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BCC Ruling No. 15-36-1425

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Ruling No.: 15-36-1425
Application No.: B 2015-25

 

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 9.10.11.3, Clause 3.1.10.2.(4)(b); Subclause 3.1.10.2.(4)(c)(iii), and Sentences 3.1.7.5.(3) and 9.11.2.1.(1) of Regulation 332/12, as amended, (the “Building Code”).

AND IN THE MATTER OF an application by Brad Stinson, Stinson Builders, for the resolution of a dispute with Ted Marecak, Chief Building Official, to determine whether the firewall system proposed to separate two units of a town house block provides sufficiency of compliance with Article 9.10.11.3, Clause 3.1.10.2.(4)(b); Subclause 3.1.10.2.(4)(c)(iii), and Sentences 3.1.7.5.(3) and 9.11.2.1.(1) of Division B of the Building Code at Stinson Avenue, City of Belleville, Ontario.

APPLICANT

Brad Stinson
Stinson Builders Ltd.
City of Belleville, Ontario

RESPONDENT

Ted Marecak
Chief Building Official
City of Belleville, Ontario

PANEL

Tony Chow, Chair
Yaman Uzumeri
Ed Link

PLACE

City of Toronto, Ontario

DATE OF HEARING

November 24, 2015

DATE OF RULING

November 24, 2015

APPEARANCES

Brad Stinson
Stinson Builders Ltd.
City of Belleville, Ontario
Applicant

Pamela Shinkoda
CGC Inc.
Mississauga, Ontario
Agent for the Applicant

Ted Marecak
Chief Building Official
City of Belleville, Ontario
Respondent

RULING

 

1. Particulars of Dispute

The Applicant has applied for a building permit and is proposing to construct blocks of townhouses. The townhouses will be comprised of combustible construction and be two storeys in building height. The townhouses will not be equipped with a standpipe and hose system or a sprinkler system.

The construction in dispute relates to the firewall assembly that is intended to separate two blocks of residential townhouses.

The proposed firewall assembly will consist of a central/inner core that is comprised of two 25.4 mm gypsum panels fitted in H clips. The central/inner core will be attached by aluminum clips to the framing of the building structure. A single layer of 12.7 mm gypsum board, attached to the framing of the building structure, will be installed on either side of the central/inner core to provide protection from mechanical damage.

The firewall assembly is designed to allow for the collapse of the construction on the fire-exposed side without causing the collapse of the entire wall. The aluminum clips, that attach the firewall assembly to the adjacent framing, are intended to melt at a certain temperature. When one side is exposed to a fire condition, the aluminum clips soften and breakaway, allowing the structure under fire conditions to collapse leaving the central/inner core intact to protect the structure on the other side of the firewall.

The dispute centres on the Building Code requirements related to firewalls constructed of materials other than masonry or concrete. There are a number of specific Building Code requirements related to the construction and performance of the proposed firewall assembly that the Commission is being asked to consider. The Commission is being asked to determine whether the proposed non-masonry firewall provides sufficiency of compliance with Article 9.10.11.3, Clause 3.1.10.2.(4)(b); Subclause 3.1.10.2.(4)(c)(iii), and Sentences 3.1.7.5.(3) and 9.11.2.1.(1).

2. Provisions of the Building Code in Dispute

Article 3.1.7.5. Rating of Supporting Construction
  1. (3) Except for noncombustible construction required by Subclauses 3.2.2.43A.(2)(c)(i) and 3.2.2.50A.(2)(c)(i), if an assembly is required to be of noncombustible construction and have a fire resistance rating, it shall be supported by noncombustible construction.
Article 3.1.10.2. Rating of Firewalls
  1. (4) A firewall permitted to have a fire-resistance rating not more than 2 h need not be constructed of masonry or concrete provided,
    1. (a) the assembly providing the fire-resistance rating is protected against damage that would compromise the integrity of the assembly,
    2. (b) the design conforms to Article 4.1.5.17.,
    3. (c) the level of performance of the firewall is not less than of masonry or concrete in the areas of,
      1. (i) performance during fire conditions,
      2. (ii) mechanical damage during the normal use of the building, and
      3. (iii) resistance to damage from moisture,
    4. (d) the firewall separates buildings or buildings with floor areas that do not contain,
      1. (i) a Group B, Division 1 major occupancy, or
      2. (ii) a Group B, Division 2 major occupancy, and
    5. (e) the firewall does not separate a building regulated by the provisions of Subsection 3.2.6. or a building within the scope of Article 3.2.2.43A. or 3.2.2.50A. from another building unless the buildings on both sides of the firewall are sprinklered.
Article 9.10.11.3. Construction of Firewalls
  1. (1) Where firewalls are used, the requirements in Part 3 shall apply.
Article 9.11.2.1. Minimum Sound Transmission Class Ratings
  1. (1) Except as provided in Sentence (2), every dwelling unit and every suite in hotels shall be separated from every other space in a building in which noise may be generated, by an assembly providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3, “Fire and Sound Resistance of Building Assemblies”.

3. Applicant’s Position

The Applicant submitted that the dispute relates to the proposal to use a non-masonry firewall to separate two blocks of residential townhouses. He indicated that based on initial discussions he believed that the dispute only related to moisture resistance; however, he agreed that the other provisions should be dealt with as part of this hearing.

The Applicant maintained that many builders use this type of wall assembly as a fire separation and that the issue of moisture has not been a problem. He suggested that, since the assembly has been accepted for use as a fire separation without concern for moisture, moisture should not be an issue for its use as a firewall.

The Agent for the Applicant stated that the proposed firewall assembly is being constructed in accordance with ULC Design No. W314. She advised that the fire resistance rating is provided by the two layers of shaftliner.

The Agent referred to pictures contained within a slide presentation that depicted how the proposed firewall assembly has performed in real life fire conditions. She pointed out that the picture clearly shows that the units adjacent to the unit which caught fire had remained protected as the firewall assembly stayed in place.

The Agent quoted Subclause 3.1.10.2.(4)(c)(iii) which requires that a non-masonry firewall needs to provide a level of performance not less than that required for a masonry firewall in the area of resistance to damage from moisture. She explained that the proposed firewall has a 12 month exposure guarantee and further that the Glass-Mat Liner Panels that form part of the firewall assembly are mould resistant.

In response to questions regarding the use of aluminum clips, the Agent explained that aluminum clips are used to attach the firewall assembly to the wood stud framing of the townhouse. She stated that, in the event of a fire, the aluminum clips would melt and the wall would collapse away while leaving the two layers of shaftliner, which provide the 2 h fire-resistance rating, in place.

The Applicant and the Agent both believe that the proposed assembly is appropriate to be used as a firewall between townhouse units.

4. Respondent’s Position

The Respondent concurred with the Applicant’s statement that during initial discussions, moisture resistance was the only issue discussed. He suggested that these initial discussions were preliminary. However, when follow up discussions and further review of the proposal took place, other concerns became apparent.

The Respondent outlined the concerns he had with the use of the proposed assembly as a firewall. He stated that he did not have any material that demonstrated that the proposed assembly will comply with Sentence 3.1.10.2.(4). He referred to the data sheet for the glass-mat liner panels which included a limitation stating that exposure to sustained temperatures exceeding 52oC should be avoided. He indicated that it is possible the attic space could exceed 52oC; he therefore was concerned how this might affect the performance of the assembly.

The Respondent expressed his concern relating to Sentence 3.1.7.5.(3), which requires an assembly that is required to be of noncombustible construction and have a fire resistance rating to be supported by noncombustible construction. He maintained that this firewall, which is required to be noncombustible and to provide a fire-resistance rating, is attached by aluminum clips to the wood stud framing. He submitted that the wood stud framing provides lateral support to the firewall. Therefore, since wood is combustible, the firewall, is not supported by noncombustible construction.

The Respondent advised that Sentence 9.11.2.1.(1) would require the proposed assembly to provide a sound transmission classification of at least 50. He acknowledged that the proposed assembly had been tested with the wood studs on either side of the gypsum panel core and that a sound transmission classification of 54 was achieved. However, he suggested that if the construction of the assembly is altered in order to address the concerns related to noncombustible construction and wood studs are no longer located on either side of the gypsum panel core, then these test results are no longer valid. Consequently, in the absence of new test results, the sound transmission classification of the assembly cannot be confirmed.

The Respondent agreed that this assembly has been permitted to be used in the construction of party walls, however, he noted that the level of performance for fire separations are different than the level of performance for a firewall.

In summary, the Respondent concluded that the proposal to use the assembly in the construction of a firewall does not meet the requirements of the Building Code.

5. Commission Ruling

It is the decision of the Building Code Commission that the firewall system proposed to separate two units of a townhouse block does provide sufficiency of compliance with Subclause 3.1.10.2.(4)(c)(iii), and Sentences 3.1.7.5.(3) and 9.11.2.1.(1) of Division B of the Building Code at Stinson Avenue, City of Belleville, Ontario, on condition that:

  1. The top of the firewall system, above the roof line, is provided with protection, similar to that which would be required for a masonry or concrete firewall, to minimize the effects of moisture penetration.

Further, it is the decision of the Building Code Commission that the firewall system proposed to separate two units of a town house block does not provides sufficiency of compliance with Clause 3.1.10.2.(4)(b) and by reference Article 4.1.5.17. of Division B of the Building Code at Stinson Avenue, City of Belleville, Ontario.

6. Reasons

  1. Sentence 9.10.11.3. of Division B of the Building Code specifies that where firewalls are used, the requirements in Part 3 shall apply. The Commission heard that the parties did not dispute that this requirement applied. It is the understanding of the Commission that it is Sentence 9.10.11.3. that leads to the reference of Clause 3.1.10.2.(4)(b) which forms part of this dispute.

    Clause 3.1.10.2.(4)(b) states that a firewall permitted to have a fire-resistance rating not more than 2 h need not be constructed of masonry or concrete provided the design conforms to Article 4.1.5.17.

    Article 4.1.5.17. provides the structural design considerations related to firewalls. In this case, insufficient documentation and evidence was presented to demonstrate compliance with the requirements contained in Article 4.1.5.17.

  2. Subclause 3.1.10.2.(4)(c)(iii) states that a firewall permitted to have a fire-resistance rating not more than 2 h need not be constructed of masonry or concrete provided the level of performance of the firewall is not less than that of masonry or concrete in the area of resistance to damage from moisture. The Commission heard that the subject firewall is permitted to have a fire-resistance rating of not more than 2 h. It is the opinion of the Commission that, as long as the subject firewall is provided with protection to minimize the effects of moisture penetration similar to that of a masonry or concrete firewall, sufficiency of compliance with Subclause 3.1.10.2.(4)(c)(iii) will be achieved.

  3. Sentence 3.1.7.5.(3) specifies that if an assembly is required to be of noncombustible construction and have a fire-resistance rating, it shall be supported by noncombustible construction. The Commission heard that the subject firewall assembly is being constructed in accordance with ULC Design No. W314, which consists of a central or inner core, comprised of two 25.4 mm gypsum panels fitted in H-studs. This inner core is attached to the wood framing studs of the building structure by aluminum breakaway clips. A single layer of 12.7 mm gypsum board is attached to the wood studs to provide the inner core with protection from mechanical damage.

    The Commission notes that the townhouse structure is permitted to be of combustible construction. The Commission acknowledges that noncombustibility of a material is determined based on testing to either CAN/ULC S-114 or S-115, however, the Commission heard that Section 4.3. of Supplementary Standard SB-2 also provides some examples of noncombustible materials. While aluminum is not explicitly referred to in the examples, the Sentence does state “noncombustible materials include…metals commonly used in buildings.”

    The Commission further notes that the Building Code does permit some combustible components to be used in the construction of buildings required to be of noncombustible construction.

    It is the opinion of the Commission that the subject firewall is supported vertically by the noncombustible footings of the structure and further that the aluminum clips are not unlike other minor combustible elements that would be permitted in a building required to be on noncombustible construction.

  4. Sentence 9.11.2.1.(1) requires every dwelling unit to be separated from every other space in a building in which noise may be generated by an assembly providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1. or as listed in Tables 1 and 2 of MMAH Supplementary Standard SB-3.

    The Commission heard that the subject firewall system, as described above, has been tested and achieves a sound transmission class rating of 54, which meets the requirement of “at least 50” specified in Sentence 9.11.2.1.(1).

Dated at the City of Toronto this 24th day in the month of November in the year 2015 for application number B 2015-25.

Tony Chow, Chair

Yaman Uzumeri

Ed Link