NATURAL
VENTILATION
COMMERCIAL BUILDINGS
A guide to Natural Ventilation, including
our unique solution offerings, consultancy
service and recommendations.
INNOVATIVE
VENTILATION
& HEATING
www.pricetwa.co.uk
Natural ventilation is a proven,
low energy, environmentally
friendly solution that controls
airflow to create a comfortable
and productive building.
We supply a number of natural
ventilation strategies with a commitment
to offer a positive and effective solution.
As well as less space required for plant
rooms the benefits are many.
Economic benefits:
– Low maintenance;
– Low capital cost;
– Low running costs.
Environmental benefits:
– Low energy use;
– Greenhouse gas reduction;
– CO2 reduction.
User benefits:
– A control system to create
comfortable conditions.
OUR SERVICE
At Price TWA we believe in providing a quality
service with quality products, our approach
is professional and knowledgeable and we
hope to show this in everything we do –
we constantly strive to be the best.
It is important to consider natural
ventilation in early development, as
efficiency and aesthetics can be
greatly improved when integrated into
a building’s design. Our dedicated
team of engineers and technical
specialists will be available to offer a
comprehensive range of services –
from application analysis, product
advice and design, through to
scheduling supply and installation.
DELIVERING
INDUSTRY EXPERTISE
Price TWA was formed in 2008 from the merger
of two leading heating and ventilation suppliers in
the UK, Price Technical Ltd (Formed in 1997 to
supply high quality ventilation and heating systems)
and TWA Panels UK Ltd (formed in 2003 to supply
radiant heating panels). Together we now offer one
of the widest ranges of heating and ventilation
solutions in the UK.
We are recognised in the industry not only for
excellent design and manufacture of heating
and ventilation systems but also for maintaining
strong relationships with both suppliers and
contractors. This combined with our strong
manufacturing background has set us among
the very best of the UK’s heating and ventilation
solutions providers.
VENTILATION STRATEGIES
PRINCIPLE
STRATEGIES
CONTROLS
PASSIVE STACK
ATRIUM
P4
P7
P8
WIND DRIVEN
HYBRID
NIGHT COOLING
OUR EXPERIENCE
We have grown and adapted as the
construction industry has, offering
modern solutions to modern issues.
We understand that every project
has individual needs and always offer
flexible informed solutions to meet the
needs of every project.
Years of experience and industry
expertise will provide you with a
solution that’s cost effective, efficient
and suited to your building’s individual
design and function.
We operate from
our manufacturing
base in Bristol
where we create
and distribute
our products.
We have a
dedicated team
of sales engineers
and representatives
throughout the
UK and Ireland
offering exceptional
customer service.
Within this brochure we detail
and compare each of our natural
ventilation strategies including
details on component parts.
STRATEGIES
P4 SINGLE SIDED CROSS-FLOW
PASSIVE STACK
P7CONTROLS
P8 PASSIVE STACK
& ATRIUM
P9 WIND DRIVEN
P10HYBRID
P11 NIGHT COOLING
COMPONENT PARTS
P12PENTHOUSE
LOUVRES &
THROUGH
WALL VENT
PRIORITY SCHOOLS
PROGRAMME
P14 BUILDING
P9
P10
P11
COMMITTED TO BECOME
THE INDUSTRY’S LEADING
SUPPLIER OF VENTILATION
AND HEATING IN THE UK
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NATURAL VENTILATION
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PRINCIPLE NATURAL
VENTILATION STRATEGIES
SINGLE SIDED
CROSS-FLOW
Wmax ~ 2.5 H
PASSIVE STACK
Wmax ~ 5 H
H
Wmax ~ 5 H
H
H
W
W
Single-sided ventilation allows air-flow
into a building with an inlet and outlet
on a single façade. This solution offers
simple air distribution.
W
With an inlet and outlet on opposite
walls, cross-flow ventilation allows
airflow to be naturally driven
through a space using differences
in façade pressures.
Guidance only. Dynamic modelling in conjunction
with building design may result in different ratios.
Passive stack combines air buoyancy
with a roof mounted turret that creates
a suction effect. Airflow naturally passes
through the building and is drawn out of
the turret using internal heat gains and
pressure differences.
NATURAL VENTILATION
OFFERS LOW MAINTENANCE,
LOW ENERGY, NO NOISE &
REDUCED CO2 EMISSIONS
INDOOR AIR QUALITY
CO2 levels during a school day
Concentration of C02 (ppm)
2500
3 l/s/p
2000
1500
Maximum
average
5 l/s/p
8 l/s/p
1000
500
0
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
Regulations and guidelines dictate
industry ventilation standards and
natural ventilation is no exception.
Building Bulletin 101 states that the
maximum average concentration of
CO2 levels must be below 1500 ppm.
Required levels:
• Minimum – 3 l/s/p
• Daily average – 5 l/s/p
• Design capability – 8 l/s/p
Time
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NATURAL VENTILATION
APPLYING NATURAL
VENTILATION
A natural ventilation solution requires many design integrated
considerations, some of which are essential to creating an effective
result. Understanding the purpose of a building, where it is situated
and how it is going to be built allow us to consider the most effective
way to integrate natural ventilation.
The three main factors that need consideration
when creating a successful natural ventilation solution:
PERFORMANCE GUIDELINES
All our strategies are designed
to meet current standards,
which include air quality, energy
consumption and CO2 levels,
internal temperatures and noise
considerations. Our solutions are
designed to meet the standards
outlined in the following documents:
• Approved Document F
• Approved Document L2
• Building Bulletin 101 & 93
• CIBSE AM10
• Priority Schools Building
Programme
NATURAL VENTILATION
OFFERS LOW MAINTENANCE,
LOW ENERGY, NO NOISE &
REDUCED CO2 EMISSIONS
OCCUPANCY
• Numbers and activity
• Building purpose
• CO2 emissions
• Heat gains
• Equipment
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ENVIRONMENT
• Location
• Orientation
• Noise levels
• Wind direction
• Temperature
NATURAL VENTILATION
BUILDING DESIGN
• Building materials
(Heavy/Light thermal mass)
• Architectural features
• Size of windows and apertures
• Dimensions (width vs. height)
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CONTROL
SYSTEM
Controls are an essential part of an efficient Natural Ventilation
solution. They allow the airflow into each room in a building to
be adjusted using high and low level dampers, which can be
controlled according to internal and external temperature, CO2
levels or humidity. Controls are increasingly covered by a central
BMS system, but can also be covered by a standalone control
system, typically by a control specialist.
CONTROL FUNCTIONS
TEMPERATURE
(INT & EXT)
TEMPERATURE
KNOWLEDGE
AIR QUALITY
(CO2) CONTROL
BMS
APERTURE
OPENINGS
TIME
KNOWLEDGE
NIGHT
COOLING
CO2 SENSOR
Maintaining good indoor air quality
is an important consideration and is
generally monitored using CO2 sensors.
Maintaining adequate CO2 levels is also
a requirement of the Education Funding
Agency’s Facilities Output Specification
and BB101 for ventilation in schools.
CONTROL PHILOSOPHY
We most commonly advise on control
requirements, either at design stage
or later in the project development,
many projects are covered by a central
Building Energy Management System
(BEMS) supplied under specialist
contract. It is important that this aspect
of the system is well coordinated and
is an area we can readily assist with,
whether with the design, project team
or control specialist.
WEATHER STATION
An external weather station allows
the control system to respond
to conditions automatically. The
sensors typically monitor some or all
of the following:
– Outside air temperature
– Wind speed
– Wind direction
– Rain
CO2 levels can be indicated in a room,
typically using’ traffic light’ system of
light which can either indicate to the
user to respond, or to give a visual
indication of air quality and how the
ventilation is operating in response to
such levels.
CONTROL MODES
AUTOMATIC
MODE
This is typically set to provide good
ventilation throughout the year
operating within set temperature and
CO2 parameters. BMS integration
gives the option of a fully automated
ventilation system.
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WINTER
MODE
MANUAL
OVERRIDE
Winter mode is a common function
automatically triggered to restrict airflow
when external temperatures are lower
than, say, 14°C. Designed to avoid the
loss of warm air It is also important to
consider set points for heating systems
and heating system design to ensure
ventilation can be delivered whilst
maintaining the desired
internal temperature.
Manual override is an important
consideration to give users control in
a space and should typically allow fully
open, closed and auto commands. The
function is typically set to operate for a
set time period before reverting back to
‘automatic’ operation
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NATURAL VENTILATION
PASSIVE STACK/ATRIUM
NATURAL VENTILATION PASSIVE STACK/ATRIUM STRATEGY
Often the most effective strategy as it combines cross-flow, air pressure differences and rising warm air to increase
airflow. Passive stack encourages warm air to rise through rooms and exit through a vertical air-path, such as an atrium.
Wmax ~ 5 H
BUILDING DESIGN
EXHAUST
THROUGH ROOF
THROUGH
WALL VENTS
Buildings that use Passive stack or Atrium
natural ventilation strategies require
many design considerations to create an
effective result. The size and positioning
of windows and apertures should vary
depending on distance from the exhaust.
Greater thermal mass of a building will aid
night cooling.
Architectural features such as tall
atrium’s, turrets and sloping roofs will
aid air movement making the solution
more effective.
THROUGH
WALL VENTS
OUR THROUGH WALL
VENTILATION IS DESIGNED
FOR MODULAR ASSEMBLIES
THROUGH WALL VENTILATION
EXTERNAL/INTERNAL LOUVRES
Our dampers are available in a number of options
to suit different design needs, including models
with insulated casing and with either manual
adjustment or actuator operation.
• Single or triple bank systems
• Extruded aluminium
• Blade configuration
• Weather protection
• High air flow
• Class A weather effectiveness to EN13030
when assembled as a through wall vent
• Thermally insulated with low U value
• Tight shut-off for low leakage performance
• Interlocking blades with double blade seals
• Slim construction
• Can be combined with other components
OPTIONAL EXTRAS
• Acoustic baffles – single, double
and triple bank to reduce noise
levels (internally or externally)
• Heater batteries – incorporated
into inlet to temper incoming air
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NATURAL VENTILATION
MOTORISED DAMPERS
Our louvres are available in a wide range of
options – including size, blade configuration and
frame type. Finish options include powder coating
to any classic RAL colour specification.
OPTIONAL EXTRAS
Includes a variety of
actuator options such
as modulator open/
close 24V and 230V
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7
WIND DRIVEN
NATURAL VENTILATION WIND DRIVEN STRATEGY
Dependant on wind behaviour, wind driven ventilation harnesses prevailing wind to supply fresh air into an indoor
space using a rooftop turret. This air then displaces and exhausts the warmer, stale air out of the same turret.
ENVIRONMENT
Wind Driven natural ventilation must take into
consideration the location and orientation of
a building. Ideally the roof should be higher
than surrounding buildings to allow the wind
to be captured, and the direction of the
prevailing wind can help determine the best
positioning of the turrets.
AIRFLOW
INLET
WIND
DIRECTION
AIRFLOW
INLET
EXHAUST
FRESH
AIR
EXHAUST
STALE
INDOOR AIR
TURRET AIR FLOW
Wind-flow is captured with the opening side(s)
of the turret facing the wind direction. This air
is then driven down into the room below where
it circulates and mixes with the stale indoor air.
Warm air rises out of the space and out of the
remaining quadrants.
A DIVIDED DUCT ASSEMBLY
ALLOWS FOR INLETS AND
OUTLETS IN ONE UNIT
ISOLATED ROOM
C
ST AS
U E
DY
NANT CELYN PRIMARY SCHOOL
Nant Celyn primary school includes the regional
centre for the Hearing Impaired. As well as
meeting Building bulletin 101 standards, attention
was required to control acoustic performance
in classrooms.
The build included:
• Eight wind driven turrets
• Weatherproofing
• BMS control integration
• Acoustic insulated splitters
THE BENEFITS
•
ACOUSTIC PERFORMANCE
•
REDUCED ENERGY USE
•
IMPROVED CARBON FOOTPRINT
•
IMPROVED LEARNING
ENVIRONMENT
•
COST EFFECTIVE SOLUTION
8
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NATURAL VENTILATION
HYBRID
NATURAL VENTILATION HYBRID STRATEGY
Hybrid ventilation uses a boost fan system to assist natural ventilation. This strategy will come into
use particularly during summer months and winter months to maintain comfortable conditions.
PENTHOUSE LOUVRES TURRET (BOOST MODE)
The hybrid strategy offers extra support to the wind driven
natural ventilation configuration. If wind pressure and
temperature differences are not sufficient to drive airflow, a
boost fan is fitted into to ducting to generate air movement
usually for peak occupancy, but also to mix cool air in winter
months when wind turbulence may not be enough, or cold
draughts need to be avoided.
HIGH INDUCTION
SLOT DIFFUSER
THE ADVANTAGES
• Can offer rapid cooling with higher
levels of air movement
• Can quickly improve air quality
• Mixes cool air with warmer room
air, reducing cold draughts
• Uses a highly efficient EC fan and
high induction slot diffuser
OUR HYBRID SYSTEM OFFERS
CONTROLLED BOOST FAN
VENTILATION SUPPORT
C
ST AS
U E
DY
SOUTH DEVON UTC
South Devon University Technical College was
designed to accommodate up to 600 students
as the first UTC in the area. A Hybrid natural
ventilation strategy was used that supports a
wind driven solution in their sports hall.
The build included:
• Wind driven hybrid vent turrets
• Weatherproofing
• BMS control integration
THE BENEFITS
•
REDUCED ENERGY USE
•
IMPROVED CARBON FOOTPRINT
•
IMPROVED SPORTS HALL
ENVIRONMENT
•
COST EFFECTIVE SOLUTION
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NATURAL VENTILATION
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NIGHT COOLING
NATURAL VENTILATION NIGHT COOLING STRATEGY
The thermal mass of building materials play an important part in the effectiveness of this strategy.
Building materials with high thermal mass will retain cool temperatures when exposed to night cooling.
UNOCCUPIED AT NIGHT
SEALED/CLOSED IN THE MORNING
INLETS
OPEN
INLETS
CLOSED
THERMAL
MASS
THERMAL
MASS
By increasing airflow and flushing out warm air, night cooling
can significantly reduce a building’s core temperature and in
turn keep a building cooler for longer in mornings.
The building is sealed in the morning keeping warmer air out.
The building will remain cool for a period of time depending
on thermal mass and occupancy.
A BUILDING’S THERMAL MASS CAN HELP
REDUCE PEAK DAYTIME TEMPERATURES
C
ST AS
U E
DY
PAIGNTON LIBRARY
The central library was designed to include
night cooling and to meet the environmental
assessment BREEAM rating Very Good. With
adjacent roads and train station this provided a
challenging environment that required integrated
acoustic baffles to control noise levels. The tall
stacks were provide greater air movement as well
as a striking design feature.
The build included:
• Passive stack turrets
• Weatherproofing
• BMS control
• Design integrated through wall ventilation
THE BENEFITS
•
ACOUSTIC PERFORMANCE
•
REDUCED ENERGY USE
•
IMPROVED CARBON FOOTPRINT
•
COST EFFECTIVE SOLUTION
10
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NATURAL VENTILATION
PENTHOUSE LOUVRES TURRET
STANDARD DETAIL
ALUMINIUM CROSS
FOLDED ROOF
MULLION FRAME
LOUVRE
BLADES
INCLUDES WEATHER ELIMINATOR
BAFFLE (NOT SHOWN)
BLADE CLIPS
ALUMINIUM CILL
GALVANISED
DUCT SLEEVE
GEARS
DAMPER BLADES
OUR PENTHOUSE LOUVRES
HAVE BEEN SPECIFICALLY
DESIGNED TO OFFER
MAXIMUM AIRFLOW AND
SECURE WEATHERPROOFING
EGG CRATE
GRILLE
FEATURES
• Tight shut-off for low leakage performance
• Interlocking blades with double blade seals
• High air flow
• Can be combined with acoustic baffles
• Heater batteries can be incorporated
• Class A weather effective to EN 13030
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NATURAL VENTILATION
PENTHOUSE
LOUVRES
Our penthouse louvres are created on our
manufacturing base and assembled ready for on
site delivery. Each unit can be customised to meet
individual size, design and colour requirements.
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11
THROUGH WALL VENT
STANDARD DETAIL
INTEGRAL BIRD MESH C/W
OPTIONAL INSECT MESH
LOUVRES
(INTERNAL)
DAMPER BLADES
(THERMALLY INSULATES TIGHT SHUT OFF)
GEARS
ACTUATOR
FLANGE FRAME
EXTERNAL LOUVRES
(‘GLAZED IN’ AND RECESSED
FRAMES AVAILABLE)
OURSLIM CONSTRUCTION THROUGH
WALL VENTS OFFER A THERMALLY
INSULATED, WEATHERPROOF
VENTILATION SYSTEM
FEATURES
• Tight shut-off for low leakage performance
• Interlocking blades with double blade seals
• High air flow
• Can be combined with acoustic baffles
• Heater batteries can be incorporated
• Class A weather effective to EN 13030
up to 2.5 m/s as an assembly
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THROUGH
WALL VENT
Our louvres are available in a wide range of
options – including size, blade configuration and
frame type. Finish options include powder coating
to any classic RAL colour specification.
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NATURAL VENTILATION
NOTES
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NATURAL VENTILATION
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PRIORITY SCHOOLS
BUILDING PROGRAMME
The Education Funding Agency’s Priority School Building Programme
forms a major area for the application of natural ventilation systems
and includes additional requirements for thermal comfort along with
proposals for both natural and mechanical ventilation.
Part of the programme was to produce a number of Baseline
Designs which could be used as a basis for developing a detailed
design for a school. Some of the general arrangements are shown
here for reference.
DELIVERING EXPERIENCE
As an experienced supplier of natural
ventilation, we are well placed to deliver
solutions to schools projects having
worked on many school projects, just
two of which are shown as case studies
in this brochure.
• Our through wall vents with acoustic
baffles are particularly well suited to
sites where external noise is a factor;
• our roof level penthouse exhaust
units offer proven weather
effectiveness and;
• hybrid vent units can offer mixing
of external air within the room it is
serving to avoid cold draughts.
B
Education Funding Agency
EFA Baseline School Designs
B
Secondary Type 2 1200 Section BB
11-16 Typical Curriculum
Scale: N/A
Dwg. No.: 2.01.006
3D LONG SECTION
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NATURAL VENTILATION
B
B
Education Funding Agency
EFA Baseline School Designs
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NATURAL VENTILATION
Secondary Type 1 1200 Section BB
11-16 Typical Curriculum
Scale: N/A
Dwg. No.: 1.01.006
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Email: [email protected]
Web: www.pricetwa.co.uk
INNOVATIVE
VENTILATION
& HEATING
Price TWA is a trading name of Price
Technical Limited. Registered Office:
Unit 1, Smiths Forge Ind Est, North
End Rd,Yatton, Bristol BS49 4AU.
Registered in England No. 3606362
• VAV/CAV Boxes
• Displacement
• Grilles & Diffusers
• Air Handling Units
• Fan Coil Units
© Price TWA 050816 – Version.2
• Natural Ventilation
• Radiant Panels
• External Louvres
• Chilled Beams
• Heat Recovery