BCAB #1940 – Restrictions on Window Openings and Requirements for Egress Windows

November 21, 2024

Re: Restrictions on Window Openings and Requirements for Egress Windows

Project Description

The project is a two storey residence.

A required egress window in a bedroom on the second storey has an in-swing casement window.  The window is approximately 1 680 mm wide by 860 mm high and the window sill is at the level of the finished floor.  The window is equipped with a device that limits the opening to not more than 100 mm and the device can be released to allow the window to swing open and function as an escape window.  The device is called a window opening control device (WOCD).

Applicable Code requirements (BCBC 2018)

Sentence 9.8.8.1.(4), Division B, Required Guards

(4) Except as provided in Sentence (5), openable windows in buildings of residential occupancy shall be protected by

(a) a guard, or

(b) a mechanism capable of controlling the free swinging or sliding of the openable part of the window so as to limit any clear unobstructed opening to not more than 100 mm measured either vertically or horizontally where the other dimension is greater than 380 mm.

 (See Note A-9.8.8.1.(4).

A-9.8.8.1.(4) Height of Window Sills above Floors or Ground. (excerpt)

The primary intent of the requirement is to minimize the likelihood of small children falling significant heights from open windows.  Reflecting reported cases, the requirement applies only to dwelling units and generally those located on the second floor or higher of residential or mixed use buildings where the windows are essentially free-swinging or free-sliding.

Free-swinging or free-sliding means that a window that has been cracked open can be opened further by simply pushing on the openable part of the window.  Care must be taken in selecting windows, as some with special operating hardware can still be opened further by simply pushing on the window.

Casement windows with crank operators would be considered to conform to Clause (4)(b).  To provide additional safety, where slightly older children are involved, occupants can easily remove the crank handles from these windows.  Awning windows with scissor hardware, however, may not keep the window from swinging open once it is unlatched.  Hopper windows would be affected only if an opening is created at the bottom as well as at the top of the window.  The requirement will impact primarily on the use of sliding windows which do not incorporate devices in their construction that can be used to limit the openable area of the window.

Sentence 9.9.10.1.(1), Division B, Egress Windows or Doors for Bedrooms

(1) Except where the suite is sprinklered, each bedroom or combination bedroom shall have at least one outside window or exterior door openable from the inside without the use of keys, tools or special knowledge and without the removal of sashes or hardware. (See Article 9.5.1.2. and Note A-9.9.10.1.(1).)

A-9.9.10.1.(1), Escape Windows from Bedrooms. (excerpt)

Sentence 9.9.10.1.(1) generally requires every bedroom in an unsprinklered suite to have at least one window or door opening to the outside that is large enough and easy enough to open so that it can be used as an exit in the event that a fire prevents use of the building’s normal exits.  The minimum unobstructed opening specified for escape windows must be achievable using only the normal window operating procedure.

Decision being appealed (Local Authority’s position)

The required egress window of the second storey bedroom is proposed to be located at finished floor height and therefore needs to satisfy the requirements for guards as well as the requirements for an egress window.

The applicant proposes to install a WOCD to satisfy both of these requirements.  The installation of the WOCD modifies the opening procedure so that special knowledge is needed in order to open the required egress window.

The Note states that "The minimum unobstructed opening specified for escape windows must be achievable using only the normal window operating procedure."

Appellant's position

The purpose of a WOCD is to provide a restricted opening to prevent falls and to provide emergency egress, satisfying both Code requirements.  The WOCD technical description is found in the ASTM F2090.  A WOCD that is compliant with ASTM F2090 satisfies both Code requirements.

The applicable code for this project is the BCBC 2018 and WOCDs are not explicitly referenced.  However, because they are becoming commonplace, the BCBC 2024 has been adjusted to address their use.  It is reasonable to look at the BCBC 2024 for guidance on this issue which is unclear in the BCBC 2018.

A BCBC 2024 Note related to fall protection refers to WOCDs and ASTM F2090 as a means of providing the fall protection required.  A Note related to escape windows does not reference a WOCD or ASTM F2090.

This interpretation issue has been reviewed in Alberta under the National Building Code - 2023 Alberta Edition and has resulted in a province wide variance allowing for the use of WOCDs to satisfy both Code requirements.

Appeal Board Decision #1940

The Board confirms the decision of the local authority.

It is the determination of the Board that the window required for egress cannot be fitted with a restrictor.  The egress window must be openable using the normal window operating procedure.

Reason for decision

A WOCD that limits the opening to not more than 100 mm can satisfy Sentence 9.8.8.1.(4), Division B, related to guards but does not satisfy Sentence 9.9.10.1.(1), Division B, related to egress.

The Board notes that a code variance in the form of an alternative solution, such as that provided in Alberta with STANDATA 23-BCV-001, would not have been necessary if the WOCD was evaluated and found to be an acceptable solution for both code requirements.  Further, the conditional STANDATA variance does not apply in BC and it relates to a Code that is based on the model National Building Code 2020 rather than the National Building Code 2015, upon which the British Columbia Building Code 2018, as applies in this case, is based.

Don Pedde
Chair, Building Code Appeal Board