Page 40 - PD 1096 BASIC LAW

The National Building Code (P.D. 1096)

supported on roofs of combustible framings. They shall be designed to withstand a wind load from
any direction in addition to any other loads.

SECTION 1211. Chimneys, Fireplaces, and Barbecues

(a) Chimneys
(1) Structural Design. Chimneys shall be designed, anchored, supported, reinforced,
constructed, and installed in accordance with generally accepted principles of engineering.
Every chimney shall be capable of producing a draft at the appliance not less than that
required for the safe operation of the appliance connected thereto. No chimney shall support
any structural load other than its own weight unless it is designed to act as a supporting
member. Chimneys in a wood-framed building shall be anchored laterally at the ceiling line
and at each floor line which is more than 1.80 meters above grade, except when entirely
within the framework or when designed to be free standing.
(2) Walls. Every masonry chimney shall have walls of masonry units, bricks, stones,
listed masonry chimney units, reinforced concrete or equivalent solid thickness of hollow
masonry and lined with suitable liners in accordance with the following requirements:
(2.1) Masonry Chimneys for Residential Type Appliances. Masonry chimneys shall
be constructed of masonry units or reinforced concrete with walls not less than 100
millimeters thick; or of rubble stone masonry not less than 300 millimeters thick. The
chimney liner shall be in accordance with this Code.
(2.2) Masonry Chimneys for Low Heat Appliances. Masonry chimneys shall be
constructed of masonry units or reinforced concrete with walls not less than 200
millimeters thick: Except, that rubble stone masonry shall be not less than 300
millimeters thick. The chimney liner shall be in accordance with this Code.
(2.3) Masonry Chimneys for Medium-Heat Appliances. Masonry chimneys for
medium-heat appliances shall be constructed of solid masonry units of reinforced
concrete not less than 200 millimeters thick, Except, that stone masonry shall be not less
than 300 millimeters thick and, in addition shall be lined with not less than 100 millimeters
of firebrick laid in a solid bed of fire clay mortar with solidly filled head, bed, and wall
joints, starting not less than 600 millimeters below the chimney connector entrance.
Chimneys extending 7.50 meters or less above the chimney connector shall be lined to
the top.
(2.4) Masonry Chimneys for High-Heat Appliances. Masonry chimneys for high-
heat appliances shall be constructed with double walls of solid masonry units or
reinforced concrete not less than 200 millimeters in thickness, with an air space of not
less than 50 millimeters between walls. The inside of the interior walls shall be of firebrick
not less than 100 millimeters in thickness laid in a solid bed of fire clay mortar with solidly
filled head, bed, and wall joints.
(2.5) Masonry Chimneys for incinerators installed in Multi-Storey Buildings
(Apartment-Type Incinerators). Chimneys for incinerators installed in multi-storey
buildings using the chimney passageway as a refuse chute where the horizontal grate
area of combustion chamber does not exceed 0.80 square meter shall have walls of solid
masonry or reinforced concrete, not less than 100 millimeters thick with a chimney lining
as specified in this Code. If the grate area of such an incinerator exceeds 0.80 square,
meter, the walls shall not be less than 100 millimeters of firebrick except that higher than
9.00 meters above the roof of the combustion chamber, common brick alone 200
millimeters in thickness may be used.

(2.6) Masonry Chimneys for Commercial and Industrial Type Incinerators.
Masonry chimneys for commercial and industrial type incinerators of a size designed for
not more than 110 kilograms of refuse per hour and having a horizontal grate area not
exceeding 0.50 square meter shall have walls of solid masonry or reinforced concrete not
less than 100 millimeters thick with lining of not less than 100 millimeters of firebrick,
which lining shall extend for not less than 12.00 meters above the roof of the combustion
chamber. If the design capacity of grate area of such an incinerator exceeds 110
kilograms per hour and 0.80 square meter respectively, walls shall not be less than 200
millimeters thick, lined with not les than 100 millimeters of firebrick extending the full
height of the chimney.

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