Ruling No. 02-11-866 Application No. 2002-06 BUILDING CODE COMMISSION IN THE MATTER OF Subsection 24(1) of the Building Code Act, S.O. 1992, c. 23, as amended. AND IN THE MATTER OF Sentences 3.1.5.5.(1), (2) and (3) of Regulation 403, as amended by O. Reg. 22/98, 102/98, 122/98, 152/99, 278/99, 593/99, 597/99, 205/00 and 283/01 (the Ontario Building Code ). AND IN THE MATTER OF an application by Matthew Stanton, Project Manager, PCL Constructors Canada Inc., for the resolution of a dispute with Frank Asta, Chief Building Official, Town of Oakville, to determine whether the combustible wood screen cladding proposed on the exterior of the north, east and south faces of a parking structure provides sufficiency of compliance with Sentence 3.1.5.5.(1), (2) and (3) of the Ontario Building Code at the Oakville Trafalgar Memorial Hospital Parking Garage, Oakville, Ontario. APPLICANT RESPONDENT PANEL PLACE Matthew Stanton PCL Constructors Canada Inc. Mississauga, ON Frank Asta Chief Building Official Town of Oakville Len King, Vice-Chair Gary Burtch Tony Chow Toronto, Ontario DATE OF HEARING March 14 th, 2002 DATE OF RULING March 14 th, 2002 APPEARANCES Les Muniak Larden Muniak Consulting Inc., Toronto, ON Agent for the Applicant Frank Asta Chief Building Official Town of Oakville The Respondent
-2- RULING 1. The Applicant Matthew Stanton, Project Manager, PCL Constructors Canada Inc., has received a building permit under the Building Code Act, S.O. 1992, c. 23, as amended, and is constructing a parking garage to serve the Oakville Trafalgar Memorial Hospital, Oakville, Ontario. 2. Description of Construction The Applicant is proposing the construction of a parking garage having an F3 occupancy classification and a building area of 4,200 m 2. The structure will be comprised of noncombustible construction and is five storeys in building height. A further two storeys, proposed below grade level, will be equipped with a sprinkler system. The construction in dispute involves the wood screen combustible cladding proposed for use on the north, east and south faces of the parking structure. The proposed cladding would be comprised of western cedar that has a low combustibility level, however, the wall assembly has not been tested in accordance with CAN/ULC-S134 standards. The cladding would be positioned approximately 406 mm (16 in) from the exterior face of the structure and tied off to the parking structure at the top and mid-point. In addition, as compensation for the use of combustible cladding which has not been subjected to Code prescribed testing, a closed-head sprinkler system is proposed around the perimeter of the structure located at the downturn on each level of the parking garage. Sprinkler heads are to be positioned approximately 2.4 m (8 ft) on centres and will be activated in the event of a fire. 3. Dispute The issue at dispute between the Applicant and Respondent is whether the proposal for combustible wood screen cladding on the north, east and west facings of the subject parking garage will provide sufficiency of compliance with Sentences 3.1.5.5.(1), (2) and (3) of the Ontario Building Code (OBC). Article 3.1.5.5. sets out restrictions on the use of combustible components in the construction of exterior walls. Sentence (1) provides that, with exceptions not applicable here, an exterior nonloadbearing wall assembly which includes combustible components may be used in a building requiring noncombustible construction provided that a) the building is not more than three storeys in building height or b) is not more than six storeys if the building is sprinklered. As a further requirement, this sentence stipulates that the interior surfaces of the wall assembly must be protected with a thermal barrier and that the wall assembly must satisfy the criteria set out in Sentences (2) and (3) when subjected to testing in conforming with CAN/ULC-S134 standards. In this regard, Sentences (2) and (3) prescribe that flaming on or in the wall shall not spread more than 5 m above the opening during the test procedure and that the heat flux during flame exposure on the wall assembly shall not be more than 35 kw/m 2 when measured at 3.5 m above the opening during the same procedure. As noted above, the proposed combustible exterior cladding has not been tested in conformance with CAN/ULC-S134 Standard Method of Fire Test of Exterior Wall Assemblies, however, testing has been conducted in accordance with CAN/ULC-S102 Standard Method of Test for Surface Burning Characteristics of Building Materials and Assemblies. The Applicant argues that there is a good
-3- correlation between these two tests when materials such as the proposed combustible cladding are being analysed. Results from the S102 test would appear to meet the parameters outlined in Sentences (2) and (3). Further, as an additional measure of fire protection for the wood cladding, a closed-head sprinkler system, which would be activated in the event of a fire, is also being offered as compensation. 4. Provisions of the Ontario Building Code 3.1.5.5. Combustible Components for Exterior Walls (1) Except for an exposing building face required to conform to Sentence 3.2.3.7.(1) or Sentence 3.2.3.7.(4), an exterior non-loadbearing wall assembly that includes combustible components is permitted to be used in a building required to be of noncombustible construction provided (a) the building is (i) not more than 3 storeys in building height, or (ii) not more than 6 storeys in building height if sprinklered, (b) the interior surfaces of the wall assembly are protected by a thermal barrier conforming to Sentence 3.1.5.11.(3), and (c) the wall assembly satisfies the criteria of Sentences (2) and (3) when subjected to testing in conformance with CAN/ULC-S134, Standard Method of Fire Test of Exterior Wall Assemblies. (See Appendix A.) (2) Flaming on or in the wall assembly shall not spread more than 5 m (16 ft 5 in) above the opening during the test procedure referenced in Sentence (1). (See Appendix A.) (3) The heat flux during the flame exposure on a wall assembly shall be not more than 35 kw/m 2 (11,100 Btu/ft 2 h) measured 3.5 m (11 ft 6 in) above the opening during the test procedure referenced in Sentence (1). (See Appendix A.) 5. Applicant s Position The Agent for the Applicant advised that the proposed parking garage was a part of the current redevelopment project for the hospital. The aim of providing the wood cladding was to make the design of the parking garage blend into the residential streetscape and to avoid creating what might appear to be a concrete bunker. The Agent described the cladding as a series of interwoven telephone poles with lattice in between. This wall assembly, he submitted, would be applied to three sides of the 5 storey parking structure. The Agent acknowledged the OBC requirement for testing in accordance with the CAN/ULC-S134 standards. He advised that this test has not been conducted because the Applicant had been unable to find a testing facility that was equipped to test a 5 storey high structure. Furthermore, he suggested that this test would be cost and time prohibitive. In support of this application, however, the Agent advised that a test had been conducted in accordance with CAN/ULC-S102 standards. He suggested that a (c)correlation has previously been demonstrated between the CAN/ULC-S134 test on a 3-storey high wall assembly and the extended CAN/ULC-S102 test in the Steiner Tunnel Furnace. In support of this argument, testimony from a former ULC employee revealed that the two flame spread tests being considered operate on the same principal. The witness submitted that, if S134 is designed to test flame spread, then all the data needed to analyse the result of flame spread for the subject assembly could be gathered in the smaller, simpler, S102 tunnel test. The Agent submitted that the correlation developed previously between CAN/ULC-S102 and the
-4- Standard CAN/ULC-S134 demonstrates that exterior claddings having 1.8 m of flame propagation in the extended Steiner Tunnel Furnace test perform favourably when tested on a 3-storey high wall assembly. Further, the Agent advised that (t)he limited distance of flame propagation in the tunnel furnace over a prolonged period indicates that the wood screen will not propagate flame more than 5 m above the opening nor develop a heat flux exceeding 35 kw/m 2 above the opening during a 3-storey high wall test. As such, the wood screen will not contribute to fire growth on the exterior face of the parking structure beyond that permitted for exterior claddings that have demonstrated favourable performance when tested in accordance with the Standard CAN/ULC-S134. The Agent advised that a sample of the lattice had been subjected to a tunnel test and was examined for a period longer than the standard test would require. In the Agent s view, he was satisfied that the results achieved in this test indicate that the wall assembly would perform well and would meet the requirements of CAN/ULC-S134. Moreover, despite the successful testing of the product, the Applicant is offering an additional measure of compensation for the use of combustible exterior wall components. To protect the wood screen, a closed-head sprinkler system will be provided at the downturn on each level of the parking garage. The sprinkler heads will be spaced at approximately 8- foot OC and will activate in the event fire occurs within the parking structure. The Agent argued that, because the OBC does not require the provision of a fire suppression system for combustible exterior cladding, this sprinkler system around the perimeter will contribute to the provision of an equivalent level of life safety to that of noncombustible exterior construction. In summation, the Agent submitted that, in his opinion, the proposal meets the intent of the requirements of Sentence 3.1.5.5.(1) of the Code. The provision of the sprinkler system around the perimeter will provide protection to the combustible elements of the proposal. A thermal barrier is, in his opinion, being provided through the use of 1,117.6 mm (44 in) of concrete upstand at the exterior walls and the 406.4 mm (16 in) separation between the wood lattice and the main structure. Further, the comparable test that has been conducted illustrates that the cladding will perform to an acceptable degree during a fire. 6. Respondent s Position The Respondent submitted that the proposed combustible wall assembly did not meet the requirements set out in Article 3.1.5.5. In his opinion, he could see no correlation between the required testing method of CAN/ULC-S134 and that of the much smaller test conducted using the CAN/ULC-S102 standard. Further, he advised that he could see no similarity of comparison in the results obtained from a closed horizontal test (S102) and the open vertical test anticipated by S134. In summation, the Respondent argued that the proposed wood screening represented a substantial amount of highly combustible material which would contribute to the overall fire load of the building. He emphasized that the building was not fully sprinklered and questioned the benefit of sprinkler heads around the perimeter as proposed by the Applicant. In his opinion, sufficiency of compliance with the prescriptive requirements of Article 3.1.5.5. was not being provided. 7. Commission Ruling It is the decision of the Building Code Commission that the combustible wood screen cladding proposed on the exterior of the north, east and south faces of the parking structure does not provide sufficiency of compliance with Sentences 3.1.5.5.(1), (2) and (3) of the Ontario Building Code at the Oakville Trafalgar Memorial Hospital Parking Garage, Oakville, Ontario.
-5-8. Reasons i) The entire building is not sprinklered as would be required by Clause 3.1.5.5.(1)(a). ii) iii) The interior surfaces of the wall are not protected in their entirety by a thermal barrier conforming to 3.1.5.11.(3). There are concerns with the sprinkler heads located along the perimeter of the building in regard to whether there would be a sufficient rise in temperature to activate the system.
Dated at Toronto this 14th day in the month of March in the year 2002 for application number 2002-06. -6- Len King, Vice-Chair Gary Burtch Tony Chow