1. Arrow Valves Ltd – The Water Regulations Solution Specialist
July 2007
Arrow Valves Ltd – The Water Regulations Solution Specialist
BACKFLOW
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2. www.arrowvalves.co.uk copyright 2006-2012
What is Backflow?
July 2007
“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
Backflow
Back Siphonage
Vacuum on supply
Back Pressure
Downstream pressure higher than supply
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3. The above diagram shows a bath with a submerged shower head
Backflow Example
July 2007
Double Check Valve model ED235
Shower head
Bath (1st floor)
Sink (ground floor)
The above diagram shows a bath with a submerged shower head
If negative pressure 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
Further (secondary) backflow protection should also be provided (see later slide)
A Double Check Valve fitted to the shower hose would prevent the bath water reaching the sink and contaminating it
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4. Fluid Categories Previous UK Classification
July 2007
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
Class 2 Schedule B Risk
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)
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5. Types of Backflow Protection Point of Use Protection
July 2007
“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
Appliances of different types e.g. a washing machine and dishwasher, must have their own protection, preventing cross contamination
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6. Types of Backflow Protection
Zone Protection
July 2007
“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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7. Types of Backflow Protection Secondary Backflow Protection
July 2007
“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
Whole site backflow protection should be provided on supply pipes to two or more separately occupied premises
Arrow Valves Branch Valve model BRV – Servicing, Double Check & Drain Tap with Solder Union connections
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8. Fluid Category 3 Protection
Double Check Valve
July 2007
ED Double Check Valve Category 3 protection
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.
Exceptionally low head-loss ED Device (Model ED132)
Double Check Valve - model ED235. For fluid category 3 protection on shower hoses. Flow limiter option No Tools Required
Applications –
Supply to flats (whole site)
Separate floors (secondary)
Stainless Steel - exceptionally low head-loss – Model ED316
Numerous others
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9. Filling Heating Systems
July 2007
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
Model CA297PRV
Fluid Category 4
“Autofill” – Fluid Category 3 Model AFCA
Optional wall mounting brackets (Model AFBRA)
Automatically fill “house” heating systems or “non-house” heating systems less than 45 kW output
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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10. Filling Heating Systems – Fluid Category 5
July 2007
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
Dose & Fill – Model DF
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11. Fluid Category 4 Protection
RPZ Valve / BA Device
July 2007
Applications
Clothes washing machines
Dishwashing machines
Fire fighting equipment
Printing and photographic equipment
Water treatment
Water softening
Vehicle washing and many more
RPZ Option B
Upstream Isolating Valve, Strainer, RPZ, downstream Isolating Valve
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
Installation requirements
Access height 0.3 m min 1.5 m max
Adequate rear clearance
Tamperproof environment
Standpipe
Freestanding watering point incorporating BA device
Model SPBA
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12. Fluid Category 4 Protection
AF Air Gap
July 2007
Based on diagram G
SgV
Outlet
Air Gap
Primarily to boost the supply pressure to Penthouse Suites and similar tall buildings requiring individual booster sets
Applications
Tall buildings (3 storey+) e.g. Penthouse suites
Boosting low pressure
“Combi” boilers and showers
Drinking (“wholesome”) water – use optional jacket
OPTIONS:
Insulation Jacket
Model BTJAC
Wall Cover
Model BTCAB3
Drip Tray
Model BTDT1
“Pent-A-Boost” Fixed speed
Compact Domestic Booster model BTAF
Incorporating type AF air gap
Variable speed also available
Shown with optional insulation jacket
Wall mounting brackets Model BTBRA
Supplied as a complete package ready for installation
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13. Fluid Category 5 Protection
AB Air Gap
July 2007
Based on diagram G
SgV
Outlet
Air Gap
Weir Overflow
Primarily to provide Fluid Category 5 backflow protection and to boost water pressure for high flow applications
Applications
Non-domestic Hose Union taps e.g.
Waste bin washing
Wash-down
Irrigation
Laboratories
Rain water
Baths / Showers – Healthcare
Bed pan washers
OPTIONS:
“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
Wall Cover
Model BTCAB3
Floor cabinet
Model BTCAB1
Drip Tray
Model BTDT1
Wall mounting brackets Model BTBRA
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14. Fluid Category 5 Protection Wall mounted Break Tank & Booster Set
AB Air Gap
July 2007
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 –
Midi-1, Midi-2A and Midi-3A
BTCAB4 - Wall Cover for “Midi-Break”
Wall mounting brackets included
Applications –  Healthcare premises (baths with shower hoses, clothes and dishwashing machines)  Bidet washing  Sinks with hoses  Non-domestic Hose Union taps  Vegetable washing
“Midi-Break”
Break Tank & Booster Set model BTMIDI
Incorporating type AB air gap
Stainless steel housing provides neat and hygienic installation
BTDT3 - Stainless steel drip tray for “Midi-Break”
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15. Fluid Category 5 Protection
Care Shower
July 2007
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)
Thermostatically controlled shower – Electric Shower & Booster Pump package (model CSABATLF)
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16. Fluid Category 5 Protection
Ablution Plant
Ablution Plant – FC5
July 2007
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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17. www.arrowvalves.co.uk copyright 2006-2012
July 2007
THE END
For further guidance or to discuss your particular application, please contact us:  
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