ASHRAE-90.1-2022- - Page 094

Extracted Content

Table 6.5.3.1-1 Fan Power Limitation [a]

Col1	Limit	Constant Volume	Variable Volume
Option 1: Fan_system_ motor nameplate hp	Allowable motor_ nameplate hp_	hp cfm_S_ × 0.0011	hp cfm_S_ × 0.0015
Option 2:fan system bhp	Allowable_fan system bhp_	bhp cfm_S_ × 0.00094 +A	bhp cfm_S_ × 0.0013 +A

a. where

cfm S = maximum design supply airflow rate to conditioned spaces served by the system in cubic feet per minute hp = maximum combined motor nameplate horsepower bhp = maximum combined fan brake horsepower A = sum of (PD × cfm D /4131) where PD = each applicable pressure drop adjustment from Table 6.5.3.1-2 in in. of water cfm D = the design airflow through each applicable device from Table 6.5.3.1-2 in cubic feet per minute

Table 6.5.3.1-2 Fan Power Limitation Pressure Drop Adjustment

Device	Adjustment
Credits Return or exhaust_systems_ required by code or accreditation standards to be fully ducted, or_systems_ required to maintain air pressure differentials between adjacent rooms. Return and/or exhaust airflow_control devices_ Exhaust filters, scrubbers, or other exhaust treatment Particulate Filtration Credit: MERV 9 through 12 Particulate Filtration Credit: MERV 13 through 15 Particulate Filtration Credit: MERV 16 and greater and electronically enhanced filters Carbon and other gas-phase air cleaners Biosafety cabinet Energy recovery device, other than coil runaround loop Coil runaround loop Evaporative humidifier/cooler in series with another cooling coil Sound attenuation section (fans serving_spaces_ with design background noise goals below NC35) Exhaust_system_ serving fume hoods Laboratory and vivarium exhaust_systems_ in high-rise_buildings_	0.5 in. of water (2.15 in. of water for laboratory and vivarium systems) 0.5 in. of water The pressure drop of device calculated at_fan system design_ condition 0.5 in. of water 0.9 in. of water Pressure drop calculated at 2× clean filter pressure drop at_fan_ system design condition Clean filter pressure drop at_fan system design condition_ Pressure drop of device at_fan system design condition_ For each airstream [(2.2 ×Enthalpy Recovery Ratio) – 0.5] in. of water 0.6 in. of water for each airstream Pressure drop of device at_fan system design condition_ 0.15 in. of water 0.35 in. of water 0.25 in. of water/100 ft of vertical duct exceeding 75 ft
Deductions Systems without central cooling device Systems without central heating device Systems with central_electric resistance_ heat	–0.6 in. of water –0.3 in. of water –0.2 in. of water

Table 6.5.3.2.1 Fan Airflow Control	Col2	Col3
Cooling System Type	Fan Motor Size, hp	Mechanical Cooling Capacity, Btu/h
DX cooling	Any	65,000
Chilled-water and evaporative cooling	1/4	Any

92 ANSI/ASHRAE/IES Standard 90.1-2022 (I-P)