CMC · California Mechanical Code
Definitions
Chapter 2 of the CMC defines the technical terms used in the code, explains how definitions are organized, and directs users how to interpret or cross‑reference undefined terms.
Last reviewed: July 6, 2026
Overview
Chapter 2 of the California Mechanical Code (CMC) collects the technical meanings that give the rest of the code precision and consistency. Its stated purpose is to assign specific meanings where ordinary usage could create ambiguity and to arrange defined terms alphabetically so users can find them quickly, as described in §201.1 and §202.1 of the CMC .
Why this matters: a single defined term can change how an installation or inspection requirement applies in practice. Key starting points in this chapter are §201.1 (applicability), §202.1 (how definitions are organized), and the alphabetical term entries beginning at §203.0 (A—), which contain the actual definitions used throughout the CMC . Where the CMC does not redefine an ordinary word, the code explains that ordinary dictionary meanings are used unless the context requires otherwise .
Definitions in the CMC also interact with other California codes and referenced standards; when a term is defined elsewhere in the California codes, cross‑references in the model/state codes explain which definition governs (see, for example, the cross‑code practice described in the California Building Code) .
In this section
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 2-4 High relevance — show source text
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2 DEFINITIONS
User notes:
About this chapter: Codes, by their very nature, are technical documents. Every word, term and punctuation mark can add to or change the meaning of a technical requirement. It is necessary to maintain a consensus on the specific meaning of each term contained in the code. Chapter 2 performs this function by stating clearly what specific terms mean for the purpose of the code. General definitions are located in Section 202 and occupancy classification definitions are located in Section 203.
SECTION 201—GENERAL
201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the California Building Code, Cali- fornia Mechanical Code or California Plumbing Code, such terms shall have the meanings ascribed to them as in those codes.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. Merriam Webster’s Collegiate Dictionary, 11th Edition, shall be considered as providing ordinarily accepted meanings.
SECTION 202—GENERAL DEFINITIONS
[BG] 24-HOUR BASIS. The actual time that a person is an occupant within a facility for the purpose of receiving care. It shall not include a facility that is open for 24 hours and is capable of providing care to someone visiting the facility during any segment of the 24 hours.
3D PRINTER. A machine used in the additive manufacturing process for fabricating objects through the deposition of a material using a print head, nozzle or other printer technology.
[M] ACCESS (TO). That which enables a device, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel or similar obstruction [see also “Ready access (to)”].
[BE] ACCESSIBLE MEANS OF EGRESS. A continuous and unobstructed way of egress travel from any accessible point in a building or facility to a public way.
[BE] ACCESSIBLE ROUTE. A continuous, unobstructed path that complies with Chapter 11 of the California Building Code .
ACTIVE RF EMITTING DEVICE. Any type of circuit component that requires an AC or DC power source with the ability to electrically control electron flow and/or amplification of RF signal, including but not limited to signal boosters, repeaters, bidirectional amplifiers and fiber-distributed antenna systems.
ADDITIVE MANUFACTURING. A process of joining materials to make objects from 3D model data, usually layer upon layer, sometimes referred to as 3D printing. This code recognizes two types of additive manufacturing:
Industrial additive manufacturing. 3D printing operations that typically utilize combustible powders or metals, an inert gas supply, a combustible dust collection system, or that create a hazardous (classified) location area or zone outside the equipment.
CMC § 2-1 High relevance — show source text
RESIDENTIAL
CODE|||||||||†||†||†|||||||||| |LOW-RISE
RESIDENTIAL BUILDING|||||||||†||†||†|||||||||| |PLANTS|||||||||†||†||†|||||||||| |RESIDENTIAL BUILDING|||||||||†||†||†|||||||||| |RESILIENT FLOORING|||||||||†||†||†||||||||||The state agency does not adopt sections identified by the following symbol: †.
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2 DEFINITIONS
SECTION 201—GENERAL
201.1 Scope. Unless otherwise stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other documents. Where terms are not defined in this code and are defined in the California Building Stan- dards Code or other referenced documents, such terms shall have the meanings ascribed to them as in those publications.
201.4 Terms not defined. Where terms are not defined as specified in this section, such terms shall have ordinarily accepted meanings such as the context implies.
SECTION 202—DEFINITIONS
2 X 2 RULE. [BSC-CG] Visual markers are the most effective collision deterrents if spaced no more than 2 inches (5.1 cm) apart, a distance through which most birds cannot fly.
ACCESSORY DWELLING UNIT. [HCD] 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 singlefamily or multifamily dwelling is or will be situated. (See Government Code Section 65852.2.)
ACCESSORY OCCUPANCIES. [HCD] Occupancies that are ancillary to the main occupancy of residential building(s) or portions thereof. Accessory occupancies shall include, but are not limited to, Group U occupancies. (See Section 312 of the California Build- ing Code. )
ACCESSORY STRUCTURE. [HCD] A structure that is accessory to and incidental to that of the dwelling(s) and that is located on the same lot.
ADDITION. An extension or increase in floor area of an existing building or structure.
ADHESIVE MARKER. [BSC-CG] An individual marker(s) applied to the first surface of glass (surface 1) in a pattern or as a custom decal.
ADJUST. To regulate fluid flow rate and air patterns at the terminal equipment, such as to reduce fan speed or adjust a damper.
AGRIFIBER PRODUCTS. Agrifiber products include wheatboard, strawboard, panel substrates and door cores, not including furniture, fixtures and equipment (FF&E) not considered base building elements.
CMC § 201.0 Medium relevance — show source text
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CHAPTER 2
DEFINITIONS
201.0 General.
201.1 Applicability. For the purpose of this code, the following terms have the meanings indicated in this chapter.
No attempt is made to define ordinary words, which are used in accordance with their established dictionary meanings, except where a word has been used loosely, and it is necessary to define its meaning as used in this code to avoid misunderstanding.
202.0 Definition of Terms.
202.1 General. The definitions of terms are arranged alphabetically according to the first word of the term.
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 62.1:5.18.1]
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 62.1:5.18.1]
Air, Class 3. Air with significant contaminant concentration, significant sensory-irritation intensity, or offensive odor.
[ASHRAE 62.1:5.18.1]
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 as harmful.
[ASHRAE 62.1:5.18.1]
Air, Combustion. See Combustion Air.
Air, Conditioned. Air that has been treated to achieve a desired level of temperature, humidity, or cleanliness.
CMC § 201.3 Medium relevance — show source text
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the California Building Code, Cali- fornia Existing Building Code, California Fire Code, California Electrical Code, California Mechanical Code or California Plumbing Code, such terms shall have the meanings ascribed to them as in those codes.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have their ordinarily accepted meanings such as the context implies.
SECTION 202—DEFINITIONS
ACCESSORY STRUCTURE. A building or structure used to shelter or support any material, equipment, chattel or occupancy other than a habitable building.
AGRICULTURE (applicable to CCR, Title 14 provisions only). Land used for agricultural purposes as defined in a Local Jurisdiction's zoning ordinances. [CCR Title 14 §1270.01(a)]
APPLICABLE BUILDING. A building that has residential, commercial, educational, institutional or similar occupancy type use.
[A] APPROVED. Acceptable to the code official.
[A] APPROVED AGENCY. An established and recognized organization that is regularly engaged in conducting tests, furnishing inspection services or furnishing product evaluation or certification where such organization has been approved by the code official.
[A] BUILDING. Any structure intended for supporting or sheltering any occupancy.
BUILDING (applicable to CCR, Title 14 provisions only). Any Structure used or intended for supporting or sheltering any use or Occupancy, except those classified as Utility and Miscellaneous Group U. [CCR Title 14 §1270.01(c)]
[A] BUILDING OFFICIAL. The officer or other designated authority charged with the administration and enforcement of the California Building Code, or the building official’s duly authorized representative.
CERTIFICATE OF COMPLETION. Written documentation that the project or work for which a permit was issued has been completed in conformance with requirements of this code.
[A] CODE OFFICIAL. The official designated by the jurisdiction to interpret and enforce this code, or the code official’s authorized representative.
CRITICAL FIRE WEATHER. A set of weather conditions (usually a combination of low relative humidity and wind) whose effects on fire behavior make control difficult and threaten firefighter safety.
DEAD-END ROAD (applicable to CCR, Title 14 provisions only). A road that has only one point of vehicular ingress/egress, including cul-de- sacs and roads that loop back on themselves. [CCR Title 14 §1270.01(e)]
DEFENSIBLE SPACE. See Sections 403.1.1 and 601.3.
DRIVEWAY (applicable to CCR, Title 14 provisions only). A vehicular pathway route that serves not more than four (4) Residential Units and any number of noncommercial or nonindustrial Utility or Miscellaneous Group U Buildings. [CCR Title 14 §1270.01(i)]
[BG] DWELLING. A building that contains one or two dwelling units used, intended or designed to be used, rented, leased, let or hired out to be occupied for living purposes.
CMC § 204.0 Medium relevance — show source text
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204.0
206.0
207.0
208.0
209.0
210.0
214.0
215.0
216.0
217.0
222.0
223.0
228.0
|||X|X|X|||||X|X|X|X|X|X|X||||||||| |Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended sections
listed below)
Adopt only those sections
that are listed below
Chapter/Section
203.0
204.0
206.0
207.0
208.0
209.0
210.0
214.0
215.0
216.0
217.0
222.0
223.0
228.0
||||||||||X||X|X|X|X||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
2025 CALIFORNIA MECHANICAL CODE 29
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), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
CHAPTER 2
DEFINITIONS
201.0 General.
201.1 Applicability. For the purpose of this code, the following terms have the meanings indicated in this chapter.
No attempt is made to define ordinary words, which are used in accordance with their established dictionary meanings, except where a word has been used loosely, and it is necessary to define its meaning as used in this code to avoid misunderstanding.
202.0 Definition of Terms.
202.1 General. The definitions of terms are arranged alphabetically according to the first word of the term.
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.
CMC § 203.7.3 Medium relevance — show source text
Title 19, Division 1]||||X|||||||||||||||||||| |Chapter / Section|||||||||||||||||||||||| |203.7.3|||X||||||||||||||||||||| |203.7.3.6 - 203.7.3.8|||X||||||||||||||||||||| |203.7.4|||X||||||||||||||||||||| |203.7.4.1|||X||||||||||||||||||||| |203.9.1|||X||||||||||||||||||||| |203.9.2|||X||||||||||||||||||||| |203.9.2.1|||X||||||||||||||||||||| |203.9.2.2|||X||||||||||||||||||||| |203.9.3|||X||||||||||||||||||||| |203.9.3.3|||X||||||||||||||||||||| |203.9.4|||X||||||||||||||||||||| |203.12|||X||||||||||||||||||||| |203.13|||X|||||||||||||||||||||- The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Fire Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
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2 DEFINITIONS
User notes:
About this chapter: Codes, by their very nature, are technical documents. Every word, term and punctuation mark can add to or change the meaning of a technical requirement. It is necessary to maintain a consensus on the specific meaning of each term contained in the code. Chapter 2 performs this function by stating clearly what specific terms mean for the purpose of the code. General definitions are located in Section 202 and occupancy classification definitions are located in Section 203.
SECTION 201—GENERAL
201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the California Building Code, Cali- fornia Mechanical Code or California Plumbing Code, such terms shall have the meanings ascribed to them as in those codes.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. Merriam Webster’s Collegiate Dictionary, 11th Edition, shall be considered as providing ordinarily accepted meanings.
SECTION 202—GENERAL DEFINITIONS
CMC § 1.5 Medium relevance — show source text
The California Code of Regulations (CCR), Title 14, Division 1.5 provisions that are found in the California Wildland-Urban Interface Code are not listed in the Matrix Adoption Tables as they are not within the State Fire Marshal’s authority to adopt. These provisions are a reprint from the current CCR, Title 14, Division 1.5 text for the code user’s convenience only and are identified in the body of the code by square brackets containing references to applicable Title 14 sections.
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2 DEFINITIONS
User notes:
About this chapter: Codes, by their very nature, are technical documents. Every word, term and punctuation mark can add to or change the meaning of a technical requirement. It is necessary to maintain a consensus on the specific meaning of each term contained in the code. Chapter 2 performs this function by stating clearly what specific terms mean for the purpose of the code.
SECTION 201—GENERAL
201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words stated in the present tense include the future; words stated in the masculine gender include the feminine and neuter; and the singular number includes the plural and the plural the singular.
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the California Building Code, Cali- fornia Existing Building Code, California Fire Code, California Electrical Code, California Mechanical Code or California Plumbing Code, such terms shall have the meanings ascribed to them as in those codes.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have their ordinarily accepted meanings such as the context implies.
SECTION 202—DEFINITIONS
ACCESSORY STRUCTURE. A building or structure used to shelter or support any material, equipment, chattel or occupancy other than a habitable building.
AGRICULTURE (applicable to CCR, Title 14 provisions only). Land used for agricultural purposes as defined in a Local Jurisdiction's zoning ordinances. [CCR Title 14 §1270.01(a)]
APPLICABLE BUILDING. A building that has residential, commercial, educational, institutional or similar occupancy type use.
[A] APPROVED. Acceptable to the code official.
[A] APPROVED AGENCY. An established and recognized organization that is regularly engaged in conducting tests, furnishing inspection services or furnishing product evaluation or certification where such organization has been approved by the code official.
[A] BUILDING. Any structure intended for supporting or sheltering any occupancy.
BUILDING (applicable to CCR, Title 14 provisions only). Any Structure used or intended for supporting or sheltering any use or Occupancy, except those classified as Utility and Miscellaneous Group U. [CCR Title 14 §1270.01(c)]
CMC § 201.1 Medium relevance — show source text
SECTION 201—GENERAL
201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the other California Codes, such terms shall have the meanings ascribed to them in those codes. [OSHPD 1, 1R, 2, 4 & 5] For terms not defined in this chapter, refer to Chapters 6 and 7 of the California Administrative Code, and Chapter 2 of the California Building Code. [DSA-SS & DSA-SS/CC] Definitions of terms given in Section 4-207 or 4-314 of the California Administrative Code govern over those in Section 202.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this chapter, such terms shall have ordinarily accepted meanings such as the context implies.
SECTION 202—GENERAL DEFINITIONS
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 multi- family dwelling is or will be situated. (See Government Code Section 65852.2.)
[A] ADDITION. An extension or increase in floor area, number of stories, or height of a building or structure.
[A] ALTERATION. Any construction or renovation to an existing structure other than a repair or addition.
[BG] AMBULATORY CARE FACILITY. Buildings or portions thereof used to provide medical, surgical, psychiatric, nursing or similar care on a less than 24-hour basis to persons who are rendered incapable of self-preservation by the services provided or staff has accepted responsibility for care recipients already incapable.
[A] APPROVED. Acceptable to the code official.
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 authorities, or technical, health, or scientific organi- zations or agencies.
Notes :
1. See Health and Safety Code Section 17920 for “Approved” as applied to residential construction and buildings or struc- tures accessory thereto as referenced in Section 1.8.2. 2. See Health and Safety Code Section 17921.1 for “Approved” as applied to the use of hotplates in residential construction as referenced in Section 1.8.2.
3. See Health and Safety Code Section 19966 for “Approved” as applied to Factory-Built Housing as referenced in Section 1.8.3.2.5.
CMC § 2-1 Medium relevance — show source text
CHAPTER 2 – DEFINITIONS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting agency BSC BSC-
CGSFM HCD Col6 Col7 DSA Col9 OSHPD Col11 Col12 Col13 Col14 Col15 BSCC DPH AGR DWR CEC CA SL SLC Adopting agency BSC BSC-
CGSFM 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5 Adopt entire CA chapter X X X Adopt entire chapter as
amended (amended sections
listed below)X X X Adopt only those sections
that are listed belowChapter/Section 201 CALIFORNIA RESIDENTIAL
CODE† † † LOW-RISE
RESIDENTIAL BUILDING† † † PLANTS † † † RESIDENTIAL BUILDING † † † RESILIENT FLOORING † † † The state agency does not adopt sections identified by the following symbol: †.
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2 DEFINITIONS
SECTION 201—GENERAL
201.1 Scope. Unless otherwise stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other documents. Where terms are not defined in this code and are defined in the California Building Stan- dards Code or other referenced documents, such terms shall have the meanings ascribed to them as in those publications.
201.4 Terms not defined. Where terms are not defined as specified in this section, such terms shall have ordinarily accepted meanings such as the context implies.
SECTION 202—DEFINITIONS
CMC § 104.1 Medium relevance — show source text
11B- 104.1 Dimensions. Dimensions that are not stated as “maximum” or “minimum” are absolute.
11B- 104.1.1 Construction and manufacturing tolerances. All dimensions are subject to conventional industry tolerances except where the requirement is stated as a range with specific minimum and maximum end points.
11B- 104.2 Calculation of percentages. Where the required number of elements or facilities to be provided is determined by calculations of ratios or percentages and remainders or fractions result, the next greater whole number of such elements or facilities shall be provided. Where the determination of the required size or dimension of an element or facility involves ratios or percentages, rounding down for values less than one half shall be permitted.
11B- 104.3 Figures. Unless specifically stated otherwise, figures are provided for informational purposes only.
FIGURE 11B -104—GRAPHIC CONVENTION FOR FIGURES
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ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMMODATIONS, COMMERCIAL BUILDINGS AND PUBLIC HOUSING
SECTION 11B- 105—REFERENCED STANDARDS
11B- 105.1 General. See Chapter 35.
SECTION 11B- 106—DEFINITIONS
11B- 106.1 General. For the purpose of this chapter, the terms listed in Section 11B- 106.5 and defined in Chapter 2 have the indicated meaning.
11B- 106.2 Terms defined in referenced standards. Terms not listed in Section 11B- 106.5 and not defined in Chapter 2, Section 202, but specifically defined in a referenced standard, shall have the specified meaning from the referenced standard unless otherwise stated.
11B- 106.3 Undefined terms. The meaning of terms not specifically listed in Section 11B- 106.5, and not defined in Chapter 2, Section 202, or in referenced standards shall be as defined by collegiate dictionaries in the sense that the context implies.
11B- 106.4 Interchangeability . See Chapter 2, Section 201.2.
11B- 106.5 Defined terms . The following terms are defined in Chapter 2, Section 202.
ACCESS AISLE
ACCESSIBILITY
ACCESSIBILITY FUNCTION BUTTON
ACCESSIBLE
ACCESSIBLE ELEMENT
ACCESSIBLE MEANS OF EGRESS
ACCESSIBLE ROUTE
ACCESSIBLE SPACE
ADAPTABLE
ADDITION
ADJUSTED CONSTRUCTION COST
ADMINISTRATIVE AUTHORITY
ADULT CHANGING FACILITY
AISLE
ALTERATION
AMUSEMENT ATTRACTION
AMUSEMENT RIDE
AMUSEMENT RIDE SEAT
ANSI
APPROVED
APPROVED TESTING AGENCY
AREA OF REFUGE
AREA OF SPORT ACTIVITY
CMC § 201.1 Medium relevance — show source text
Division 1
Section|Gov Code
Section|PRC
Section|HSC
Section| |---|---|---|---|---|---|---|---|---|---|---| |Section|Title|Title|Title|Title|Title|Title|Title|Title|Title|Title| |Chapter 2|Definitions|Definitions|Definitions|Definitions|Definitions|Definitions|Definitions|Definitions|Definitions|Definitions| |201|General|Y||||||||| |201.1|Scope|Y||||||||| |201.2|Interchangeability|Y||||||||| |201.3|Terms defined in
other codes|Y||201.3||||||| |201.4|Terms not defined|Y||||||||| |202|Definitions|Y||||||||| ||Accessory structure|Y||||||||| ||Agriculture (T14)|Y||||1270.01(1)||||| ||Applicable building|Y||702A||||||| ||Approved|Y||||||||| ||Approved agency|Y||||||||| ||Building|Y||||1270.01(c)||||| ||Building (T14)|Y||||||||| ||Building official|Y||||||||| ||Certificate of
completion|Y||||||||| ||Code official|Y||||||||| ||Critical fire weather|Y||||||||| ||Dead-end road (T14)|Y||||1270.01(e)||||| ||Defensible space (T14)|Y||||||||| ||Driveway (T14)|Y||||||||| ||Dwelling|Y||702A||1270.01(i)||||| ||Exterior wall assembly|Y||702A||||||| ||Exterior wall covering|Y||702A||||||| ||Fire chief|Y||||||||| ||Fire code official|Y|||202|||||| ||Fire flow calculation
area|Y||||||||| ||Fire hazard severity
zones|Y||702A|4902.1|||2201||| ||Fire protection plan|Y||702A|4902.1|||||| ||Fire weather|Y||||||||| ||Fire-resistance-rated
construction|Y||||||||| ||Fire-smart vegetation|Y|||4902.1|1271.01||||| ||Flame spread index|Y||||||||| ||Fuel|Y||||||||4291(a)(1)(A)| ||Fuel break_(T14)|Y||||1270.01(n)||||| ||Fuel modification|Y||||||||| ||Fuel mosaic|Y||||||||| ||Fuel-loading|Y||||||||| ||Green belt(T14)|Y||||1270.01(o)||||| ||Greenways (T14)|Y||||1270.01(p)||||| ||Hammerhead/T (T14)|Y||||1270.01(q)||||| ||Hazardous land use
(T14)_|Y||||1270.01(r)||||| ||Hazardous materials|Y||||||||| ||Heavy timber
construction|Y||||||||| ||Ignition-resistant
building material|Y||||||||| ||Local responsibility
area (LRA)|Y||702A|4902.1|||||| ||Log wall construction|Y|||||||||2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-25
CMC § 1.11. Medium relevance — show source text
REPAIR|||X|||||||||||||||||||||| |ROOF REPLACEMENT|||X|||||||||||||||||||||| |SPC SEISMIC SEPARATION||||||||||X|X|||||||||||||| |SUBSTANDARD BUILDING||||X|X|||||||||||||||||||| |SUBSTANTIAL STRUCTURAL
DAMAGE||||||||||X|X|||||||||||||| |UNREINFORCED CONCRETE||||||||||X|X|X||X|X|||||||||| |UNREINFORCED MASONRY||||||||||X|X|X||X|X|||||||||| |UNSAFE|||X|X|X|||||||||||||||||||| |VOLUNTARY STRUCTURAL
IMPROVEMENTS||||||||||X|X|X||X|X|||||||||| |WORK AREA|||X||||||||||||||||||||||The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
2-2 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
2 DEFINITIONS
User notes:
About this chapter: Codes, by their very nature, are technical documents. Every word, term and punctuation mark can add to or change the meaning of a technical requirement. It is necessary to maintain a consensus on the specific meaning of each term contained in the code. Chapter 2 performs this function by stating clearly what specific terms mean for the purpose of the code.
SECTION 201—GENERAL
201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other codes. Where terms are not defined in this code and are defined in the other California Codes, such terms shall have the meanings ascribed to them in those codes. [OSHPD 1, 1R, 2, 4 & 5] For terms not defined in this chapter, refer to Chapters 6 and 7 of the California Administrative Code, and Chapter 2 of the California Building Code. [DSA-SS & DSA-SS/CC] Definitions of terms given in Section 4-207 or 4-314 of the California Administrative Code govern over those in Section 202.
201.4 Terms not defined. Where terms are not defined through the methods authorized by this chapter, such terms shall have ordinarily accepted meanings such as the context implies.
SECTION 202—GENERAL DEFINITIONS
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 multi- family dwelling is or will be situated. (See Government Code Section 65852.2.)
Frequently asked questions
Where do I look first for a defined term in the CMC?
Look in Chapter 2, Section 202 — definitions are arranged alphabetically and the alphabetical entries begin at §203.0 (A—) so you can find the exact term used in the body of the code .
What should I do if a term I need isn’t defined in Chapter 2?
The CMC states that ordinary words are used in their ordinary dictionary sense unless specifically defined otherwise; consult the Chapter 2 preface (§201.1) and, if needed, related California codes or referenced standards for cross‑definitions .
Do CMC definitions reference standards or other sources?
Yes. Many definitions cite national standards or other authorities (for example, ASHRAE or NFPA references appear with certain terms), and those references are part of the definition context in Chapter 2 .
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