ASHRAE+62.1-2022+(1) - Page 005
Extracted Content
b. Patient care areas not listed in this standard c. Laboratories with hazardous materials
3. DEFINITIONS
3.1 Terminology (See Figure 3-1)
acceptable indoor air quality (IAQ): air in which there are no known contaminants at harmful concentrations, as determined by cognizant authorities, and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.
air:
ambient air: air surrounding a building; the source of outdoor air brought into a building. cool air: air whose temperature is less than the average space temperature. exhaust air: air removed from a space and discharged to outside the building by means of mechanical or natural ventilation systems. indoor air: air in an enclosed occupiable space. makeup air: any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. outdoor air: ambient air and ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation, or by infiltration. primary air: air supplied to the ventilation zone prior to mixing with any locally recirculated air. recirculated air: air removed from a space, or treated within the space, that is reused as supply air. return air: air removed from a space to be recirculated or exhausted. supply air: air delivered by mechanical or natural ventilation to a space and composed of any combination of outdoor air, recirculated air, or transfer air. transfer air: air moved from one indoor space to another. ventilation air: that portion of supply air that is outdoor air plus any recirculated air that has been treated for the purpose of maintaining acceptable IAQ. warm air: air whose temperature is greater than the average space temperature.
air-cleaning system: a device or combination of devices applied to reduce the concentration of airborne contaminants such as microorganisms, dusts, fumes, respirable particles, other particulate matter, gases, vapors, or any combination thereof.
air conditioning: process of treating air to meet the requirements of a conditioned space by controlling its temperature, humidity, cleanliness, and distribution.
breathing zone: region within an occupied space between planes 3 and 72 in. (75 and 1800 mm) above the floor and more than 2 ft (600 mm) from the walls or fixed air-conditioning equipment.
ceiling return: air removed from the space more than 4.5 ft (1.4 m) above the floor.
ceiling supply: air supplied to the space more than 4.5 ft (1.4 m) above the floor.
classroom: a space for instruction in which the instructor regularly occupies and stores supplies in the space.
lecture classroom: a space for instruction in which all occupants are interim and no supplies are stored in the space.
cognizant authority: an agency or organization that has the expertise and jurisdiction to establish and regulate concentration limits for airborne contaminants, or an agency or organization that is recognized as authoritative and has the scope and expertise to establish guidelines, limit values, or concentrations levels for airborne contaminants.
concentration: quantity of one constituent dispersed in a defined amount of another.
conditioned space: that part of a building that is heated or cooled or both for the comfort of occupants.
contaminant: an unwanted airborne constituent with the potential to reduce acceptability of the air.
contaminant mixture: two or more contaminants that target the same organ system.
demand controlled ventilation (DCV): any means by which the breathing zone outdoor airflow ( Vbz ) can be varied to the occupied space or spaces based on the actual or estimated number of occupants, ventilation requirements of the occupied zone, or both.
design compounds (DCs): chemical compounds found in the indoor environment that have the potential to reduce acceptability of the air and are considered in designing to the IAQ Procedure (IAQP).
ANSI/ASHRAE Standard 62.1-2022 3