ASHRAE-90.1-2022- - Page 008
Extracted Content
the calculations for the reference fan: using an airflow constant ( Q 0) of 26,500 cfm, a pressure constant ( P 0) of 0.002700 in. of water, and a fan efficiency constant (η0) of 42%.
ceiling fan, large diameter: a ceiling fan that is greater than or equal to 84.5 in. in diameter.
chi-factor (χ or Chi): thermal transmittance of a point thermal bridge in units of Btu/(h·°F).
circuit breaker: a device designed to open and close a circuit by nonautomatic means and to open the circuit automatically at a predetermined overcurrent without damage to itself when properly applied within its rating.
class of construction: for the building envelope, a subcategory of roof, above-grade wall, below-grade wall, floor, slab-on-grade floor, opaque door, vertical fenestration, or skylight . (See roof, wall, floor, slab-on- grade floor, door, and fenestration .)
clear-field thermal bridge: see thermal bridge.
code official: see building official.
coefficient of performance (COPH), heat pump—heating: the ratio of the rate of heat delivered to the rate of energy input, in consistent units, for a complete heat-pump system, including the compressor and, if applicable, auxiliary heat, under designated operating conditions.
combined energy efficiency ratio (CEER): a ratio of the total cooling one year divided by the total energy from active, standby, and OFF modes as specified in 10 CFR 430.23.
commissioning: a quality-focused process for enhancing the delivery of a project for verifying and documenting that the building and its systems, controls, and building envelope are planned, designed, installed, tested, and include plans for operation and maintenance to meet specified requirements.
commissioning provider: an entity who manages the commissioning team to implement building commis- sioning .
computer room: a room whose primary function is to house equipment for the processing and storage of electronic data and that has a design electronic data equipment power density exceeding 20 W/ft [2] of conditioned floor area.
computer room energy: annual energy use of the data center, including all IT equipment energy, plus energy that supports the IT equipment and computer room space, calculated in accordance with industry-accepted standards defined as Total Annual Energy (see Informative Appendix E).
condensing unit: a factory-made assembly of refrigeration components designed to compress and liquefy a specific refrigerant. It consists of one or more refrigerant compressors, refrigerant condensers (air-cooled, evaporatively cooled, and/or water-cooled), condenser fans and motors (where used), and factory-supplied accessories.
conditioned floor area, gross: see floor area, gross .
conditioned space: see space.
construction: the fabrication and erection of a new building or any addition to or alteration of an existing building .
construction documents: drawings and specifications used to construct, add to, or alter building s, systems, or equipment, or portions thereof.
continuous air barrier: the combination of interconnected materials, assemblies, and sealed joints and components of the building envelope that minimize air leakage into or out of the building envelope .
continuous daylight dimming: method of automatic lighting control using daylight photosensors, where the lights are dimmed continuously, or using at least four preset levels with at least a five-second fade between levels, where the control turns the lights off when sufficient daylight is available.
continuous dimming: a lighting control strategy that varies the light output of a lighting system over a continuous range from full light output to a minimum light output in imperceptible steps without flickering.
control: to regulate the operation of equipment . ( Informative Note: This definition is not applicable to the use of this word as a noun to describe a combination of control devices and software, used to achieve control of HVAC, lighting, or other equipment or systems .)
control device: a specialized device used to regulate the operation of equipment .
6 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)