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BCC Ruling No. 99-09-665

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BUILDING CODE COMMISSION DECISION ON B.C.C. #99-09-665

IN THE MATTER OF Subsection 24 (1) of the Building Code Act, 1992. AND IN

THE MATTER OF Sentence 3.2.8.1.(1) of Regulation 61, as amended by O. Reg. 22/98, 102/98 and 122/98 (the "Ontario Building Code").

AND IN THE MATTER OF an application by Mr. Stan Radway, Senior Associate, Webb, Zerafa Menkes Housden Partnership, 95 St. Clair Avenue West, Suite 1500, Toronto, Ontario for the resolution of a dispute with Mr. Yaman Uzumeri, Chief Building Official, City of Toronto, Ontario to determine whether the 2 hour fire-resistance rated window sprinkler assembly that is proposed for one side only of the fire separation on floors three, four and Five of the atrium provides sufficiency of compliance with Sentence 3.2.8.1.(1) of the Ontario Building Code at the Bay/Adelaide Centre, Toronto, Ontario.

APPLICANT

Mr. Stan Radway, Senior Associate
Webb, Zerafa Menkes Housden Partnership
95 St. Clair Avenue West, Suite 1500
Toronto, Ontario

RESPONDENT

Mr. Yaman Uzumeri
Chief Building Official
City of Toronto

PANEL

Mr. Roy Philippe, Chair
Mr. Ross Thomson
Mr. James Lischkoff

PLACE

Toronto, Ontario

DATE OF HEARING

February 11, 1999

DATE OF RULING

February 11, 1999

APPEARANCES

Mr. Jonathan Rubes
President
Leber/Rubes Inc.
Agent for the Applicant

Mr. Peter Au
Senior Plans Examiner
City of Toronto
For the Respondent

RULING

  1. The Applicant

Mr. Stan Radway, Senior Associate, has applied for a building permit under the Building Code Act, 1992 to construct a new 50 storey office tower, known as the Bay/Adelaide Centre, in Toronto, Ontario.

  1. Description of Construction

The Applicant proposes to construct a new 50 office storey tower, with a building area of 4,700 m2. The structure is proposed to contain four major occupancies. It will be predominantly Group D - Business occupancy, however the building will also contain Group A2 - Assembly, Group E - Mercantile, and Group F3 - Low Hazard Industrial occupancies. The building will be equipped with a fire alarm, standpipe and hose and sprinkler systems.

The structure, as designed, will contain an atrium on the outer portion of the west side of the building that will extend from the ground floor to the ceiling of the fifth floor. The atrium, including its roof, will be constructed of glass, supported by a structural steel frame.

The ground floor of the subject building has, at its eastern end, an interconnected floor area, that is open to the concourse level below and the second floor above. These areas will be constructed in accordance with the applicable interconnected floor space requirements. The second floor also has a mezzanine that overlooks the atrium.

As a part of the atrium construction, the Applicant is proposing to build the walls that terminate on the interior side of the atrium on floors three, four and five entirely of glass. As walls that do not terminate at an exterior wall, the walls on these three floors would be constructed as fire separations with a two hour fire-resistance rating. To achieve this level of fire separation, the Applicant is proposing to install a window sprinkler assembly built in conformance with the Ruling of the Minister of Municipal Affairs and Housing, # 97-01-49-(12752)R. However, his intention is to achieve the two hour fire-resistance rating by installing sprinklers only on the floor area side of the window assembly. This means that the atrium side of these separations would be unrated, and would essentially act as a smoke separation.

With this two hour separation between floors three, four and five and the atrium, the Applicant is proposing to waive certain requirements related to interconnected floor spaces. The measures they intend not to incorporate for floors three, four and five are "pressurization of the stair vestibule (3.2.8.4.), pressurization of a vestibule at the low-rise elevator core (3.2.8.5.) and exhaust from the ceiling of the fire separated atrium (3.2.8.9)." However, the Applicant indicated that he plans to comply with some of the interconnected floor space requirements by designing the atrium large enough to incorporate a 7 m ellipse with a 65 m2area (3.2.8.3.), by limiting travel distance to 40 m (3.2.8.4.), and by providing full sprinklering throughout the building (3.2.8.7.), smoke detection at the perimeter of the unprotected floor opening (3.2.8.8.), and zoned smoke exhaust (3.2.8.9.).

  1. Dispute

The issue at dispute between the Applicant and Respondent is whether the proposed two hour rated window sprinkler assembly, installed with sprinkler heads on only the floor area side of the separation, located where floors three, four and five terminate at the atrium provides sufficiency of compliance with Sentence 3.2.8.1.(1) of the Ontario Building Code. This provision stipulates that a floor area that does not terminate at an exterior wall must have a fire separation with at least the same fire-resistance rating required for the floor assembly. A 2 hour rating is required in this instance. If the proposed modified window sprinkler assembly is deemed to provide sufficiency with Sentence 3.2.8.1.(1), then floors three, four and five would not be considered as interconnected with the lower floors, and therefore the requirements for interconnected floor areas found in OBC Articles 3.2.8.3. to 3.2.8.11. would not apply to those floors.

  1. Provisions of the Ontario Building Code

Sentence 3.2.8.1.(1) Application

(1) Except as permitted by Article 3.2.8.2. and Sentence 3.3.4.2.(3), the portions of a floor area or a mezzanine that do not terminate at an exterior wall, a firewall or a vertical shaft shall

(a) terminate at a vertical fire separation having a fire-resistance rating not less than that required for the floor assembly and extending from the floor assembly to the underside of the floor or roof assembly above, or

(b) be protected in conformance with the requirements of Articles 3.2.8.3. to 3.2.8.11.

  1. Applicant's Position

The Applicant submitted that the proposed construction, including the window sprinkler assembly, provides sufficiency of compliance with the Sentence 3.2.8.1.(1) of the OBC and would protect against the spread of smoke and fire between floors. The App licant indicated that it was his belief that fire exposure to the third, fourth and fifth floors would arise from a fire situation actually on one of these floors. Bearing this in mind, he noted that the floor assemblies would provide a two hour fire-res istance rating, as would the window sprinkler system facing the subject floor areas which, in the event of a fire, would actuate and thereby achieve the necessary two hour fire-resistance rating.

As a result, in the Applicant's view, the only concern is the threat of fire from the atrium. On this issue, the Applicant argued that the shape of the atrium and how it would be used would mean that fire exposure to the unrated glazing would not be sufficient to activate a window sprinkler. He indicated that the ground floor and the associated mezzanine are basically intended as circulation space. Restaurant seating and/or retail kiosks would be the most likely use for that area, and as the Ap plicant stated, this would not create a large fuel load. In fact, he noted that such a limited fuel load would make it highly unlikely that sprinkler heads on the third, fourth and fifth floors would activate. Since there are sprinklers on the ceiling o f the ground floor, their activation would probably suppress much of the fire and preclude the actuation of the atrium sprinklers.

Another problem with respect to the atrium sprinklers, the Applicant pointed out, is their height above the ground level floor. At heights ranging from approximately 14 m at the third floor level to 25 m at the fifth floor level, sprinkler heads in th e atrium space would be at a considerable height from the source of heat. The Applicant discussed the results of various testing models to determine sprinkler activation. His analysis indicated that the third and fourth floor sprinklers would probably o nly actuate if they were directly in a fire plume, and the fifth floor atrium level sprinklers would most likely never respond. This is assuming, as the Applicant pointed out, that the ground floor sprinklers would not have already significantly reduced the fire.

Based on these factors, he asserted that sprinklers would not be effective nor practical as a way of controlling fire on the atrium side of the window assembly.

The Applicant felt that smoke spread was the primary hazard associated with the atrium. Nevertheless, he contended that the proposed unrated fire separation would adequately control the spread of smoke from the atrium to the third, fourth and fifth flo ors. He also noted that the ground and second floors are equipped with a zoned smoke exhaust system that, when activated, would probably clear much of the smoke before it was allowed to build up in the atrium space.

1) The Applicant indicated that if his proposal was found to provide sufficiency of compliance with Sentence 3.2.8.1.(1) and that the third, fourth and fifth floors were deemed not to be interconnected with the building's lower areas, then it would f ollow that none of the OBC measures relating to interconnected floor space therefore applied. Nevertheless, he drew the Commission's attention to the fact that many of these requirements were being included in the subject floor areas regardless (des cribed above).

The Applicant concluded his arguments by stating that it was his intention to demonstrate sufficiency of compliance with various provisions in the OBC. He made it clear that he was not seeking to sufficiently comply with a Ruling of the Minister of Mu nicipal Affairs and Housing, or modify or amend such a ruling in any way.

  1. Respondent's Position

The Respondent submitted that the relevant Ruling of the Minister of Municipal Affairs and Housing requires that the window sprinkler assembly proposed as a 2 hour vertical fire separation be protected on both sides of the windows. Since this proposal only intends to provide the two hour rating on one side, then it does not conform with the subject Minister's Ruling.

He also questioned whether the Building Code Commission was the appropriate body to hear this issue since building standards covered within Minister's Rulings are not found in the OBC.

  1. Commission Ruling

It is the decision of the Building Code Commission that:

The design, as proposed, provides sufficiency of compliance with Articles 3.2.8.3. to 3.2.8.11 of the Ontario Building Code for an interconnected floor space design.

  1. Reasons

1) Fire protection engineering design calculations indicate that unprotected glazing on the atrium side would not be affected by fire in the atrium.

2) The atrium is protected from fire occurring in floor levels 3 to 5 by an engineering designed sprinkler system which provides a 2-hour fire separation.

3) It is the opinion of the Building Code Commission that the proposed design does not reduce the level of safety intended by the Code.

Dated at Toronto this 11th day in the month of February in the year 1999 for application number 1998-70.

Mr. Roy Philippe, Chair

Mr. Ross Thomson

Mr. James Lischkoff