Arrow Valves Ltd – The Water Regulations Solution Specialist
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What is Backflow?
“Backflow” means flow upstream, that is in a direction
contrary to the intended normal direction of flow, within or
from a water fitting
Flow of water
Back Siphonage
Vacuum on supply
Back Pressure
Downstream pressure higher than supply
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Backflow
Backflow Example
Shower head
Double
Check Valve
model ED235
Bath (1st floor)
Sink (ground floor)
The above diagram shows a bath with a submerged shower head
Further
(secondary)
protection
should
also
be provided
(see
later
slide)
If negative
pressure backflow
should occur,
dirty bath
water
could
be sucked
back
into
the
pipework and be discharged from the sink as water used for hand washing,
drinking etc
A Double Check Valve fitted to the shower hose would prevent the bath water
reaching the sink and contaminating it
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Fluid Categories
Previous UK
Classification
European/New UK
Classification
Backflow Prevention Examples
(Used in Building Services)
Class 1
Schedule A Risk
European
Fluid Category 5
Air Gap – AA AB
Pipe Interrupter - DC
European
Fluid Category 4
RPZ – BA
Pipe Interrupter - DB
European
Fluid Category 3
Double Check – ED
Class 3
Schedule C Risk
European
Fluid Category 2
Single Check – EB
Wholesome
Water
European
Fluid Category 1
No Protection Required
(Except Secondary, at times)
Class 2
Schedule B Risk
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Types of Backflow Protection
Point of Use Protection
“The provision of zone or
whole site backflow
protection should be in
addition to individual
requirements at points of
use and within the system”
G15.25
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Appliances of different types e.g.
a washing machine and
dishwasher, must have their own
protection, preventing
cross contamination
Types of Backflow Protection
Zone Protection
“Any taps and fittings used for supplying
water for non-domestic applications, such
as commercial, horticultural, agricultural or
industrial purposes should be provided with
a. backflow protection devices appropriate
to the downstream fluid category; and
b. where appropriate, a zone protection
system”
G15.18
Where several appliances of the same type and same Fluid Category are
used within a commercial building, water suppliers may accept single
protection for multiple appliances.
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Types of Backflow Protection
Secondary Backflow Protection
“A whole-site or zone backflow prevention
device should be provided on the supply
or distributing pipe, such as a single
check valve or double check valve, or other
no less effective backflow prevention
device, according to the level of risk as
judged by the Water Undertaker…”
G15.24
Arrow Valves Branch Valve model BRV
– Servicing, Double Check & Drain Tap
with Solder Union connections
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Whole site backflow
protection should be
provided on supply pipes to
two or more separately
occupied premises
Fluid Category 3 Protection
Double Check Valve
ED Double Check Valve
Category 3 protection
Exceptionally low head-loss ED Device
(Model ED132)
Stainless Steel - exceptionally low headloss – Model ED316
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ED is “non-verifiable”
meaning there are no test
points provided. EC is
verifiable but none is
approved and since
protection is still Fluid
Category 3, there is no
benefit.
Applications –
Supply to flats (whole site)
Separate floors (secondary)
Numerous others
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Double Check Valve model ED235. For fluid
category 3 protection on
shower hoses. Flow
limiter option
No Tools Required
Filling Heating Systems
Fluid Category 3 (heating permanent connection)
“Autofill” – Fluid Category 4
Model AFS
Filling Valve – CA Device with
Pressure Reducing Valve and
inlet/outlet servicing valves
Fluid Category 4
Model CA297PRV
Automatically fill
“house” heating
systems or
“non-house”
heating systems
less than 45 kW
output
Optional wall mounting
brackets (Model AFBRA)
“Autofill” – Fluid Category 3
Model AFCA
Fills and pressurises
“non-house” heating
systems with output
greater than 45 kW
Accessories available include Expansion Vessels (EVCP), Expansion Vessel Isolators (BVEV)
and Air Dirt Removers (ADR), Water Meter (WMV3P)
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Filling Heating Systems – Fluid Category 5
Features –
“Midi-Fill” Digital
Model MFD
• All the features of the “Midi-Fill” Digital plus –
• Low chemical BMS warning
• Manual internal dosing facility
• External dosing facility – replaces need for dosing
pot
Advanced Pressurisation Unit
“Midi-Fill” Digital
with Automatic
Dosing
Features –
• Weekly self test – BMS alerts to avoid heating
system shutdown
• Anti-seize daily pump pulse
• Integral water meter and excessive filling alarms
• No annual testing
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Dose & Fill – Model DF
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Fluid Category 4 Protection
RPZ Valve / BA Device
Applications
• Clothes washing machines
• Dishwashing machines
• Fire fighting equipment
• Printing and photographic equipment
RPZ Option B
•Water treatment
Upstream Isolating Valve,
Strainer, RPZ, downstream
Isolating Valve
•Water softening
• Vehicle washing and many more
Compact RPZ Valve
Model BA3T
Reduced Pressure Zone
(RPZ) Valves – also known as
BA device. Mechanical
backflow preventer for Fluid
Category 4 backpressure and
backsiphonage protection
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Installation requirements
Access
heightrear
0.3
m min 1.5 m
Adequate
clearance
Tamperproof
environment
max
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Standpipe
Freestanding watering
point incorporating
BA device
Model SPBA
Fluid Category 4 Protection
AF Air Gap
Air Gap
SgV
Primarily to boost the supply pressure to
Penthouse Suites and similar tall buildings
requiring individual booster sets
Applications
Based on diagram
G15.31.2
• Tall buildings (3 storey+) e.g.
Penthouse suites
Outlet
• Boosting low pressure
“Pent-A-Boost”
Fixed speed
• “Combi” boilers and showers
Compact
Domestic Booster
model BTAF
• Drinking (“wholesome”)
water – use optional jacket
Incorporating type
AF air gap
Variable speed
also available
Shown with
optional insulation
jacket
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Supplied as a complete
package ready for installation
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DripCover
Tray
Insulation
Jacket
Wall
Wall mounting
Model
brackets
BTDT1
Model
BTJAC
Model
BTCAB3
Model BTBRA
Fluid Category 5 Protection
AB Air Gap
Air Gap
SgV
Weir
Overflow
Primarily to provide Fluid Category 5
backflow protection and to boost water
pressure for high flow applications
Applications
Based on diagram
G15.31.2
Outlet
“Boost-A-Break”
Fixed speed
Break Tank and
Booster Set
model BTAB
Incorporating type
AB air gap
Variable speed
also available
Suitable for all
backflow
prevention
applications
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Non-domestic Hose Union
taps e.g.
• Waste bin washing
• Wash-down
• Irrigation
• Laboratories
• Rain water
•Baths / Showers – Healthcare
• Bed pan washers
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Dripcabinet
Tray
Floor
Wall
Cover
Wall mounting
Model
brackets
BTDT1
Model
BTCAB1
BTCAB3
Model BTBRA
Fluid Category 5 Protection
AB Air Gap
Wall mounted Break Tank & Booster Set
Primarily to provide Fluid Category 5
backflow protection and to boost water
pressure for high flow applications
Three models –
BTCAB4 - Wall Cover for “Midi-Break”
Wall mounting brackets included
Midi-1, Midi-2A and Midi-3A
“Midi-Break”
Break Tank & Booster Set
model BTMIDI
Incorporating type AB air gap
Stainless steel housing
provides neat and hygienic
installation
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Applications –  Healthcare premises (baths with
shower hoses, clothes and dishwashing
machines)  Bidet washing  Sinks with hoses 
Non-domestic Hose Union taps  Vegetable
washing
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BTDT3 - Stainless steel drip tray for
“Midi-Break”
Fluid Category 5 Protection
Care Shower
Supplies instantaneous hot water to an
accurate maximum temperature
Fluid Category 5 backflow protection
Meets BEAB Care Mark Requirements
as safe for use by elderly, young or sick
Applications –
 Healthcare (assisted bathing) 
Nursing homes  Veterinary  Dog
grooming  Medical  Mortuary 
Butchery  Bidet  Toilet
(paperless)
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Thermostatically controlled shower –
Electric Shower & Booster Pump
package (model CSABATLF)
Fluid
Ablution
Category
Plant
5 Protection
– FC5
Ablution Plant
Fluid Category 5 backflow protection
Consists of • Break Tank with Type AB air gap
• Booster Pump • Storage Heater • TMV
Assists with multi-cultural facilities
Applications –
Toiletry (paperless), animal washing, butchery
Safe hot water with
Fluid Category 5
backflow protection
– Model BTHW
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For further guidance or to discuss
your particular application,
please contact us:
 01442 823123
 info@arrowvalves.co.uk
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