Grilles and Louvres booklet » Our grilles and louvres booklet covers the different types of grilles, diffusers, external louvres and dampers we supply. The booklet includes the different sizes, specifications, dimensions, pictures and safety information.

1. 2013 product line
Grilles
Diffusers
External Louvres
Dampers

2. www.airtherm.co.uk
Grille & diffuser range
Single deflection and fixed blade grilles
Series SD & FB
Single deflection grilles have a single bank of fully adjustable blades
for throw adjustment in one plane.
Fixed blade grilles have the blade pack fixed at either 0°, 15° or 45°.
Double deflection grilles
Series DD
Double deflection grilles add a second set of adjustable blades, set at
90° to the first set. This allows throw adjustment in both planes,
allowing greater throw adjustment than single deflection grilles.
Stock product
The following sizes are kept in stock for quick delivery.
Satin anodised and RAL9010 available.
1502, 2002, 2502, 3002, 3502, 4002, 4502, 5002
200 x 150, 300 x 150, 300 x 200, 400 x 200
25mm flat (Opt)
A Nominal + 30mm
B 46mm
C 90mm
D 25mm
32mm bevelled (Std)
A Nominal + 45mm
B 46mm
C 90mm
D 32mm
25mm flat (Opt)
A Nominal + 30mm
B 46mm
C 90mm
D 25mm
32mm bevelled (Std)
A Nominal + 45mm
B 28mm
C 72mm
D 32mm
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Egg crate grilles
Series ECG
The industry standard extract grille, egg crate grilles have a free area
of around 90%, meaning they can handle large air volumes with
minimal pressure drops or noise generation.
30mm flat (Opt)
A Nominal + 30mm
B 28mm
C 72mm
D 30mm
37mm bevelled (Std)
A Nominal + 45mm
B 28mm
C 70mm
D 37mm
Stock product
The following sizes are kept in stock for quick delivery.
RAL9010 finish, with and without opposed blade dampers.
1502, 2002, 2502, 3002, 3502, 4002, 4502, 5002, 5952 Overall face
Non vision grilles
Series NV
Designed to block line of sight from all angles (NV4 from most), non
vision grilles are used where privacy must be maintained, like
bathrooms and doctors surgeries.
NV1
NV2
Door
NV3
Darkrooms
NV4
Surface
mounted
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Grille & diffuser range continued
Curved blade (eyelash) grilles
Series CB
Curved blade grilles have an unconventional appearance, and allow
throw adjustment thanks to the single bank of individually adjustable
blades.
1, 2, 3 and 4 way blow set ups available.
Perforated plate grilles
Series PPG
Perforated plate grilles use a perforated steel core, to create a tamper
resistant unit providing a stable downward throw, perfect for
laboratories, hospital operating theatres etc.
Deflector plates can be fitted behind the face to allow different blow
patterns to be created.
30mm flat flange (Opt)
A Nominal + 30mm
B 28mm
C 72mm
D 30mm
37mm bevelled (Std)
A Nominal + 45mm
B 28mm
C 70mm
D 37mm
25mm flat (Opt)
A Nominal + 30mm
B 46mm
C 90mm
D 25mm
32mm bevelled (Std)
A Nominal + 45mm
B 28mm
C 72mm
D 32mm
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° ° °
°
Linear bar grilles
Series LG
An extremely versatile grille series. Blade profiles include 0° with 3mm
or 6mm tops, 15° and 45°, all of which can be set on a 12.5mm or
20mm blade pitch.
Other options like removable and hinged cores are also available.
If required a reinforced linear bar grille can be offered, for use in floors
or walls where impact resistance is required.
31mm flat flange (Opt)
A Nominal + 30mm
B 33mm
C 76mm
D 31mm
E Actual neck + 15mm
36mm bevelled (Std)
A Nominal + 45mm
B 33mm
C 76mm
D 36mm
E Actual neck + 9mm
Computer room floor grilles - BS Heavy Grade
Series CFLG
Designed to suit raised access flooring systems, computer room floor
grilles have been tested to BS EN 13264:2001.
Manufactured from extruded aluminium throughout, the grilles have
supreme strength, yet are lightweight enough to allow one man to lift
and fit comfortably.
Stock product
600mm2 units are kept in stock for quick delivery.
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Grille & diffuser range continued
Fixed blade swirl diffusers
Series FSW
Fixed blade swirl diffusers are extremely effective diffusion units. They
create a downward throw of swirling air which rapidly pulls in
surrounding air, mixing the supplied and resident air very effectively.
Adjustable blade swirl diffusers
Series SWA
Just like their fixed counterparts, adjustable swirls are extemely
effective diffusion units.
Instead of pressed blades fixed at an angle, these have individually
adjustable, matt black deflector blades set behind the face. This
allows clockwise, anti-clockwise or straight down throws to be created.
SWF A (mm) B (mm) C (mm) D (mm)
1 595 254 80 40
2 595 356 100 40
3 595 457 160 40
4 595 533 200 40
Stock product
The following sizes are kept in stock for quick delivery,
RAL9010 finish.
254mm, 356mm, 457mm, 533mm (Core sizes)
SWA A (mm) B (mm) C (mm)
1 595 537 240
Dimensions explained on fixed swirl diagram.
Dimension B describes diameter between outermost points of
deflector blades. Not a small spigot as with fixed swirls.
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Stock product
Adjustable blade swirl diffusers are kept in stock for quick delivery,
RAL9010 finish.

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Ceiling diffusers
Series CD
A consistently popular product, ceiling diffusers are found in almost
every commercial building.
Made from extruded aluminium throughout, ceiling diffusers are
guaranteed to be rattle free, unlike some cheaper pressed models.
All sizes under 1200mm x 1200mm have a spring-loaded removable
core as standard.
Drum jet diffusers
Series DJS
Providing an exceptionally long throw, drum jet diffusers are supply
units capable of handling large air volumes whilst also giving
maximum control over throw direction.
Stock product
All sizes shown in the table are kept in stock for quick delivery, in both
RAL9010 and satin anodised finish.
Size Nominal (mm) Overall (mm)
Depth
Depth
c/w OBD
Depth c/w
OBD & VEDW H W H
A 244
164
297
208 62 106 194
B 321 373
C 473 525
D 625 678
E 524
259
576
303 100 144 232
F 651 703
G 778 830
H 905 957
Stock product
The following sizes of four way blow ceiling diffuser are kept in stock for
quick delivery.
RAL9010 finish, with and without opposed blade dampers.
1502, 2002, 2252, 3002, 3752, 5952 Overall face
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Grille & diffuser range continued
Linear slot diffusers
Series LSD
Commonly seen in commercial installations, runs of unlimited lengths
can be created using multiple linear slot diffusers.
When used for supply, matt black internal deflectors can be specified
enabling throw adjustment. End caps and pressure equalising grids
can also be specified.
Slot boxes to suit can also be supplied.
Linear ceiling diffusers
Series LCD
Much like linear bar grilles in construction, linear ceiling diffusers use a
larger 45° blade set at a 20mm pitch. This creates a large free area for
high air volumes, whilst also having the blade surface to deflect air
effectively.
Available in one or two way blow models, with two ways having an
equal or unequal split.
32mm bevelled (Opt)
A Nominal + 45mm
B 46mm
C 91mm
D 25mm
25mm flat flange (Std)
A Nominal + 30mm
B 46mm
C 91mm
D 32mm
Slot number
Overall face
(mm)
Actual
neck (mm)
1 76 40
2 115 78
3 154 117
4 193 155
5 232 193
6 271 232
7 310 270
8 349 309
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Perforated plate diffusers
Series PPD
Using the same outer frame as standard louvre faced ceiling diffusers,
perforated plate diffusers are tamper resistant, and create a stable
throw creating areas of clean supplied air.
This is in contrast to other units like ceiling diffusers which are
designed to mix supplied and resident air as quickly as possible.
Small format circular diffusers
Series SFCDA
Normally found in arenas, exhibition centres etc, circular diffusers are
suitable for use in large open plan areas requiring high changeover
rates.
SIZE DIMENSIONS (mm)
A B C
150 257 149 225
200 307 199 275
250 357 249 325
300 407 299 375
350 457 349 425
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Intumescent fire blocks
Fire rated for 1 hour, intumescent fire blocks expand quickly when
exposed to flames to create a barrier through which fire and smoke
cannot pass.
The intumescent material is covered with a smooth finish to help
prevent dust build up and aiding cleaning.
Grille & diffuser range continued
Pressed steel grilles, diffusers and registers
A cost effective type of grille, normally used in domestic warm air
heating systems. Can also be used in fire doors in conjunction with
intumescent fire blocks or slimline fire dampers.
Pressed steel ceiling diffuser
No.28 Type B
Incorporates a cord operated damper
Pressed steel floor diffuser
Incorporates a roller operated damper
Pressed steel grille
No damper Pressed steel register
Incorporates a lever operated damper
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Curved access doors
Series ADC
Galvanised steel with blue plastic handles. Rubber seal between inner
and outer parts seals the duct once the door is tightened.
Single blade dampers
Series SBD
A cost effective volume control damper for use in small diameter
ductwork where a full shut off is not required.
Fitted with a locking quadrant for simple operation.
Body length 170mm on all sizes.
Stock product
The following sizes are kept in stock for quick delivery.
100mm, 125mm, 150mm, 200mm, 250mm, 300mm, 315mm.
Stock product
The following sizes are kept in stock for quick delivery.
Size To suit duct diameter
180mm x 80mnm 100mm / 125mm
250mm x 150mm 150mm / 160mm
250mm x 150mm 180mm / 200mm
250mm x 150mm 250mm
250mm x 150mm 300mm / 315mm
250mm x 150mm 350mm / 355mm
250mm x 150mm 400mm / 500mm
400mm x 300mm 400mm
400mm x 300mm 450mm
400mm x 300mm 500mm
400mm x 300mm 560mm
400mm x 300mm 630mm
400mm x 300mm 710mm

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Grille & diffuser range
Grille & diffuser options
Polyester powder coating
The majority of grilles and diffusers shown in the catalogue can be
polyester powder coated to any RAL or BS colour.
Some products cannot be powder coated due to plastic parts etc.
Please see the table.
Nylon coating
A specialist finish, nylon coating is used in favour of polyester coating
where extreme durability or resistance to static electricity build up is
needed.
These qualities mean computer room floor grilles are often nylon
coated, as static electricity build-ups in data centres can be
disasterous.
Opposed blade dampers
Fitted to the rear of many grilles and diffusers, opposed blade
dampers are used to trim the airflow through the terminal.
Suitable for use in supply or extract situations.
Please see the table for which products can be fitted with OBDs.
Plenum boxes
Series PB
Although not a grille or diffuser, plenum boxes are just as integral in
the majority of ventilation systems.
Fire rated plenum boxes are available.
Grille/Diffuser type PPC OBD Notes
Single deflection
Fixed blade
Double deflection
Egg crate
Non vision
Curved blade
Perforated plate
Linear bar
Computer room floor
Pressed steel grille x
Pressed steel register x x Includes damper
Pressed steel diffuser x x Includes damper
Ceiling diffuser
Drum jet
Linear slot
Linear ceiling
Circular diffuser x Includes butterfly damper
Fixed swirl x
Adjustable swirl x x RAL9010 only

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Aluminium dampers
Volume control damper
Series VCD
A large format, all aluminium damper, HVC VCDs can be made in
larger sizes than their steel counterparts.
Using a protected push rod linkage means these dampers require
minimal torque to operate, even at large sizes.
Back draught shutter / Non return damper
Series BDS
Designed to permit airflow in one direction only, back draught shutters
are fully aluminium for excellent durability.
Blades can be linked and weighted if required to enable the damper to
open only once the required pressure has been reached.

14. www.airtherm.co.uk
External louvre range
Standard single bank louvres
Series WL
38mm, 50mm and 75mm pitch single bank louvres.
Single bank of blades provide good protection against rain ingress,
whilst preserving 50% free area for high airflow.
Flanged, reversed frame, recessed frame and concealed (not on 38
pitch) units available. Bird and insect mesh optional.
Stainless steel & galvanised louvres
Series WLSS & WLG
Bespoke made to order, stainless and galvanised louvres can be
made to replicate a regular format or custom made to your own
dimensions.
Grades of stainless available are 430, 316 and 304.
Stock product
The following sizes of 38mm pitch standard louvre are kept in
stock for quick delivery.
Mill finish, powder coating to RAL/BS colour optional.
1502, 2002, 2502, 3002, 3502, 4002, 4502,
5002, 5502, 6002, 7002, 8002, 9002, 10002
WL38
WL50
WL75
WL100
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Acoustic louvres
Series AL
Using a two part hollow aluminium blade forming a cavity which is
then filled with mineral wool, acoustic louvres prevent noise transfer
without impeding airflow.
Available in 150mm, 300mm (standard) and 600mm deep models.
Sand trap louvres
Series STL
Designed to be the first stage of filtration, sand trap louvres catch and
collect airbourne particles like sand and grit which would otherwise
clog up finer filters inside the ventilation system.
Constructed from two banks of interlocking vertical channels, all
straight paths through the unit are eliminated. Any caught material
then falls onto the slanted cill and is ejected through the front of the
louvre.
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BSRIA testing to BS EN 13181:2001
Tested by BSRIA to BS EN 13181:2001, sand trap louvres have been
proven over 90% effective at 0.5m/s wind velocity, and over 60%
effective at 1 m/s wind velocity.

16. www.airtherm.co.uk
External louvre range
High performance louvres - Class A
Series HPL
With the addition of two banks of vertical channels behind a standard
louvre, high performance louvres have been tested to confirmed to
give Class A levels of rain protection at velocities up to 0.5m/s.
The channels prevent any straight path through the unit, catching any
rain or spray which made it past the louvre blades. This caught water
then falls onto a special slanted drip cill which quickly ejects it through
the louvre face.
Penthouse louvres
Series PHL
Commonly used in natural ventilation systems, penthouse louvres are
perfect for high efficiency installations, like the new generation of
school buildings and hospitals.
Class A Penthouse Louvres can be manufactured using the same
blade arrangement as high performance louvres shown above.
Options include:
Ÿ Doors.
Ÿ Internal dividers (insulated or un-insulated).
Ÿ Flat, single slant, double slant and HIP roofs.
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External louvre options
Polyester powder coating
All louvres shown in the catalogue can be polyester powder coated to
any RAL or BS colour.
Nylon coating
A specialist finish, nylon coating is used in favour of polyester coating
where extreme durability or resistance to static electricity build up is
needed.
Fixing methods
Although normally drilled on site, louvres can be supplied with face
fixing holes in the flange, or rear mounted fixing lugs.
Bird mesh
Screwed to the back of louvre blades, bird mesh prevents large
objects like leaves, rubbish and birds being able to penetrate the
louvre.
Bird mesh has no real effect on airflow.
Insect mesh
With much smaller gaps than bird mesh, insect mesh prevents all but
the smallest objects penetrating the louvre. The vast majority of
insects and debris are caught.
Insect mesh will reduce a louvre’s free area.
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Steel dampers
S100 Fire Dampers
S100 Fire Dampers are standard fusible link operated curtain type fire
dampers.
Spring driven to enable installation in vertical or horizontal alignments,
S100 dampers are available with HEVAC, plasterboard or curtain
frames and can be fitted with fixing lugs to suit drop rod installa
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Certification
S100 Fire Dampers have been tested to and passed:
BS1366-2 (ISO10294-1): 4 Hour fire test at 300 Pa.
Test conducted by Building Research Establishment.
BS476-20: 6 Hour fire test.
Test conducted by Warrington FRC.
Fire damper cases are manufactured in accordance with DW144.
Options
Installation frames: HEVAC
Plasterboard
Curtain
Fixing lugs
Material: Fully galvanised
Stainless blade pack & galvanised case
Fully stainless
Stainless available in 430, 316 and 304 grades.
Connection types: Square spigotted
Circular spigotted
Flat oval spigotted
S200 & S300 Fire Dampers
S200 fire dampers are designed to be fitted inside ductwork and as
such have no spigot. Spring driven they can be installed vertically or
horizontally.
S300 fire dampers are designed for use in fire doors as an alternative
to intumescent dampers. Exceptionally slim at 38mm deep, they are
gravity driven and so must be installed vertically with the blade pack at
the top.
Certification: S200
S200 Fire Dampers have been tested to and passed:
BS1366-2 (ISO10294-1): 4 Hour fire test at 300 Pa.
Test conducted by Building Research Establishment.
BS476-20: 6 Hour fire test.
Test conducted by Warrington FRC.
Certification: S300
S300 Fire Dampers have been tested to and passed:
BS476-20: 6 Hour fire test.
Test conducted by Warrington FRC.
Options
Material: Fully galvanised
Stainless blade pack & galvanised case
Fully stainless
Stainless available in 430, 316 and 304 grades.
Connection types: Square flanged

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S600 Fire Smoke Dampers
S600 Fire Smoke Dampers are as much a life safety device as a way
to protect buildings. Having an opposed blade construction and fitted
with actuators, they can be remote operated upon detection of smoke
or fire anywhere in a building.
We can supply and fit the full range of Belimo Fire Smoke Damper
actuators to S600 dampers.
Certification
S600 Fire Smoke Dampers have been tested to and passed:
BS476-20: 6 Hour fire test.
Test conducted by Warrington FRC.
Fire damper cases are manufactured in accordance with DW142.
Options
Installation frames: HEVAC
Plasterboard
Curtain
Fixing lugs
Material: Fully galvanised
Stainless blade pack & galvanised case
Fully stainless
Stainless available in 430, 316 and 304 grades.
Connection types: Square spigotted
Circular spigotted
Flat oval spigotted
S900 Volume Control Dampers
S900 Volume Control Dampers are a general purpose unit, best suited
to sizes under 1m2. Manufactured from roll formed galvanised or
stainless steel and with a fully protected gear drive mechanism, S900
VCDs are extremely durable and require minimal maintenance.
We can supply and fit the full range of Belimo actuators to your new
S900 Volume Control Dampers.
Options
Material: Fully galvanised
Stainless blades & galvanised case
Aluminium blades and galvanised case
Fully stainless
Stainless available in 430, 316 and 304 grades.
Connection types: Square flanged
Square spigotted
Circular spigotted
Flat oval spigotted

20. www.airtherm.co.uk
Plastic dampers for natural ventilation
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uPVC volume control damper showing total seal
Extruded uPVC frame and blades.
Integrated flexible plastic blade nose seals.
Brush side seals.
Rolled steel section inside each blade for
reinforcement (not exposed to airstream).
Stainless steel screws to join frame (not exposed to
airstream).
White.
Minimum size 300mm x 300mm / 300mm Ø.
Maximum size 1000mm x 1000mm / 1000mm Ø.
Above these sizes units would be made in sections.
Precision linkage
Manufactured from highly
corrosion resistant materials, the
custom designed gearset is so
precise it can drive up to 10
blades and cogs with very limited
play, for maximum performance
even at large sizes.
Corrosion resistance
In coastal or swimming pool
applications, traditional steel
dampers will corrode very
quickly. uPVC on the other hand
has excellent resistance to salt
and chlorine, and cannot rust.
Overview
Ultra high shut off
Excellent corrosion resistance
The revolutionary uPVC Volume control damper
incorporates a copyrighted and never before seen
feature for a plastic volume damper. It’s unprecedented
performance originates with the unique ‘Eccentric
Aerofoil’© blade design. This unieu, incorporates a
blade with an off centre axis.
This enables the edge seal to be complete, and
uninterrupted by blade axles. Combine this with the
integrated, specially designed blade nose seal which
fuses the blades together on closure, a performance
emulating that of a full shut off damper is achieved,
whilst still providing the excellent functionality of a
traditional volume control damper.
Specifications:
Materials:
Finish:
Sizes:

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Model B - Square, spigotted.
Model C - Circular, spigotted.
Model D - Flat oval, spigotted.
Model A - Square, no spigot.
Ultra high shut off
In independent tests, large format uPVC volume control dampers
yielded leakage results normally only achieved by dedicated shut off
dampers.
The VCD sent for testing had a nominal size of 1000mm x
806mm, the large size tantamount to our confidence in the damper.
With even 10Pa rarely being exceeded in natural ventilation
situations, it is clear how uPVC volume control dampers can
enhance the efficiency of your new natural ventilation system.
No cold bridge
Close a steel or aluminium volume control damper, and you will
go on losing heat, not through airflow but conduction of heat from
one side to the other.
HVC large format uPVC volume control dampers have a
theoretical U value of 0.973W/m2K when closed, atleast 40 times
better than a steel damper and 250 times better than an aluminium
unit.
Of course this can help to cut heating bills, and reduces the
carbon footprint of any building using them.
*Figures sourced from www.engineeringtoolbox.com
Leakage (1000mm x 806mm uPVC VCD)
m3/s m3/hr/m m3/hr/m2
10Pa 0 0 0
25Pa 0.000857 0.29 3.83
50Pa 0.002850 0.97 12.73
75Pa 0.004975 1.69 22.22
100Pa 0.005398 1.83 24.11
150Pa 0.007909 2.68 35.33
Thermal conductivity of steel and
aluminium*
Steel Aluminium
W/mK 40 250
Btu 23.12 144.46

22. Ÿ Flues & chimneys
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Ÿ Air Conditioning
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www.airtherm.co.uk
T: 0844 809 2509
F: 01562 887312
M: 07715 360958
sales@airtherm.co.uk
Unit 8a
Gainsborough Trading Estate
Rufford Road
Stourbridge
West Midlands
DY9 7ND