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May 1, 2005  Canadian Consulting Engineer

CODES

New building code brings big changes

By September this year, consulting engineers will have a radically new version of one of their mainstay documents. After almost a decade in the making, Canada’s new National Building Code, National Fire Code and National Plumbing Code are due to be published in the fall.

The 2005 codes are the first to be based upon the concept of “objective based principles,” marking a seismic shift in approach. The new format is designed to help designers understand the reason why a particular provision must be met, and will allow them to try alternative approaches rather than simply complying with prescribed methods.

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The building code will have three divisions. Division A will set out the code’s functions and objectives, and explain how compliance can be achieved. Division B will contain all the familiar technical provisions but updated. These will now be referred to as “acceptable solutions.” Division C will contain the administrative provisions.

The code also introduces changes to the basic design requirements. For example, in Part 3, Fire Protection, Occupant Safety and Accessibility, there are changes to the requirements for firewalls, mezzanines, and barrier-free routes. In materials, changes include allowing factory-produced insulated panels in cold storage buildings, and a change to allow larger sized non-metallic conduit within a fire compartment.

In Part 6, Heating, Ventilating and Air-Conditioning, changes now allow natural ventilation where climatic conditions make it feasible.

One proposal that has not been passed would have made the maximum hot water temperature at fixture outlets 49C to prevent people scalding themselves. There was much opposition to this concept because a temperature of 49C leaves plumbing systems open to contamination by Legionella and other bacteria.

For structural engineers there are many changes, including the adoption of dynamic analysis instead of static analysis as the default design procedure in certain seismic situations, particularly in central and eastern Canada. The new requirements will affect the design of tall buildings in urban areas such as Ottawa-Gatineau, Montreal and Quebec City.

ENVIRONMENT

Fire retardant chemicals seen as threat

The environmental impact of flame retardants is causing concern among environmentalists, with groups on both sides of the question arguing that they have the welfare of the public in mind.

Polybrominated diphenyl ethers (PBDEs) are chemicals that for 30 years have been used to slow the spread of fire in furnishings, including carpets and upholstery, as well as in equipment like computers and televisions — in short everywhere in our indoor environments. The lobby group for the manufacturers who make the retardants is the Bromine Science and Environment Forum in Washington, D.C. It points out on its website that fire retardants using PBDEs probably saved 280 lives in the U.S. in one year alone.

However, an article “Everyday Poisons,” by Paul Webster in The Walrus (December/January 2005), was a lengthy critique of PBDEs. The article noted that they were among 123 substances screened under the “red flag” criteria for safety after the Canadian Environmental Protection Act was passed in 1999. Of seven formulations all raised concerns.

Two of the flame retardants that are considered to be most worrisome — Octa-BDE and Penta-BDE — are banned in Europe and California. The industry claims that another form, deca-BDE, is less harmful.

Environment Canada also released a draft scientific assessment of the chemicals in May 2004 that suggested they are harmful to the environment and some are bioaccumulative. In animal studies the chemicals have been linked to possible impairment of attention, learning and memory. Canada’s Environment Ministry is preparing an action plan to minimize the impact of PBDEs on the environment.

Studies last year reported that the fire retardant chemicals were present in B.C. farmed salmon and were at rising levels in the eggs of Herring Gulls around the Great Lakes.

STRUCTURES

Columns pass fire tests

Fire tests on concrete columns, slabs and beams reinforced with fibre-reinforced polymer, or FRP, have passed a milestone. Fibre reinforced polymer is seen as a promising new material for strengthening concrete because it is strong, lightweight and does not corrode.

Researchers at the National Research Council’s Institute for Research in Construction in Ottawa conducted fire endurance experiments on various type of structural assemblies strengthened with carbon or glass fibre-reinforced polymer wraps. The assemblies were also treated with spray applied insulation and intumescent paint fire protection.

The assemblies endured the fire for more than four hours. They managed to maintain their structural integrity and stability even after temperatures exceeded the “glass transition temperature.”

NOTES

Pearson International Training Facility

The Greater Toronto Airport Authority is building a major firefighter training facility at Pearson International Airport. The $11-million complex will include a 2,400-m2 building for classrooms, lecture theatres, staff facilities etc. There is also a “Burn Building,” and a five-storey rescue tower. Consultants include Halsall Associates (structural and environmental), Trow (civil), PT Engineering and Termodeck Canada (mechanical and electrical). Kleinfeldt Mychajlowycz is the architect.

Fire in Alberta oilsands halves Suncor’s production

A large fire early this year at Suncor’s oilsands operation in Fort McMurray, Alberta, cut its production by almost half. The company said it would take over six months to return to full production.

The fire on January 4 burned for nine hours, crippling one of the company’s two upgraders. It is believed the cause was a recycle line that filters heavy oil from a fractionator. The line had corroded and released hydrocarbon vapour that ignited. The damage was caused by fire and by ice that formed in minus 35C temperatures.

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