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BCC Ruling No. 97-32-574

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BUILDING CODE COMMISSION DECISION ON B.C.C. #97-32-574

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

AND IN THE MATTER OF Sentence 9.10.9.14.(3) of "the Building Code" (Ontario Regulation 419/89 as amended by Ont. Reg. 183/88, 581/88, 11/89 and 115/89)

AND IN THE MATTER OF an application by Ms Jill Moir, Grey Condominium Corporation No. 18, Collingwood, Ontario, for the resolution of a dispute with Mr. Mina Tesseris, Chief Building Official, Township of Collingwood, Ontario, whether the roof truss assembly provides sufficiency of compliance with the Ontario Building Code at Chateau Ridge Condominiums (Grey Condominium Corporation No. 18), Collingwood, Ontario.

APPLICANT


Ms Jill Moir
Grey Condominium Corporation
Collingwood, Ontario

RESPONDENT


Mr. Mina Tesseris
Chief Building Official
Township of Collingwood

PANEL


Mr. Roy Philippe (Chair)
Mr. Rick Florio
Mr. Ross Thomson

PLACE


Toronto, Ontario

DATE OF RULING


Tuesday, July 22nd, 1997

APPEARANCES


Mr. David Syrett
Leber Rubes Inc.
Toronto, Ontario
For The Applicant

Mr. Graeme Scott
Halsall Associates Ltd.
Toronto, Ontario

Mr. Mina Tesseris
Chief Building Official
Township of Collingwood
The Respondent

RULING

  1. The Applicant

Ms Jill Moir, Grey Condominium Corporation is the holder of a building permit under the Building Code Act, 1992 to install fire separations at existing 3 storey townhouse condominiums in the Township of Collingwood, Ontario.

  1. Description of Construction

There are 6-12 dwelling units in each building. Each building contains upper and lower units in which one dwelling unit is located above another. The design and construction of each building was regulated by Part 9 of the Ontario Building Code as each building is not more than three storeys in height or 600 square metres in building area. Since the building is a condominium, the separation between residential suites is governed by Sentence 9.10.9.14.(3) which requires a fire separation having a fire-resistance rating of not less than 1 hour.

The buildings are permitted by the Building Code to be of combustible construction. The buildings were constructed of a combination of combustible and non-combustible construction. The roofs are framed using timber trusses spaced 16 inches apart except at dormer locations where the roof has been constructed using conventional lumber framing. The roof trusses span parallel to these vertical fire separations except at the ensuite bath where the fire separation jogs 90 degrees and runs perpendicular to the span of the trusses. This condition exists in 18 upper units.

The vertical fire separations were originally constructed to the underside of the trusses with no fire separations within the attic space. They were recently extended through the attic space to the underside of the wood roof sheathing. This new fire separation is constructed of rated gypsum board on both sides of metal studs and is required by Article 9.10.9.10. to have a 1 hour fire resistance rating. Where the fire separation jogs around the ensuite bath, the timber trusses penetrate this new fire separation

  1. Dispute

The dispute between the Applicant and Respondent concerns whether the installed wood roof truss penetration of the combustible 1 hour fire separation in the attic space is permitted under the Building Code.

  1. Provisions of the Building Code

Sentence 9.10.9.14. Separation of Residential Suites

(3) Dwelling units that contain 2 or more storeys including basements shall be separated from the remainder of the building by a fire separation having a fire-resistance rating of not less than 1 hr.

Article 9.10.3.1. Fire-Resistance and Fire-Protection Ratings

Where a fire-resistance rating or a fire-protection rating is required in this Section for an element of a building, such rating shall be determined in conformance with the test methods described in Part 3, or in accordance Chapter 2 of the Supplement to the NBC 1990, or with Tables 9.10.3.A. and 9.10.3.B.

Sentence 9.10.9.10.(1) Concealed Spaces above Fire Separations

(1) Except as provided in Sentence (2), a horizontal service space or other concealed space located above a required vertical fire separation shall be divided at the fire separation by an equivalent fire separation within the space.

Article 9.10.5.1 Permitted Openings in Wall and Ceiling Membranes

(1) Except as permitted in Sentences (2) and (4), a membrane forming part of an assembly required to have a fire-resistance rating shall not be pierced by openings into the assembly unless the assembly has been tested and rated for such openings.

(2) A wall or ceiling membrane forming part of an assembly required to have a fire-resistance rating may be pierced by openings for electrical and similar service outlet boxes provided such outlet boxes are tightly fitted.

  1. Applicant's Position

The one hour fire separation within the attic space is constructed of rated gypsum board on both sides of wood studs in accordance with Chapter 2, "Fire Performance Ratings" of the Supplement to the National Building Code of Canada, 1990. The engineered wood roof trusses span parallel to the attic fire separation except where the fire separation jogs around the ensuite bathroom. The trusses clear span the length of each dwelling unit and the trusses are spaced at 600 mm on centre. Where members of the truss penetrate the 1 hour fire separation, the gypsum board on both sides of the vertical fire separation has been tightly fitted or firestopped around each member as required by the Building Code.

The Applicant submitted that the issue raised by the Respondent regarding the collapse of the unrated roof trusses may cause premature collapse of the 1 hour fire separation in the attic only applies to firewalls and noncombustible fire separations supporting combustible construction. The requirements for firewalls and combustible construction supported by noncombustible fire separations do not apply to combustible construction supported by combustible fire separations. The Applicant is of the opinion that the Building Code does not prohibit the collapse under fire conditions of a rated vertical fire separation as a result of the collapse of unrated or lesser rated construction supported by it where the rated fire separation and unrated construction are of the same construction type. Furthermore, the Applicant submitted that the roof assembly is not required by the Code to have a fire-resistance rating.

  1. Chief Building Official's Position

The Chief Building Official submitted that the attic fire separations of the units are required to be constructed as one hour fire separations in accordance with Sentence 9.10.9.10(1). Eighteen of the 27 upper units within the development contain 6 or 7 of the 17 trusses within the attic which penetrate the fire separation. The ceiling of these units has not been constructed as a fire rated separation.

The Respondent also submitted that the fire resistance rating of a fire separation penetrated by wood roof trusses cannot be determined by using Chapter 2, "Fire Performance Ratings" of the Supplement to the NBC 1990 because this document does not assign a time of contribution to wallboard membranes penetrated by wood roof trusses or any other type of framing members. Approved fire tests are not known to have been conducted on such an assembly. Therefore, the fire resistance rating of the fire separations penetrated by the wood roof trusses is unknown. It is the position of the Respondent that the attic fire separations penetrated by the wood roof trusses have not been constructed in accordance with fire-resistance and fire-protection ratings under Article 9.10.3.1 and therefore do not provide a 1 hour fire resistance rating as required by Sentence 9.10.9.10.(1).

The Respondent indicated that should a fire occur in the attic of one of the units adjacent to the fire separations in question, the roof trusses which penetrate the separation could lose their integrity in as little as 5 minutes and would take the fire separation down along with them.

  1. Commission Ruling

It is the decision of the Building Code Commission that the protection of penetrations of the 1 hr fire separation by wood trusses provides sufficiency of compliance with 9.10.9.14.(3) of the Building Code.

  1. Reasons:

i) The penetrations by wood trusses of the fire separations are sealed and the exposed chords are protected for at least 1 foot by fire resistance rated materials.

Dated at Toronto this 22nd day in the month of July in the year 1997 for application number 1997-36

Roy Philippe, Chair

Mr. Rick Florio

Mr. Ross Thomson