203.0 – A –

Absorption Unit. An absorption refrigeration system that has been factory-assembled and tested prior to its installation. Accepted Engineering Practice. That which conforms to technical or scientific-based principles, test, or standards that are accepted by the engineering profession. Access Panel. A closure device used to cover an opening into a duct, an enclosure, equipment, or an appurtenance.

[NFPA 96:3.3.1] Accessible. Where applied to a device, appliance, or equipment, “accessible” means having access thereto, but which first may require the removal of an access panel, door, or similar obstruction. Accessible, Readily. Having a direct access without the necessity of removing a panel, door, or similar obstruction. Accessory Dwelling Unit [HCD 1 & HCD 2]. An attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. Accessory dwelling units shall include permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as the single-family or multifamily dwelling is or will be situated. (See Government Code Section 65852.2.) Air, Class 1. Air with low contaminant concentration, low sensory-irritation intensity, and inoffensive odor. [ASHRAE 62.1:5.16.1] Air, Class 2. Air with moderate contaminant concentration, mild sensory-irritation intensity, or mildly offensive odors. Class 2 air also includes air that is not necessarily harmful or objectionable, but that is inappropriate for transfer or recirculation to spaces used for different purposes. [ASHRAE 62.1:5.16.1] Air, Class 3. Air with significant contaminant concentration, significant sensory-irritation intensity, or offensive odor.

[ASHRAE 62.1:5.16.1]

Air, Class 4. Air with highly objectionable fumes or gases or with potentially dangerous particles, bioaerosols, or gases, at concentrations high enough to be considered harmful.

[ASHRAE 62.1:5.16.1] Air, Combustion. See Combustion Air. Air, Conditioned. Air that has been treated to achieve a desired level of temperature, humidity, or cleanliness. Air, Dilution. Air that enters a draft hood or draft regulator and mixes with the flue gases. [NFPA 54:3.3.2.2] Air, Exhaust. Air being removed from any space or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts. Air, Makeup. Air that is provided to replace air being exhausted. Air, Outside. Air from outside the building intentionally conveyed by openings or ducts to rooms or to conditioning equipment. Air, Relief. [OSHPD 1, 1R, 2, 3, 4 & 5] Air being exhausted directly from a building or a return duct system which is not contaminated by odors or other contaminants and could oth- erwise be used as return air if not exhausted from the building. Air, Return. Air from the conditioned area that is returned to the conditioning equipment for reconditioning. Air, Supply. Air being conveyed to a conditioned area through ducts or plenums from a heat exchanger of a heating, cooling, absorption, or evaporative cooling system. Air Dispersion Systems. Materials intended for use in air handling systems in exposed locations operating under positive pressure. Air-Handling Unit. A blower or fan used for the purpose of distributing supply air to a room, space, or area. Air Intakes. An opening in a building’s envelope whose purpose is to allow outside air to be drawn into the structure to replace inside air that is removed by exhaust systems or to improve the quality of the inside air by providing a source of air having a lower concentration of odors, suspended particles, or heating content. [NFPA 96:3.3.2] Air-Moving System. A system designed to provide heating, cooling, or ventilation in which one or more air-handling units are used to supply air to a common space or are drawing air from a common plenum or space. Air Pollution Control Devices. Equipment and devices used for the purpose of cleaning air passing through them or by them in such a manner as to reduce or remove the impurities contained therein. [NFPA 96:3.3.3] Anodeless Riser. An assembly of steel-cased plastic pipe used to make the transition between plastic piping installed underground and metallic piping installed aboveground.

[NFPA 54:3.3.4]

2022 CALIFORNIA MECHANICAL CODE 29

DEFINITIONS

Appliance. A device that utilizes an energy source to produce light, heat, power, refrigeration, air conditioning, or compressed fuel gas. This definition also shall include a vented decorative appliance.

Appliance, Fan-Assisted Combustion. An appliance equipped with an integral mechanical means to either draw or force products of combustion through the combustion chamber or heat exchanger. [NFPA 54:3.3.5.4] Appliance, Low-Heat. A fuel-burning appliance that produces a continuous flue gas temperature, at the point of entrance to the flue, of not more than 1000°F (538°C). Appliance, Medium-Heat. A fuel-burning appliance that produces a continuous flue gas temperature, at the point of entrance to the flue, of more than 1000°F (538°C) and less than 2000°F (1093°C). Appliance Categorized Vent Diameter/Area. The minimum vent diameter/area permissible for Category I appliances to maintain a nonpositive vent static pressure when tested in accordance with nationally recognized standards.

[NFPA 54:3.3.6] Appliance Flue Outlet. The opening or openings in a cooking device where vapors, combustion gases, or both leave the cooking device. [NFPA 96:3.3.4] There might or might not be ductwork attached to this opening. Appliance Fuel Connector. An assembly of listed semirigid or flexible tubing and fittings to carry fuel between a fuel-piping outlet and a fuel-burning appliance. Approved. Acceptable to the Authority Having Jurisdiction. Exception: [HCD 1 & HCD 2] “Approved” means meeting the approval of the Enforcing Agency, except as otherwise provided by law, when used in connection with any system, material, type of construction, fixture or appliance as the result of investigations and tests conducted by the agency, or by reason of accepted principles or tests by national author- ities, or technical, health, or scientific organizations or agen- cies. Notes : (1) See Health and Safety Code Section 17920 for

“Approved” as applied to residential construction and buildings or structures accessory thereto, as referenced in Sections 1.8.2.1.1 and 1.8.2.1.2. (2) See Health and Safety Code Section 17921.1 for

“Approved” as applied to the use of hotplates in resi- dential construction referenced in Sections 1.8.2.1.1 and 1.8.2.1.2. (3) See Health and Safety Code Section 19966 for

“Approved” as applied to Factory-Built Housing as ref- erenced in Sections 1.8.2.1.1 and 1.8.2.1.2. (4) See Health and Safety Code Section 18201 for

“Approved” as applied to Mobilehome Parks as refer- enced in Section 1.8.2.1.3. (5) See Health and Safety Code Section 18862.1 for

“Approved” as applied to Special Occupancy Parks as referenced in Section 1.8.2.1.3.

Approved Testing Agency. An organization primarily established for purposes of testing to approved standards and approved by the Authority Having Jurisdiction. [HCD 1 & HCD 2] “Approved Testing Agency” is any agency which is determined by the Enforcing Agency, except as otherwise pro- vided by statute, to have adequate personnel and expertise to carry out the testing of systems, materials, and various types of construction, fixtures or appliances. Appurtenance. An accessory or a subordinate part that enables the primary device to perform or improves its intended function. [NFPA 96:3.3.5] Assembly Building. A building or a portion of a building used for the gathering together of 50 or more persons for such purposes as deliberation, education, instruction, worship, entertainment, amusement, drinking, dining, or awaiting transportation. [HCD 1, HCD 2 and SFM] Refer to the Cal- ifornia Building Code, Title 24, Part 2 for use and occupancy classification. Authority Having Jurisdiction. The organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, installations, or procedures. The Authority Having Jurisdiction shall be a federal, state, local, or other regional department or an individual such as a plumbing official, mechanical official, labor department official, health department official, building official, or others having statutory authority. In the absence of statutory authority, the Authority Having Jurisdiction may be some other responsible party. This definition shall include the Authority Having Jurisdiction’s duly authorized representative. [HCD 1, HCD 2, OSHPD 1, 1R, 2, 3 & 5 and SFM] “Authority Having Jurisdiction” shall mean “Enforcing Agency” as defined in Section 207.0 of this code. Automatic. That which provides a function without the necessity of human intervention. Automatic Boiler. A boiler equipped with certain controls and limit devices. Azeotrope. A refrigerant blend containing two or more refrigerants whose equilibrium vapor and liquid phase compositions are the same at a given pressure. At this pressure, the slope of the temperature vs. composition curve equals zero, which mathematically is expressed as ( dt / dx ) p = 0, which, in turn, implies the occurrence of a maximum, minimum, or saddle point temperature. Azeotropic blends exhibit some segregation of components at other conditions. The extent of the segregation depends on the particular azeotrope and the application. [ASHRAE 34:3]