ICC M3 key terms

Accepted by the authority having jurisdiction as meeting applicable code provisions, typically because it is listed by a recognized testing agency or otherwise shown to be suitable for the intended use.

The individual or office responsible for enforcing code requirements, approving materials and methods, and interpreting provisions where the code text leaves room for judgment.

A written authorization issued by the code official allowing specified mechanical work to proceed; work generally may not begin until the permit has been issued and posted as required.

The official on-site review of installed work by the code official at defined stages to confirm compliance before the work is covered, energized, or placed in service.

A document issued after final inspection confirming that a building or altered space complies with code and may lawfully be used or occupied for its stated purpose.

Equipment, materials, or services included in a published list by an approved agency that maintains periodic inspection and whose listing states compliance with a recognized standard.

Bearing a label, symbol, or other identifying mark of an approved agency indicating that the product conforms to a specific standard and is subject to the agency's follow-up inspection.

A change in the use or classification of a building or space that may trigger requirements to upgrade mechanical systems, ventilation, or exhaust to meet current code for the new use.

A room or enclosed area intended for human activity, excluding spaces used only for mechanical equipment, storage, or similar purposes not meant for continuous occupancy.

The number of persons for which a space is designed, determined from use and floor area; it drives required ventilation, egress, and combustion air calculations.

Outdoor air supplied to a space, plus any recirculated air treated to acceptable quality, intended to dilute contaminants and support occupant health and comfort.

The opening and associated ductwork through which fresh air enters a ventilation system; it must be located away from contaminant sources such as exhaust outlets, plumbing vents, and loading areas.

Air removed from a conditioned space and conveyed back to the air-handling unit for recirculation, reconditioning, or relief to the outdoors.

Conditioned or tempered air delivered by a mechanical system into a space for heating, cooling, or ventilation purposes.

An enclosed chamber or space used to distribute or collect air, such as a ceiling cavity used as a return-air pathway; its use is restricted by material and construction rules.

A mechanical arrangement of fans, hoods, ducts, and discharge outlets that removes air, fumes, grease, or other contaminants from a space and discharges them to a safe location.

The terminal point where an exhaust system discharges air to the outdoors; its location and height must prevent re-entry into buildings or intakes and avoid nuisance to adjacent property.

Air supplied to a space to replace air removed by exhaust or other means, preventing negative pressure that can impair combustion, venting, or exhaust performance.

Ductwork serving commercial cooking exhaust that is constructed and sealed to resist grease accumulation and fire, with defined clearances, materials, and cleanout provisions.

A hood designed for cooking appliances that produce grease or smoke, equipped with grease filtration and listed for that service, with defined minimum airflow and construction requirements.

A hood intended for cooking appliances producing only heat, moisture, or odors without significant grease, used for light-duty equipment such as ovens and dishwashers.

A closed conduit for conveying air between equipment and spaces; ducts must be sized, supported, sealed, and constructed of materials suited to the pressure class and application.

Thermal or acoustical material applied to duct surfaces to limit heat gain or loss, control condensation, or reduce sound; it must meet flame-spread and smoke-developed limits.

A rating describing how quickly a material propagates flame across its surface under test; interior finish and duct materials are limited to specified maximum values.

A material that will ignite and burn, or add appreciable heat to a fire; its proximity to heat-producing equipment, chimneys, and vents is restricted by clearance rules.

The minimum distance between heat-producing equipment, vents, or chimneys and combustible construction or materials, measured to maintain safe surface temperatures.

Air supplied to fuel-burning appliances to support complete combustion; inadequate supply causes incomplete burning and hazardous byproducts and must be verified by calculation or prescriptive means.

For combustion air purposes, a space whose volume is small relative to appliance input, requiring either indoor air from adjacent spaces or outdoor air openings sized by code.

A vertical passageway of masonry or listed factory-built construction that conveys flue gases from appliances to the outdoors, with defined materials, liners, and clearances.

The internal passage within a chimney or vent through which combustion products travel; its size and liner must suit the connected appliances and their combined draft characteristics.

A pipe or passage that conveys combustion gases from an appliance to the outdoors, classified by category according to flue-gas temperature and pressure conditions.

The pressure difference that moves combustion gases through a vent or chimney; it may be produced by buoyancy of hot gases or by a mechanical draft fan.

A fluid used in a refrigeration cycle to transfer heat by changing phase; its classification, safe quantity limits, and handling requirements depend on toxicity and flammability.

A room housing refrigeration equipment, compressors, or related machinery, subject to requirements for access, ventilation, refrigerant detection, and emergency controls based on refrigerant quantity.

Sensors and alarms installed in spaces containing refrigeration equipment that sense refrigerant concentration and trigger alarm, ventilation, or shutdown at set thresholds.

An assembly containing a fan, coils, filters, and controls that conditions and moves air through ductwork to serve one or more spaces.

An outlet device that distributes supply air into a space in a controlled pattern, promoting mixing and avoiding drafts while maintaining desired throw and drop.