45
7.4.6 Elbows
Two elbows are available - 30° (product
code: WPB/30) and 45° (product code:
WPB/45). To allow for alignment, the
female collars of these elbows do
NOT have the twist lock flutes, but
the locking band MUST still be used
to secure the two flue components
together.
There should be no more than 2 elbows
– of maximum angle 45° from the
vertical – fitted between the inspection
hatch of the flue Inspection pipe (at
the boiler) and the terminal. This can
be increased to a maximum of four
elbows (maximum 45°) between the
boiler and terminal if there is a second
flue Inspection Pipe fitted between
the second and third elbows. Any
Inspection hatch must be accessible for
checking and cleaning purposes.
7.4.7 Wall Sleeves
In accordance with the Building
Regulations Approved Document J, a
wall sleeve should be used where the
flue system passes through a wall. A
suitable wall sleeve is available as part
of the Grant ‘Biomass’ flue system
(product code: WP/SLE).
This 45° angled wall sleeve is available
in 230mm diameter - giving a 25mm
clearance all round from the 180mm
diameter outer surface of the flue
passing through it.
The sleeve is 45° mitred at one end.
The other end of the sleeve should
be cut on site to the correct length,
to leave it flush with the wall on both
sides. The sleeve should be adequately
weatherproofed using a good quality
mastic and fibre rope.
Oval one-piece trim collars are available
to be fitted at either end of the wall
sleeve (product code: WPB/TC). These
should be fastened to the inside or
outside wall using a suitable method
of fixing. The trim collars should be
adequately weatherproofed back to
the wall using a good quality building
mastic or similar.
7.4.8 Firestop Plates
Ventilated Fire Stop Plate (product
code: WPB/FP)
A Ventilated Fire Stop Plate should be
fixed to the ceiling below a Ventilated
Support Plate. When passing through
a second upstairs floor (in a 3-storey
house) either a second support plate
can be fitted or alternatively two
ventilated fire-stop plates (one above
and one below) need be fitted if the
flue is adequately supported at the first
upstairs floor level.
The slots in the Stop Plate allow air
to pass through but will not allow the
passage of flame. Also, the slots enable
the distance from combustibles to be
checked. If no combustible material
is visible though the slots, then the
minimum clearance distance of 60mm
has been met.
Magnetic Fire Stop Plate Cover
Plate (product code: WPB/MF)
This can be fixed below a Ventilated
Fire Stop Plate to cover the ventilation
slots but still allow air flow through
them. The Cover Plate is held in place
by the four circular magnets provided
in the kit. These are fixed using the four
screws securing the Ventilated Fire
Stop Plate to the ceiling. The cover can
be lowered for inspection purposes by
pulling it downwards and off the four
magnets.
The Magnetic Fire Stop Plate can also
be used as a ‘Bungalow’ Fire Stop
Plate. This unventilated fire stop plate
may only be used on a combustible
ceiling in a bungalow where there is a
minimum distance of 60mm between
the flue and any combustibles, where
the flue penetrates the ceiling area
and the roof space above the ceiling
is open and ventilated. Within the roof
space a protective wire mesh guard
must be built around the flue to ensure
a minimum distance of 60mm from
combustibles is maintained.
To fix the plate to the ceiling: drill four
equi-spaced holes 25mm in from the
outer edge and use suitably sized
screws to secure to ceiling.
Failure to maintain a clean flue can
result in the emission of flue gases
into the dwelling or damage from
fire in the flue. Refer to Section 11.4.
!
WARNING
