The Building and Safety Standards Branch (BSSB) held seven Technical Advisory Group (TAG) meetings involving a wide range of residential building sector stakeholders and experts. These meetings were held between Sept. 7 and Nov. 5, 2008 to identify potential issues connected to mid-rise wood-frame residential construction and offer suggestions for managing those issues. Meeting topics included:
The key objectives of the TAGs were to discuss ways to change the Building Code without increasing risk and to foster dialogue and cooperation among stakeholders on how to implement the changes effectively. Each suggestion was carefully reviewed and assessed against two criteria: whether it addressed the incremental risk of raising the allowable height of wood-frame residential buildings from four to six storeys; and, whether they were specific to five-and six-storey residential wood-frame construction. Some of the suggestions involved the work of other ministries, for example the Office of the Fire Commissioner. The BSSB worked with these ministries to determine the best way of proceeding.
The majority of technical concerns discussed at the TAG meetings are addressed in the code change announced in January 2009 and by applicable performance requirements that already existed in the code. New APEG-BC guidelines on mid-rise construction are available for building designers addressing a number of the process issues identified in this document. BSSB continues to work with stakeholder groups on implementation, including an exploration of the education and training needs.
Each issue and suggestion raised at the TAG meetings was carefully considered. Issues and suggestions not related to managing the incremental risk of raising the allowable height of wood-frame residential buildings from four to six storeys were not including in changes to the Code. Some issues and suggestions also require more study and have been flagged for future consideration. The following table shows the suggestions/comments, BSSB’s actions, and the rationale for each action:
Suggestion/Concern |
Action |
Rationale |
|---|---|---|
| FIRE SAFETY - Exiting | ||
Horizontal exiting |
Included as a question in the online public review. |
This suggestion is not specific to mid-rise residential wood-frame construction and more analysis on the implications of horizontal exiting is required before a change will be contemplated. |
Pressurized exit stairs |
No further action |
Pressurized shafts exceed what is required to maintain the current level of safety. |
Noncombustible exit shafts |
No further action |
Exit shafts must already meet a one-hour fire rating regardless of the building material. It was decided that consideration of the performance rating supersedes the requirement for construction type. |
| FIRE SAFETY - Construction | ||
Allow use of Part 9 floor and wall assembly listings in Part 3 buildings |
BSSB is working with industry stakeholders on how to best approach this issue |
This suggestion is not specific to mid-rise residential wood-frame construction and more analysis is required to develop options for Part 3 floor and wall assemblies. |
Fire stopping in concealed spaces |
Concealed spaces already protected. No further action required. |
The BC Building Code (BCBC) already requires fire stopping in concealed spaces. To meet NFPA 13, these buildings will also have sprinklers in some concealed spaces providing further protection. |
Openings in rated ceiling membranes |
APEGBC guidelines provide guidance to engineers on the need to maintain integrity of fire separations |
The issue of openings in rated ceiling membranes is not specific to mid-rise residential wood-frame construction and was addressed through a regulation change adopted in December 2008. |
More detailed drawings of services to guide mechanical systems installers |
APEGBC guidelines clarify drawings to maintain integrity of fire stopping |
This is an implementation issue common to all wood buildings. The TAG discussions clarified the need for better coordination between designers and trades to ensure key building elements are identified and maintained. |
Make trades responsible for fire stop integrity |
No further action |
Design professionals, project managers and trades people have a shared responsibility for ensuring fire stop integrity is maintained. |
Require masonry block or concrete fire walls |
No further action |
This suggestion is not specific to mid-rise residential wood-frame construction and fire walls must meet prescribed fire resistance rating regardless of material. |
Cumulative effects on fire stopping of wood shrinkage issues and seismic events |
Appendix note reminds designers to account for shrinkage. APEGBC guidelines also remind designers to account for shrinkage and seismic events |
Building designers have the guidance on how to maintain the integrity of fire stopping in the event of wood shrinkage or a seismic event. |
Reliability of fire stopping |
APEGBC guidelines remind designers to field review fire stopping installation to ensure reliability |
Building designers are reminded to inspecting installation for fire stopping during field reviews to address concerns over improper installation of membranes. |
| FIRE SAFETY - Fire Departments | ||
Fire fighting assumptions |
APEGBC guidelines remind designers of the importance of building in redundancies depending on level of fire services available. |
Expert risk assessment has concluded that the fire fighting assumptions included in the appendix of the BC Building Code are the same for mid-rise concrete, steel or wood buildings. |
Rating of Fire Departments (FDs) |
No further action |
Local governments can zone for development that matches the capacity of their fire departments to provide an adequate level of service. |
FD access - landscaping |
No further action |
Local government can use bylaws and development permits to direct appropriate landscaping for each site. |
FD access - defining grade |
No provincial action needed |
Grade is defined by BC Building Code. |
FD - Fire Control Room |
No further action |
Fire control rooms exceed what is required to maintain the current level of fire safety. |
Sprinkler all balconies (regardless of size) |
No further action |
NFPA 13 requires sprinklers on balconies over four feet deep. Noncombustible exterior cladding will provide further protection against external fire spread. |
Enhanced fire alarms |
No further action |
Enhanced fire alarms exceed what is required to maintain the current level of fire safety. |
| FIRE SAFETY - Course of Construction | ||
Site supervisor enforces fire safety or other site supervision methods |
The Office of the Fire Commissioner (OFC) has produced a bulletin clarifying fire safety planning requirements, including responsibility for compliance. |
Analysis of construction fire statistics indicates a very low incidence of construction fires due to poor worksite practices. Fire safety plans are required and already provide for supervision and enforcement. Greater clarity of fire safety planning requirements can offset the small increase in risk for higher wood buildings. |
Improve site security |
No further action |
Analysis of construction fire statistics indicates a very low incidence of intentional construction fires. Builders/developers are encouraged to share information on jobsite practices to deter vandalism and arson. |
Consistent requirement and enforcement of fire safety plans as per BC Fire Code |
The Office of the Fire Commissioner (OFC) has produced a bulletin clarifying fire safety planning requirements. |
OFC posted a bulletin on its website clarifying fire safety plan requirements. |
Ban drywall heaters |
No further action |
Open flame heaters are already disallowed under the Fire Code. |
Incremental protection - install standpipes, sprinklers, temporary wireless alarms, fire separations and fire doors as construction progresses |
No further action |
Owners/contractors can sequence construction to allow a range of incremental protection measures to be in place as construction progresses. |
| Structural Issues | ||
Improve field review regime |
APEGBC guidelines discuss enhanced field reviews for this building type. |
APEGBC guidelines address field reviews. |
Address hybrid buildings |
APEGBC guidelines remind designers to consider interfaces of wood and non-shrinking (concrete) building components. |
APEGBC guidelines address hybrid building. |
Increase wood building design fees to reflect increased complexity |
No further action |
Architects, engineers and developers negotiate fees. |
Firewalls and elevator shafts |
(see Address Hybrid buildings) |
(see Address Hybrid buildings) |
Vulnerability of engineered wood assemblies to fire |
APEGBC guidelines remind designers to protect engineered wood assemblies with fire stopping to prevent premature structural failure. |
Building designers have guidance on how to maintain the structural integrity of engineered wood assemblies during fires. |
| Shrinkage Issues The code change includes an appendix note reminding designers to properly account for shrinkage and to coordinate their calculations for all building elements. |
||
Reduce allowable moisture content and test moisture at time of enclosure, not installation |
APEGBC guidelines reminds designers to account for changes in moisture content during the course of construction |
APEGBC guidelines address moisture content. |
Differential shrinkage in hybrid buildings |
APEGBC guidelines remind designers to consider interfaces of wood and non-shrinking (concrete) building components. |
APEGBC guidelines address differential shrinkage in hybrid building. |
Update CMHC’s guide on designing building envelopes for residential wood buildings in BC |
HPO, AIBC and APEGBC are updating the CMHC guide, the APEGBC guidelines also include information for designers on building envelopes. |
The revised guide addresses issues arising from the increased allowable height of wood frame buildings which will increase environmental exposures. |
| Local Government Implementation | ||
Advise how local government can manage this form of development |
No further action |
Local governments can use OCP and zoning bylaws to determine the appropriate height and density. |
Provide advice for design guidelines |
No further action |
Local governments can use development permit areas to describe the desired form and character of their community. |
Options for other bylaws to manage implementation of code change |
No further action |
Bylaws that describe the type of allowed building material are subject to concurrent authority. |
Assessment of fire service requirements |
No further action |
Local governments can zone for development that matches the capacity of their fire departments to provide an adequate level of service. |
Requiring additional (prescribed) inspections/reviews |
No further action |
Local governments, through their building bylaw, can prescribe when inspections must occur. |
Requiring peer review |
No further action |
Local governments can require specific designations, such as a structural engineer. Engineers are required to have their work peer reviewed. |
| Workmanship/Trades Issues | ||
Quality of workmanship concerns |
Work with stakeholders on education and training. |
The building code sets standards for building construction and is not intended to address workmanship issues. The APEGBC guidelines includes a discussion on how to ensure adequacy of workmanship. |
Require a journeyman for each trade on site at all times |
No further action |
This suggestion is not specific to mid-rise residential wood-frame construction. |
Mandating additional (prescribed) inspections/reviews |
No further action |
APEGBC guidelines include discussion of enhanced field reviews to ensure adequacy of workmanship and local governments, through their building bylaw, can prescribe when municipal inspections must occur. |
More detailed services drawings to guide mechanical services installers |
APEGBC guidelines clarify drawings required to maintain integrity of fire stopping, building envelope and structural integrity. |
This is an implementation issue common to all wood buildings. The TAG discussions clarified the need for better coordination between designers and trades to ensure key building elements are maintained. |
