Waterloo
The Green Book
The Green Book
Welcome to the latest edition of the Waterloo Green Book.
For over 100 years Waterloo has earned and maintained an enviable
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The Green Book
AIR DIFFUSION
Page No.
4
5
6
1
Terms, definitions and symbols
2
3
Conventional air diffusion patterns
Basis of Waterloo performance data
4
5
Air Terminal Device selection
Comparative selection data
6
Comfort criteria
8
14
22
7
8
Special air diffusion applications
Jet theory and characteristics
24
27
ACOUSTIC
9
General acoustic information
30
10
11
Spectrum correction factors
Octave band analysis procedure
12
Waterloo octave band analysis chart
31
32
34
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1. Terms, definitions and symbols
THROW or RADIUS of DIFFUSION
Throw
Forward travel of a jet to the point where the maximum
velocity has decayed to a nominated terminal velocity.
Drop
(Vt ) TERMINAL VELOCITY
Decaying velocity at centre of the jet, which in used to
define the throw (Typically Vt = 0.15 to 0.5 m/s).
Envelopes
DROP or RISE
Vertical distance between the jet centreline and supply
outlet centreline at a nominated throw.
ENVELOPE
Jet area within the boundary of a nominated air velocity.
Spread
EXPANSION or SPREAD
Normal divergence of a jet as it leaves an outlet and
Free Jet
entrains surrounding air.
FREE JET
A supply jet which is able to entrain surrounding air
on all sides.
CONFINED JET or CEILING EFFECT JET
A supply jet which is located so close to one or more
surfaces that entrainment is reduced or eliminated.
CEILING EFFECT
Confined Jet
The tendency of an air stream that is discharged close
to and parallel to a surface, to cling to the surface.
This is also called the Coanda effect.
OCCUPIED ZONE
Defined as the area up to 1.8m from the floor and as
close as 150mm from any room surface.
(Vr ) ROOM AIR VELOCITY
Average air velocity recorded within the occupied zone.
(
t) TEMPERATURE DIFFERENTIAL
Difference between supply temperature and room air
temperature.
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Vr
Room Air Velocity
2. Conventional room air diffusion patterns
Introduction
A well-designed room air diffusion scheme ensures that when conditioned air is supplied into a room, it
causes no discomfort to the occupants. The criteria for comfort are discussed in detail in Section 6.
With a conventional diffusion arrangement, primary air is supplied over the occupied zone where it
entrains and mixes with room or secondary air. This process results in a decay of the initial temperature
and velocity difference between the supply and room air so that when the supply jet reaches the occupied
zone, the velocity and temperature are close to room conditions.
The location, type and size of the air terminal device will determine the manner in which the supply
jet and resultant room air motion behave. With full air conditioning schemes, the change in supply air
temperature from a cooling to a heating cycle will also modify the jet trajectory and room air movement
pattern.
Air terminal device location
Typical air movement pattern
Terminal types
Interior
Ceiling
Circular,
Square,
Rectangular
& Linear
Diffusers
Perimeter
Ceiling
Square,
Rectangular
& Linear
Diffusers
Sidewall
Modular &
Linear grilles
Sill or
Floor
Modular &
Linear grilles
Bulkhead
(Side)
Modular &
Linear grilles
Linear
Diffusers
Bulkhead
(Bottom)
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3. Basis of Waterloo performance data
3.1 Throw
Data for the supply air diffusers and grilles is usually based on a quoted throw or radius of diffusion to
a specific jet terminal velocity. An acceptable terminal velocity varies with the type of air terminal
device, the particular requirements of the conditioned area and its occupants. For critical applications,
a maximum jet air velocity of 0.25 m/s may be necessary while for industrial heating systems, jet
velocities as high as 1 m/s may be acceptable.
3.1.1 Supply air diffusers
Circular, linear and square ceiling mounted diffusers provide an efficient and predictable room air diffusion pattern. For these diffusers, a strong correlation exists between jet throw, jet terminal velocity
and room air velocity in the occupied zone. Data is therefore presented in the form of minimum and
maximum radius of diffusion which provides a convenient and safe selection technique.
Minimum radius of diffusion is the smallest area that can be covered by one diffuser resulting
in an average air velocity in the occupied zone of 0.25 m/s.
Maximum radius of diffusion is the largest area that can be covered by one diffuser resulting
in an average air velocity in the occupied zone of 0.1 m/s.
Data is based on a room with a ceiling and diffuser mounting height of 2.7 m; add one metre
to the throw for each additional metre of mounting height.
3.1.2 Supply air grilles
Grilles generally produce a less efficient and less predictable air movement pattern than ceiling
mounted diffusers.
In addition, the correlation between jet terminal velocity, throw and room air
movement is tenuous. For this reason, the data is presented in the form of a throw to a specified terminal velocity. It is possible to determine the maximum jet velocity as it enters the occupied zone, and
hence ensure that uncomfortable conditions are avoided.
3.2 Exhaust air terminal devices
Selection is usually based on a maximum noise generation level or pressure loss. For most applications,
an exhaust grille only affects air movement patterns within 0.5m of the terminal itself.
3.3 Noise levels
Data in the tables or nomograms is presented in one of the following forms:
dBA LEVEL: Predicted maximum Noise Criteria (dBA) level based on sound power level less
8dB room absorption.
Lw dBA:
Maximum dBA sound power level.
Lw NR:
Maximum NR sound power level.
For critical projects it may necessary to carry out a complete acoustic analysis. Using the Waterloo
Acoustic Manual, it is possible to estimate octave band sound power levels for most grilles and
diffusers.
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3. Basis of Waterloo performance data
3.4 Pressure loss
Data is presented for either:
Static Pressure Loss (PS ):
Pressure loss measured at the duct sidewall.
Total Pressure Loss (PT ):
Pressure loss measured in the duct using a pitot tube “total head”
connection.
PT = PV + PS
Where PV
= velocity pressure
= ½ PV2
using P
= 1.2 kg/m 3
PV
= 0.6 V 2
Where V
= duct air velocity (m/s)
3.5 Data correction factors
3.5.1 Heating and cooling differentials (
t)
The latest test data is presented for isothermal air conditions (where the supply and room air
temperatures are equal). Individual tables and nomograms include correction factors for heating
or cooling differentials as applicable.
3.5.2 Terminal velocity (V t)
Throw data should be corrected where necessary for the most suitable jet terminal velocity. For
commercial projects, grilles are usually selected using terminal velocities of 0.25 – 0.5m/s while
ceiling mounted diffusers are selected with jet terminal velocities of 0.25 – 1 m/s depending upon
the particular application.
3.5.3 Jet spread
The supply air should be spread as widely as possible as this improves entrainment and results in the
selection of smaller air terminal devices. Throw corrections are given where applicable on the nomograms
and tables referring to individual products.
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4. Air Terminal Device selection
Introduction
Frequently the type and location of grille or diffuser will be determined by architectural or other
requirements. If this is the case, performance data can be applied directly to determine whether the
resulting performance is acceptable. If an entirely free choice is available, refer to Sections 2 and 5
where comparative selection data can be used to determine the most suitable air terminal device.
Usually, the sizing of a particular terminal device is based on the throw, but at each stage, it is
necessary to check that any acoustic or pressure loss specification is satisfied.
Having decided which type of grille or diffuser is required, apply the following techniques for
selection in conjunction with necessary information, such as total airflow rate and room size, it is
helpful to have scale drawings of air terminal device layouts.
4.1 Linear slot diffusers
These diffusers can be selected or set to provide horizontal diffusion in one or two directions across a
flat ceiling surface drawing up on the ceiling effect. As the supply jet entrains room air, it expands in
the vertical plane and must be prevented from prematurely entering the occupied zone. Using the
following table, determine the maximum throw according to the ceiling height:
Ceiling height (m)
2.5
2.7
3.0
3.5
4.0
Maximum throw (m)
4.0
5.5
6.5
9.5
12.0
For continuous slot diffuser arrangements, divide the ceiling area into convenient strips, based on
the maximum throw.
Determine the available active lengths of diffuser sections.
Calculate the diffuser duty by dividing the active length into the total airflow rate to be supplied.
With the available information of maximum throw and diffuser duty, draw two lines on the selection
nomogram; one passing through the minimum radius of diffusion and the other passing through the
maximum radius of diffusion. This produces a band of possible selections.
It is now necessary to find the optimum selection, which is usually a compromise between economy
(minimum number of slots) and comfort (maximum number of slots to produce the ideal room air
movement for the particular application).
If the optimum selection falls below a one-slot diffuser, then the active length can be reduced as
necessary.
If the optimum selection is greater than eight slots, it is possible that a slot diffuser arrangement is
not practical and further advice should be obtained from Waterloo.
Min
throw
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Max
throw
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4. Air Terminal Device selection
4.2 Circular, square and rectangular diffusers
Circular diffusers produce a radial air diffusion pattern while square and rectangular devices can be
selected or adjusted to produce 4, 3, 2 or 1 way directional air patterns and drawing up on the ceiling
effect. Wherever possible, select a 4 way or radial pattern as this results in the most efficient air diffusion.
Using the following table, determine the maximum throw or radius of diffusion based on the zone ceiling
height. This will prevent the supply jet from entering the occupied zone prematurely, as it expands in the
vertical plane.
1
Ceiling height (m)
2.5
2.7
3.0
3.5
4.0
Maximum throw (m)
4.0
5.5
6.5
9.5
12.0
Using a scaled ceiling plan, divide the area into convenient squares twice the size of the derived maximum
throw. A circular or square diffuser at the centre of each area can now be selected to handle its proportion
of the total airflow rate.
Using selection tables or nomograms, determine the diffuser sizes which satisfy the throw parameter. The
most economical selection will produce a minimum radius of diffusion very close to the required throw.
However, the optimum selection will probably be a compromise between the most economical selection
and that which will produce the most comfortable room air movement.
If the maximum radius of diffusion produced by the smallest available diffuser is less than the required
throw, then insufficient room air movement and high level stagnation will result. An alternative air terminal
device should be considered.
Similarly, if the minimum radius of diffusion produced by the largest available diffuser is greater than the
required throw, it is probable that the particular air terminal device is unsuitable.
Wherever possible, diffuser selections should be within the limits given in the tables; extrapolating data
down to very low-neck velocities will usually result in poor air diffusion, for example; high-level stagnation
with heating cycles, and draughts due to dumping with cooling cycles.
Minimum
radius of
diffusion
Maximum radius of
diffusion
Max
throw
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4. Air Terminal Device selection
4.3 Linear grilles
Continuous grilles mounted at high level on a sidewall or bulkhead may be treated in a similar manner
to linear slot diffusers. If the grille is mounted to take advantage of the ceiling effect; this is always
beneficial with cooling differentials as the risk of dumping is minimised. To avoid draughts at head
level, the maximum throw should be limited to the figures shown in the table below, based on ceiling
height:
Ceiling height (m)
2.5
2.7
3.0
3.5
4.0
Maximum throw (m)
2.5
3.3
4.5
6.3
8.0
If the required throw exceeds the maximum throw shown above, consider supplying air from both
sides of the room or using an alternative terminal device.
Calculate the grille duty by dividing the maximum available active length into the total flow rate.
Determine the most suitable terminal velocity for the particular application; for year round airconditioning with linear grilles, a terminal velocity of 0.3 – 0.4 m/s is satisfactory.
Using selection nomograms, determine the most suitable grille height based on the required duty
and throw.
Consider the use of directional vanes to direct the air upwards towards the ceiling surface to improve
the ceiling effect.
Single sidewall supply
Max
throw
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Double sidewall supply
Max
throw
4. Air Terminal Device selection
4.4 Individual grilles
Sidewall supply grilles may be selected or adjusted to discharge air to take advantage of the ceiling
effect with or without spread in the horizontal plane. If possible, use the available area to spread the
supply air as this reduces throw and will result in smaller grilles and ducting as well as more efficient
air diffusion.
The maximum available throw should be based on the ceiling height according to the table shown
below.
Ceiling height (m)
2.5
2.7
3.0
3.5
4.0
Maximum throw (m)
2.5
3.3
4.5
6.3
8.0
If the required throw exceeds the maximum throw shown above, consider an alternative scheme.
Choose suitable grille locations and calculate the individual grille duty.
Determine the most suitable terminal velocity on which the throw is to be based; in general, a jet
terminal velocity of 0.25 – 0.4m/s will be satisfactory for year round air conditioning schemes using
sidewall grilles.
Using selection tables or nomograms, select the most suitable grille size.
Grilles with an aspect ratio (width to height ratio) between, 2:1 and 5:1 produce a better air diffusion
pattern than square grilles and are less likely to cause draft problems due to excessive drop of the
supply jet.
Max
throw
Grille
spacing
( see table)
Jet
spread
Jet spread
Minimum grille spacing
20
o
45
o
60
o
0.2 x Throw 0.4 x Throw 0.6 x Throw
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4. Air Terminal Device selection
4.5 Free jet applications
Sections 4.1 to 4.4 are based on situations where the supply air jet is discharged close to the ceiling
surface, allowing consideration of the ceiling effect. When the terminal device is mounted away from
any surface the velocity decay is more rapid and the throw is reduced. Use the following table to
determine the correction factor to be applied to the selection tables and nomograms.
Terminal
Distance between terminal
device
device and ceiling surface ‘X’
300mm
300-600mm
600-1000mm
1000mm +
Diffusers
1.0
0.9
0.8
0.7
Linear grilles
1.0
0.8
0.7
0.7
Grilles
1.0
0.7
0.7
0.7
The above information is generalised and corrections should only be applied in the absence of specific
information given for individual products.
Diffuser application - free jet
X
Throw
Grille application - free jet
X
Throw
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4. Air Terminal Device selection
4.6 Vertical projection
For applications with high ceiling levels (greater than 4m) it may be sensible to utilise a vertical
projection scheme using grilles or diffusers mounted at high level. Such schemes require very careful
selection techniques as outlined in the performance data and are usually the most successful for
heating and ventilation schemes. With a full air conditioning scheme, the vertical projection throw
varies greatly because buoyancy forces produce a strong influence on the jet travel.
Projects such as factories, warehouses, sports halls and general purpose halls are best designed
for the heating cycle. Auditoria, concert halls and reception areas should be designed for the cooling
cycle because occupants are usually sedentary and require more specific comfort conditions.
2
Typical jet characteristics cooling & heating
Cooling
Projection
Projection
Heating
Cooling
Heating
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5. Comparative selection data
Introduction
This section of the guide may be used to determine the most suitable air terminal device for a particular
application, given certain restricting parameters.
5.1
5.2
5.3
5.4
Supply terminal location and type of distribution
Supply terminal air pattern
Architectural requirements
Product / project applications guide
5.1 Supply terminal location and type of distribution
Location / Distribution
Suitable Terminals
Ceiling – horizontal & vertical
Linear Slots
CS Series
Square & rectangular
DFA
Location / Distribution
2
Circular
Ceiling – horizontal only
DSL
FCD
Square & rectangular
D Type
M Type
CPD
KRCP
ACD
Ceiling – vertical only
Linear Grilles
AL Series
Linear Slots
CS Series
Square & rectangular
Series 1 & 2
SDACH
RWH
WR
MC
Linear Slots
Swirl
Sidewall – confined jet
Suitable Terminals
Sidewall – free jet
Circular
RWH
Nozzles
EBD
VS4
Linear Grilles
AL Series
Linear Slots
CS Series
Square & rectangular
Series 1 & 2
SDV Series
SDF Series
Bulkhead – side
AL Series
Linear Grilles
(only suitable if ceiling is 4m+)
Circular
RWH
Nozzles
EBD
VS4
WDJ
Linear Grilles
AL Series
Linear Slots
CS Series
Square & rectangular
Series 1 & 2
RTC
Sill & floor
Sill Grilles
AL Series
RTC
Floor Grilles
HDFG
AFG
Floor Diffusers
Bulkhead – underside
WFO Series
Circular
RWH
Nozzles
EBD
VS4
Linear Grilles
AL Series
Linear Slots
CS Series
DSL
Square & rectangular
D Type
See also section 5.4 for product descriptions & applications
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5. Comparative selection data
5.2 Supply terminal device air pattern
Diffusers
Air Patterns – Diffuser
Linear
Directional
4 Way – D types, M types,
CPD, KRCP
3 Way D types, M types,
CPD, KRCP
CS Series, DSL, FCD
Circular
2 Way D types, M types,
CPD, KRCP
1 Way D types, M types,
CPD, KRCP
Vertical – SDACH
Projection – DFA
– WR
– MC
MC, WR, RW Series, SDF, SDV
Grilles
Linear
Modular
AL Series
AL Series, Series 1 & 2, RTC
Grilles providing spread control in one plane
Grilles providing spread control
in two planes
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5. Comparative selection data
5.3 Architectural requirements
Ceiling system integration: where it is necessary to select a terminal to suit a given ceiling system,
use the following information:
Ceiling Type
Typical Arrangement
Tee bar ctrs
Exposed T
or
Lay-in T
Tee bar ctrs
Concealed T
Suitable Terminals
D Type
DFA
M series
CPD
KRCP
Exhaust grilles
Swirl
D Type
DFA
CPD
KRCP
Exhaust grilles
SDV
SDF
Tee bar
centres
Spring type or
Burgess
Ceiling opening
Cut tile
or
Cut opening
30 mm
Tegular
depth
Plank
Tegular
8 or 16 mm
Tegular
depth
D Type
KRCP
Exhaust grilles
CPD
D Type
M Type
KRCP
CPD
AL series
Circular
MC
CS Series
Swirl
CS
LCS
DF
DE
SDF
SDV
DF
DE
Special & Integrated Ceilings
Waterloo can provide air terminals to integrate with most special ceilings, luminaries, emergency
lamp fittings, sprinkler heads etc., consultation with head office is recommended.
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5. Comparative selection data
5.4 Waterloo product range – description and applications
Category
Type
CS Series
CSB
Linear
Diffusers
LCS
DSL
FCD
DF, DE, DFA
DES
Aircell M
Series
Description
Normal
Application
Small format linear
slot diffusers.
Adjustable 1 way, 2
way or vertical
projection
Small format linear
barrel slot diffuser
Small format single
blade linear slot
diffuser
Plenum or plenum
duct supply in
individual or
continuous runs.
Supply and
exhaust modules
Large format linear
slot diffuser. Fixed 1
or 2 way
Fan coil and
ceiling induction
unit supply.
Adjacent ceiling
void return/recirc
Linear fan coil
diffuser with fixed
1 or 2 way
Multicone diffuser
with fixed or
adjustable 1, 2, 3 and
4 way or vertical
projection
Commercial:
offices, shops,
computer
suites,
laboratories
Perforated face
diffusers
KRCP
Perforated face
diffusers with
multicone cores for 1,
2, 3 and 4 way
projection
Fan coil or VAV
supply
WPD
Stub duct or
plenum supply
and extract
Commercial:
offices, shops,
halls etc
Ducted supply
Commercial:
offices, shops,
computer
suites,
laboratories
Kitchens,
restaurants,
some
commercial
applications
Stub duct or
plenum supply
and extract
Commercial:
offices, shops,
halls etc
Ducted supply
Hospital,
operating
theatre,
martuaries
WID
LF
RWI
RWK
Circular
Diffusers
RWV
MC
WR
Perforated face
diffusers
Perforated face
diffuser
Plain face diffuser
Plain face,
Adjustable
Small format
compact circular
diffuser
Stub duct or
plenum supply
and extract
Ducted supply
Very flexible supply
and exhaust
diffuser. Highly
suitable for VAV
applications
Cost effective
solution
MWVP
Perforated face
diffusers
Comments
Low pressure loss
Polymer multicone
diffuser
CPD
Square &
Rectangular
Diffusers
Project Type
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Polymer
alternative. non
conductive.
Suitable for areas
requiring high
change rates
Features hinged
face plate for
access. Excellent
for high change
rates
Flush fitting with
optional extract
filter. Lined as
standard
Adjustable pattern
settings
Adjustable drop
face and pattern
settings
Linear
downward
flow.
Commercial and
industrial
offices, shops,
foyers,
warehouses,
factories, halls
Large format circular
diffuser
Inexpensive.
Integrates well with
most ceiling
arrangements
Adjustable pattern
settings
Horizontal and
vertical use
Effective flexible
diffuser
Adjustable core.
Vertical and
horizontal use
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5. Comparative selection data
5.4 Waterloo product range – description and applications
Category
Swirl
Diffusers
Type
Description
SDF
SDFP
Fixed blade swirl
diffuser
SDV
Vane swirl diffuser
Large capacity swirl
diffuser
SDACH
Jet Diffusers
Floor
Diffusers
WDJ
Drum jet diffuser
VS4
EBD
Jet nozzle
Eyeball jet diffuser
RWH
Adjustable multicone
jet diffuser
WFO Series
Round format
polymer floor
diffusers
Linear grilles
with fixed flat
or angled vanes
Linear Grilles AL Series
Stub duct or
plenum supply
and extract
Commercial and
industrial
offices, shops,
foyers,
warehouses,
factories, halls
Excellent mixing
characteristics
Duct mounted
supply. Ideal for
long directional
throw
High volume
reversible air flow
pattern for large
spaces
Pressurised void
or plenum supply
diffusers
Sill and floor fan
coil supply in
individual or
continuous runs.
Ducted sidewall
supply.
Auditoria, atria,
terminal
buildings, sports
halls, factories
Good range of
adjustability.
Low pressure drop
o
Up to 30 offset
Nozzle or diffuser
pattern
Commercial:
offices, shops,
halls etc
3 discharge pattern
options
Commercial:
offices, shops,
halls etc
Many vane profiles.
Flexible and
functional
Ducted sidewall or
ceiling supply
Reversible core grille
Sill coil. High
ducted sidewall
supply.
Commercial:
offices, shops,
halls etc
Aesthetically
pleasing.
Reversible core
prevents accidental
adjustment
3H Series,
GC5, PER
Exhaust grilles
Ducted or void
exhaust grilles.
Any exhaust
application
Any
Functional grilles
WPT
Sidewall grille
Ducted sidewall
supply
Any
Aircell Range
Polymer grille range
Ducted sidewall or
ceiling supply and
exhaust
Any
Acoustic transfer
grille
Intumescent transfer
grille
No line of sight
transfer grille
Door and panel
transfer grille
DSR
WFV, GR
NS, DV
18
Comments
Industrial and
domestic. Small
commercial;
factories, shops
etc
RTC
Transfer &
Door Grilles
Project Type
Adjustable single and
double deflection
grilles
1 & 2 Series
Square &
Rectangular
Grilles
Normal
Application
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Any
Excellent for up or
down wall
applications
Alternative Polymer
range. Non
conductive
For cross talk
applications
Rectangular and
round options
Restricted airflow
5. Comparative selection data
5.4 Waterloo product range – description and applications
Category
Type
Description
Chilled
Beams
ABM Series
Active chilled beam
PBM Series
Passive chilled beam
HDFG
Heavy duty floor
grille
Floor Grilles
Security
Grilles
AFG
Linear floor grille
SG
Prison anti ligature
grilles
YG, WG
Small and large
format external
weather louvres
YGK, WGK
External
Louvres
YGT
WGA
WGD, WGPH
Adjustable external
weather louvres
No sight small format
external weather
louvre
Acoustic weather
louvres
Penthouse louvres
PRD
Low pressure relief
damper
BPD
Back pressure
damper
WDD
Regulating Damper
WR
Circular format
actuated VAV
WLM
Rectangular format
actuated VAV
WVR
Circular format
constant volume
WVK
Rectangular format
constant volume
WVSV
VAV/attenuator
combination
Dampers
VAV
Normal
Application
Project Type
Ducted supply.
Ceiling mounted
or suspended
In void or cased
suspended
Commercial:
offices, shops
etc
Lay in tile for
raised floors
Commercial:
computer suites
etc
Range of loading
capacity. XS is
certified
Any
Light duty
Prisons, cells
Three levels of
security
Industrial and
commercial
Accessories
available: Doors,
bird screens, insect
screens
Sill and floor light
traffic
applications.
Ducted or lay in.
Sidewall/panel
mounted supply
and extract
Individual or
louvre wall
applications.
Rooftop screens
Dividing wall,
panel or door
mounted for fine
pressure relief
Dividing wall,
panel, door or
duct mounted for
coarse pressure
relief or non return
Duct mounted
Comments
Eurovent certified
performance
Industrial and
commercial,
Pressure
regulated
rooms,
stairwells etc
Good response
Any
Shut off option
Low precision
Belimo actuator as
standard
Duct mounted
Any
Easily set with dial
scale
Belimo actuator as
standard
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19
5. Comparative selection data
Offices, Schools,
Colleges,
Libraries, Hotels,
Retail
Atria,
Exhibition Halls,
Terminals,
Shopping Malls
Leisure centres,
Warehouses,
Large Spaces
Cleanrooms,
Hospitals
Washrooms,
Lavatory areas,
Showers, Small
rooms
Industrial,
Commercial,
Retail
Residential
Prisons, Custody
suits, Courts
MRI, Chemical
environment
Data centres, Call
centres
Sidewall supply,
any application
Supply and
exhaust to
atmosphere
Kitchens,
Restaurants
Wet areas
Ceiling or wall
mounted, any
application
Most Buildings
Industrial
Buildings
Ductwork Systems
Natural
Ventilation
20
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1 and 2 Series
WFO
VA, VB, VC
SDV, SDF
SDACD, SDICH,
SDFCH, WR
RWI, RWK,
RWV
MW
MC
LFF, LFM
KRCP
EBD, WDJ, VS4,
RWH
DF, DE, MD,
WID
CS, FCD
CPD
Aircell Range
ABM, PBM
5.5 Application to product usage cross reference
5. Comparative selection data
YGT
SL
WG
YG
WRD, WLM
WVK2,WVR1,
WVSV
BPD, WDD
PRD
WFV
RTC
SG
NS, DV
HDFG
AFG
DSR
AL Series
3 Series, PER,
GC5
5.5 Application to product usage cross reference
Offices, Schools,
Colleges,
Libraries, Hotels,
Retail
Atria,
Exhibition Halls,
Terminals,
Shopping Malls
Leisure centres,
Warehouses,
Large Spaces
Cleanrooms,
Hospitals
Washrooms,
Lavatory areas,
Showers, Small
rooms
Industrial,
Commercial,
Retail
Residential
Prisons, Custody
suits, Courts
MRI, Chemical
environment
Data centres, Call
centres
Sidewall supply,
any application
Supply and
exhaust to
atmosphere
Kitchens,
Restaurants
Wet areas
Ceiling or wall
mounted, any
application
Most Buildings
Industrial
Buildings
Ductwork Systems
Natural
Ventilation
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21
6. Comfort criteria
Introduction
Air terminal device selection is influenced by thermal and acoustic criteria.
6.1 Human thermal comfort
This depends primarily on:
air temperature
mean radiant temperature
air velocity
relative humidity
type of clothing
degree of activity
ISO 7730 provides guidance on defining and setting comfort criteria for occupied areas. Air velocity
is the most important factor in the design of air diffusion schemes providing that:
o
dry bulb air temperature is controlled according to air movement in the range 20 – 26 C.
o
mean radiant temperature is within 10 C of mean air temperature.
relative humidity is in the range 30 – 70%
activity and clothing type is taken into account for the occupants.
The graph below has been extracted from CIBSE Guide A1 Comfort and shows combinations of mean
air speed, air temperature and turbulence intensity for a draught rating of 15%.
Recommended specification for offices
Light, mainly sedentary activity during winter (heating
o
period), i.e. operative temperature between 20 and 24 C.
Mean air velocity, va less than 0,15 m/s.
Light, mainly sedentary activity during summer (cooling
period), i.e. operative temperature between 23 and 26 oC.
Mean air velocity, va less than 0,25 m/s.
0.5
0%
15% dissatisfied
Turbulence
Mean air speed m/s
0.4
intensity (Tu)
10%
0.3
20%
30%
40%
50%
60%
0.2
0.1
0
18
20
22
24
26
o
Air temperature t a / C
22
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28
6. Comfort criteria
6.2 Acoustic environment
The noise level within a conditioned space may be derived from the table shown below which is based
primarily on the room use. Excessively high noise levels are obviously not acceptable but very low
noise levels can also result in problems; for example, it is pointless designing an air diffusion scheme
for a large general office on an 25dBA (NR20) parameter. It is desirable to approach, as closely as
possible, the design noise level as this results in the most economical selection.
For critical applications, the noise data given in the selection nomograms and tables may be
inadequate. In this case, a specialist approach may be necessary and reference may be made to the
acoustic section of this manual.
Recommended Noise Ratings
dBA
NR
LEVEL LEVEL
Situation
Concert halls, opera halls, studios for sound reproduction, live theatre (500 seats).
25
20
Bedrooms in private homes, live theatres (500 seats), large religious buildings,
30
25
35
30
40
35
45
40
50
45
3
television studios, large conference and lecture rooms (50 people).
Living rooms in private homes, board rooms, top management offices, conference
and lecture rooms (20-50 people), multi-purpose halls, medium and small religious
buildings, libraries, bedrooms in hotels, etc., banqueting rooms, operating theatres,
cinemas, hospital private rooms, large courtrooms.
Public rooms in hotels, etc., ballrooms, hospital open wards, middle management
and small offices, small conference and lecture rooms (20 people), school classrooms,
courtrooms, museums, libraries, banking halls, small restaurants, cocktail bars, quality
shops.
Toilet and washrooms, large open offices, drawing offices, reception area (offices),
halls, corridors, lobbies in hotels, hospitals, etc., laboratories, recreation rooms, post
offices, large restaurants, bars and night clubs, department stores, shops, gymnasia…
Kitchens in hotels, hospitals, etc., laundry rooms, computer rooms, accounting
machine rooms, cafeteria, canteens, supermarkets, swimming pools, covered garages
in hotels, offices, etc bowling alleys.
Acknowledgement
Some details appearing in this section have been extracted from the CIBSE Guide - Section A.1 - Comfort.
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7. Air diffusion – Special applications
7. Introduction
Applications not covered by the general performance data should, if necessary, be referred for specialist
consideration. The following sections may however be used as a guideline for initial selection.
7.1 Variable air flow rate systems
The obvious energy conservation advantages provided by variable air volume (VAV) systems will
inevitably result in a compromise of air diffusion performance. There are various techniques which
may be used to ensure reasonable air diffusion.
7.1.1 Selection optimisation
The majority of VAV projects can be designed with standard grilles or diffusers, selected and sized
to optimise performance.
Variable volume systems, by design, should operate at maximum flow rate for only a few days
each year. It is therefore reasonable to assume that, on those occasions, the room occupants will
accept less than design conditions.
In addition, the demand for maximum cooling and hence
maximum flow rate is coincident with the subjective demand for more air movement (i.e. summer
design conditions). Similarly, the minimum flow rate is coincident with the demand for less air
movement (i.e. winter design conditions).
The above factors make it possible to “undersize” the air terminal device when handling the
maximum flow rate. Thus when the airflow is turned down, a reasonable air diffusion pattern is
maintained. For most projects, the “optimum” selection should be based on a flow rate of 60 –
80% of maximum, this range covering the majority of operating days in the cooling cycle.
An example of a perfect selection will result in a seasonal change in room air movement
within the range shown below (based on a VAV system operating from 100% - 40%).
Duty
40%
60%
80%
100%
Vr (m/s)
0.10
0.15
0.20
0.25
7.1.2 Variable geometry devices
Most air terminals, particularly diffusers, may be modified to incorporate mechanical, pneumatic or
electric actuators which vary the outlet area. The terminal then operates at maximum flow with
maximum outlet area which is reduced progressively with flow rate.
By this method, the outlet
velocity, and hence throw, is kept almost constant and a fairly consistent room air diffusion pattern
is obtained. Such devices are usually expensive and are only necessary for projects which cannot be
satisfied by selection optimisation techniques such as those in Section 7.1.1.
7.1.3 Ideal VAV air terminal devices
A well-designed VAV diffusion scheme can utilise virtually any air terminal device but there are certain
diffusers which are better suited to such applications.
Linear slot diffusers have been successfully applied to VAV systems because they operate with
relatively high outlet velocities and consequently have a wide operating range. When diffuser size is
minimised, it is usually possible to use slot diffusers for VAV systems with turndown to 30% of maximum.
It is desirable to restrict the minimum duty to approximately 10 l/s per slot for each metre run of diffuser,
although the operating characteristics of particular diffusers should be considered.
Circular and square ceiling diffusers are commonly applied to VAV schemes with turndown ratios to
50% of maximum. In order to maintain reasonable outlet velocities, and hence prevent “dumping” of
the supply jet, it is usually necessary to limit the minimum neck velocity to approximately 1.5m/s (again,
it is necessary to check performance of particular diffusers).
24
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7. Air diffusion – Special applications
7.1.4 Split variable and constant volume systems and terminal devices
With this technique, a system is divided into a constant volume (CV) system handling the minimum
flow rate throughout the year and a VAV system handling the balance of the duty.
It is then
possible to optimise terminal selection for minimum duty (CV terminal device) and maximum duty
(VAV terminal device).
Each system has to be served by a separate air terminal unit but it is usually possible to
simplify the CV system, because adjacent zones may be supplied from the same terminal unit. The
arrangement also has inherent advantages; the CV system may be used exclusively for the heating
cycle, thus overcoming the need for reheat coils at each terminal (the minimum duty being
designed to balance perimeter heat losses); morning “warm-up” cycle is handled by an “optimised”
air terminal device selection.
The following examples indicate typical arrangements for linear and modular ceiling diffuser
systems.
Modular
Maximum Duty
Linear
VAV
Minimum
Radius of
Diffusion
CV
VAV
CV
Minimum Duty
VAV
CV
Maximum
Radius of
Diffusion
CV
7.1.5 Variable volume systems with reheat
Selection of diffusers is more critical if a conventional VAV cooling system is operated with a reheat
cycle. There is always a risk that low airflow rates combined with warm supply air temperatures will
result in high level stagnation. To avoid this, diffusers should be undersized at maximum flow rate,
or the turndown ratio should be reduced so that reasonably high outlet velocities are maintained at all
times.
Whenever possible, the morning warm-up cycle should be operated at maximum flow rate as this
results in the most efficient mixing of low-level air.
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7. Air diffusion – Special applications
7.1.5 Variable volume systems with reheat - continued
For systems with very low air flow rates operating predominantly on a cooling cycle, a horizontal air
pattern may not be required. Linear slot diffusers integrate well with most ceiling systems and are
versatile enough to provide a wide range of air patterns.
Selection of diffusers for this projection
arrangement is more critical than for conventional air diffusion because the supply jet has less throw
in which to mix before entering the occupied zone. Wherever possible, the diffuser supply should be
split into numerous individual jets, which entrain and mix more efficiently than large, high momentum
flow jets.
7.2 Special ceilings
7.2.1 Sculptured or coffered ceilings
Even with very large contoured ceiling arrangements, it is possible to produce a conventional air
diffusion pattern. Location and type of diffuser is however critical; expert advice should be obtained
for medium and large sized projects. Testing may be advisable.
In order to produce a strong ceiling jet, it is usually necessary to provide a surface adjacent to
the diffuser; this instigates the ceiling effect by which the air jet is made to attach to a surface.
450mm
min
In certain circumstances, flat surfaces are not available and the diffuser itself must produce the desired trajectory.
26
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8. Jet Theory and characteristics
Introduction
This section provides a summary of established theoretical data.
8.1 Jet theory
A free isothermal jet supplied from a circular, square or nearly square outlet maybe divided into four
distinct zones, described with the following terms:
Vt =
jet terminal velocity (m/s)
Vo=
jet outlet velocity (m/s)
X =
jet throw (m)
A =
jet outlet area (m 2 )
K =
a constant depending on outlet type
1st Zone: Vt = K
Vo
A short zone in which the maximum centreline velocity remains constant.
1
2nd Zone: Vt
Vo
X
Transition zone in which the jet velocity varies inversely with the square root of the throw. Zone
length is approximately equal to 8 hydraulic diameters but is longer for high aspect ratio grilles.
3rd Zone: Vt
Vo
1
X
Extends up to 100 hydraulic diameters and jet velocity varies inversely with throw. Throw performance
data is usually established for this zone because terminal velocities approach 0.5 m/s which ensures
fairly reliable measurements.
4th Zone: Vt
Vo
1
X2
The jet terminal zone where velocity decay is very rapid and jet velocities approach 0.25 m/s.
Throw data for the 3rd Zone can be described by the following equation:
Vt
=
Vo
K
A
X
Where K = a constant which can be derived for various outlet types.
It is usually possible to describe the completed jet with an equation of the following form:
Vt
=K
Vo
X
A
+ K2
m
Where m = a constant which varies according to outlet type. For square or circular outlets m = 1 and
for linear devices m approaches 0.5.
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8. Jet Theory and characteristics
8.2 Jet spread
o
A free jet expands naturally at an inclusive angle of 20 – 25 o while a confined ceiling effect jet expands
o
on one side with an angle of 7 – 12
o
depending on outlet type.
Directional vanes may be used to expand a supply jet further and this results in a decrease in
throw for a given terminal velocity.
8.3 The effect of non-isothermal supply conditions
The theoretical jet throw as discussed in Section 8.1 is dramatically modified if isothermal conditions
are replaced by cooling or heating conditions. Buoyancy forces due to the difference between the
supply and room air temperature differentials can overcome the inertia forces present in a jet.
8.3.1 Drop or rise of a horizontal jet
In addition to natural or forced expansion, a jet trajectory is influenced by buoyancy forces if the
supply air temperature is higher or lower than the surrounding air temperature.
o
The following nomogram gives the drop for a free sidewall jet when handling air at a 10 C cooling
differential.
As drop is proportional to cooling differential, it may be calculated for the other differentials.
A
=
grille outlet area (m 2)
Vo
=
grille outlet velocity (m/s)
X
=
throw (m)
D
=
drop of jet centreline (m)
tr
ts
D
X
o
T = t r - t s = 10 C (cooling)
A
(m 2)
0.5
Example:
X
o
Grille handling air at 7 C cooling with an
(m)
2
Vo
(m/s)
outlet velocity of 3m/s and outlet area of
2
0.1m producing a throw of 7m.
10
0.2
D(m)
0.1
5
0.05
0.1
0.2
0.5
1
2
5
10
20
0.02
10
0.01
28
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5
o
Drop of jet centreline = 3m ( t = 10 C)
When
2
1
o
t = 7 C drop = 7/10 x 3 = 2.1m
8. Jet Theory and characteristics
8.3.2 Vertical projection
Drop or rise of a supply jet has already been discussed in Section 8.3 but there is a special case for
vertical projection of heated air commonly used for industrial warm air heating systems. In this case,
it is possible for the buoyancy forces within the warm air jet to overcome completely the inertia forces
resulting in a 180o turn in jet trajectory. The download throw is then called the maximum downward
projection which can be estimated from the nomogram below.
CEILING
FLOOR
COOLING
HEATING
Maximum downward
projection (m)
Vo
(m/s)
10
o
T = 20 C
20
15
5
10
o
o
T = 10 C
T=5 C
Ao
ts
30
20
30
15
20
10
15
5
10
tr
1
x
0.5
5
2
A o = outlet area (m 2 )
Example:
A o = 0.01 m 2
V o = 3 m/s
t = tr - ts
Heating differential
0.05
T
2
1
Vo = outlet velocity (m/s)
0.10
5
2
(m 2)
2
x
1.0
1
o
o
o
20 C
10 C
5 C
2.3m
3.3m
4.7m
0.01
1
0.005
0.5
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9. General acoustic information
9. General acoustic information
9.1 Catalogue data
Acoustic performance data for Waterloo air terminal devices is presented in the dBA format which is
based on the generated sound power level less 8dB for room absorption.
9.2 Obtaining octave band sound power levels
For each air terminal device spectrum correction factors are presented on page 31 and these should be
-12
added to the catalogue sound level to obtain approximate sound power levels (re: 10
W).
9.3 Octave band analysis
A simplified analysis procedure is given on pages 32, 33 and 35; this is illustrated by an example. A
calculation sheet, which may be photocopied as necessary, is given on page 34 for the purpose of
further examples.
Note: The spectrum correction data given below has been rationalised from original test data.
9.4. Controls
When a damper or deflection control is fitted to the rear of a air terminal device the noise level will
increase. The factors given below correct basic data & also indicate noise generation levels due to
throttling the damper. The pressure ratio is equal to the ratio of available duct pressure to the pressure
loss of the air terminal device. Use the spectrum correction factors given on page 31 for pressure ratios
of 1 – 4.
OBD or ED - fully open
LD - fully open
Size
100+ 200+
dB addition
+12
+9
+7
+4
+3
dB addition
+3
+2
+1
Ps Multiplier
2.5
2.0
1.8
1.5
1.2
Ps Multiplier
1.2
1.1
1.05
300+
600+ 1000+
150+ 300+
Size (DIA)
450+
9.5 Damper throttling factors
Obtain air terminal device static pressure loss (from catalogue data).
Apply Ps multiplier (from table above)
5
Calculate pressure ratio PR
Duct static pressure (Pa)
4
PR =
(air terminal device + damper) pressure (Pa)
3
2
Obtain noise correction (from graph opposite).
1
0
5
10
dB addition
30
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15
20
PR
Pressure
Ratio
10. Spectrum correction factors
10. Spectrum correction factors
Air terminal
device
MC
D
Velocity (m/s)
Blade
Vo = face velocity
setting
Vn = neck velocity
KRCP
+8
+1
Vn > 3.5
data
+5
+5
+5
+4
+8
+3
+16
+13
+8
+16
+13
+8
+9
+8
+6
+8
+8
+8
-5
-2
0
-10
-7
-5
0
+4
+9
+8
-16
_
0
+3
+6
+8
-5
-11
+8
+8
+8
0
-25
_
+2
+2
+6
+8
-3
-12
+25
+14
+12
+8
+6
+3
+23
+18
+12
+8
+6
+4
+20
+15
+10
+8
+3
-15
+12
+6
+9
+8
+5
+2
0O
15 O
45 O
+14
+13
+12
+8
+7
+6
+11
+10
+9
+8
+8
+8
+5
+5
+6
-2
0
+2
_
+13
+4
+9
+7
+6
0
+8
+0
+5
+5
+6
+3
+13
+17
+17
+3
+8
+7
+7
+11
+10
+8
+8
+8
+1
+5
+6
-9
+2
+4
+13
+12
+9
+1
0
-2
+3
+2
-1
+8
+7
+6
+6
+6
+6
+3
+4
+4
+10
+12
+12
+8
+2
-3
+5
+9
+9
+8
+4
+1
+5
0
-5
+5
0
-5
+4
0
-3
+4
0
-3
+4
+3
+2
-1
+1
+3
Vn < 2
Vn = 2 - 3.5
Vn > 3.5
See
D type
data
_
Vn > 5
Vn < 3
_
_
_
ACD
_
_
Series 1&2
RTC
_
Vo < 3
Vo > 3
Vo < 2
Vo = 2 - 5
Vo > 5
Vo < 2
Vo = 2 - 5
Vo > 5
Vn < 3
PER (supply)
PER (exhaust)
4k
+7
_
GC5 (exhaust)
2k
+8
_
ALF (exhaust)
1k
+9
DSL
3HF
500
+9
CS 3-8
3HG, 3HJ
ALG, ALJ, ALJ10
ALN, ALG10
250
See MC
Vn > 3
CS 1-2
125
Vn < 3.5
Vn < 5
CPD
Frequency (Hz)
_
_
_
Vn = 3 - 5
Vn < 2.5
Vn = 2.5 - 3
Vn = 3 - 5
_
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31
11. Octave band analysis procedure
11. Octave band analysis procedure
A complete acoustic analysis can be made for projects where the resultant room sound pressure level
is critical. Using the sound power level data given in this manual, it is possible to estimate the sound
pressure level at any point in the room. It is necessary to know room dimensions and characteristics in
addition to the ATD location(s).
An example of the analysis procedure is given on page 35 and a chart which may be photocopied is
given on page 34.
Recommended noise ratings
NR
Situation
5
NR curves
2
90
20
Bedrooms in private homes, live theatres (500
seats), large religious buildings, television
studios, large conference and lecture rooms
(50 people).
25
Living rooms in private homes, board rooms,
top management offices, conference and
lecture rooms (20-50 people), multi-purpose
halls, medium and small religious buildings,
libraries, bedrooms in hotels, etc, banqueting
rooms, operating theatres, cinemas, hospital
private rooms, large courtrooms.
30
Public rooms, in hotels, etc, ballrooms, hospital
open wards, middle management and small
offices, small conference and lecture rooms (20
people), school classrooms, small courtrooms,
museums, libraries, banking halls, small
restaurants, cocktail bars, quality shops.
35
Toilets and washrooms, large open offices,
drawing offices, reception areas (offices),
halls, corridors, lobbies in hotels, hospitals,
etc, laboratories, recreation rooms, post
offices, large restaurants, bars and night clubs,
department stores, shops, gymnasia.
40
Kitchens in hotels, hospitals, etc, laundry
rooms, computer rooms, accounting machine
rooms, cafeteria, canteens, supermarkets,
swimming pools, covered garages in hotels,
offices, etc, bowling alleys.
45
85
80
80
75
70
70
65
60
60
55
50
50
45
40
40
35
NR Values
Concert halls, opera halls, studios for sound
reproduction, live theatres (500 seats).
Sound pressure level (dB)
1
30
30
25
20
20
15
10
10
5
0
0
FREQ(Hz)
125
250 500 1000 2000 4000 8000
Suggested corrections for room characteristics based upon the average random incidence absorption coefficient
3
32
Typical Room Classification
Octave Band Centre FREQ.
125
250
500
1k
2k
Live
Factories, Canteens, Churches, Op Theatres
+16
+15
+14
+12
+13
Med. Live
Classrooms, Galleries, Public Houses
+13
+11
+9
+7
+6
Average
Standard Offices, Libraries, Banks
+11
+9
+7
+5
+4
Med. Dead
Private Offices, Boardrooms, Restaurants
+9
+6
+5
+3
+2
Dead
Studios (TV & Recording)
+6
+4
+2
0
-1
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11. Octave band analysis procedure
11. Octave band analysis procedure - continued
4
Generated total sound power (Lwt)
dB addition
3
REVERBERANT:- Use performance data for size and flow
rate of the considered terminal. If more than one terminal
2.5
serves a space the logarithmically summed Lwt should be
2
dB addition
calculated by using either the adjacent table or the
formula:
Lwt =
10 Log...[ Antilog ( Lw1 ) + Antilog ( Lw2 ) + .....]
10
10
1.5
1.0
DIRECT: This is calculated for the terminal nearest to the
point of interest. If however, two or more terminals are
0.5
equidistant or within a ratio of 2:1 to the point of interest,
5
6
Correction for room
surface area
10
8
6
2
0
generated noise for each terminal.
4
dB Difference
the Direct Lwt is obtained by logarithmically summing the
Correction for
distance
2000
Surface area m 2
1500
Distance
1000
800
600
400
200
100
-ve dB
10
12
14
16
18
20
22
24
26
28
50
7
Directivity correction
ATD
Location
A
A
C
B
B
C
Outlet
Area (m 2 )
0.01
0.05
0.10
0.50
0.01
0.05
0.10
0.50
All
Correction
m
dB
1
-11
1.5
-14
2
-17
2.5
-19
3
-21
5
-25
7
-28
Octave band centre FREQ.
125
250
+4
500
+5
1k
+6
2k
+7
-8
+5
+6
+7
+6
+7
+8
+8
+6
+7
+7
+7
+8
+8
+8
+7
+8
+8
+7
+8
+9
+9
+8
+9
+9
+8
+9
+9
+9
-9
+9
+9
+9
+9
-3
-4
-4
-6
-6
-7
-7
Tel: +44 (0) 1622 717 861
email: [email protected]
33
12. Waterloo octave band analysis chart
12. Waterloo octave band analysis chart
Project:
Customer:
Air terminal device reference/location:
Ait terminal device type:
Duty:
Size:
Controls:
No. Units:
Room size:
Usage:
Location Sketch:
Frequency (Hz)
See
Reverberant field
Analysis chart
fig
Lw - Air terminal device
4
Corr - Room surface area
5
- Room characteristic
Notes
63
125
3
Direct field
Lp (arithmetic sum)
Lw - Air terminal device
4
Corr - Distance
6
- Directivity
7
Lp (arithmetic sum)
Total
Lp (Total)=Lp(Rev) + Lp(Dir)
NR level required
4
1&2
Excess if any
34
Tel: +44 (0) 1622 717 861
email: [email protected]
250
500
1k
2k
4k
Procedure and example
Example
Supply 200 l/s through two linear slot diffusers into
an office detailed on the diagram opposite.
2.5
Air terminal type = CS2/1800
From nomogram noise level in 36 dBA
1.5
Apply spectrum correction from page 31.
Room DIM = 5 x 4 x 3m
Frequency (Hz)
125
250
500
1k
2k
Noise level dBA
36
36
36
36
36
Room - surface area = 94m 2
- distance to listener = 2m
Correction
+25
+14
+12
+8
+6
SWL (dB)
61
50
38
44
42
- outlet area = 0.02m 2
Example procedure
Total
Direct field
Reverberant
field
Octave band centre frequency (Hz) 125
ATD - Lw
64
250
500
1k
2k
53
41
47
45
Comments
Lw + 3dB (2 units)
2
See
fig
4
5
-13
-13
-13
-13
-13
94m
+11
+9
+7
+5
+4
Average room
3
Lp (arithmetic sum)
62
49
35
39
36
ATD - Lw
64
53
41
47
45
Lw + 3dB (2 units)
4
Correction - distance
-17
-17
-17
-17
-17
2m = - 17 dB
6
+3
+4
+5
+6
+7
Location A
7
Lp (arithmetic sum)
50
40
29
36
35
Total Lp = Lp (rev) + Lp (dir)
62
49
36
41
39
Required (NR) level
57
44
40
37
Excess (if any)
5
50
_
2
1
2
Correction - room surface area
- room characteristic
- directivity
= - 13dB
4
NR 35
Tel: +44 (0) 1622 717 861
1&2
email: [email protected]
35
Waterloo product range
GRILLES
A complete range of products suitable for all wall, ceiling and floor applications.
Most grilles are made from aluminium, and have a range of fixed or moveable
blades designed to give performance whilst remaining aesthetically pleasing to
the eye. Grilles are made to customer specified sizes and colours (PPM/G);
standard colour is PPM9010 (20% Gloss White). This range is complemented by
the Aircell range of polymer Grilles and Diffusers.
DIFFUSERS
A complete range of products designed to be installed in various ceiling
systems. Most diffusers are made from aluminium, and can be ordered with or
without plenum chambers for easy connection to duct work. Diffusers can be
ordered in customer specified (PPM/G) colours; standard colour is PPM 9010
(20% Gloss White). This range is complemented by the Aircell range of polymer
Grilles and Diffusers.
ACTIVE AND PASSIVE CHILLED BEAMS
The finest quality range of high output active beams, used for ventilated heating
and cooling applications. These units have 4 pipe coils to allow heating and cooling
circuits to run simultaneously, giving constant and responsive control. The design
allows a large optimum capacity, and also allows the customer to specify the
nozzle type and pitch for individual circumstances.
Active beams are made from steel to a large range of customer specified sizes and
as such are suitable for various different ceiling systems. Standard finish is PPM
9010, however other (PPM/G) colours are available on request.
AIR VOLUME CONTROL DAMPERS
A complete range of pressure independent Variable Air Volume and Constant air
Volume dampers. Most volume dampers are regulated with an electronic motor
and sensors, and are calibrated to customer specifications before delivery. The
constant air volume damper requires no power source as it is controlled via a
mechanical device, it is also calibrated before delivery. All volume dampers are
made from Zintec plate and all units can be ordered with a single or double skin
(with insulation).
EXTERNAL LOUVRES
A quality range of products for external wall applications. Made from
aluminium, with birdscreen or insect screen options. All louvres are made to
customer specified sizes and (PPM/G) colours; standard colour is PPM 9006.
DISPLACEMENT
A complete range of diffusers for displacement air distribution providing high
ventilation efficiency with excellent comfort. The very low pressures involved
also offer quiet installations. Diffusers are available as wall or floor mounted, or
indeed integrated within the architectural design.
36
Tel: +44 (0) 1622 717 861
email: [email protected]
What makes Waterloo exceptional
QUALITY
When only the highest standards will do, Waterloo are your partner. Quality and quality improvement is at the core of everything we do at Waterloo. It is our fundamental
responsibility as a manufacturer to deliver air terminal devices that are consistently
reliable and durable, and meet the stated performance.
SERVICE
Waterloo has a well justified reputation for very quick service - when others might offer
four or six weeks delivery periods, Waterloo prides itself in delivering small and
medium orders in five (yes, five) days.
TECHNICAL EXCELLENCE
Waterloo's technical excellence, built upon our 100 years of ventilation experience,
coupled with our technical and management expertise can give you confidence that
your project will meet the required performance.
FLEXIBILITY
When you need special help with innovative solutions or unexpected site requirements,
then Waterloo's famous flexibility is at your service.
OUR PEOPLE
The foundation of Waterloo's continuing success is our people. The performance of our
staff is key to the quality of the service we offer and we recognise that to maintain our
continued success we need to recruit, develop and retain the best talent.
PRICING
Although our pricing at Waterloo is normally a little lower than our competitors
because of our modern production facilities, we do not choose to compete entirely on
price. Of far greater value is our understanding of what you are trying to achieve and
our understanding of the commercial world we all work in.
STRENGTH OF CHARACTER
We will not bear false witness. We demand of ourselves and our clients the highest
integrity. We are not afraid to tell a client that we cannot do his work, or that a
competitor might suit them better.
Tel: +44 (0) 1622 717 861
email: [email protected]
37
Notes
38
Tel: +44 (0) 1622 717 861
email: [email protected]
Notes
Tel: +44 (0) 1622 717 861
email: [email protected]
39
Waterloo Air Products plc
Mills Road, Aylesford
Maidstone, Kent ME20 7NB
Tel: +44 (0)1622 717861
Fax: +44 (0)1622 710648
email: [email protected]
internet: www.waterloo.co.uk
Northern Office
Hyde Park House, Cartwright Street,
Newton Hyde. SK14 4EH
Tel: +44 (0)161 367 1264
Fax: +44 (0)161 367 1262
email: [email protected]
internet: www.waterloo.co.uk
February 2014