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BCC Ruling No. 95-11-431

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BUILDING CODE COMMISSION DECISION ON B.C.C. #95-11-431

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

AND IN THE MATTER OF Section 9.22., specifically, Articles 9.22.1.4. & 9.22.7.1. of the Revised Regulation of Ontario 1990, Regulation 61, as amended by O.Regs. 400/91, 158/93, 160/93 and 355/94 (the "Building Code").

AND IN THE MATTER OF an application by Mr. Gary Sharp, Post Harvest Developments Inc. for the resolution of a dispute with Mr. John Harkness, Chief Building Official, City of Kanata, concerning whether a high mass radiant masonry heater provides sufficiency of compliance with the Building Code, at 1423 Houston Crescent, (Lot 9, Plan 4M-549), Kanata, Ontario.

APPLICANT

Post Harvest Developments Inc.
Ottawa, Ontario

RESPONDENT

Mr. John Harkness
Chief Building Official
City of Kanata

PANEL

PLACE

Toronto, Ontario

DATE OF RULING

March 13th, 1995

APPEARANCES

Mr. Gary Sharp, Director
AND
Mr. Richard Davies
Post Harvest Developments Inc.
For the Applicant

Mr. John Plitz
Plans Examiner
City of Kanata
For the Respondent

RULING

  1. The Applicant

Mr. Gary Sharp, Post Harvest Developments Inc. is the holder of a permit under the Building Code Act, 1992 to construct a single family dwelling (i.e. house) at 1423 Houston Crescent (Lot 9, Plan 4M-849), Kanata, Ontario.

  1. Description of Constrution

A pre-manufactured, site assembled high thermal mass masonry heater is proposed to be constructed in the subject house. The heater is completely different internally than a conventional masonry fireplace. The core of the heater is built of pre-cast, interlocking components that form the firebox and heat transfer passages. Also, combustion air is not provided from outdoors, the throat of the fireplace does not contain a damper and there are numerous 90 degree turns in the combustion chamber.

  1. Dispute

The dispute between the Applicant and Respondent concerns sufficiency of compliance with the technical interpretation of Section 9.22., specifically, Articles 9.22.1.4. & 9.22.7.1. of the Building Code. At issue is whether the high mass radiant masonry heater provides sufficiency of compliance with the masonry fireplace provisions in the Building Code.

  1. Provision of the Building Code

Section 9.22. Fireplaces

Article 9.22.1.4. Combustion Air

  1. Except as permitted in Article 9.22.1.5. and 9.22.1.6., every fireplace, including a factory-built fireplace, shall have a supply of combustion air from outdoors in accordance with Sentence (2) to (12).

  1. The combustion air shall be supplied by a noncombustible and corrosion-resistant supply duct.

  1. The combustion air shall be supplied by a noncombustible and corrosion-resistant supply duct.

  1. The supply duct shall have

    1. a diameter of at least 100 mm (4 in) or an equivalent area,
    2. an exterior intake for entry of air from the outdoors, and
    3. an interior outlet for providing air for the fire chamber.

  1. The supply duct shall contain a tight-fitting damper that shall be located close to the interior outlet and be operable from the room containing the fireplace.

  1. The operating mechanism shall clearly indicate the actual position of the damper.

  1. The interior outlet shall,

  1. be located as close as possible to the opening in the face of the fireplace.
  2. be designed to prevent embers from entering the supply duct, and
  3. where it is placed inside the fire chamber, be located at the front centre of the fire chamber hearth and be equipped with a noncombustible hood.

  1. The exterior intake shall be protected against the entry of rain and direct wind and have an insect screen of corrosion-resistant material.

  1. Where the exterior intake is located above the level of the fire chamber hearth, the interior outlet shall be located at a level at or below the level of the hearth.

  1. Where the interior outlet is located in the fire chamber and the exterior intake is located at or below the level of the fire chamber hearth, the supply duct shall be installed with a minimum clearance from combustible material of 50 mm (2 in) for a distance of 1 m (3 ft 3 in) measured from the outlet.

  1. Where the interior outlet is located in the fire chamber hearth and the exterior intake is located above the level of the fire chamber hearth, the supply duct shall be installed with a minimum clearance from combustible material of,

  1. 50 mm (2 in) for a distance of 1 m (3 ft 3 in) measured from the outlet, and
  2. 25 mm (1 in) for the remainder of the supply duct to the intake.

  1. The exterior intake shall be located to avoid being blocked by snow or fallen leaves.

  1. Where the supply duct is exposed to a heated space, the duct shall be insulated to provide a thermal resistance of not less than RSI 1.4 (R 8).

Article 9.22.7.1. Slope of Smoke Chamber

The sides of the smoke chamber connecting a fireplace throat with a flue shall not be sloped at an angle greater than 45° to the vertical.

  1. Applicant's Position

The applicant submitted that masonry heaters are not addressed by the Building Code. The internal operation of a high thermal mass masonry heater is completely different than a conventional fireplace. Masonry heaters take advantage of tonnes of mass in the form of bricks or stone to store and later release the heat they produce.

The applicant stated that although the masonry heater design does not comply with some of the prescriptive requirements for fireplaces in Section 9.22, test data and past experience indicate sufficiency of compliance with the performance level intended for conventional fireplaces in the Building Code.

  1. Chief Building Officials Position

The respondent submitted the following comments concerning the installation of a high thermal mass masonry heater:

  1. The combustion air supply duct does not satisfy Article 9.22.1.4. of the Building Code. The supply duct does not provide a tight fitting damper as required and its location does not prevent embers from entering the supply duct.

  1. The smoke chamber does not satisfy Article 9.22.7.1. of the Building Code. The sides of the smoke chamber connecting the throat with the flue exceeds the 45 degrees to the vertical maximum.

The schematic drawing and assembly manual clearly indicates that the flue gasses, once in the secondary chamber, must make numerous 90 degree turns before entering the chimney.

  1. Draft: The respondent questioned whether the down draft design would provide sufficient draft to start a fire or to exhaust gases when the fire is in its final burning stages.

  1. Creosote: There may be creosote that does not get fully consumed and therefore is deposited in the secondary combustion chamber, side flue collection manifolds and lower manifold under the hearth.

  1. Maintenance: The collection manifold appears to be fully enclosed with no access for visual inspection or ability to perform regular maintenance. This may lead to inefficient operation of the heater.

  1. Design Criteria: The respondent questioned the design criteria of the flue size, chimney height, etc. The applicant did not provide evidence of approval by any recognized testing agencies or design standards such as CAN/CSA A-405-M87 "Design and Construction of Masonry Chimneys and Fireplaces".

  1. The information provided by the applicant indicates that the heater produces hotter fires and retains more heat than conventional masonry fireplaces. Therefore, caution must be taken with respect to clearance from combustibles.

  1. Commission Ruling:

In favour of the Respondent. It is the decision of the Building Code Commission that this pre-manufactured, site assembled, high thermal mass masonry heater does not conform to the present requirements of the Building Code.

  1. Reasons:

    1. The Building Code does not address engineered, pre-manufactured, site assembled high thermal mass masonry heaters.

    1. The documentation provided by the applicant is insufficient for the Commission to formulate conclusions regarding sufficiency of compliance with the Building Code.

    1. An application to the Building Materials Evaluation Commission is recommended.

Dated at Toronto, this 13th day, in the month of March, in the year 1995, for application number 1995-01.

Michael Lio

Remus Tsang

Rick Florio