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BCC Ruling No. 99-53-709

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BUILDING CODE COMMISSION DECISION ON B.C.C. #99-53-709

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

AND IN THE MATTER OF Sentence 3.1.5.4.(5) of Regulation 403, as amended by O. Reg. 22/98, 102/98, 122/98, 152/99 and 278/99 (the "Ontario Building Code").

AND IN THE MATTER OF an application by Mr. David M. Welton, Assistant Secretary, Oakridge Heights Limited, Oakville, Ontario, for the resolution of a dispute with Mr. Frank Asta, Chief Building Official, City of Oakville, Ontario to determine whether the proposed combustible PVC window units installed in certain suites as a floor to ceiling wall assembly with approximately only 250 mm of non-combustible vertical separation between storeys and constituting openings of roughly 50 to 70 percent aggregate area of the exterior wall face provides sufficiency of compliance with Sentence 3.1.5.4.(5) of the Ontario Building Code at Oakridge Heights, 50 Old Mill Road, Oakville, Ontario.

APPLICANT

Mr. David M. Welton, Assistant Secretary
Oakridge Heights Limited
Oakville, Ontario

RESPONDENT

Mr. Frank Asta
Chief Building Official
City of Oakville

PANEL

Mr. Kenneth Peaker (Chair-Designate)
Mr. Robert De Berardis
Mr. Stewart Smith

PLACE

Toronto, Ontario

DATE OF HEARING

August 5, 1999

DATE OF RULING

August 5, 1999

APPEARANCES

Mr. Peter Colquhoun, Consultant
Arencon Inc.
Mississauga, Ontario
Agent for the Applicant

Mr. Frank Asta, Chief Building Official
City of Oakville
The Respondent

RULING

  1. The Applicant

Mr. David M. Welton, Assistant Secretary, Oakridge Heights Limited, has applied for a building permit under the Building Code Act, 1992 to construct a high rise apartment building known as Oakridge Heights at 50 Old Mill Road, Oakville, Ontario.

  1. Description of Construction

The Applicant is proposing to construct a new ten storey (plus two levels of underground parking), Group C - residential apartment building. The structure will have a building area of 4,052.1 m2. The building is to be of noncombustible construction and will be equipped with a sprinkler system, a fire alarm system and a standpipe and hose system.

The construction in dispute involves the use of combustible polyvinyl chloride (PVC) window units in certain suites of the subject building, which is required to be noncombustible according to Article 3.2.2.42. of the OBC. These PVC window units have been installed in suite types A1 and A2 on level A, suite types B1 and B2 on level B, suite types 3 and 4 on floors Main to 7 inclusive, suite types 8 and 9 on floors 2 to 7 inclusive, suite types 5 and 6 on floors 8 and 9, and suite types 4 and 5 on floor 10. Specifically, the Applicant wishes to install the window units in the sunrooms/nooks of some suites as floor to ceiling window walls. As a result, the vertical separation of noncombustible material between suites of contiguous storeys will be approximately 250 mm. Further, the sunroom window walls, as an aggregate area of opening in the exterior wall face, will comprise 49.7% in suite types 2 and 3 and 70.7% in suite types 8 and 9.

To provide additional protection to prevent fire from spreading from suite to suite, the Applicant intends to cover the edge of the floor slab with an aluminium panel and will firestop it with a listed firestop system. The same firestopping will also be included at the demising walls between adjacent suites on the same storey.

The design and arrangement of the subject window units is similar to conventional units regarding their framing and glazing with insulated glass. The Applicant intends to install the subject window units because, in his view, they provide superior thermal, moisture and environmental performance and functionality.

  1. Dispute

The issue at dispute between the Applicant and Respondent is whether the proposed combustible PVC window units, as a floor to ceiling window wall assembly with approximately only 250 mm of noncombustible vertical separation between storeys and constituting openings of roughly 50 to 70% aggregate area of the exterior wall face, provides sufficiency of compliance with Sentence 3.1.5.4.(5) of the Ontario Building Code. Clause (b) of this Sentence requires a separation of 1,000 mm of noncombustible material between windows in exterior walls in contiguous storeys. The proposed separation of noncombustible material between the PVC window units is roughly 250 mm. As well, Clause (c) of Sentence 3.1.5.4.(5) stipulates that only a total of 40% of an exterior wall face of a fire compartment can be used as window openings. In the Applicant's proposed sunrooms/nooks the aggregate area of window opening ranges from approximately 50 to 70%, depending on the suite.

  1. Provisions of the Ontario Building Code

Sentence 3.1.5.4.(5) Combustible Glazing and Skylights

(5) Combustible window sashes and frames are permitted in a building required to be of noncombustible construction provided

(a) each window in a exterior wall face is an individual unit separated by noncombustible wall construction from every other opening in the wall,
(b) windows in exterior walls in contiguous storeys are separated by not less than 1000 mm (3 ft 3 in) of noncombustible construction, and (c) the aggregate area of openings in an exterior wall face of a fire compartment is not more than 40% of the area of the wall face.

  1. Applicant's Position

The Applicant submitted that the subject windows provide sufficiency of compliance with Sentence 3.1.5.4.(5) for the following reasons.

Conventional aluminium thermally broken window systems are typically held together with a PVC or thermal vinyl break meaning that the integrity of such window units depend on the same combustible components as the subject windows. He noted that the frames of the proposed window walls are reinforced with formed steel sections inserted into the cavities of the PVC extrusions similar to aluminium window wall frames. Moreover, the use of PVC as the window frame material contributes very little combustible load to a suite when considering its contents, he asserted.

The Applicant also argued that the PVC frames will not adversely affect the flash-over time from one suite to another. As he noted, this is because fire containment in a suite depends on the integrity of the glazing. The glazing, he insisted, would break from radiant heat or thermal shock either prior to or at the time of flash-over. The failure of the glazing therefore would be the principal cause of flash-over from suite-to-suite. This would be the same for conventional aluminium frame windows with thermal breaks (which are not limited in terms of their vertical separation and aggregate opening area). The Applicant noted that the glazing in the subject window units provides standard thermal resistance. He also indicated that the additional firestopping provided vertically and horizontally between units would assist in the prevention of suite-to-suite flash-over.

The Applicant submitted several reports to support his arguments of sufficiency of compliance. He also submitted test results done at Underwriters' Laboratories of Canada in which the PVC window frames were tested for flame spread rating and smoke developed classification in accordance with CAN/ULC-S102.2, "Standard Method of Test for Surface Burning Characteristics of Floor Coverings, and Miscellaneous Materials and Assemblies." The tests showed that the PVC material had a flame spread rating of between 55 and 65 and a smoke developed classification of between 425 and 475. The Applicant argued that these test results demonstrate that the PVC window frames posed no usually high risk in terms of their combustibility.

The Applicant indicated that the same window units are also proposed for two other high rise buildings (40 and 60 Old Mill Road) as part of the same complex.

  1. Respondent's Position

The Respondent submitted that he supports the use of the PVC window units but he indicated that he feels it exceeds his jurisdiction under the OBC to allow these relaxations concerning the lack of the 1,000 mm vertical separation and the excess aggregate window opening area. He indicated that he had concerns regarding suite-to-suite spread of fire.

  1. Commission Ruling

It is the decision of the Building Code Commission that the proposed combustible PVC window units installed in certain suites as a floor to ceiling wall assembly with approximately 250 mm of non-combustible vertical separation between storeys and constituting openings of approximately 50 to 70 percent of the aggregate area of the exterior wall face does not provide sufficiency of compliance with Sentence 3.1.5.4.(5) of the Ontario Building Code at Oakridge Heights, 50 Old Mill Road, Oakville, Ontario.

  1. Reasons

i) The current reference, Sentence 3.1.5.4.(5) reads:

(a) each window in an exterior wall face is an individual unit separated by noncombustible wall construction from every other opening in the wall,
(b) windows in exterior walls in contiguous storeys are separated by not less than 1000 mm of noncombustible construction, and
(c) the aggregate area of openings in an exterior wall face of a fire compartment is not more than 40% of the area of the wall face.

ii) These minimum code requirements of 3.1.5.4.(5) have not been satisfied and no alternative compliance measures have been proposed.

Dated at Toronto this 5th day in the month of August in the year 1999 for application number 1999-55

Mr. Kenneth Peaker, Chair-Designate

Mr. Robert De Berardis

Mr. Stewart Smith