13
13.2 - FIREPLACE MINIMUM REQUIREMENTS (See diagram in Section 13.1)
With the Majority of Pre-Cast Flue Fireplaces there will be insufficient depth-width and building work with
either a Purpose Made Non Combustible Fire Surround or Rebated Fire Surround Will be Required to Create
the Necessary Fireplace Prior to Installation. Prior to any Building work and to provide adequate flow condi-
tions to the flue, ensure the Minimum Pre-Cast Flue Requirements are available as detailed in a) & b), also
make reference to the Diagrams.
a.
The Minimum Pre-cast Flue Size is 67mm deep by 198mm wide with Starter Blocks providing a Minimum Depth of 115mm by
305mm wide.
Note: additional depth requiring building work to 175mm will be required.
No part of the Flue must be less than
63mm. Refer to diagrams on previous
b.
The height of the Pre-cast Fireplace opening must be between 555mm and 580mm. If the Starter Blocks have not been provided
down to Floor level then building work will be required.
c.
With the Minimum Pre- cast Flue Requirements satisfied as detailed in a) and b) a Fireplace Opening with a minimum depth of
175mm and a front minimum width of 370mm will be required possibly requiring a purpose built extension. More detail is shown
in the diagrams and some later Pre-Cast Flues may already have sufficient depth. Any Building Extension must be made of
Non-Combustible materials and be fully sealed to the Existing Fireplace.
d.
The 175mm of depth required caters for a 10mm gap at the rear of the fire to allow for debris build -up.
e.
With the minimum depth it may be necessary to rebate/sink the Eye Bolts to prevent the heads fouling on the back of the fire.
See Section 16.2 g.
f.
If the Fire is to be fitted with a purpose made Rebated Fire Surround it must have a temperature rating of 150
º
C.
g.
The Fire Surround must be fully sealed to the Fireplace Opening to ensure a good flue seal.
h.
The Fire requires a non-combustible hearth of at least 12mm thick.
i.
The surface of the hearth must stand at least 50mm above the floor and level with the fireplace opening.
j.
The hearth must project at least 300mm in front of the fireplace opening and 150mm either side (700mm minimum hearth width).
k.
The base of the fireplace must be flat, level and square to the face of the fireplace opening.
l.
The Surround must cater for a minimum flat surface around the Fireplace Opening allowing 625mm high by 530mm wide. This is
essential in order to achieve a good seal between the face of the surround and the sealing flanges of the fire.
m.
The Fireplace Opening should have provision for a gas supply through the rear, see Section 11 Gas Supply.
n.
The High Level and Thermatronic control systems are fitted with Electronic Equipment, which is sensitive to dampness and high
humidity so it is very
important
that any rendering/building work is allowed to thoroughly dry out before Installation.
! IMPORTANT NOTE !
Dry lined walls – ensure that any air gaps between the back of the plasterboard and wall are
sealed around the builders opening or fireplace as this can affect flue pull and wall staining.
Pre-Cast Flues – ensure the walls are dry lined over the route of the flue and no dabs or battens
are in direct contact with the flue blocks otherwise wall cracking will occur as detailed in
BS 5440 Pt 1 2008.
13.3 - CLEARANCES TO COMBUSTIBLE MATERIALS AND SHELVES (Ref: Diagram in Section 13.1)
a.
A
non combustible
shelf can be fitted above the fire and should be positioned at least 95mm above the builders opening. We
recommend the depth of the shelf should be a maximum of 75mm as anything deeper will reduce convection air and the
efficiency of the fire. For deeper non-combustible shelves they must be raised a further 25mm for every extra 25mm of depth.
b.
A 150mm
combustible
shelf can be fitted above the fire but must be positioned at least 150mm above the builders opening. For
deeper combustible shelves they must be raised a further 25mm for every extra 25mm of depth.
c.
Any combustible sidewall must be at least 500mm from the inside of the builders/fireplace opening, however with a combustible
fire surround it can be 150mm from the inside of the builders/fireplace opening provided it does not protrude more than 150mm
and must be increased by 25mm for every extra 25mm of depth.
d.
With all heating appliances, soft furnishings, decorations and wall coverings may discolour or scorch if placed too close.
e.
No combustible material, e.g. curtains must be closer than 500mm to the builders opening.
f.
Any combustible wall claddings (wall paper) must be cut back to a height of 750mm and 300 mm either side of the Fireplace
Opening.
g.
Due to the heat output of The Hotbox H.E. it is
not recommended
to use blown vinyl wall covering around the fire.
NOW PROCEED TO SECTION 16 - FIXING THE FIRE.
