November 28, 2011

Building Code

Ontario should consider emergency change to building code on balcony glass: Report

Current standards set 20 years ago

KELLY LAPOINTE

staff writer

Action is needed on glass balconies, says a report from the City of Toronto’s planning and growth management committee.

Last summer there was a series of incidents of glass panel failure on high-rise condominiums in Toronto. These failures often resulted in the tempered glass falling onto streets and sidewalks below. So far no serious injuries have resulted.

The planning and growth management committee recommends city council direct Toronto Building’s chief building official and executive director on four initiatives concerning the review of the use of glass panel balcony guards.

The first recommendations is a request that the Canadian Commission on Building and Fire Codes and the Ministry of Municipal Affairs and Housing consider an emergency amendment to the Ontario Building Code over public safety concerns in the event of more glass panel failures.

Key stakeholders, such as the Toronto Building and Land Development Association (BILD), TARION, Ontario Association of Architects and Professional Engineers Ontario, are being encouraged to update their practice and professional training regarding the use of glass panels in balcony guards.

“Supporting the continuous improvement in the building process is a priority for the association and its 1,350 member companies. Therefore, the industry has been actively working with the City of Toronto Chief Building Official and staff to study the glass balcony panel guards,” said BILD in a statement.

“BILD will continue to work with the City of Toronto and has committed to supporting and educating its members as they continue to build a greater GTA.”

Another recommendation encourages Industry Canada, Canadian Glass Association, the Safety Glazing Certification Council and the Glass Association of North America to communicate and coordinate a comprehensive review of compliance safety standards for the manufacturing of non-metallic product used to produce architectural glazing materials.

The final recommendation is that Toronto Building re-evaluate wind tunnel standards and criteria and report to the planning and growth management committee on changes to improve modeling and application standards.

Through Toronto Building, an engineer conducted a technical review of glass balcony, guard manufacturers and design and identified a few key findings in the evolution of glass balconies.

Among them, the manufacture of glass inherently introduces impurities which result in inclusions from nickel sulphide particles trapped in the glass that expand, causing some glass panels to fail. It was found that an overwhelmingly concentrated amount of failures occur in the period within two to seven years after manufacture.

Nickel sulphide inclusions have been identified as the most likely cause of failure in the buildings where the highest frequency of failure occurred. The assessment of failures, by the engineer, says these nickel sulphide inclusions were potentially aggravated by factors like loading or deflection, either by causing glass inclusions to rupture at a higher rate or as a result of glass to metal contact. Significant rates of glass to metal contact were identified on two of the four towers.

In the case of the building at Regent Park, the results indicate there was no connection made to nickel sulphide inclusions.

In response to the failure of many tempered glass balcony panels in their buildings, Lanterra Developments announced in August that it was replacing the tempered glass on its buildings’ balconies with a laminated solution resembling the type of safety glass used in vehicle windshields.

The report indicated there is a lack of clarity and potential conflict within the building code and its standards.

The applicable standard for tempered glass referenced in the building code is 21 years old and was written primarily for “glazed exterior/interior passageway doors, storm (combination) doors, patio doors, shower and bathtub doors and their enclosures”.

But tempered glass is the standard usually applied to balcony construction. The consultant notes that “this standard does not require assurance that the glass will not break, only that the glass will break into small pieces of a maximum size.”

The planning and growth management committee adopted the report and has sent to on to city council be considered tomorrow.

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