Fall Protection - Window Restrictors

Recently I was asked about when window restrictors are required in a dwelling unit of a Part 9 building. The Building Code sets many occupant safety requirements to protect occupants from falls, including from windows. For dwelling units, the restrictions are set in Article 9.8.8.1. for Part 9 buildings in the 2024 British Columbia Building Code.

Within dwelling units, openable windows are required to be protected by a guard or be restricted from opening more than 100 mm in either the horizontal or vertical direction, by a device commonly referred to as a window restrictor, where the bottom edge of the openable portion of the window is less than 900 mm above the finished floor and the drop on the other side is more than 1800 mm, measured from the bottom edge of the openable portion of the window to the adjacent floor or ground.

In most traditional home design, window rough openings are placed at 36 or 42 inches  (915  or 1067 mm) above the floor. This design approach allows avoiding a guard or window restrictor, as the bottom edge of the openable portion of the window exceeds the minimum 900 mm above the finished floor.

However, where additional window area is desired in the design with the bottom portion of the openable window located less than 900 mm above the finished floor, a guard or window restrictor can be avoided where the window is placed adjacent to the ground, a patio, or a balcony that is not more than 1800 mm below the opening. In many cases, windows on the lower-level of a house can meet the 1800 mm height limitation. For upper-level windows, balconies can be provided to avoid a window restrictor.

Another approach is to not make the window openable. However, in the case of bedrooms in an unsprinklered Part 9 building, an openable escape window is required to be provided. In this case, the escape window requirement must be met, which does not allow for use of a window restrictor or placement of a guard in front of the window opening. In essence, the escape window requirements dictate that the openable portion of the window must be located more than 900 mm above the finished floor of the bedroom where the exterior height to the adjacent ground, patio, or balcony is more than 1800 mm.

Using Sliding Doors

The Building Code places restrictions on the types of doors that can be used in building. So, when can a sliding door be used, including vertically sliding doors?

To apply the Building Code provisions, one must first know if the proposed sliding door will be an exit door, an egress door, or a convenience door. The Building Code regulates both exit and egress doors. Exit doors are doors that are part of an exit system (doors leading into, doors within, and doors leading out of an exit system) that provide a protected space for occupants to reach safety. Exits typically include enclosed stairs and nearly all exterior doors of a building. Egress doors are located within the floor area (occupied space) of a building and are in the egress path leading to an exit (access to exit), such as a door from a suite into a public corridor.

Detailed exit door requirements are outlined in Subsection 3.4.6., with specific allowances for sliding doors provided in Article 3.4.6.14. of the 2024 British Columbia Building Code. As an exit door, a sliding door is only permitted where the door leads directly to the exterior and the door can also swing on a vertical axis when pressure is applied. These doors are commonly referred to as break-away sliding doors and are typically power operated and used on commercial building entrances for hotels, and retail stores. There are four exceptions to the above, specifically for detention occupancies, impeded egress zones, self-storage suites, and dwelling units.

Within occupied floor areas, the allowances for sliding doors are more relaxed and sliding doors are generally permitted. However, where the sliding door serves an occupant load more than 60, or the door opens onto a corridor or other facility providing access to exit from a suite or a room not within a suite, the door must also swing on a vertical axis when pressure is applied per the above “break-away” requirements.

Doors that are not required to achieve life safety requirements for access to exit and exiting, can be designated as convenience doors and therefore are not restricted by the Building Code. This is often seen in the case of vertically sliding overhead doors in storage garages and commercial warehousing to allow vehicles, equipment, and materials to be easily moved around and in and out of the building. In this case, occupant egress or exiting requirements are met by pairing the sliding door with a regular swing door so that compliance with travel distance and occupant load requirements are met.

Sliding doors used in an accessible path of travel have additional requirements including door operating hardware that is capable of being opened with a closed fist, and requiring no grasping, pinching, or twisting motions as noted in Article 3.8.3.8. In some cases – the operating hardware may prevent the sliding door from opening to its full width, so care must be taken to ensure that the clear opening will still meet the minimum 850 mm required by Sentence 3.8.3.6.(2). Additionally, sliding doors in an accessible path require a clear floor space with a dimension not less than 1200 mm parallel to the closed door and 1500 mm perpendicular to the closed door. Where a power door operator is used, the parallel dimension is permitted to be reduced to 1000 mm.

Revisions to the 2024 British Columbia Building Code, Division B - Part 3

In cooperation with Nick Bray Architecture, we’re excited to be presenting a webinar focused on reviewing and explaining the changes that you should be aware of when designing to the 2024 BC Building Code.

WHEN: Tuesday, April 16, 12:00-1:00pm

WHERE: Online

COST: Free

AIBC Registered Education Provider: 1 Core Learning Unit

Presented by Marc Showers, P.Eng., C.P., and Brian Fraser, P.Eng., C.P.

Suburban and Rural Water Supplies

The Building Code requires Part 3 buildings to be provided with an “adequate water supply for firefighting”. This provision is intended to ensure that firefighting operations will be effective as part of the OS1 Fire Safety objective with the functional requirement of F02 to limit the severity of and effects of fire or explosion. Where the building is sprinklered throughout, this requirement is deemed met. However, how is this requirement met for unsprinklered building and in rural environments with limited or no municipal water supply available?

In urban environment, the local municipality typically will have planned and installed sufficient water supply for the building uses and sizes in relation to their property use bylaws (often called zoning bylaws) as part of the original subdivision development of the land. However, where the permitted property use allowances are changed as part of a development application, the available water supply can be insufficient to meet the current municipal civil engineering standards and the underlying Building Code assumptions.

In contrast, in rural environment, land may be being developed for buildings for the first time, and an adequate municipal water infrastructure does not exist or at best be severely inadequate.

We often deal with this issue, particularly for rural environments. The Building Code provides some guidance in the Notes to Part 3, and municipalities typically will have a minimum civil engineering standard or mandate the use of the Fire Underwriter’s Survey (FUS) to determine minimum firefighting water supply to the subject site. For urban environments where the dense building environment has a risk of conflagration, the FUS standard is often used and results in a significant water supply demand to support firefighting operations. However, the application of FUS to the rural environment can result in significant municipal upgrades being required that do not make the development feasible despite there being no urban conflagration risk. For the rural environment, alternative water supply design methods such as NFPA 1142, Standard on Water Supplies for Suburban and Rural Firefighting, often provides more affordable options with lower water demand requirement matched to the specific hazard with non-municipal water sources. Water sources can include rivers, ponds, and water storage tanks that are available for firefighters to draft from.

Recently, we supported an aerosol filling plant that was proposed to be located in the middle of a large field in a rural location. The local municipality did not provide a water service infrastructure, with private wells being the only available water source for landowners. For this project, we reviewed the proposed building in accordance with NFPA 1142 and were successful in negotiating with the local authority to provide a service road to the small river that flowed adjacent to the rear property line, so that the fire department could use the river as a water source for firefighting operations in a fire emergency.

If your project has water supply challenges, contact us to see how we might be able to support your project.

Visibility of Exit Signs – Good Practices for Life Safety

The National Building Code of Canada, and subsequently the British Columbia Building Code, (Building Code) generally require buildings to be provided with illuminated exit signs. While these codes provide considerable details about the pictograms associated with exit signs and how they are to be illuminated there is little discussion about visibility of exit signs other than being “visible upon approach to the exit”. Like many of the Acceptable Solutions in Division B of the Building Code this statement is not based on any technical merit as is wholly subjective. This can potentially create life safety issues during emergency evacuations.

CSA 22.2 No. 141 “Emergency Lighting Equipment” requires internally illuminated signs to be placed at intervals so that the maximum viewing distance is no more than 30.5 m, however this is not strictly a requirement in the Building Code. Further, no additional consideration is given to the overall size of the sign. Considering that the legibility of a sign is directly proportional to the size of the sign and the viewing distance, adjustments in sign size should be made based on the viewing distance.

Most international standards provide some guidance on the size of an exit sign with respect to the distance it is viewed at. For example, in New Zealand the compliance document F8/AS1 provides information about minimum viewing distances for both internally illuminated and externally illuminated/photoluminescent signs and exit sign pictogram height.

Acceptable Solutions and Verification Methods for New Zealand Building Code Clause F8

Further, viewing distances greater than 32 m, the minimum element height shall be determined in accordance with the following equation:

Minimum element height, mm = Maximum viewing distance, mm / 160

and rounded up to the nearest 50 mm.

In the United Kingdom, BS 5266 pt7 details exit sign heights as follows:

Internally Illuminated:

Maximum Viewing Distance, mm = 200 X panel height, mm

Externally Illuminated:

Maximum Viewing Distance, mm = 100 X panel height, mm

Although the Building Code does not specifically call out exit sign size, consideration should be given to the size of the sign and the respective viewing distance. This can aid in emergency wayfinding and promote for efficient evacuation.