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ASHRAE 170 Occupancy Category
ASHRAE 170 Occupancy Category

Function of Space, ASHRAE Standard 170, Healthcare, Laboratory, ACH

Patrick Chopson avatar
Written by Patrick Chopson
Updated over a week ago

The ventilation requirements for healthcare and laboratory facilities take into account the environmental comfort, asepsis, and odor. This is done with minimum values for outdoor air, supply air, and in some case exhaust air. It is important to note that hospital operators, authority having jurisdiction (AHJ), or standards may require higher than minimum air flow, in these case the defaults can be modified.

ASHRAE Standard 170 defines the Function of Space (Occupancy Category) in Table 7.1 Design Parameters - Hospital Spaces. The defined parameters are:

  • Pressure Relationship to Adjacent Areas

  • Minimum Outdoor ACH

  • Minimum Total ACH

  • All Room Air Exhaust Directly to Outdoors

  • Air Recirculated by Means of Room Units

  • Design Relative Humidity

  • Design Temperatures

Based on the standards definition of these parameters, the bold items above are automatically populated in the Room Template or Ventilation Calculation Table. There are 88 total options and their inputs are defined as follows:

  • OA ACH = Minimum Outdoor ACH

  • SA ACH = Minimum Total ACH

  • EA ACH = Minimum Total ACH when All Room Air Exhaust Directly to Outdoors = Yes

Note: Not all facilities allow systems to turn down during unoccupied periods. Because of this all the Unoccupied defaults are 0 (systems will run at occupied flow at all times). If a project allows for this energy saving feature, engineers can entered the allowed minimum values.

Tip: There is also a Custom category available for unique spaces within a project.

Looking for the Occupancy Categories for ASHRAE Standard 62.1? Check out this article.

Table of available Occupancy Categories

Occupancy Category

Min Outdoor ACH

Min Supply (Exhaust) ACH

Critical and intensive care

2

6

Delivery room (Caesarean)

4

20

Emergency department decontamination

2

12 (EA)

Emergency department exam/treatment room

2

6

Emergency department public waiting area

2

12 (EA)

Intermediate care

2

6

Laser eye room

3

15

Medical/anesthesia gas storage

8 (EA)

Newborn intensive care

2

6

Operating room

4

20

Operating/surgical cystoscopic rooms

4

20

Procedure room

3

15

Radiology waiting rooms

2

12 (EA)

Recovery room

2

6

Substerile service area

2

6

Trauma room (crisis or shock)

3

15

Treatment room

2

6

Triage

2

12

Wound intensive care (burn unit)

2

6

AII anteroom

10 (EA)

AII room

2

12 (EA)

Combination AII/PE anteroom

10 (EA)

Combination AII/PE room

2

12 (EA)

Continued care nursery

2

6

Labor/delivery/recovery (LDR)

2

6

Labor/delivery/recovery/postpartum (LDRP)

2

6

Newborn nursery suite

2

6

Nourishment area or room

2

Patient corridor

2

Patient room

2

4

PE anteroom

10

Protective environment room

2

12

Toilet room

10 (EA)

Bathing room

10 (EA)

Occupational therapy

2

6

Physical therapy

2

6

Resident gathering/activity/dining

4

4

Resident room

2

2

Resident unit corridor

4

Darkroom

2

10 (EA)

Xray (diagnostic and treatment)

2

6

Xray (surgery/critical care and catheterization)

3

15

Autopsy room

2

12 (EA)

Bronchoscopy, sputum collection, and pentamidine adminstration

2

12 (EA)

Dialysis treatment area

2

6

Dialyzer reprocessing room

10 (EA)

ECT procedure room

2

4

Endoscope cleaning

2

10 (EA)

Gastrointestinal endoscopy procedure room

2

6

General examination room

2

4

Hydrotherapy

2

6

Laboratory work area, bacteriology

2

6 (EA)

Laboratory work area, biochemistry

2

6 (EA)

Laboratory work area, cytology

2

6 (EA)

Laboratory work area, general

2

6

Laboratory work area, glasswashing

2

10 (EA)

Laboratory work area, histology

2

6 (EA)

Laboratory work area, media transfer

2

4

Laboratory work area, microbiology

2

6 (EA)

Laboratory work area, nuclear medicine

2

6 (EA)

Laboratory work area, pathology

2

6 (EA)

Laboratory work area, serology

2

6 (EA)

Laboratory work area, sterilizing

2

10 (EA)

Medication room

2

4

Nonrefrigerated bodyholding room

10 (EA)

Nuclear medicine hot lab

6 (EA)

Nuclear medicine treatment room

2

6 (EA)

Pharmacy

2

4

Physical therapy

2

6

Special examination room

2

6

Treatment room

2

6

Sterilizer equipment room

10 (EA)

Clean workroom

2

4

Decontamination room

2

6 (EA)

Sterile storage room

2

4

Bathroom

10 (EA)

Bedpan room

10 (EA)

Clean linen storage

2

Dietary storage

2

Food preparation center

2

10

Janitor’s closet

10 (EA)

Laundry, general

2

10 (EA)

Linen and trash chute room

10 (EA)

Soiled linen sorting and storage

10 (EA)

Warewashing

10 (EA)

Clean workroom or clean holding

2

4

Hazardous material storage

2

10 (EA)

Soiled workroom or soiled holding

2

10 (EA)

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