BUILDING CODE COMMISSION

Transcription

1 Ruling No Application No 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 Article of Regulation 403, as amended by O. Reg. 22/98, 102/98, 122/98, 152/99, 278/99, 593/99, 597/99, 205/00, 283/01 and 220/02 (the Ontario Building Code ). AND IN THE MATTER OF an application by Grace Sweatman, Christie Gardens, for the resolution of a dispute with Ann Borooah, Chief Building Official, City of Toronto, to determine whether the asinstalled vertical exhaust shafts serving a residential high rise building which extend three storeys in height, and which are constructed using paper-lined gypsum shaftboard liners, comply with the intent of Sentence (1) of the Ontario Building Code (OBC) or, in the alternative, whether these same shafts provide sufficiency of compliance with Sentence (2) of the OBC at 600 Melita Crescent, Toronto, Ontario. APPLICANT RESPONDENT PANEL PLACE Grace Sweatmam Christie Gardens Toronto, Ontario Ann Borooah Chief Building Official City of Toronto Len King, Vice-Chair Gary Burtch Donald Pratt Toronto, Ontario DATE OF HEARING December 4, 2003 DATE OF RULING December 4, 2003 APPEARANCES Randy Brown Randy Brown & Associates Willowdale, Ontario The Applicant Peter Kaczmarek Building Inspector City of Toronto Designate for the Respondent

2 -2- RULING 1. The Applicant Grace Sweatman, Christie Gardens, has received a building permit under the Building Code Act, S.O. 1992, c. 23, as amended, and is constructing an addition to an existing building referred to as Christie Gardens, 600 Melita Crescent, Toronto, Ontario. 2. Description of Construction The Applicant is constructing an addition to an existing building that contains a Group A, Division 2 assembly occupancy, Group B, Division 2 care and treatment occupancy, Group C residential occupancy, and Group F, Division 3 low hazard industrial occupancy. The structure is seven storeys in building height, with a three storey addition being constructed on top of the existing building. The building is approximately 4, 642 m 2 in building area and is comprised of non-combustible construction. The building is partially sprinklered and is equipped with both a fire alarm and standpipe and hose system. The construction at dispute pertains to the vertical exhaust shafts that have been used in the three storey addition. The subject exhaust shafts are constructed as extensions of brick-lined exhaust shafts serving the residential units in the existing seven storey building. The subject exhaust shafts are located within the new building envelope rising vertically to the roof and are finished with an enclosed exhaust fan. There are 24 shafts at issue. They range in size between 203 mm x 305 mm (8 in x 12 in) and 203 mm x 457 mm (8 in x 18 in). The various connector ducts supplying these exhaust shafts are 101 mm (4 in) in diameter. The subject exhaust shafts are constructed as 1 hr. fire separations in accordance with cul Design No. U 469, using paper-lined shaftboard liners. 3. Dispute The issue at dispute between the Applicant and Respondent pertains to whether the as-installed vertical exhaust shafts serving a residential high rise building which extend three storeys in height, and which are constructed using paper-lined gypsum shaftboard liners, comply with the intent of Sentence (1) of the Ontario Building Code (OBC) or, in the alternative, whether these same shafts provide sufficiency of compliance with Sentence (2) of the OBC. Sentence (1) of Article of the OBC outlines the various materials that are permitted to be used in the construction of ducts, duct connectors, associated fittings and plenums used in air duct systems. As per the requirements of Sentence (1), all ducts shall be constructed of steel, aluminum alloy, copper, clay, asbestos-cement or similar noncombustible material. Noncombustible is a defined term in the Code. Its meaning is found in Article ; Noncombustible means that a material meets the acceptance criteria of CAN4-S114, Standard Method for Determination of Non-Combustibility in Building Materials. It should be noted that Article of the Code provides a list of minor combustible components that are permitted to be found in a building that is required to be of non-combustible construction. Of particular importance to the issue at dispute is Clause (1)(b), which permits the use of tightly adhering paper covering not more than 1 mm (0.039 in) thick applied to noncombustible backing

3 -3- provided that the assembly has a flame-spread rating not more than 25. The as-installed exhaust shafts at dispute have been constructed using paper-lined gypsum shaftboard liners and have a flame-spread rating of 20. Sentence (2) is an exception to Sentence (1) of the Code in that it permits ducts, associated fittings, and plenums to contain combustible material provided that they comply with the stipulated clauses that are assigned therein. In Clause (2)(a), ducts, associated fittings, and plenums are permitted to contain combustible material provided they conform to the appropriate requirements for Class 1 duct materials in CAN/ULC-S110-M, Standard Methods of Test for Air Ducts. The Standard CAN/ULC-S110-M includes tests with respect to surface burning, flame penetration, corrosion, mould growth and humidity, temperature, puncture, static load, impact, erosion, tension, pressure, collapse, bending and leakage. In terms of fire safety, the standard permits combustible air ducts and connectors provided that they have a flame spread rating of not more than 25 and a smoke developed classification of no greater than 50. It should also be noted that the standard requires mould growth and humidity tests in situations where a duct carries air that contains excessive moisture or is exposed to moisture. The ducts must also have no appreciable loss of strength when wet and must be corrosion resistant. Also relevant to the case at dispute is Clause (2)(e), which limits the use of ducts containing combustible materials to vertical runs serving only two storeys in a non-combustible building. The purpose of this Code provision is to minimize the fire load and heat generation in the case of fire, as well as limit the spread of fire and production of combustion products, such as smoke, in air distribution systems. As previously mentioned, the subject exhaust shafts rise vertically through the three storey addition and, as such, are in contravention with the two-storey vertical run limit stipulated in Clause (2)(e) of the Code. The root of the issue at dispute, therefore, appears to be whether the exemption for combustible materials found in Clause (1)(b) of the OBC is intended to extend also to the requirement for noncombustible shafts found in Sentence (1). If so, there is no need to examine the as-installed exhaust shafts against the requirements found in Sentence (2). In other words, the exemption found there is not necessary and not applicable. If, however, the duct material is considered to be combustible, then Sentences (2) to (4) are applicable. Moreover, if the criteria set out in Sentences (2) to (4) are not met then the proposal will be assessed for its sufficiency of compliance with these Sentences. 4. Provisions of the Ontario Building Code Materials in Air Duct Systems (1) Except as provided in Sentences (2) to (4) and in Article , all ducts, duct connectors, associated fittings and plenums used in air duct systems shall be constructed of steel, aluminum alloy, copper, clay, asbestos-cement or similar noncombustible material. (2) Ducts, associated fittings and plenums are permitted to contain combustible material provided they (a) conform to the appropriate requirements for Class 1 duct materials in CAN/ULC-S110- M, "Standard Methods of Test for Air Ducts", (b) conform to Article in a building required to be of noncombustible construction, (c) conform to Subsection , (d) are not used in horizontal runs in a building required to be of noncombustible construction, (e) are not used in vertical runs serving more than 2 storeys in a building required to be of noncombustible construction, and (f) are not used in air duct systems in which the air temperature may exceed 120 C (248 F).

4 -4- (3) Duct sealants shall have a flame-spread rating of not more than 25 and a smoke developed classification of not more than 50. (4) Duct connectors that contain combustible materials and that are used between ducts and air outlet units shall (a) conform to the appropriate requirements for Class 1 air duct materials in CAN/ULC-S110-M, "Standard Methods of Test for Air Ducts", (b) be limited to 4 m (13 ft 1 in) in length, (c) be used only in horizontal runs, and (d) not penetrate required fire separations. (5) Materials in Sentences (1) to (4) which when used in a location where they may be subjected to excessive moisture shall have no appreciable loss of strength when wet and shall be corrosion-resistant. 5. Applicant s Position The Agent for the Applicant began by providing a brief overview of the building at dispute. He stated that the project involves a three storey addition on top of an existing seven story residential building. The Agent advised that the issue at dispute pertains to the construction of the exhaust shafts that serve the kitchens and bathrooms of both new and existing residential units. As described by the Agent, the shaft walls consist of one layer of e inch Type X gypsum wallboard on steel studs with 25 mm shaft liner panels. As per the Agent, this design is in accordance with cul Design No. U469, and achieves a 1 hour fire-resistance rating. The Agent submitted that while gypsum board has combustible properties, it is his belief that the asconstructed exhaust shafts comply with Sentence (1) of the OBC. He stated that since Clause (1)(b) of the Code specifically permits the use of tightly adhered paper on noncombustible backing provided the assembly has a flame spread rating of not more than 25, it is his opinion that the as-constructed exhaust shafts, with a flame spread rating of 20, meet the intent of noncombustibility inherent within Sentence (1). In this regard, the Agent submitted that since the as-installed exhaust shafts comply with Sentence (1), there is no need to assess them on the basis of their compliance with Sentences (2) to (4) of the Code. The Agent stated that he disagrees with the Respondent s position that the subject exhaust shafts are combustible since they are constructed using paper-lined gypsum, and as a result their construction is required to meet the provisions of Sentence (2) of the OBC. He noted that the Respondent is of the view that the subject shafts do not comply with Clause (a) or (e) of this provision, nor do they comply with the CAN/ULC-S110-M Standard Method of Test for Air Ducts or the two storey vertical rise limit respectively. In response, the Agent acknowledged that the shafts do rise three storeys, however, he reiterated his position that, in his view, the gypsum constructed shafts are an equivalent to the ducts specified in Sentence (1) of the Code. The Agent then stated that he also disputed the Respondent s concern regarding whether the subject exhaust shafts are prone to excessive moisture and will thereby experience mould and mildew growth. He indicated that while some condensation may occur, it his opinion that the shafts will not be subjected to excessive moisture. He argued that as the exhaust shafts serving the residential units are only marginally humidified and are located in interior walls, the dew point of the exhausted air will not be reached. Consequently, mould and mildew will not grow in the as-built shafts, existing and new. As support for this argument, the Agent referenced a letter from the project s mechanical engineer indicating that the conditions for condensation and thus potential mould and mildew growth would not occur in the subject building. The Agent continued by stating that Sentence (5) of the Code

5 -5- addresses the issue of excessive moisture and that this would not be a problem in the building at dispute and the shafts will not experience an appreciable loss in strength as a result. When questioned, the Agent advised that the Applicant was not made aware of the fact that the 24 subject air shafts were an issue until after the renovation was complete, which was in the summer of He also stated that he found the municipality s position to be surprising, because there is ample precedence of the use of the exhaust shafts at dispute and that their installation is quite common. In summary, the Agent submitted that while gypsum board has combustible properties, it is his belief that the subject exhaust shafts can be viewed as an equivalent to those required under Sentence (1) of the OBC, since Clause (1)(b) of the Code specifically permits the use of tightly adhered paper on noncombustible backing with a flame spread of less than 25. The Agent maintained that compliance has, in his opinion, been achieved with Sentence (1) and, therefore, the asinstalled exhaust shafts do not need to be assessed on the basis of their compliance with Sentences (2) to (4) of the Code. 6. Respondent s Position The Designate for the Respondent submitted that Sentences (1) and (2) of the OBC address materials acceptable for duct system construction and also provide for exceptions. He stated that it is the Respondent s position that the construction of the subject exhaust shafts do not comply with Sentence (1) as they are viewed as being of combustible construction. The Designate submitted that, in his opinion, drywall is not a realistic material when one is exhausting a kitchen or bathroom and he stated that one cannot say that gypsum board is classified in the OBC as a non-combustible material. In this regard, the subject exhaust shafts, in his view, do not comply with Sentence (1) of the Code and, as a result, he directed the Commission s attention to Sentence (2) of the Code. Sentence (2) of the Code, the Designate explained, permits the use of ducts that are constructed of combustible material provided that they comply with the specific clauses contained therein. He then specifically addressed Clause (2)(a) of the Code, which permits the use of ducts, associated fittings, and plenums, provided that they conform to the appropriate requirements for Class 1 duct materials in CAN/ULC-S110-M, Standard Method of Test for Air Ducts. The Designate submitted that this Clause was of particular importance to the issue at dispute, because he does not know whether the subject exhaust shafts would be able to pass the tests associated with CAN/ULC-S110-M, Standard Method of Test for Air Ducts. The Designate then raised the issue of allowable height limits and stated that Clause (2)(e) maintains that ducts constructed of combustible material shall not be used in vertical runs serving more than 2 storeys. He stated that the purpose of this particular Code provision is to prevent the growth of mould and mildew in the exhaust shaft. He advised that this issue was of particular importance to the City, because the building at dispute is a home for senior citizens who are extremely vulnerable and susceptible to potential health risks. In addition to this, he added that no information was submitted by the Applicant party to indicate that gypsum board has been tested to be resistant to moisture and would therefore make this material acceptable under Sentence (5) of the Code. In summary, the Designate maintained that gypsum board is not an acceptable material for duct system construction. He stated that the subject exhaust shafts do not provide sufficiency of compliance with Sentences (1) and (2) of the OBC and that both their materialistic properties and installation are an inappropriate application of the Code.

6 -6-7. Commission Ruling It is the decision of the Building Code Commission that the as in-stalled exhaust shafts extending three storeys in height, which are constructed using paper-lined gypsum shaftboard liners, do not comply with the intent of Sentence (1) of the Ontario Building Code at 600 Melita Crescent, Toronto, Ontario. It is also the decision of the Building Code Commission that these same shafts do not provide sufficiency of compliance with Sentence (2) of the Code at the subject building. 8. Reasons i) Sentence (1) states that except as provided in Sentences (2) to (4) and in Article , all ducts, duct connectors, associated fittings and plenums used in air duct systems shall be constructed of steel, aluminum alloy, copper, clay, asbestos-cement or similar non-combustible material. ii) iii) iv) Non-combustible, as defined, means that a material meets the acceptance criteria of CAN4-S114 Standard Method of Test for Determination in Building Materials. Appendix A (1)(b) of the Ontario Building Code states: [g]ypsum board of the typical thickness used in building construction and that is paper faced will not generally comply with the criteria in CAN4-S114-M, Standard Method of Test for Determination of Non- Combustibility in Building Materials, even though there are no combustible components in the core. Gypsum board has satisfactory properties for resisting the spread of fire and Clause (1)(b) has been included to specifically permit the use of paper faced gypsum board in a building of noncombustible construction. The exemption found in provision (1)(b), however, in the BCC s view, is intended for the general noncombustible construction requirements of Part 3. The OBC does not state that this exemption may be extended to a Part 6 mechanical system. Sentence (2) prohibits the use of combustible elements in a vertical shaft serving more than 2 storeys. The subject building at dispute is seven stories in height, with a three storey addition. v) There were no compensating measures provided by the Applicant party.

7 -7- Dated at Toronto this 4th day in the month of December in the year 2003 for application number Len King, Vice-Chair Gary Burtch Donald Pratt