Operable windows

Achieving natural ventilation through open windows, doors and louvers can provide a positive occupant experience but challenges the ability to maintain strict control over interior air quality. When weather and local environmental conditions are suitable for high quality outdoor air, WELL encourages natural ventilation strategies. Open windows can then provide a supply of fresh air and lower levels of carbon dioxide and VOCs, rather than introducing particulate matter and ozone into the space from outside.

This feature requires that local outdoor air quality conditions, including annual prevailing breeze patterns and average contaminant levels, be analyzed before integrating operable windows into the design.

Part 1: Relative Humidity

At least one of the following is required:

a.⁸ A ventilation system with the capability to maintain relative humidity between 30% to 50% at all times by adding or removing moisture from the air.

b. Modeled humidity levels in the space are within 30% to 50% for at least 95% of all business hours of the year. Buildings in climates with narrow humidity ranges are encouraged to pursue this option.

Part 2: Outdoor Air Measurement

Outdoor levels of ozone, PM₁₀, temperature and humidity are monitored based on the following requirement, and data collected is made available to the building occupants:

a. A data-gathering station located within 0.8 km [0.5 mi] of the building.

Part 3: Window Operation Management

If the outdoor air measurement system indicates that outdoor air either (i) exceeds ozone levels of 51 ppb or PM₁₀ levels of 50 μg/m³; (ii) has a temperature of 8 °C [15 °F] above or below indoor set temperature; or (iii) has a relative humidity above 60%, then one of the following is used to discourage occupants from opening windows:

a. Software on occupants' computers or smartphones.

b. Indicator lights at all operable windows.

Part 4: (OLD) Natural Ventilation Standards

If Parts 1, 2 and 3 are met:

a. The building may comply with the Natural Ventilation Procedure of ASHRAE 62.1-2013 or 62.2-2013 instead of the Ventilation Rate Procedure or IAQ Procedure normally required in the WELL Building Standard.

Cardiovascular

Respiratory

	Core & Shell	Tenant Improvement	New Construction
Part 1: Relative Humidity	-	O	O
Part 2: Outdoor Air Measurement	O	O	O
Part 3: Window Operation Management	O	O	O
Part 4: (OLD) Natural Ventilation Standards	-	-	-

	Commercial Kitchen	Schools	Multifamily Residential	Restaurant	Retail
Part 1: Relative Humidity	O	O	O	O	O
Part 2: Outdoor Air Measurement	-	O	-	-	O
Part 3: Window Operation Management	-	O	-	-	O
Part 4: (OLD) Natural Ventilation Standards	-	-	-	-	-

Verification Methods Matrix

	Letters of Assurance	On-Site Checks
PART 1 (Design) Relative Humidity	MEP	Spot Measurement
PART 2 (Design) Outdoor Air Measurement	Architect	Spot Check
PART 3 (Design) Window Operation Management	Architect	Spot Check

Show Standard Citations

13

**International Living Future Institute. Living Building Challenge 3.0. Seattle; 2014: 38, 43-49, 60.**
19.1.a	The International Living Future Institute's Living Building Challenge 3.0 Imperative 07 requires full control of windows.

This is a legacy version of the WELL Building Standard. Please check the latest version here.

19. Operable windows