Responding to concerns about wood frame structures

The column in the May 18 issue of the Journal of Commerce by Carolyn Campbell with the B.C. Ready Mixed Concrete Association significantly misrepresented the fire in the Remy in Richmond.

It notably confused the fire risk of a building under construction with the fire risk of a completed building.

These risks are entirely dissimilar.

One could equally use the argument that a fire in a car plant means that all cars are unsafe to drive.

Six-storey wood-frame buildings are built in full compliance with the B.C. Building Code and B.C. Fire Code.

When complete, six-storey wood buildings are as safe as or safer than any other buildings constructed with any other materials.

The Remy construction fire is not a six-storey or wood building issue: the issue is fire protection of buildings during the vulnerable construction phase.

The risk of fire in a completed building is largely determined by the extent of passive and active fire mitigation measures.

Passive measures include elements such as fire-rated floors and walls, for instance, between suites, protecting corridors and around service shafts.

This fire resistance, or the ability to restrict fire spread, is a way of confining fires to their point of origin, thereby providing both property protection and life safety.

Other key fire mitigation measures include firewalls to prevent fire spread from building to building; fire alarm systems to detect fires and alert occupants throughout the premises; fire- rated exit stair enclosures; and fire suppression, such as automatic sprinkler systems to detect fires and extinguish them in the vicinity of the fire.

Automatic sprinklers increase the probability that fires will be controlled or extinguished in the combustible contents in a compartment, before the structure of the building becomes involved.

This is an important aspect, which complements firewalls and fire separations, such as fire-rated floors and walls. It is important to note that none of the three redundant fire safety features was yet installed at the Remy – fire sprinklers, fire separations or firewalls.

The very high reliability of sprinkler systems, in combination with passive fire control systems, means that protected four and six-storey buildings in B.C. actually have a higher degree of safety than unprotected buildings of other materials.

This is supported by historical evidence of failures of buildings that lacked internal fire suppression systems. Despite being referred to as “non-combustible”, unprotected structures of other materials can fail when exposed to uncontrolled internal fires.

The inclusion of automatic sprinkler systems, as a key element of six-storey construction, supplements their inherent passive fire resistance systems and renders the building inherently more robust and resistant to failures, such as doors, which may be left open during actual fires.

This means that the overall reliability of a building is increased and the probability of failure is much lower, once the building is completed and occupied.

This is true of all construction types.

On the other hand, during the course of construction, virtually none of the passive or active fire mitigation elements is in place until the building is completed.

Consequently, openings exist throughout the building and there is limited ability to restrict vertical and horizontal fire spread; walls and ceilings are not yet covered in fire resisting wall-board that helps to confine the fire to a single compartment.

In addition, firewalls between buildings have openings and therefore can easily be breached; the main fire alarm system does not exist, which means a fire will not be automatically detected and/or responded to; and sprinkler systems are incomplete and will not function.

This means that fire risk when a building is under construction is completely different than fire risk in a completed building.

These important differences are not mentioned in Campbell’s column.

The Remy project was under construction and not a completed building. Most of her comments use the Remy fire as an opportunity to discredit the safety of completed wood buildings.

The industry needs to spend its energies on working together to improve vigilance throughout the industry, rather than fear-mongering in an effort to serve the interests of any specific construction material.

The impact of fires during the course of construction is a substantial concern, whether it results in the collapse of unprotected steel structures, the involvement of wood formwork used in the creation of concrete buildings, or losses like the Remy.

Fire risk during construction needs to be managed in accordance with sound fire engineering principles and enhanced security, rather than rhetoric.

In practice, any fire safety plan for a building under construction revolves around such preventative practices as restricting unauthorized access, controlling the fire risks and promptly communicating alarms to the fire services, if a fire is discovered.

In conclusion, fires in the course of construction must be analyzed and lessons learned to minimize future losses on jobsites. An official fire investigation report is not yet available, but certainly the outcome should be a review of fire safety plans on construction sites during the time of vulnerability for all buildings to mitigate the risk of fire.

In the meantime, let us get on with the task of building a better industry that will respect our past whilst ensuring that there is room for future innovation for all.

John Ivison, BSc (Hons), P Eng, MSFPE, MIFE, is the senior technical advisor for the Wood Enterprise Coalition.