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BCC Ruling No. 99-61-717

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

AND IN THE MATTER OF Article of Regulation 61, as amended by O. Reg. 400/91, 158/93,383/94, 20/95 and 395/96 (the "Ontario Building Code").

AND IN THE MATTER OF an application by Ms. Susan Croswell, Associate, Griffiths Rankin Cook Architects, Ottawa, Ontario, for the resolution of a dispute with Ms. Terry Dalkowski, Chief Building Official, City of Nepean, Ontario, to determine whether the proposed four wired glass panels, none of which exceed 0.8 m2 ,but which have an aggregate area of 1.9 m2 , as part of a wall assembly providing a 3/4 hour fire-resistance rating complies with Article of the Ontario Building Code at John McCrae Secondary School, Walter Baker Centre, Nepean, Ontario.


Ms. Susan Corswell, Associate
Griffiths Rankin Cook Architects
Ottawa, Ontario


Ms. Terry Dalkowski
Chief Building Official
City of Nepean


Mr. James Lischkoff (Chair-Designate)
Mr. Robert De Berardis
Mr. Stewart Smith


Toronto, Ontario


September 23rd, 1999


September 23rd, 1999


Mr. Tom Dunfield, Principal
Morrison Hershfield Limited
Ottawa, Ontario
Agent for the Applicant

Mr. Peter Black, Building Official
City of Nepean
Designate for the Respondent


1. The Applicant

Ms. Susan Croswell, Associate, Griffiths Rankin Cook Architect, Ottawa, Ontario, has received a building permit under the Building Code Act, 1992 to construct an addition onto the John McCrae Secondary School, Walter Baker Centre, Nepean, Ontario.

2. Description of Construction

The Applicant proposes to construct a new wing to the south of an existing Group A, Division 2 (secondary school and sports facility) occupancy. The completed building will be three storeys in building height, 4,675 m2 (in building area) and will be of noncombustible construction. The structure will be equipped with a sprinkler system, a standpipe and hose system and a fire alarm system. The three storey addition is to be provided with 3 exit stairs.

The construction in dispute involves the amount of glazed area in the interior enclosure wall assemblies that separate exit stairs number two and three from the corridors they serve. Specifically, the stair enclosures in dispute are located at the ground, second and third floors for exit stair number two and at the second and third floors for exit stair number three. All of the proposed stair enclosures are to be constructed of wired glass supported by a hollow metal frame providing a 3/4 hour fire-resistance rating.

In terms of their design, the exit enclosures on the ground and second floor of stair number two and on the second floor for stair number three have four fixed windows of differing sizes (the largest of which measures 600 mm by 800 mm for an area of 0.72 m2 ) , for a total aggregate glazed area of approximately 1.9 m2 . For the wider third floor enclosures at stairs number two and three, the window pattern at the other locations is repeated separated by a 600 mm drywall partition. All stair enclosures are provided with two access to exit doors each.

A temporary solution of 18 mm thick drywall has been installed over the glazed area in excess of 0.8 m2 .

The amount of glazed area in the access to exit doors serving the subject exit stairs is not in dispute.

3. Dispute

The issue at dispute between the Applicant and Respondent is to determine whether the proposed exit stair enclosures containing a set of four wired glass panels (and in some cases two sets), none of which exceed 0.8 m2 , but which have an aggregate area of 1.9 m2 , as part of a wall assembly providing a 3/4 hour fire-resistance rating complies with Article of the 1990 Ontario Building Code. Among other things, this provision sets out in Table 3.1.8.B. the maximum glazing allowed in an area which is not in a door. As indicated in the Table, the maximum aggregate area of wired glass permitted which is not in a door is 0.8 m2 . The Applicant's stair enclosures exceed this amount by at least 1.1 m2 .

4. Provisions of the Ontario Building Code

Article Area Limits for Wired Glass or Glass Block

Except as provided by Article, the maximum area of wired glass in a door and the maximum area of wired glass panels or glass block not in a door shall conform to Table 3.1.18.B. when used in the locations shown in the Table.

5. Applicant's Position

The Applicant submitted that proposed stair enclosures, as designed, complies with the intent of Article of the OBC. As he argued, the intent of this provision is to minimize radiant heat caused by the ignition of combustible materials located near the enclosure walls t hat may pass through the glass panels and expose occupants to excessive temperatures during emergency exiting. The glazed area restriction in the Code, he noted, does not apply to the access to exit doors in the subject enclosures because the placement of combustible materials, or any type of materials for that matter, would disrupt the usage of the door.

The same rationale of permitting the waiving of standards for the doors, however, can be applied back to the rest of the enclosure wall assembly, he argued. This is due to the fact that there is no occupancy in the adjacent corridors, and thus no storage will be permitted next to the enclosure walls. Regardless, no materials would be placed there because, as the Applicant stated, the point of the increased glazed area is to enhance natural lighting and security in the stairs.

The Applicant compared the proposed design to other situations envisage in the Building Code. In Article, "Exit Through Lobbies", for example, an exit is allowed to lead through a lobby with an unrated separation provided the lobby and adjacent areas are sprinklered. As well, Article, "Wall Exposed to Another Wall", waives the requirement for a limiting distance between two unprotected openings in two separate fire compartments if both compartments are sprinklered. In both these examples he argued that the effect of the sprinklers would be to control the fire and would therefore control the fire exposure. In the case in the first example, this control of the fire exposure would specifically allow exiting to occur unimpeded. It is also an example of where an active system - the sprinklers - is allowed to replace a passive system, i.e., a fire separation. Drawing a parallel between those examples and the subject building, the Applicant argued that since this is a fully sprinklered facility, the fire suppression that would be provided would act to minimize radiant heat from a fire thereby allowing safe passage of occupants in the exit stairs.

To support this assertion, the Applicant presented the results of a fire modelling analysis done on this project conducted by a fire safety research scientist. The fire modelling analysis looked at two scenarios, the worst of which placed a fire in a room with an open door directly opposite from the third floor enclosure which has an aggregate glazed area of 3.8 m2 . The findings of the analysis demonstrated that the sprinkler system would actuate and control the fire before dangerous levels of radiant heat exposure was experienced in the exit stair.

In conclusion, the Applicant stated that the design of the stair enclosure meets the intent of the Code and that no radiant heat problem would occur. As a result of the building being sprinklered no aggregate limit of wired glass should be imposed on the stair enclosures.

6. Respondent's Position

The Respondent submitted that the exit stair enclosures that have 1.9 and 3.8 m2 of glazed area contravene the prescriptive requirements of Table 3.1.8.B. of the 1990 OBC. A relaxation of the 0.8 m2 maximum glazed area requirement is only possible by providing enhanced physical separations through the introduction of vestibules or rated corridors, as per Article The Respondent noted, however, that the Applicant has not chosen to exercise this option.

The Respondent rejected the argument that the fact the building is of noncombustible construction and is sprinklered that the proposed glazed area should be permitted. The Code does not allow a trade off between sprinklers and the amount of glazed area allowed, he noted. The exiting of occupants is the highest priority of building fire safety, he argued, and while the noncombustible construction and the sprinkler system assist in maintaining the integrity of the building in a fire, it is only the exit route that provides for a way out in an emergency. The integrity of the exit itself should not be reduced, he stated.

7. Commission Ruling

It is the decision of the Building Code Commission that the requirements of Article of the Ontario Building Code have not been satisfied.

8. Reasons

The Applicant did not submit any compensating measures or alternative proposals to achieve sufficiency of compliance.

Dated at Toronto this 23rd day in the month of September in the year 1999 for application number 1999-54.

Mr. James Lischkoff, Chair-Designate

Mr. Robert De Berardis

Mr. Stewart Smith