independent and stable ignition source, and that provides ignition energy required to immediately light off the main burner. Piping. The pipe or tube mains for interconnecting the various parts of a system. Piping includes pipe, tube, flanges, bolting, gaskets, valves, fittings the pressure-containing parts of other components such as expansion joints, strainers, and devices that serve such purposes as mixing, separating, snubbing, distributing, metering, or controlling flow, pipe-supporting fixtures and structural attachments. Pitched. To be fixed or set at a desired angle or inclination.

[NFPA 96:3.3.39]

Plenum. An air compartment or chamber including uninhabited crawl space areas above a ceiling or below a floor, including air spaces below raised floors of computer/data processing centers or attic spaces, to one or more ducts are connected and that forms part of either the supply-air, return-air, or exhaust-air system, other than the occupiable space being conditioned. Plumbing Code. The Uniform Plumbing Code promulgated by the International Association of Plumbing and Mechanical Officials, as adopted by this jurisdiction. [HCD 1 & HCD 2] Whenever the term “Plumbing Code” is used in this code, it shall mean the California Plumbing Code, Title 24, Part 5. Portable Cooling Unit. A self-contained refrigerating system, not over 3 horsepower (hp) (2.2 kW) rating that has been factory assembled and tested, installed without supply-air ducts and without connecting any refrigerant-containing parts. This definition shall not include an absorption unit. Portable Evaporative Cooler. An evaporative cooler that discharges the conditioned air directly into the conditioned area without the use of ducts and can be readily transported from place to place without dismantling any portion thereof. Portable Heating Appliance. A heating appliance designed for environmental heating that may have a self-contained fuel supply and is not secured or attached to a building by any means other than by a factory-installed power supply cord. Portable Ventilating Equipment. Ventilating equipment that can be readily transported from place to place without dismantling a portion thereof and that is not connected to a duct. Power Boiler. A boiler in which steam is generated at pressures exceeding 15 psi (103 kPa). Power Boiler Plant. One or more power steam boilers or power hot water boilers and connecting piping and vessels within the same premises. Power Hot Water Boiler (High Temperature WaterBoiler). A boiler used for heating water or liquid to a pressure exceeding 160 psi (1103 kPa) or to a temperature exceeding 250°F (121°C). PP. Polypropylene. Pressure, Design. The maximum working pressure for which a specific part of a refrigeration system is designed. Pressure, Field Test. A test performed in the field to prove system tightness. Pressure-Imposing Element. A device or portion of the equipment used for the purpose of increasing the pressure of the refrigerant vapor. Pressure-Limiting Device. A pressure-responsive mechanism designed to automatically stop the operation of the pressure-imposing element at a predetermined pressure. Pressure-Relief Device. A pressure-actuated valve or rupture member or fusible plug designed to automatically relieve excessive pressure. Pressure Test. The minimum gauge pressure to which a specific system component is subjected under test condition.

2019 CALIFORNIA MECHANICAL CODE 39

DEFINITIONS any other purpose or distributed to any other persons or parti es.

Pressure Vessel (Unfired). A closed container, having a nominal internal diameter exceeding 6 inches (152 mm) and a volume exceeding 1 ¹ ⁄2 cubic feet (0.04 m ³ ), for liquids, gases, vapors subjected to pressures exceeding 15 psi (103 kPa), or steam under a pressure. Pressure Vessel, Refrigerant. A refrigerant-containing receptacle that is a portion of a refrigeration system, but shall not include evaporators, headers, or piping of certain limited size and capacity. Process Piping. Piping or tubing that conveys liquid or gas, which is used directly in research, laboratory, or production processes. Product-Conveying Duct. Ducting used for conveying solid particulates, such as refuse, dust, fumes, and smoke; liquid particulate matter, such as spray residue, mists, and fogs; vapors, such as vapors from flammable or corrosive liquids; noxious and toxic gases; and air at temperatures exceeding 250°F (121°C). Purge. The acceptable method of scavenging the combustion chamber, boiler passes, and breeching to remove combustible gases. PVC. Polyvinyl chloride.

219.0Qualified. A competent and capable person or company that – Q – has met the requirements and training for a given field acceptable to the Authority Having Jurisdiction. Quick-Disconnect Device, Fuel Gas. A hand-operated device that provides a means for connecting and disconnecting an appliance or an appliance connector to a gas supply and that is equipped with an automatic means to shut off the gas supply when the device is disconnected. [NFPA 54:3.3.28.3]

220.0Radiant Room Heater. A room heater designed to transfer – R – heat primarily by direct radiation. [NFPA 211:3.3.88.2.2] Receiver, Liquid. A vessel permanently connected to a refrigeration system by inlet and outlet pipes for storage of liquid. Recirculating Systems. Systems for control of smoke or grease-laden vapors from commercial cooking equipment that do not exhaust to the outside. [NFPA 96:3.3.41] Reclaimed Refrigerants. Refrigerants reprocessed to the same specifications as new refrigerants by any means, including distillation. Such refrigerants have been chemically analyzed to verify that those specifications have been met.

[ASHRAE 15:3] Recovered Refrigerants. Refrigerants removed from a system in any condition without necessarily testing or processing them. [ASHRAE 15:3] Recycled Refrigerants. Refrigerants for which contaminants have been reduced by oil separation, removal of noncondensible gases, and single or multiple passes through filter driers or other devices that reduce moisture, acidity, and particulate matter. [ASHRAE 15:3]

Refrigerants.** Refrigerants removed from a system in any condition without necessarily testing or processing them. [ASHRAE 15:3] Recycled Refrigerants. Refrigerants for which contaminants have been reduced by oil separation, removal of noncondensible gases, and single or multiple passes through filter driers or other devices that reduce moisture, acidity, and particulate matter. [ASHRAE 15:3]

Class A. Refrigerants have an occupational exposure limit (OEL) of not less than 400 parts per million (ppm). Class B. Refrigerants have an OEL of less than 400 ppm. Refrigeration Machinery Room. A room designed to house compressors and refrigerant pressure vessels. Refrigeration Room or Space. A room or space in which an evaporator or brine coil is located for the purpose of reducing or controlling the temperature within the room or space to less than 68°F (20°C). Refrigeration System, Absorption. A heat-operated closed refrigeration cycle in which a secondary fluid, the absorbent, absorbs a primary fluid, the refrigerant that has been vaporized in the evaporator. Refrigeration System, Direct. A system in which the evaporator or condenser of the refrigerating system is in direct contact with the air or other substances to be cooled or heated.

[ASHRAE 15:5.1.1] Refrigeration System, Indirect. A system in which a secondary coolant cooled or heated by the refrigerating system is circulated to the air or other substance to be cooled or heated. Indirect systems are distinguished by the method of application given below. [ASHRAE 15:5.1.2]

Refrigerant Designation. The unique identifying alphanumeric value assigned to an individual refrigerant. Refrigerant Safety Classifications. Made up of a letter (A or B), that indicates the toxicity class, followed by a number (1, 2, or 3), that indicates the flammability class. Refrigerant blends are similarly classified, based on the compositions at their worst cases of fractionation, as separately determined for toxicity and flammability. In some cases, the worst case of fractionation is the original formulation.

Flammability Classification. Refrigerants shall be classified for flammability in accordance with one of the following:

Class 1. Refrigerants that do not show flame propagation where tested in air at 14.7 pound-force per square inch absolute (psia) (101 kPa) and 140°F (60°C). Class 2. Refrigerants having a lower flammability limit (LFL) of more than 0.00625 pound per cubic foot (lb/ft ³ ) (0.10012 kg/m ³ ) at 140°F (60°C), 14.7 psia (101 kPa), and a heat of combustion of less than 8169 British thermal units per pound (Btu/lb) (1.8988 E+07 J/kg). Class 3. Refrigerants that are highly flammable having a LFL of not more than 0.00625 lb/ft ³ (0.10012 kg/m ³ ) at 140°F (60°C) and 14.7 psia (101 kPa) or a heat of combustion not less than 8169 Btu/lb (1.8988 E+07 J/kg). Toxicity Classification. Refrigerants shall be classified for the toxicity in accordance with one of the following:

ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE

40 2019 CALIFORNIA MECHANICAL CODE

DEFINITIONS

Self-Contained. Having all essential working parts, except energy and control connections, so contained in a case or framework that they do not depend on appliances or fastenings outside of the machine. Service Corridor. A fully enclosed passage used for transporting hazardous production materials and purposes other than required exiting. Service Piping. The piping and equipment between the street gas main and the gas piping system inlet that is installed by, and is under the control and maintenance of, the serving gas supplier. Shaft. An interior space enclosed by walls or construction extending through one or more stories or basements that connect openings in successive floors, or floors and roof, to accommodate elevators, dumbwaiters, mechanical equipment, or similar devices to transmit light or ventilation air. Shaft Enclosure. The walls or construction forming the boundaries of a shaft. Shall. Indicates a mandatory requirement. Should. Indicates a recommendation or that which is advised but not required. Single Hazard Area. Where two or more hazards can be simultaneously involved in fire by reason of their proximity, as determined by the Authority Having Jurisdiction. [NFPA 96:3.3.44] Smoke Detector. An approved device that senses visible or invisible particles of combustion. Solid Cooking Fuel. A solid, organic, consumable fuel such as briquettes, mesquite, hardwood, or charcoal. [NFPA 96:3.3.45] Solid-Fuel Cooking Equipment. Cooking equipment that utilizes solid fuel. [NFPA 96:3.3.23.2] This equipment includes ovens, tandoori charcoal pots, grills, broilers, rotisseries, barbecue pits, or other type of cooking equipment that derives all or part of its heat source from the burning of solid cooking fuel. Solvent. A substance (usually liquid) capable of dissolving or dispersing another substance; a chemical compound designed and used to convert solidified grease into a liquid or semiliquid state in order to facilitate a cleaning operation.

[NFPA 96:3.3.46] Spark Arrester. A device or method that minimizes the passage of airborne sparks and embers into a plenum, duct, and flue. [NFPA 96:3.3.48] Standard. A document, the main text of which contains only mandatory provisions using the word “shall” to indicate requirements and that is in a form generally suitable for mandatory reference by another standard or code or for adoption into law. Nonmandatory provisions shall be located in an appendix, footnote, or fine-print note and are not to be considered a part of the requirements of a standard. Stationary Fuel Cell Power Plant. A self-contained package or factory-matched packages that constitute an automatically operated assembly of integrated systems for generating useful electrical energy and recoverable energy that is permanently connected and fixed in place.

ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE ASHRAE

Indirect Open Spray System. A system in which a secondary coolant is in direct contact with the air or other substance to be cooled or heated. [ASHRAE 15:5.1.2.1] Double Indirect Open Spray System. A system in which the secondary substance for an indirect open spray system is heated or cooled by the secondary coolant circulated from a second enclosure. [ASHRAE 15:5.1.2.2] Indirect Closed System. A system in which a secondary coolant passes through a closed circuit in the air or other substance to be cooled or heated. [ASHRAE 15:5.1.2.3] Refrigeration System, Mechanical. A combination of interconnected refrigerant-containing parts constituting one closed refrigerant circuit in which a refrigerant is circulated for the purpose of extracting heat and in which a compressor is used for compressing the refrigerant vapor. Refrigeration System, Self-Contained. A complete factory-assembled and tested system that is shipped in one or more sections and has no refrigerant-containing parts that are joined in the field by other than companion or block valves. Registered Design Professional. An individual who is registered or licensed by the laws of the state to perform such design work in the jurisdiction. Relief Valve, Vacuum. A device which automatically opens or closes for relieving a vacuum with the system, depending on whether the vacuum is above or below a predetermined value. Removable. Capable of being transferred to another location with a limited application of effort and tools. [NFPA 96:3.3.42] Replacement Air. See Air, Makeup. Residential Building. A building or portion thereof designed or used for human habitation. Riser Heat Pipe. A duct that extends at an angle of 45 degrees (0.79 rad) from the horizontal. This definition shall not include any boot connection. Room Heater. A freestanding, nonrecessed, environmental heating appliance installed in the space being heated and not connected to ducts. Room Heater, Unvented. An unvented, self-contained, freestanding, nonrecessed, fuel- gas-burning appliance for furnishing warm air by gravity or fan circulation to the space in which installed, directly from the heater without duct connection. [NFPA 54:3.3.56.6] Rupture Member. A pressure-relief device that operates by the rupture of a diaphragm within the device on a rise to a predetermined pressure.

Seam, Welded.221.0 See Joint, Welded. – S – Secondary Filtration. Fume incinerators, thermal recovery units, air pollution control devices or other filtration media installed in ducts or hoods located in the path of travel of exhaust products after the initial filtration.

2019 CALIFORNIA MECHANICAL CODE 41

DEFINITIONS any other purpose or distributed to any other persons or parti es.

Steam-Heating Boiler. A boiler operated at pressures not exceeding 15 psi (103 kPa) for steam. Strength, Ultimate. The highest stress level that the component can tolerate without rupture. System Outdoor Airflow. The rate of outdoor airflow required at the ventilation system outdoor air intake.

Termination, Duct.222.0 The final or intended end portion of a – T – duct system that is designed and functions to fulfill the obligations of the system in a satisfactory manner. [NFPA 96:3.3.19] Testing Agency. [HCD 1 & HCD 2] See “Approved Test- ing Agency”. Thermal Recovery Unit. A device or series of devices whose purpose is to reclaim only the heat content of air, vapors, gases, or fluids that are being expelled through the exhaust system and to transfer the thermal energy so reclaimed to a location whereby a useful purpose can be served. [NFPA 96:3.3.49] Trained. A person who has become proficient in performing a skill reliably and safely through instruction and practice/field experience acceptable to the Authority Having Jurisdiction.

[NFPA 96:3.3.50] Transition Gas Riser. A listed or approved section or sections of pipe and fittings used to convey fuel gas and installed in a gas piping system for the purpose of providing a transition from belowground to aboveground. Trap. A cuplike or u-shaped configuration located on the inside of a duct system component where liquids can accumulate. [NFPA 96:3.3.51] Type B Gas Vent. A factory-made gas vent listed by a nationally recognized testing agency for venting listed or approved appliances equipped to burn only gas. Type B-W Gas Vent. A factory-made gas vent listed by a nationally recognized testing agency for venting listed or approved gas-fired vented wall furnaces. Type L Gas Vent. A venting system consisting of listed vent piping and fittings for use with oil-burning appliances listed for use with Type L or with listed gas appliances.

223.0UMC. [HCD 1, HCD 2, OSHPD 1, 1R, 2, 3, 4 & 5] – U – The most recent edition of Uniform Mechanical Code published by the International Association of Plumbing and Mechanical Officials. Unit Heater. A heating appliance designed for nonresidential space heating and equipped with an integral means for circulation of air. Unusually Tight Construction. Construction where: (1) Walls and ceilings exposed to the outdoors have a con tinuous water vapor retarder with a rating of 1 perm or less with openings gasketed or sealed. (2) Weatherstripping is on openable windows and doors.

(3) Caulking or sealants are applied to areas such as joints

around window and door frames, between sole plates and floors, between wall-ceiling joints, between wall panels, and at penetrations for plumbing, electrical, and gas lines and at other openings. Use (Material). The placing in action or making available for service by opening or connecting a container utilized for confinement of material, whether a solid, liquid, or gas.

224.0Vacuum. A pressure less than that exerted by the atmos- – V – phere. Valve, Pressure-Relief. A pressure-actuated valve held closed by a spring or other means and designed to automatically relieve pressure in excess of its setting. Valve, Stop. A device in a piping system to shut off the flow of the fluid. Valve, Three-Way-Type Stop. A manually operated valve with one inlet that alternately can stop flow to either of two outlets. Valves, Companion or Block. Pairs of mating stop valves valving off sections of refrigeration systems and arranged so that these sections may be joined before opening these valves or separated after closing them. Vent, Gas. A passageway composed of listed factory-built components assembled in accordance with the manufacturer’s installation instructions for conveying vent gases from appliances or their vent connectors to the outdoors. [NFPA 54:3.3.53] Vent Connector, Gas. That portion of a gas-venting system that connects a listed gas appliance to a gas vent and is installed within the space or area in which the appliance is located. Vent Offset. An arrangement of two or more fittings and pipe installed for the purpose of locating a vertical section of vent pipe in a different but parallel plane with respect to an adjacent section of a vertical vent pipe. [NFPA 54:3.3.102] Vented Appliance Categories.Category I. An appliance that operates with a nonpos itive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

[NFPA 54:3.3.5.11.1] Category II. An appliance that operates with a nonpositive vent static pressure and with a vent gas temperature that can cause excessive condensate production in the vent. [NFPA 54:3.3.5.11.2] Category III. An appliance that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

[NFPA 54:3.3.5.11.3] Category IV. An appliance that operates with a positive vent static pressure and with a vent gas temperature that can cause excessive condensate production in the vent.

[NFPA 54:3.3.5.11.4] Vented Decorative Appliance. A vented appliance whose only function is providing an aesthetic effect of flames.

42 2019 CALIFORNIA MECHANICAL CODE

DEFINITIONS

Vented Wall Furnace. A self-contained, vented, fuel gasburning appliance complete with grilles or equivalent, designed for incorporation in or permanent attachment to the structure of a building and furnishing heated air, circulated by gravity or by a fan, directly into the space to be heated through openings in the casing. [NFPA 54:3.3.45.7] Ventilating Ceiling. A suspended ceiling containing many small apertures through which air, at low pressure, is forced downward from an overhead plenum dimensioned by the concealed space between the suspended ceiling and the floor or roof above. Ventilation System. All of that equipment intended or installed for the purpose of supplying air to or removing air from, any room or space by mechanical means, other than equipment that is a portion of an environmental heating, cooling, absorption, or evaporative cooling system. Venting Collar. The outlet opening of an appliance provided for connection of the vent system. Venting System. The vent or chimney and its connectors, assembled to form a continuous open passageway from an appliance to the outdoors for the purpose of removing products of combustion. This definition also shall include a venting assembly that is an integral part of an appliance. Venting System, Gravity-Type. A system that depends entirely on the heat from the fuel being used to provide the energy required to vent an appliance. Venting System, Power-Type. A system that depends on a mechanical device to provide a positive draft within the venting system. Volume, Internal Gross. The volume as determined from internal dimensions of the container, with no allowance for the volume of the internal parts.

Wall Heater. 225.0 See Vented Wall Furnace. – W – Warm Air Furnace. An environmental heating appliance designed or arranged to discharge heated air through any duct or ducts. This definition shall not include a unit heater. Water Heater or Hot-Water-Heating Boiler. An appliance designed primarily to supply hot water for domestic or commercial purposes and equipped with automatic controls limiting water temperature to a maximum of 210°F (99°C).

No definitions. 226.0 – X –