Presentation on theme: "Www.arrowvalves.co.uk copyright 20061 Primarily Focusing on Backflow Prevention Presentation By Steve Grace B-Eng FIPHE Technical Director - Arrow Valves."— Presentation transcript:
copyright Primarily Focusing on Backflow Prevention Presentation By Steve Grace B-Eng FIPHE Technical Director - Arrow Valves Ltd March 2006 References to the Water Regulations Guide with practical solutions
copyright Objectives Fluid Categories – risk classification - New UK standards Regulations 2 – 6 – requirements and solutions Backflow – how it occurs, back siphonage vs back pressure Backflow prevention devices - Fluid Categories 2 – 5 RPZ valves – use, installation & testing Sealed heating – regulations and devices Water Fittings Approval Standards – Kiwa, WRAS Water conservation – requirements and devices Hose Union Taps - requirements and devices Temperature – limit and control Summary
copyright The legal UK Water Regulations include - Regulations & Guidance Available Information The Water Supply (Water Fittings) Regulations – Statutory Instruments 1148 Schedule 1 – Fluid Categories Schedule 2 – Requirements for Water Fittings The Water Regulations Guide contains all the Regulations and Guidance (Replaces Water Supply Byelaws Guide) Guidance is produced by DETR (DEFRA) and WRAS Water Regulations Advisory Scheme
copyright Schedule 1 – Fluid Category Risk Comparison European Fluid Category 5 European Fluid Category 4 European Fluid Category 3 European Fluid Category 2 European Fluid Category 1 Class 1 Schedule A Risk Class 2 Schedule B Risk Class 3 Schedule C Risk Previous UK Classification European/New UK Classification Wholesome Water Air Gap – AA AB Pipe Interrupter - DC RPZ – BA Pipe Interrupter - DB Double Check – ED Single Check – EB No Protection Required (Except Secondary, at times) Backflow Prevention Examples (Used in Building Services)
copyright (1) Subject to the following provisions of this regulation, these Regulations apply to any water fitting installed or used, or to be installed or used, in premises to which water is or is to be supplied by a water undertaker. (4) Nothing in these Regulations shall require any person to remove, replace, alter, disconnect or cease to use any water fitting which was lawfully installed or used, or capable of being used, before 1 st July Regulation 2 Application of Regulations lawfully means conformance to the Water Byelaws
copyright Example of New Water Regulations applying to existing installations R15.21 While the Regulations are not retrospective appropriate measures must be taken against any known situation where there is a potential backflow risk from hoses. The offence will be deemed to have been committed when the hose was attached and not when the tap was first installed. Regulation 2 Retrospective Clause The same applies to filling loops etc.
copyright (1) No person shall - (a) instal a water fitting to convey or receive water supplied by a water undertaker, or alter, disconnect or use such a water fitting; or (b) cause or permit such a water fitting to be installed, altered, disconnected or used in such a manner that it causes or is likely to cause - (i) waste, misuse, undue consumption or contamination of water supplied by a water undertaker; or (ii) the erroneous measurement of water supplied by a water undertaker. Regulation 3 Restriction on installation etc. of water fittings
copyright Back Siphonage Courtesy of WRAS This tap is sucking up water due to a vacuum in the supply pipe and an inadequate air gap.
copyright What is Backflow? Back Siphonage (Vacuum on supply) Back Pressure (Downstream pressure higher than supply) Some devices are suitable for Back Siphonage only - e.g. DC Pipe Interrupter. Others e.g. BA (RPZ Valve) are suitable for both. Backflow means flow upstream, that is in a direction contrary to the intended normal direction of flow, within or from a water fitting.
copyright Backflow Example – Hotel Baths Supply pressure lost – mains or booster failure Tap turned on – Negative pressure – could suck fluid out of bath via shower hose Contaminated! Solution - Point of Use Protection Shower Hose Double Check Valve Model ED235 Solution – Secondary Protection Branch Valve Double Check Valve Model BRV
copyright Secondary Backflow Protection Servicing Valves, Double Check and Drain Taps should be fitted to every branch (G11.3, G11.4, G11.5, G15.24, R )
copyright Branch Valve Servicing Valve, Double Check and Drain Tap should be fitted to every branch (G11.3, G11.4, G11.5, G15.24, R ) Model BRV Servicing, Double Check & Drain Tap with Solder Unions Model BRPRV Servicing, Pressure Reducing, Double Check & Drain Tap
copyright Point of Use Protection - The Law Backflow prevention devices MUST be fitted at POINTS OF USE - paragraph 15 (1) of the Statutory Instruments (Water Regulations). 15.(1) Subject to the following provisions of this paragraph, every water system shall contain an adequate device or devices for preventing backflow of fluid from any appliance, fitting or process from occurring. (3) The device used to prevent backflow shall be appropriate to the highest applicable fluid category to which the fitting is subject downstream before the next such device. G15.25 The provision of zone or whole-site backflow protection should be in addition to individual requirements at points of use and within the system. 3) The device used to prevent backflow shall be appropriate to the highest applicable fluid category to which the fitting is subject downstream before the next such device.
copyright Whole Site Protection Example of Whole Site Protection - Florida USA (Frost Protection unnecessary!)
copyright Point of Use Protection Where the appliances are of different types, e.g. a Washing Machine and Dishwasher (commercial use), each appliance must have its own Backflow Protection - RPZ Valve Assembly - (Water Regulations Schedule 2, Paragraph 15) Point of Use Protection Prevents Cross Contamination Point of Use Protection Built-in Category 3 protection – too low
copyright Zone Protection Where several appliances of the same type and same Fluid Category are used within a commercial building, Water Suppliers may accept a single RPZ Valve to protect multiple appliances. Zone Protection Cross Contamination Possible
copyright Backflow Example Problem - Steel Pipe is Fluid Category 2 Risk E.g. Fire Sprinkler Cistern (with AA / AB air gap) Solution - Single Check Valve at Branch Wholesome Water Fluid Category 1 Fluid Category 5 Model EB402
copyright Single Check Valve EB Single Check Valve Category 2 protection EB is non-verifiable meaning there are no test points provided. EA is verifiable but none is approved and since protection is still category 2, there is no benefit. Applications – Single Check Valve above DN50 are described as Non- Return but are currently acceptable for backflow protection. For double check valves, ensure upstream check valve cannot open downstream valve! Single Check Valve. To provide backflow protection from flexible hoses. Washing machine version pictured -(Model EB20FM235) No Tools Required Connections to steel pipe Prevent mixing of hot & cold (e.g. TMV) Fire sprinklers (no additives)
copyright Double Check Valve 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. Applications – Exceptionally low head-loss ED Device (with optional Drain Tap - Model ED132) Stainless Steel - exceptionally low head- loss – Model ED316 Double Check Valve - model ED235. For fluid category 3 protection on shower hoses. Flow limiter option No Tools Required Supply to flats (whole site) Separate floors (secondary) Numerous others
copyright Double Check Valve – Low Loss E.g. Model ED132 - size 15 mm - has 1 m head loss compared with 4.5 m for conventional Double Check Valve at 3 m/s.
copyright Pipe Interrupters DB Pipe Interrupter Category 4 protection There are many restrictions on its use - No control valves downstream 300 mm min. above spillover level or free discharge point Applications – Model – DB20IL15 with quick release hose connector Porous hoses for house only (Hose Union tap also requires a separate Double Check Valve)
copyright Pipe Interrupters DC Pipe Interrupter Category 5 protection There are many restrictions on its use - Minimal restriction downstream 300 mm min. above spillover level or free discharge point 150 mm above sparge outlet Applications – Model DC257 Urinals (fed directly from supply pipe)
copyright RPZ (BA) Assembly in Cabinet A large capacity fine strainer should be used for high volume applications Small cabinet (300 mm square) to house a 15 mm RPZ. E.g. for dishwashers etc. Waterless Traps are ideal - conventional traps can dry out (check approved for application) RPZ Compact High performance
copyright Initial Connection RPZ (BA) How it Works With no pressure in the system, both Check Valves (1) and (2) are closed and the Relief Valve (3) is open. Once the upstream pressure (A) reaches about 0.3 bar, sufficient pressure exists above the Diaphragm (5) to compress the Spring (6) and close the Relief Valve (3). At approximately 0.5 bar, Check Valve (1) opens allowing water to flow into Zone (B). (Look at Check Valve (1)) A further 0.1 bar is required to open Check Valve (2) and thereafter flow is maintained through the Valve. Closed
copyright Initial Connection RPZ (BA) How it Works With no pressure in the system, both Check Valves (1) and (2) are closed and the Relief Valve (3) is open. Once the upstream pressure (A) reaches about 0.3 bar, sufficient pressure exists above the Diaphragm (5) to compress the Spring (6) and close the Relief Valve (3). At approximately 0.5 bar, Check Valve (1) opens allowing water to flow into Zone (B). A further 0.1 bar is required to open Check Valve (2) and thereafter flow is maintained through the Valve.
copyright Downstream Pressure Increase RPZ (BA) How it Works If Check Valve (2) fails to seal whilst the downstream pressure (C) is higher than (B), the Relief Valve (3) will open before (B) gets to within 0.14 bar of the Supply Pressure (A). The Relief Valve (3) orifice is substantially larger than the open area of a leaking Check Valve and therefore prevents fluid reaching the base of Check Valve (1). Backflow - due to an increase in downstream pressure - is prevented by Check Valve (2). Failsafe (Positive Action)
copyright Installation Diagram Ground / Floor / Cabinet Access Height 0.3 m min 1.5 m max Upstream Isolating Valve Downstream Isolating Valve Strainer RPZ Valve Air Gap Discharge Pipe IGN Issue 3 requires RPZ installations to feature - Adequate Rear Clearance RPZ Valves must be annually tested Tamperproof environment – Plant Room or use Cabinet
copyright RPZ Typical Applications Sealed Heating Systems – Non house (Filling loops with Double Check Valve prohibited) Hose Union Taps - Commercial - (where Fluid Category 4) Clothes Washing Machines - Commercial use Dishwashers - Commercial use Cooling Coils - Commercial Under Floor Heating - Commercial Dyeing Equipment Printing and Photographic Equipment Pressurised Fire Fighting Systems Water Treatment Plant Vehicle Washing Plant Water Softening - not Salt The Following MUST be protected with either an appropriate air gap or an RPZ assembly
copyright RPZ (BA) Guidance On the inlet to a pump - fit to outlet On gravity systems - unless at least 10 m head On elevated mains systems - e.g. second floor and above RPZs have a pressure drop of about 0.6/0.7 bar inherent in their design. The supply pressure must be more than 0.7 bar. (The increase in pressure drop after 0.7 bar is small) Do not use an RPZ - RPZ Valves (BA device) need to be tested by an Accredited Tester after installation and annually thereafter.
copyright Break Tank – with AB Air Gap AB Air Gap Category 5 protection Either gravity supply from storage cistern or Boost with pumps Applications –Non-Domestic Hose Union taps e.g. Waste Bin Washing Wash-down Irrigation Laboratories Rain water Baths/Showers - Healthcare Bed pan washers Air Gap AB Boost-A-Break Fixed speed Break tank and Booster - model BTABV Boost-A-Break Variable speed
copyright Break Tank – with AF Air Gap AF Air Gap Category 4 protection Applications – Pent-A-Boost Fixed speed Compact Domestic Booster - model BTAFV Pent-A-Boost Variable speed Boosts pressure for high buildings where the mains supply is inadequate e.g. penthouse suites
copyright Break Tank Accessories RPZ Valves, Break Tanks and other fittings must be protected from freezing Outdoor GRP Kiosk with thermostatically controlled heater for break tank (model BTABV). Note - low level screened Type AB slot Applications – Wall cover Note – brackets required Wash-down Irrigation Drip Tray
copyright Filling Heating Systems – Category 3 Unlike BA (RPZ) valves, CA devices do not need to be tested. A discharge pipe is required to be connected to the tundish. A CA device (with pressure control) can be used to automatically fill house and non-house heating systems less than 45 KW output. Filling Valve - CA device with PRV, strainer and servicing valves Model – CA296PRV
copyright Filling Heating Systems – Category 4 Quick-fill loops (with Double Check valve) are prohibited for other than house applications. Fill and pressurise with Autofill supply from - Mains – ground (& first floor) Boosted CWS R24.2 The type of backflow protection device required should be suitable for Fluid Category 3 in the case of a house or for Fluid Category 4 risk for installations in premises other than a house. Autofill is a Fluid Category 4 device for filling and pressurising (Water Industry now accept systems less than 45 KW output as Fluid Category 3) Wall mounting brackets available
copyright Heating System Accessories Unvented heating systems require a correctly sized & rated Expansion Vessel Model EVCP (4 bar) Vessels must be correctly pre-charged Model EVUP (10 bar) Approved for heating & domestic water Model BVEV Proper vessel valve – lock shield, wired, drain tap and union
copyright Heating System Accessories Common accessories for commercial unvented systems include - Model WMV3 Water Meter – establish system volume and leaks Volumetric & readable to 1 litre Model ADR Air and Dirt Removers (separators) DN20 – DN250 Model DP5 Dosing Pots (3.5 – 25 litres) to add inhibitors – water meter helps determine system volume With anti-blowback and anti-scald
copyright (1) Every water fitting shall - (a) be of an appropriate quality and standard; and (b) be suitable for the circumstances in which it is used. (2) For the purposes of this regulation, a water fitting is of an appropriate quality or standard only if - (a) it bears an appropriate CE marking in accordance with the Directive; (b) it conforms to an appropriate harmonized standard or European technical approval; (c) it conforms to an appropriate British Standard or some other national specification of an EEA State which provides an equivalent level of protection and performance; or (d) it conforms to a specification approved by the regulator. Regulation 4 Requirements for water fittings etc. It is necessary to prove conformance – only use Water Regulations approved fittings. There are several organisations now -
copyright Regulation 4 Approval Organisations Remember – to comply with Regulations, all fittings in contact with (wholesome) water supplied by the water company must be approved. Available free on Internet Also available free on Internet
copyright Regulation 4 - Compliance All fittings KIWA UK approved assure compliance with Regulation 4 – see their web site for approved products –
copyright (1) Subject to paragraph (2), any person who proposes to install a water fitting in connection with any of the operations listed in the Table below - (a) shall give notice to the water undertaker that he proposes to begin work; (b) shall not begin that work without the consent of that undertaker which shall not be withheld unreasonably; and (c) shall comply with any conditions to which the undertaker's consent is subject. Regulation 5 Notification Water Companies are permitted to make reasonable terms and conditions Unreasonably means 10 working days from receipt of application
copyright The erection of a building or other structure, not being a pond or swimming pool. 2. The extension or alteration of a water system on any premises other than a house. 3. A material change of use of any premises. Regulation 5 continued Notification Notification is required for the following - (2) This regulation does not apply to the installation by an approved contractor of a water fitting falling within paragraph 2, 4(b) or 4(g) in the Table. Commercial alterations, bidet, RPZ Valve. There are others but these are for house installations. Everything requires notification in a non-house structure – see above
copyright Regulation 6 Contractor's Certificate 6. - (1) Where a water fitting is installed, altered, connected or disconnected by an approved contractor, the contractor shall upon completion of the work furnish a signed certificate stating whether the water fitting complies with the requirements of these Regulations to the person who commissioned the work. (2) In the case of a fitting for which notice is required under regulation 5 (1), the contractor shall send a copy of the certificate to the water undertaker.
copyright Water Conservation Automatic Flow Limiting Valve Combined Servicing Valve and Automatic Flow Limiting cartridge. Constant flow between 1 – 10 bar. Applications – Cartridges can be changed though side port with pliers 8 Colour-coded cartridges available - with matching colour on disc that snaps into plug Automatic Flow Limiting Cartridges 0.07 – 0.43 Lt/s Every appliance 15 or 22 mm
copyright New Features & Benefits sheet available Water Conservation Equi-Flow - Shower Flow Limiter Ensures even distribution of water in a controlled and balanced manner. Model AFLE Applications – WITHOUT WITH Showers in multiple occupancy buildings e.g. flats, hotels and student accommodation. 1 bar 5 bar 10 bar Excessive flow Insufficient flow – Even distribution
copyright Standpipe – Category 3 ED Double Check Valve is required for Hose Union Taps used for domestic purposes Taps with integral check valves (HUK1) are no longer acceptable Applications – Above ground garden watering Offices, Schools, Recreation Ground Standpipe - Model SPED Miniature Standpipe – model SPTB. Only 250 mm high
copyright Standpipe – Category 4 Non Domestic Hose Union Taps may be risk assessed as Fluid Category 4 (G15.18) & a BA device could be used Applications – Standpipe - Model SPBA Hose and medium duty washdown gun Hand held hoses should be fitted with a self –closing mechanism at the outlet of the hose. G15.17 Car Washing & Degreasing Plants Mini Irrigation Systems
copyright Standpipe – Installation 750 mm MDPEPile Standpipe Insulation
copyright Conceal-A-Tap Flush Hose Union Tap – vandal resistant, frost proof Model - HUC New Features & Benefits sheet available
copyright Conceal-A-Tap Suits any wall thickness – cut copper tube to suit Model - HUC
copyright Tap Box To prevent unauthorised use and prevent waste – use a lockable Tap Box. Available in rear entry or bottom entry. G11.5 warns against using spherical valves in frost prone areas. The Tap Box features a right angle pattern spherical valve, which does not have a trapped cavity and is therefore frost resistant. Applications – Tap Box - Model HUTB Tap Box (surface entry)- Model HUTBS Shown with optional hose guard and pipe cover Wall mounted Hose Union Tap (Backflow prevention provided separately)
copyright Hose Union Tap Below Ground Below ground hose union tap All irrigation outlets less than 150 mm above the ground are considered a Fluid Category 5 risk and must be fed via an AB or AUK1 air gap. E.g. Boost-A- Break model BTABV Model HUBG
copyright Temperature Control Supplied with AFL Servicing Valves fitted (including strainer) Copes with unbalanced pressures Applications – G18.5 Terminal fittings or communal showers in schools or public buildings, and other facilities used by the public, should be supplied with water through thermostatic mixing valves so that the temperature of water discharged at the outlets does not exceed 43 O C. Model TMV5213 Kit with AFL valves TMV Servicing Valve model BVTMV Wash basins Showers Baths Sinks Bidet
copyright Pressure Control Model PRV535 With Solder Unions to allow secure and neat connection to copper tube Model PRV536 With Solder Unions and Servicing Valves Model PRVNGE Pilot Operated. Range of other controls - solenoid Model PRV1300 Exceptionally Low head loss
copyright Regulations Penalty for contravening Regulations 8 Modification of section 73 of the Act 9 Inspections, measurements and tests 10 Enforcement 11 Relaxation of requirements 12 Approval by the regulator or the water undertaker 13 Disputes 14 Revocation of the Byelaws
copyright Resources – Specification Clauses Available at - Simply copy & paste into any project specification
copyright Summary The salient points of this presentation are – The Water Regulations Guide is the single most useful source of information The local water company has the authority to enforce, inspect and risk assess The Regulations apply to the whole building (if supplied by the water company) Point of use backflow protection is required – not whole site Communal bin washing – where a hose can be submerged – is Fluid Category 5 Irrigation outlets less than 150 mm above the ground are Fluid Category 5 The Fluid Category is dependant on the risk – not the fluid per sé Non House heating systems above 45 kW are Fluid Category 4 It is an offence to waste water – even if metered Water fittings must be approved – e.g. KIWA, WRAS, BSI
copyright The End Thank You To view datasheets Tel Fax