ASHRAE 62.1
HVAKR implements ASHRAE Standard 62.1 - Ventilation for Acceptable Indoor Air Quality using the Ventilation Rate Procedure.
Standard Overview
Section titled “Standard Overview”Purpose
Section titled “Purpose”ASHRAE 62.1 establishes minimum ventilation rates to maintain acceptable indoor air quality:
- Dilute contaminants
- Provide oxygen
- Control odors
Applies to:
- Commercial buildings
- Institutional buildings
- High-rise residential (4+ stories)
Ventilation Rate Procedure
Section titled “Ventilation Rate Procedure”Zone Level
Section titled “Zone Level”For each breathing zone:
Vbz = Rp × Pz + Ra × AzWhere:
- Vbz = Breathing zone outdoor airflow
- Rp = Outdoor air per person
- Pz = Zone population
- Ra = Outdoor air per area
- Az = Zone floor area
Zone Outdoor Air
Section titled “Zone Outdoor Air”Adjust for distribution effectiveness:
Voz = Vbz / EzWhere:
- Voz = Zone outdoor airflow
- Ez = Zone air distribution effectiveness
System Level
Section titled “System Level”For a multi-zone system, HVAKR sums the zone outdoor airflows across the spaces the system serves:
Vot = Σ VozWhere:
- Vot = System outdoor airflow
HVAKR does not apply a system ventilation efficiency (Ev) factor or a critical-zone adjustment — the system requirement is the direct sum of zone Voz.
Ventilation Rates
Section titled “Ventilation Rates”Table 6.2.2.1
Section titled “Table 6.2.2.1”HVAKR includes all rates from Table 6.2.2.1:
| Space Type | Rp (CFM/person) | Ra (CFM/ft²) |
|---|---|---|
| Office | 5 | 0.06 |
| Conference | 5 | 0.06 |
| Classroom (9+) | 10 | 0.12 |
| Retail | 7.5 | 0.12 |
| Restaurant | 7.5 | 0.18 |
| Gym | 20 | 0.18 |
Default Occupancy
Section titled “Default Occupancy”When occupancy isn’t specified, use Table 6.2.2.1 defaults.
Zone Air Distribution Effectiveness
Section titled “Zone Air Distribution Effectiveness”Table 6.2.2.2
Section titled “Table 6.2.2.2”Ez values based on supply configuration:
| Configuration | Ez |
|---|---|
| Ceiling supply, ceiling return | 1.0 |
| Ceiling supply, floor return | 1.0 |
| Floor supply, ceiling return | 1.2 |
| Floor supply, floor return | 1.0 |
| Stratified/displacement systems with high ceiling return | 1.2–1.5 |
| Personalized ventilation systems | 1.2–1.5 |
Ceiling Supply
Section titled “Ceiling Supply”Most common configuration:
- Supply air from ceiling
- Good mixing assumed
- Ez = 1.0
Exhaust Requirements
Section titled “Exhaust Requirements”Table 6.5
Section titled “Table 6.5”Minimum exhaust for specific spaces:
| Space | Exhaust Rate |
|---|---|
| Restroom | 50 CFM/fixture |
| Locker room | 0.5 CFM/ft² |
| Kitchen (commercial) | Per equipment |
Transfer Air
Section titled “Transfer Air”Exhaust can be satisfied by:
- Direct outdoor air
- Transfer from adjacent spaces
HVAKR Implementation
Section titled “HVAKR Implementation”Automatic Calculation
Section titled “Automatic Calculation”HVAKR automatically:
- Applies rates from space types
- Calculates zone and system requirements
- Checks compliance
IAQP Report
Section titled “IAQP Report”Generate compliance documentation:
- Zone calculations
- System calculations
- Compliance summary