Pellet Storage Room Design And Required System Components - Viessmann VITOFLEX 300-UF Technical Manual

Fuel storage
(cont.)

Pellet storage room design and required system components

A
K
H
G
A Protective boards at the entrance to the storage room
B Extraction area, screw conveyor system
C Baffle mat
D Discharge to feed screw conveyor
E Min./max. length of extraction area
General requirements for the pellet storage room and required
system components
Note
For further information, we advise consulting VDI 3464 "Storage of
wood pellets at the consumer's premises" and leaflet "Recommenda-
tions for the storage of wood pellets" issued by DEPV e. V. and
DEPI.
■ The pellet storage room must be dry, as pellets will swell up mark-
edly if exposed to moisture. This leads to substantial difficulties in
supplying pellets to the boiler.
■ The pellet storage room must be dust-tight and of solid construc-
tion since filling creates dust and exerts high pressure on the
walls.
■ The pellet storage room or the installation room for prefabricated
stores must be vented. Vents should not be positioned directly
below windows or supply air apertures. Observe the requirements
for the ventilation of pellet stores according to VDI Directive 3464.
Vents should be closed during filling, so that the vacuum fan can
create a slight negative pressure in the storage room.
■ According to static requirements, the following wall thicknesses
have proven to be useful:
For example, bricks 17 cm, rendered on both sides; hollow breeze
blocks 12 cm, rendered on both sides; concrete 10 cm, plaster
block 12 cm.
If the stored amount of pellets exceeds 6.5 t, surrounding walls
and intermediate ceilings must comply with fire resistance cate-
gory F90.
VITOFLEX 300-UF
B C
200
E < 9250
< 10000
F
D
F Max. storage room length
G Return air connector
H Fill connector
K Slanted panel to compensate for the length of the storage room/
extraction area
■ Doors or access hatches into the pellet storage room must open
outwards and must be dust-tight (with an all-round gasket). With a
stored amount of pellets in excess of 6.5 t, doors must be self-
closing and have a fire resistance rating of T30.
■ Fit protective boards on the inside of the door opening, so that pel-
lets do not push against the door (see chapter "Protective boards
with Z brackets").
■ There should be no electrical installations inside the pellet storage
room. Essential electrical installations must be explosion-proof – in
accordance with current regulations.
■ a In Austria, surrounding walls and ceilings in the storage room
must be designed in accordance with fire resistance class F90,
and doors or access hatches in accordance with T30. Observe fire
regulations according to TRVB H-118 and the respective statutory
requirements. For more information, please refer to
ÖNORM M 7137.
■ Due to condensation and the risk of burst pipes, the installation of
water pipes inside the storage room should be avoided.
■ Pellet storage rooms should be equipped with a fill connector H
and a return air connector G with a Storz coupling, type A,
Ø 100 mm (fire hose connector), with extension pipes leading into
the pellet storage room. Pipes should be metal, connected to the
brickwork and earthed.
■ Fit a baffle mat C opposite the fill connector to protect the pellets
and the brickwork.
■ The pellet storage room must be free from foreign bodies (small
stones, wood particles, etc.).
■ The wall duct for the room discharge should be sealed from the
storage room side with fireproof material (e.g. rendered).
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