Table of Contents
Advertisement
Stratford Fireplace Installation and Operation Manual
The heat in the flue gases that pass from the fireplace into the chimney is not waste heat. This heat is what
the chimney uses to make the draft that draws in combustion air, keeps smoke inside the fireplace and
safely vents exhaust to outside. You can think of heat in the flue gas as the fuel the chimney uses to make
draft.
8.2 SUITABLE CHIMNEYS
Your wood fireplace will provide optimum efficiency and performance when connected to a 6-inch
diameter chimney.
8.3 MINIMUM
HEIGHT
The top of the chimney should be tall
enough
to
be
above
turbulence caused when wind blows
against the house and its roof. The
chimney must extend at least 1 m (3
ft.) above the highest point of contact
with the roof, and at least 60 cm (2 ft.)
higher than any roof line or obstacle
within a horizontal distance of 3 m
(10 ft.).
8.4 THE RELATIONSHIP BETWEEN THE CHIMNEY AND THE HOUSE
Because the venting system is the engine that drives the wood heating system, it must have the right
characteristics. The signs of bad system design are cold backdrafting when there is no fire in the fireplace,
slow kindling of new fires, and smoke roll-out when the door is opened for loading.
8.4.1 WHY THE CHIMNEY SHOULD PENETRATE THE HIGHEST HEATED SPACE
When it is cold outside, the warm air in the house is buoyant so it tends to rise. This tendency of warm air
to rise creates a slight pressure difference in the house. Called 'stack effect', it produces a slightly negative
pressure low in the house (relative to outside) and a slightly positive pressure zone high in the house. If
there is no fire burning in a heater connected to a chimney that is shorter than the warm space inside the
house, the slight negative pressure low in the house will compete against the desired upward flow in the
chimney.
__________________________________________________________________________ 45
CHIMNEY
the
air
Advertisement
Table of Contents
