A4 Grilles - Spiral Duct.qxd - Scottaire

GRILLES-Spiral Duct
SPIRAL DUCT
GRILLES
These grilles are designed to be fitted directly to exposed
circular ducting without the need for a boot or special
adaptor. The hit and miss supply damper acts as an air turn as
well as a damper. Each height of grille is designed to fit a
range of duct diameters. For industrial application however,
in commercial and retail applications it may be desirable to
manufacture the grilles to fit a specific duct size in order to
improve the aesthetic appearance. See option alternatives.
STANDARD •
Code 0386. Single deflection. Vertical front blades.
Supply or Extract.
Code 0387. Double deflection. Vertical front blades.
Horizontal rear blades. Supply.
Code 0388. Angled hit and miss damper for supply grille.
Code 0389. Straight hit and miss damper for extract grille.
STANDARD SPECIFICATION
OPTIONAL ALTERNATIVES/ADDITIONS
SIZES
There are four nominal lengths of 300mm, 500mm,
800mm and 1000mm and three nominal heights of
70mm, 165mm and 210mm. See the table on page 32
for the range of duct diameters suitable for each
height. Please advise the duct diameter to which each
grille is to be fitted by adding an additional four
figures to the usual 13 digit code.
CONSTRUCTION
Grilles are manufactured from high quality zintec
coated sheet steel, extruded aluminium blades and
neoprene sealing gasket. Dampers are manufactured
from high quality sheet zintec coated steel.
FINISH
Grilles are powder coated Silver metallic (Ref HBN
5462). The dampers are powder coated RAL 9005
matt (black).
FIXINGS
Countersunk screw holes through the border. Size no.
6 x 1 1 /2˝ self tapping screws provided with each grille
and painted the same colour as the grille. (Fixing type
0F1). See Fixing Methods section for screw fixing
centres.
PACKAGING
The grille and damper are packaged in separate
cardboard cartons.
TECHNICAL INFORMATION
See pages 33
DRAWINGS
See pages 32
CONSTRUCTION
We can manufacture with aluminium frames as well
as blades and also include stainless steel fittings for
situations where steel is inappropriate. We can also
manufacture with the flanges angled to fit a specific
size of circular duct which improves the appearance
for commercial and retail applications. Please note
the product code prefix will be 9 instead of 0 on the
grille. Please contact Head Office for details.
FINISHES
Any BS, RAL or NCS colour. Code 0145. Please
specify the colour reference.
ORDERING DETAILS
• The Code for the basic product should have at least
13 digits. See page 1. Then add four more figures for the
actual duct diameter to which it is to be fitted. Make
sure that the duct has a sufficiently large diameter to
take the grille and damper, if fitted, and still leave sufficient
space behind the damper to let the air past them.
EXAMPLE:
A single deflection spiral duct grille, 500mm x
165mm, to be used on supply air, fitted to a
500mm diameter duct, painted BS00A05 satin
would be coded:- 0386/00500/0165-
0500+0388+0145- BS00A05 satin.
Applications. Supply * Extract *
Spiral Duct Mounted * Transfer *
G31

GRILLES-Spiral Duct
H
10
BASIC GRILLE
D = Nominal opening sizes (Height)
Code
386
C
D
Code
387
5
Duct Dia. E
Code 386 is a single deflection
Code 387 is a double deflection
N
A
D+ 30
Code 386 + 389 Code 387 + 389
D = Nominal Opening Sizes (Length)
D+ 30
Code 386 + 388 Code 387 + 388
D = Nominal Opening Sizes (Length)
10
10
Grille with extract damper
Grille with supply damper
Dimensions relating to a Single deflection grille
Dimensions relating to a Double deflection grille
G32

GRILLES-Spiral Duct
PERFORMANCE DATA FOR
SPIRAL DUCT GRILLES
• To size a grille handling 0.5m3 /s at 13m throw:
Place a rule on the volume scale at 0.25m 3 /s volume
scale and on 13m on the throw scale. Read off relevant
noise rating and pressure drop. Note the appropriate
grille length and height.In this case, either a 500 x
165mm or a 1000 x 70mm, whichever is the more
suitable. Design throws should be corrected using table
1 before entering the nomogram and if the grille is to
be used with a horizontal throw within 600mm of the
ceiling, the design throw should also be divided by
1.33. All other corrections should be applied to
nomogram data.
PERFORMANCE DATA
TABLE 1
For other terminal
velocities (V t )
(Vt)
0.375
0.50
Throw
÷0.67
÷0.50
Data given for isothermal conditions, supply air with damper fully open and free space
application. For Code 386 reduce NR by 2. Blades set straight.
Nominal Grille Height
210mm 165mm 70mm
300
Volume (Q)
m 3 /s
500
TABLE 2
Correction for Extract
Damper
Pressure Drop
Noise Rating
x 0.8
x 0.5
1.20
1.00
0.90
0.80
300
800
0.70
40
0.60
30
Pressure drop
(∆Pt ) Pa
300
500
1000
TABLE 3
Without Dampers
(Code 389)
Pressure Drop
Noise Rating
x 0.5
x 0.4
0.50
0.40
0.30
0.20
0.15
20
15
10
5
4
55
50
45
40
35
30
25
NRLW
150
100
60
40
30
20
15
10
500
800
800 1000
1000
Nominal Length (mm)
3
0.10
0.09
0.08
Throw (Lt)m
at Terminal Vel. (Vt)=0.25m/s
0.07
0.06
0.05
0.04
G33