Extract Ventilation Systems - Passivent

EXTRACT
VENTILATION
SYSTEMS
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Passive Stack Ventilation (PSV) 11-15
PSV Whole-House 12
PSV Single-Stack 13
Mechanical Extract Ventilation (MEV) 16-23
Passivent MEV 18
Passivent iMEV 19
Passivent AV 20-21
Passivent Flair 22-23
Positive Input Ventilation (PIV) 24-25
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EXTRACT VENTILATION SYSTEMS
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PASSIVENT SYSTEMS
Passivent have ventilation systems tailored for all types of domestic applications and to meet
the requirements of building regulations.
Passive Stack Ventilation (PSV) see pages 11-15
(System 2)
Applications: Public and private housing, primarily for individual
houses and flats.
New-build, major refurbishment
Main features: Continuous demand controlled ventilation, silent operation,
no energy consumed
Mechanical Extract Ventilation (MEV) see pages 16-23
(System 3)
Applications: Public and private housing. Houses, flats,
multi-occupancy buildings such as nursing homes,
student accommodation, hotels.
New-build, major or minor refurbishment
Main features: Single central fan connected to multiple extracts,
continuous low-level ventilation, quiet operation
Positive Input Ventilation (PIV) see pages 24-25
Applications: Public and private housing. Houses, flats.
Major or minor refurbishment
Main features: Ductless system, easy to install.
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EXTRACT VENTILATION SYSTEMS
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PASSIVE STACK VENTILATION (PSV)
PASSIVE STACK VENTILATION (PSV)
System 2
The PSV principle
Passive stack ventilation (PSV) is driven
primarily by the natural stack or convection
effect by which warm air rises.
Moisture-laden air is extracted directly from
wet rooms (kitchens, bathrooms etc)
through ducting up to a roof terminal where
it is vented to the outside. The air inside a
house is almost always warmer than that
outside, and so rises up the duct by natural
convection, carrying moisture with it. Wind
blowing across the roof provides additional
suction (the venturi effect).
Warm moist air inside
Colder air outside
Moisture-laden warm air rises up
duct and is exhausted through
roof terminal
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EXTRACT VENTILATION SYSTEMS
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PASSIVE STACK VENTILATION (PSV)
PSV WHOLE-HOUSE
A PSV Whole-House system ventilates all the
rooms in a property effectively, using the
concept of planned air routes to ensure a
fresh healthy environment.
Planned air routes
Moisture is extracted at source from wet
rooms (kitchens, bathrooms etc).
Air inlets located in dry rooms (living rooms,
bedrooms etc) provide a flow of replacement
fresh air into the building.
The siting of the inlets and extracts ensures
that air always moves from dry rooms to wet
rooms, so that moisture is removed and the
whole house is ventilated.
Applications
Suitable for both new-build and
refurbishment in private and social housing.
Primarily designed for individual houses and
low-rise flats and apartments.
Demand control
Ventilation is controlled by ‘intelligent’ inlets
and extracts which respond automatically to
changes in relative humidity, thereby
modulating the ventilation rate in each
room to meet demand. When humidity is
low the ventilation rate is minimised,
irrespective of external weather conditions,
preventing unnecessary heat loss.
Both inlets and extracts are operated by a set
of nylon strands which respond to humidity
levels and regulate the size of the air opening,
giving greater ventilation when humidity is
high whilst preventing unnecessary
ventilation when humidity is low.
Features and benefits
● Natural and energy-efficient
No electrical connection or power source
is required, so Passivent PSV systems are
naturally energy-efficient.
● Continuous operation
The system provides 24-hour
condensation control with continuous
gentle extraction. It operates all day and
every day as required, combating
condensation and mould growth.
● Reduces requirement for background
ventilation
Using PSV means fewer tricklevents or
wall vents are required, when compared to
using intermittent fans.
● No noise
Passivent PSV systems are completely
silent in operation.
● Ideal for special needs
With its automatic response and no
operating controls, Passivent PSV is ideal
for special-needs applications.
● Minimal maintenance
No mechanical components to go wrong.
● BBA approved
Passivent PSV Whole-House systems are
covered by BBA (British Board of
Agrément) Certificate No 96/3273.
● Design service
Passivent Limited offers a design
service for PSV systems, see over.
Typical PSV Whole-House ventilation system
All air inlets and extracts respond automatically
to relative humidity in rooms. Air movement
is from dry to wet rooms.
Building regulations
Passivent systems can be used to satisfy
building regulations requirements
throughout the UK and the Republic of
Ireland for extract and whole-house
ventilation for domestic and domestic-type
properties
See also the general introduction page 8.
More information is available on request.
Passivent systems also meet the regulatory
requirements for security, avoiding draughts
and preventing rain ingress.
Bedroom with air inlet
Living room with air inlet
Bathroom
with air
extract
Separate roof
terminal for each
stack
Kitchen with air extract
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PSV SINGLE-STACK
As a quiet alternative to an individual room
extract fan, PSV Single-Stack systems can be
installed to ventilate individual en-suites or
bathrooms.
They operate by the same natural stack effect
as PSV Whole-House systems, and hence
represent a superior alternative to a fan.
They provide the same benefits of demand
control, continuous operation and energy
efficiency as PSV Whole-House systems, and
are easy to install.
Typical PSV Single-Stack system
Extract responds automatically
to relative humidity.
Individual or
en-suite bathroom
with air extract
Applications
Suitable for both new-build and
refurbishment in private and social housing.
Particularly useful as a low-cost
refurbishment installation in social housing.
Roof terminal
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EXTRACT VENTILATION SYSTEMS
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PASSIVE STACK VENTILATION (PSV)
SYSTEM DESIGN AND INSTALLATION
Design of a system for an individual property
is quite simple using our online design and
quotation web site at www.passivent.com .
Alternatively Passivent Limited offers a
design service for PSV systems, based on
building drawings supplied.
A full installation guide is supplied with
every Passivent PSV system.
Typical layout (schematic)
Actual installations may differ in detail. Follow the
design layout if one is provided.
Terminals must be no more than 0.5 metre
down from the ridge.
Each duct must run to a separate terminal
Ducts must rise vertically or near-vertically,
preferably not more than 45° from vertical
with a maximum of 2 no. bends
Use insulated
ducting in the roof
void and other unheated
spaces
Bedroom Bathroom
Site air inlets in ‘dry’ rooms
(living rooms, bedrooms etc)
Site each air
extract in a
‘wet’ room
(kitchen,
bathroom)
Air flow from ‘dry’ to ‘wet’ rooms
Living room
There is usually sufficient air flow around internal doors
to provide replacement air. If this is insufficient a door
undercut of 10mm or an air transfer door grille should be
used.
No electrical connections are required.
The main features of a typical installation
with the points which must be observed are
shown below.
For simplicity of design and ordering, a
number of standard stack kits are available.
Ordering
To order Passivent-designed PSV systems
simply state the quotation number and plot
or plots required followed by the ridge or tile
manufacturer, make and colour. For selfdesigned
PSV systems simply quote the stack
kit reference and quantity of each required,
followed by the ridge or tile manufacturer,
make and colour, and the inlet type and
quantity required.
Support
flexible
ducting every
300mm to a wire
or timber batten to
prevent sagging
Within the building, run circular
ducting in a room corner or inside a
fitted cupboard or wardrobe.
Alternatively run flat channel ducting
within a stud partition
Kitchen
System components
Standard stack kits are available as shown.
Where these are not suitable, alternative
configurations can be supplied. Extension
ducting is also available for properties over
two storeys.
For individual components (air inlets,
terminals, ducting) see the Components
section page 58.
Code Description
A161 Humidity-sensitive extract
F12513 Uninsulated flexible ducting, 3.0m
F12524 Insulated flexible ducting, 4.0m
FCA3 Flat channel straight connector
FCA4 Flat channel circular connector
FCA6 Flat channel circular adaptor
FCA10 Flat channel elbow connector
FCA11 Round pipe
FCD1 Flat channel ducting, 1.5m
MC01 Sleeve coupling, male 125mm
PRT Ridge terminal
TT7 In-Line tile/slate terminal
TT9 Tile terminal
X332 Speed clamp
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PSV 01 Kit
Typical ground floor kitchen:
Flat ducting, ridge terminal.
PRT
X332
F12524
X332
FCA4
FCA6
FCD1
FCA3
FCD1
FCA6
A161
PSV 05 Kit
Typical first floor bathroom:
Ridge terminal.
PRT
X332
F12524
X332
A161
PSV 06 Kit
Typical first floor bathroom:
Tile terminal.
TT9
X332
F12524
X332
A161
PSV 02 Kit
Typical ground floor kitchen:
Circular ducting, ridge terminal.
PRT
X332
F12524
A161
PSV 03 Kit
Typical ground floor kitchen:
Circular ducting, tile terminal.
X332 X332 X332
MC01
X332 X332
F12513
X332
PSV 07 Kit
Typical ground floor kitchen:
Wall extract, flat ducting, tile
terminal.
TT9
X332
F12524
X332
FCA4
FCA6
FCD1
FCA3
FCD1
FCA10
A161
FCA11
TT9 PRT
X332 X332
F12513
X332
A161
PSV 04 Kit
F12524 F12524
MC01
PSV 08 Kit
Typical ground floor kitchen:
Flat ducting, tile terminal.
TT9
X332
F12524
X332
FCA4
FCA6
FCD1
FCA3
FCD1
FCA6
A161
Typical ground floor kitchen:
Wall extract, flat ducting, ridge
terminal.
Specification clause
Select options required,
and insert information
where necessary.
Passivent PSV Whole-
House ventilation system
Provide a BBA-Certificated
ventilation system
complying with Building
Regulations (England and
Wales) Approved
Document F OR Building
(Scotland) Regulations
Technical Handbook
Domestic Section 3 OR
Building Regulations
(Northern Ireland)
Technical Booklet K OR
Building Regulations
(Republic of Ireland)
Technical Guidance
Documents Part F, by
means of a whole-house
passive stack ventilation
(PSV) automatic system
comprising:
Humidity-sensitive
wall/window inlet vents
operating between 47%
and 65% relative humidity,
sited in habitable rooms as
required. Humiditysensitive
ceiling extracts
operating between 30%
and 75% relative humidity
sited in kitchen, bathroom,
utility room and WC; each
extract to be ducted
separately to a roof
terminal matching and
forming an integral part of
the ridge, or to pitched roof
tile/slate terminals sited no
lower than 0.5 metres
down from the ridge.
Ridge terminals to have an
air flow resistance not
exceeding 10Pa at an air
movement rate of 100m 2 /h.
Tile/slate terminals to have
an air flow resistance not
exceeding 5Pa at an air
movement rate of
100m 2 /h. All terminals to
provide insect and weather
protection, and be
designed to ensure any
condensate forming will
run off on to the roof. All
ducting in roof spaces and
other unheated spaces to
be fully insulated with
25mm insulation.
The system to be Passivent
PSV Whole-House system
covered by BBA Certificate
96/3273, supplied by
Passivent Limited,
2 Brooklands Road, Sale,
Cheshire M33 3SS.
Telephone: 0161 962 7113,
fax: 0161 969 5346,
email: info@passivent.com.
Installation to be in
accordance with the
manufacturer’s
instructions, and to be
carried out by a Passivent
Mastercare trained
installer holding a current
certificate.
Layout and installation
must comply with any
design recommendations
supplied.
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FCA4
FCA6
FCD1
FCA3
FCD1
FCA10
A161
FCA11
PSV 09 Kit
Typical first floor bathroom:
In-Line tile/slate terminal.
Not suitable for kitchens.
TT7
X332
F12524
X332
A161
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EXTRACT VENTILATION SYSTEMS
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MECHANICAL EXTRACT VENTILATION (MEV)
MECHANICAL EXTRACT VENTILATION
(MEV)
System 3
Passivent MEV systems
Passivent Mechanical Extract Ventilation
(MEV) systems provide continuous
mechanical extraction at a low rate,
boostable (manually or automatically) to
extract at a higher rate when required.
Whole-house systems comprise a remotely
located central extract fan connected by
ducting to extracts in wet rooms (kitchen,
bathrooms etc), with air inlets located in dry
rooms only (eg living rooms, dining rooms,
bedrooms).
Planned air paths
Moisture is extracted at source from wet
rooms. Air inlets located in dry rooms
provide a flow of replacement fresh air into
the building. The siting of the inlets and
extracts ensures that air always moves from
dry rooms to wet rooms, so that moisture
and other pollutants are removed at source
and the whole building is ventilated.
Air extracts
located in wet
rooms
MEV Systems
Passivent has a range of MEV systems
which can be matched to the intended
application.
Passivent MEV
Continuous extract system with boost,
automatic or manual, provided by extracts.
Primarily individual systems for houses
and apartments.
Passivent iMEV
Continuous extract system with boost
provided by automatic humidity-sensitive
control of fan speed and extracts. Provides
individual room control automatically.
Passivent AV
Continuous extract system with boost,
automatic or manual, provided by extracts.
Primarily multiple systems for apartments
and multi-occupancy applications.
Passivent Flair
Continuous extract system for new-build
apartments, integrating the latest design
in cooker hoods.
Air is exhausted
through roof (or
wall) terminals
Low-power continuouslyrunning
central extract fan located in
loft space (or cupboard)
Extract ducts may serve
a number of rooms
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Applications
MEV systems are suitable for a wide range of
applications including houses, apartments
and multi-occupancy buildings such as
nursing homes, student accommodation and
hotels.
In flats and apartments MEV systems can be
designed to ventilate either an individual
apartment or several apartments
simultaneously.
Systems are suitable for both new build and
refurbishment.
Features and benefits
● Tailored systems
The range of extracts enables systems to
be tailored specifically to suit individual
room applications.
● Demand control
Humidity-sensitive system, with
automatic boost to meet greater demand
when required, provides greater comfort
and energy efficiency.
● Planned air movement
The positions of inlets and extracts ensure
that air always moves from dry rooms to
wet rooms, where it is extracted.
● Continuous extraction with boost
Continuous gentle extraction at all times;
the system operates all day and every day,
boosting as required.
● No noise problems
The fan is normally installed in the roof
space or a cupboard to avoid noise
problems.
● Ideal for special needs
Automatic iMEV option ideal for special
needs, with no manual control required.
● Energy-efficient, low maintenance
Fans have a low energy consumption, and
minimal maintenance is required.
● Simple installation
Requirement for background ventilation
(air inlets) is significantly reduced
compared with intermittent extract fans.
● Design service
Passivent Limited offer a design service for
MEV systems.
Building Regulations and energy
performance
The Government’s Standard Assessment
Procedure (SAP) is the method for
calculating the energy rating or performance
of dwellings to comply with Building
Regulations. Registered SAP assessors use a
computer program to calculate
- the SAP rating
- the Target CO2 Emission Rate (TER) based
on standard values for a dwelling of the same
size and shape, and
- the Dwelling CO2 Emission Rate (DER),
based on the performance values for the
actual dwelling being assessed.
For compliance, the DER must be no worse
than the TER.
Appendix Q of the SAP allows the use of
actual performance data derived from
independent assessments of systems, in place
of default values. For energy efficient
systems such as Passivent MEV this method
can provide an enhanced SAP rating.
The A151DC fan used in the Passivent MEV
system is included on the Appendix Q web
site.
System design
Passivent offer a design service for our MEV
systems, based on building drawings
supplied.
Initially an outline proposal and estimate for
a system will be prepared; following
acceptance of this, a full design and costing
will be prepared.
System installation
A full installation guide is supplied with each
mechanical extract ventilation system.
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EXTRACT VENTILATION SYSTEMS
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PASSIVENT MEV
Description
Extraction is driven by a single low-power
consumption DC fan. This is normally
installed in the roof space or a cupboard and
mounted to avoid noise disturbance. Fans
operate efficiently at all times whether vents
are fully open or virtually closed.
Extraction can be boosted by a control
switch, which shows the user via an LED
display, the level at which the fan is
operating.
BBA approved
Passivent MEV Whole-House systems are
covered by BBA (British Board of Agrément)
Certificate No 96/3273.
System components
Extract fan A151DC
Low-wattage DC continuously-running fan,
specially designed for efficient extraction of
air along lengthy ducts.
Extract
A125 extracts located in ‘wet’ rooms.
Other components
For air inlets, terminals, and ducting, see the
Components section on page 58.
Typical MEV Whole-House ventilation systems
Air movement is from ‘dry’ to ‘wet’ rooms
Individual house Apartments: individual systems
Bathroom
Extract fan
Kitchen
System installation
A full installation guide is supplied with each
system.
Extract fan
Extract fan
Kitchen
Bathroom
Kitchen Bathroom
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PASSIVENT iMEV
Description
Innovative and intelligent, iMEV is a totally
new concept in central mechanical extract
ventilation. The system automatically
provides, without any occupant involvement,
individual room control, and is eminently
suitable for both houses and apartments.
The low-energy DC central extract fan
incorporates a humidity sensor linked to a
microprocessor that continuously monitors
the relative humidity of the extracted air.
The fan is linked via ducting to humidity
responsive extracts located in the ‘wet’
rooms. These open and close in response to
relative humidity. Sensing increasing
humidity the processor will progressively
boost the fan.
Therefore when relative humidity increases
in that room:
1. the extract in that room will open
2. the humidity of the exhaust air will
increase
3. the fan speed will increase
4. thus boosting the extract rate from the
room containing the open extract.
As humidity is reduced the extract will close
and the fan will slow down to its normal
running setting, until relative humidity in a
wet room increases again.
Typical iMEV Whole-House ventilation systems
EXTRACT VENTILATION SYSTEMS
System components
Extract fan A151DCH
Low energy central extract fan containing
integral humidity sensor and
microprocessor. Progressively boosts extract
rate in response to increasing levels of
relative humidity in the extracted air.
Extracts
A121 humidity
sensitive extracts
located in ‘wet’ rooms
respond automatically
to changes in relative
humidity, opening and closing to meet
demand, working in harmony with the fan to
boost individual room extraction.
Other components
For air inlets, terminals, and ducting, see the
Components section on page 58.
System installation
A full installation guide is supplied with each
system.
Individual house Apartments: individual systems
Bathroom
Extract fan
Kitchen
Extract fan
Extract fan
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Kitchen
Bathroom
Kitchen Bathroom
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PASSIVENT AV
Description
Extraction ventilation is driven by a
continuously-running central DC extract fan
connected to extracts located in the ‘wet’
rooms. Ventilation is boosted by the wider
opening of the extracts, which can provide
either automatic or manual boosts.
Passivent AV is eminently suitable for
apartments, where a single system can
ventilate several apartments, and for student
accommodation, hotels and care and nursing
homes.
The system is specially designed for efficient
extraction of low volumes of air along
lengthy ducts.
The use of one system for several dwellings
can reduce running costs and energy
consumption per dwelling. It also minimises
the number of roof penetrations required.
BBA approved
Passivent AV Whole-House systems are
covered by BBA (British Board of Agrément)
Certificate No 96/3273.
System components
Extract fan A151DC
Low-wattage DC central extract fan for
efficient extraction of air along lengthy duct
runs.
Extracts
All extracts are for ceiling or wall-mounting
in wet rooms. Boost is provided by wider
opening of the vents, controlled as shown
below.
● Humidity-sensitive extracts respond to
room humidity automatically.
● Timed electrical boost is activated
manually and operates for a preset time.
● Constant volume extracts are selfregulating
to maintain a constant extract
rate.
● PIR (passive infrared) boost is activated
when a person is detected in the room,
and operates for a preset time.
The range of extracts enables the whole
design and ventilation strategy to be tailored
to individual room requirements and use.
Other components
For air inlets, terminals, ducting, see the
Components section page 58.
Typical AV Whole-House ventilation systems
Apartments: multiple system
Multi-occupancy: nursing homes, student accomodation, hotels etc
Bedroom
Bedroom
Extract fan
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Kitchen
Bathroom
Kitchen Bathroom
Extract fan
Ensuite
bathroom
Ensuite
bathroom
Corridor
Corridor

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Specification clause
Select options required,
and insert information
where necessary.
Passivent MEV/iMEV/AV
ventilation system
Provide a ventilation
system complying with
Building Regulations
(England and Wales)
Approved Document F
OR Building (Scotland)
Regulations Technical
Handbook Domestic
Section 3 OR Building
Regulations (Northern
Ireland) Technical Booklet
K OR Building Regulations
(Republic of Ireland)
Technical Guidance
Documents Part F, by
means of a mechanical
extract ventilation system
comprising:
Humidity-sensitive
wall/window inlet vents
operating between 47%
and 65% relative
humidity, sited in
habitable rooms as
required.
Ceiling extracts sited in
kitchen, bathroom, utility
room and WC … , and
ducted to a central fan.
Central extract fan ducted
a roof terminal.
All ducting in roof spaces
and other unheated spaces
to be fully insulated with
25mm insulation.
The system to be
Passivent MEV/iMEV/AV
ventilation system
supplied by Passivent
Limited,
2 Brooklands Road, Sale,
Cheshire M33 3SS.
Telephone: 0161 962 7113,
fax: 0161 969 5346,
email: info@passivent.com.
Installation to be in
accordance with the
manufacturer’s
instructions, and to be
carried out by a Passivent
Mastercare trained
installer holding a current
certificate.
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Typical Flair system for
an apartment
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EXTRACT VENTILATION SYSTEMS
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PASSIVENT FLAIR
Description
Passivent Flair is an innovative and
extremely quiet extract ventilation system
for new-build apartments. Aesthetically
pleasing and discreet, it ensures a fresh,
clean and healthy internal environment
throughout an apartment with low energy
consumption.
The system ventilates the kitchen,
bathrooms (which may be ensuite) and WCs.
Elegant kitchen cooker hoods and discreet
bathroom extracts are linked to a low-noise,
low-energy central extract fan.
Self-regulating extracts operate constantly to
keep the bathroom and ensuite ventilation at
its planned level. In the kitchen, increased
extraction when cooking is provided by the
boost switches on the cooker hood.
Cooker hoods
Features and benefits
● Efficient ventilation
Provides ventilation where it is most
needed - kitchen and bathrooms.
● Quiet and effective
Quieter and more effective than individual
room extract fans. Central extract fan can
be located discreetly in a cupboard.
● Aesthetically attractive
Elegant Italian-designed cooker hoods in
stainless steel, with height-adjustable duct
and dishwasher-proof grease filter for easy
cleaning. Attractive wall- or ceilingmounted
bathroom extracts.
● Single outlet
Single wall or roof outlet minimises façade
disruption.
S2 Roma S5 Siena
S7 Napoli
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Cooker hood dimensions (mm)
System components
Central extract fan
Low-wattage continuously-running fan.
S125 - spigot diameter 125mm
S150 - spigot diameter 150mm
Code & description Height
(min - max)
Width Depth
S2 Roma 710 - 1130 600, 900 500
S5 Siena 780 - 1130 600, 900 500
S7 Napoli 710 - 1130 600, 900, 1000, 1200 500
S10 Ancona 780 - 1130 600, 900 500
S11 Verona 850 - 1270 900 600 width
S10 Ancona S11 Verona
Extracts
Ceiling-mounted constant volume extracts
are self-regulating to maintain a constant
extract rate, and are sized to suit the
bathroom or ensuite.
Extract code Airflow at 80Pa
SRE/15 15m3 /h (4.2 l/s)
SRE/30 30m3 /h (8.4 l/s)
SRE/45 45m3 /h (12.6 l/s)
SRE/60 60m3 /h (16.8 l/s)
SRE/90 90m3 /h (25.2 l/s)
Terminals, Ducting
Refer to the Components section page 58.
System installation
A full installation guide is supplied with each
system.
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height
depth
Specification clause
Select options required,
and insert information
where necessary.
Passivent Flair
ventilation system
Provide a ventilation
system complying with
Building Regulations
(England and Wales)
Approved Document F
OR Building (Scotland)
Regulations Technical
Handbook Domestic
Section 3 OR Building
Regulations (Northern
Ireland) Technical Booklet
K OR Building Regulations
(Republic of Ireland)
Technical Guidance
Documents Part F, by
means of a mechanical
extract ventilation system
comprising:
Self-regulating extracts
sited in bathroom[s] and
WC, ducted to a central
fan
Cooker hood ….. [insert
code] sited in kitchen and
ducted to the fan.
Central extract fan …
ducted to a wall/roof
terminal.
Continuously running
central extract fan sited
… and ducted to a wall
terminal.
All ducting in unheated
spaces to be fully
insulated with 25mm
insulation.
The system to be
Passivent Flair system
supplied by
Passivent Limited,
2 Brooklands Road, Sale,
Cheshire M33 3SS.
Telephone: 0161 962 7113,
fax: 0161 969 5346,
email: info@passivent.com.
Installation to be in
accordance with the
manufacturer’s
instructions, and to be
carried out by a Passivent
Mastercare trained
installer holding a current
certificate.
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EXTRACT VENTILATION SYSTEMS
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POSITIVE INPUT VENTILATION (PIV)
Passivent PIV system
Positive Input Ventilation uses air
displacement to ventilate a whole dwelling,
thereby improving indoor air quality and
stopping or preventing condensation
problems from occuring. Predominantly
designed for installation in existing
properties, the PIV units are very easy to
install.
A single fan unit mounted in the roof space
(or central location for flats) supplies fresh
filtered air into the dwelling via a central
hallway or landing. This creates a slight
positive air pressure which forces stale
vapour-laden air out via fortuitous air gaps
or through humidity-sensitive window vents.
Whole-house system
Eaves ventilation to roof space
provides fresh air supply
Air exhausted through
window vents
Continuous-running fan
draws air from the roof space
and supplies it to the dwelling
Bedroom
Living room
PIV unit
The PIV unit comprises a fan with connector
duct and ceiling diffuser. The fan runs
continuously unless the loft temperature
exceeds 25ºC, when the unit will switch off.
Above this temperature the hot incoming air
would be uncomfortable for the occupants
and the risks of condensation are somewhat
reduced. When the temperature falls below
25ºC the unit will automatically switch itself
back on. At temperatures between 19ºC and
25ºC the unit operates in heat recovery mode
harnessing the benefits of solar gains,
whereby the air in the loft is warmer than
outside air.
The ceiling diffuser has been
aerodynamically designed to direct incoming
air along the ceiling (coanda effect) where it
mixes with warm buoyant air before recirculating
downwards, thereby ensuring a
more even thermal gradient between the
floor and ceiling.
Solar gain
Bathroom
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Kitchen

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Applications
Due to its ease of installation, PIV is
designed primarily for the refurbishment of
houses and flats.
Features and benefits
● Energy savings
Supply air taken from the roof space is
slightly warmer than outside air, so can
provide some energy saving compared
with a conventional extract system.
● Simple and easy installation
Requires only a single electrical
connection. Does not require ducting
through the interior spaces.
● Low running costs
With its DC fan, the PIV system is
extremely energy-efficient, costing from as
little as a penny a day to run.
● Elapsed time meter
Shows total run time, providing landlords
with a foolproof check to prove usage.
● Minimal maintenance
Replacement of the long-life filter is only
required every 5 years.
● Aerodynamically designed diffuser
The diffuser is designed to direct incoming
air along the ceiling, thereby mixing with,
re-using and re-circulating high level
warm air.
Quotation
Passivent offer full advice and guidance for
PIV systems, and will prepare an estimate
and specification.
System installation
A full installation guide is supplied with each
system.
The ceiling must be as airtight as possible to
minimise recirculation of air from within
the dwelling.
Roof space must be ventilated from outside,
eg by eaves vents.
Energy performance
The Passivent PIV loft unit incorporates an extremely low wattage DC motor minimising
energy usage.
Incoming Ventilation Air volume Airflow Power Outlet noise
air temp mode setting (l/s) consumption dBA at 1 metre
(fan speed) (W)
25ºC Comfort 1 0 0 -
2 0 0 -
3 0 0 -
4 0 0 -
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Specification clause
PIV Unit
Provide a loft mounted
positive input ventilation
system (Passivent
PIVROOF) comprising a
DC fan unit, ducting and
ceiling diffuser. The fan
unit to have 4 air volume
settings, incorporate an
elapsed time meter and
have a one piece long life
filter. System to switch to
condensation control mode
at loft temperatures below
19ºC, heat recovery mode
between 19ºC and 25ºC and
comfort mode above 25ºC.
PIV system to be supplied
by Passivent Ltd,
2 Brooklands Road,
Sale, Cheshire M33 3SS,
Telephone: 0161 962 7113
Fax: 0161 905 2085
Email :info@passivent.com
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