Standard Air Changes per Hour (ACH) – Reference Guide

Commercial, Institutional & Industrial Facilities

This page provides typical Air Changes per Hour (ACH) reference values for spaces commonly encountered in commercial, institutional, and industrial buildings.

The intent is to support:

• concept HVAC design,
• BOQ preparation,
• preliminary equipment sizing,
• ventilation strategy alignment during tender and procurement stages.

Values shown are industry-accepted reference ranges, aligned with guidance from ASHRAE.
Final design must comply with local codes, fire authority requirements, and process-specific conditions.

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Residential & Light Commercial Areas

Application Area	Typical Recommended ACH
Residential basements	3 – 4
Bedrooms	5 – 6
Living / family rooms	6 – 8
Residential kitchens	7 – 8
Bathrooms / toilets	6 – 7
Laundry rooms	8 – 9

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Offices & Administrative Buildings

Application Area	Typical Recommended ACH
Business offices (open plan)	6 – 8
Conference / meeting rooms	8 – 12
Break rooms / pantry	7 – 8
Copy / print rooms	10 – 12
Medical / examination offices	9 – 10
IT / computer rooms (non-critical)	10 – 14
Smoking areas (where permitted)	13 – 15

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Restaurants, Canteens & Food Facilities

Application Area	Typical Recommended ACH
Dining areas	8 – 10
Food courts	8 – 12
Commercial kitchens	14 – 18
Bars & beverage areas	15 – 20
Food staging / preparation rooms	10 – 12

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Public Buildings & Assembly Spaces

Application Area	Typical Recommended ACH
Corridors / hallways	6 – 8
Retail stores	6 – 10
Foyers / lobbies	8 – 10
Auditoriums / theatres	12 – 14
Banquet halls	6 – 10
Ballrooms	6 – 12
Places of worship	8 – 12
Public restrooms	10 – 12

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Educational Facilities

Application Area	Typical Recommended ACH
Classrooms	6 – 8
Laboratories	8 – 12
Libraries	6 – 8
Staff rooms	6 – 8
School / college toilets	10 – 12

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Industrial, Utility & Service Areas

Application Area	Typical Recommended ACH
Basement / enclosed parking	6 – 10
DG rooms / generator rooms	12 – 20
Pump rooms	6 – 10
Electrical rooms / switchgear rooms	6 – 10
Battery rooms (UPS / ESS)	10 – 20
Machine rooms / plant rooms	10 – 15
Compressor rooms	10 – 15
Workshops / fabrication areas	8 – 12
Warehouses (non-hazardous)	4 – 6

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Sewage & Wastewater Facilities

Application Area	Typical Recommended ACH
STP blower rooms	10 – 15
STP pump rooms	10 – 15
Sludge handling rooms	12 – 20
Chemical dosing / storage rooms	10 – 15

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Short Technical Notes (Design & Procurement Use)

• ACH values represent air volume turnover, not indoor air quality alone. Occupancy-based ventilation must be checked separately.
• High-risk areas (DG rooms, battery rooms, kitchens, STP areas) are exhaust-driven spaces, not comfort-driven spaces.
• Basement parking ventilation is commonly governed by CO sensor logic and fire authority requirements, not fixed ACH alone.
• High ceiling spaces require air distribution effectiveness evaluation; ACH alone may be misleading.
• Smoke exhaust and fire ventilation systems are separate from normal ventilation and must meet fire code criteria.
• For equipment rooms, manufacturer temperature limits often govern final airflow selection.

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