1、BRITISH STANDARDBS EN14623:2005Devices to prevent pollution by backflow of potable water Air gaps with minimum circular overflow (verified by test or measurement) Family A, type GThe European Standard EN 14623:2005 has the status of a British StandardICS 13.060.20; 91.140.60g49g50g3g38g50g51g60g44g4
2、9g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14623:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 26
3、January 2006 BSI 26 January 2006ISBN 0 580 47620 0National forewordThis British Standard is the official English language version of EN 14623:2005. It supersedes BS 6281-2:1982 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee B/504, Water supply, to Su
4、bcommittee B/504/14, Backflow prevention, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document ma
5、y be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users a
6、re responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, an
7、d keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover.The BSI copyright notice displayed
8、 in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14623May 2005ICS 13.060.20; 91.140.60English versionDevices to prevent pollution by backflow of potable water - Airgaps with minimu
9、m circular overflow (verified by test ormeasurement) - Family A, type GDispositifs de protection contre la pollution de leau potablepar retour - Surverse avec trop plein (dfinie par essai dedpression) - Famille A, type GSicherungseinrichtungen zum Schutz des Trinkwassersgegen Verschmutzung durch Rck
10、flieen - Freier Auslaufmit kreisfrmigem berlauf mit Mindestdurchmesser(Nachweis durch Prfung oder Messung) - Familie A, Typ GThis European Standard was approved by CEN on 25 March 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving
11、 this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (
12、English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, C
13、zech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NOR
14、MALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14623:2005: EEN 14623:2005 (E) 2 Contents Page Foreword 3 Introduction4 1 Scope .5 2
15、Normative references .5 3 Terms and definitions.5 4 Designation .6 5 Symbolization7 6 Materials 7 7 Requirements 7 8 Marking (not required for site constructed products)10 9 Technical documents .10 EN 14623:2005 (E) 3 Foreword This European Standard (EN 14623:2005) has been prepared by Technical Com
16、mittee CEN/TC 164 “Water supply“, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2005, and conflicting national standards shall be withdrawn at
17、 the latest by November 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Icela
18、nd, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14623:2005 (E) 4 Introduction In respect of potential adverse effects on the quality of water intended for human consumption, caused
19、by the product covered by this European Standard: a) this European Standard provides no information as to whether the produce may be used without restriction in any of the Member state of the EU or EFTA; b) it should be noted that, while awaiting the adoption of verifiable European criteria, existin
20、g national regulations concerning the use and/or the characteristics of this product remain in force. EN 14623:2005 (E) 5 1 Scope This European Standard specifies the characteristics and the requirements of air gaps with overflow, family A, type G for nominal flow velocity not exceeding 3 m/s. Air g
21、aps are devices for protection of potable water in water installations from pollution. This European Standard applies to air gaps in factory assembled products and to constructed air gaps in situ, and defines the physicochemical characteristics of materials of construction used for the purpose and a
22、pplication to ensure compliance with this document during normal working use. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the refe
23、renced document (including any amendments) applies. EN 1717:2000, Protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow. 3 Terms and definitions For the purposes of this European Standard, the terms and definitions o
24、f EN 1717:2000 and the following apply. 3.1 air gap with overflow family A, type G permanent and vertical distance between the lowest point of the feed orifice and the critical water level having an overflow capable of draining the maximum inflow of water under fault condition NOTE See Figure 1 for
25、the design principle. Figure 1 Design principle 3.2 spillover level level at which water will start to overflow the receiving vessel with all outlets closed 3.3 critical water level physical or piezometric level of liquid reached in any part of the appliance 2 s after closing the water inlet startin
26、g from the maximum fault level 3.4 dimension h height between the spillover level and the critical level 3.5 maximum operational level in an open system the level that will be reached in normal operation (as defined by the manufacturer) EN 14623:2005 (E) 6 3.6 maximum level highest water level H rea
27、ched above the spillover level under positive pressure fault condition with all outlets closed 3.7 splashing (requirements for protection) when maintaining the maximum flow rate at the maximum level if a contact is observed between the upstream component and the liquid in the receiving vessel due to
28、 splashing, foaming or turbulence, the air gap shall be increased to a point where no contact is observed 3.8 diameter of feed pipe (Bore D) diameter D is the maximum internal diameter within the last metre of the supply pipe or the DN of the inlet connection 4 Designation An air gap with overflow f
29、amily A, type G is designated by: name; reference to this European Standard; denomination (see 3.8 DN or D); family and type. Example for a designation of an air gap with minimum circular overflow (verified by test or measurement) Family A (A), type G (G), DN 15 Air gap, EN 14623, Family A, Type G,
30、DN 15 EN 14623:2005 (E) 7 5 Symbolization Figure 2 Graphic symbol 6 Materials The manufacturer shall state the type of materials chosen in his technical and commercial documents. The materials used in water installations, including the materials of protection units in contact with drinking water, sh
31、all satisfy the European standards and national acceptance criteria and/or national restrictions for use currently in force in EU and EFTA. They shall be compatible with each other, with the water supplied and with the fluids or substances that can come into contact with them. There are no special r
32、equirements concerning the materials downstream of the atmospheric outlet opening provided they do not have any harmful effect on the upstream part. 7 Requirements 7.1 General The protection assembly comprises four parts: water inlet device; receiving vessel (container); overflow; air break to drain
33、. 7.2 Water inlet device Every feed pipe, float-operated valve or other device which controls the inflow of water to a receiving vessel shall be securely and rigidly fixed to maintain air gap. The outlet of the inlet device shall not come into contact in any way with a product from downstream, and w
34、ill always be above the maximum level H (see Figure 3). Adjustable or dismantleable joints are not permitted below the maximum operational level. Submerged supply pipes shall be made from corrosion resistant materials and be pressure tested as part of the inlet device. EN 14623:2005 (E) 8 Key 1 Feed
35、 pipe 2 Feed orifice 3 Receiving vessel 4 Spillover level 5 Critical level (distance h) 6 Overflow pipe A Air gap (distance) D Internal diameter of feed pipe (bore) H Maximum level Figure 3 Air gaps with minimum circular overflow (verified by test or measurement) family A, type G 7.3 Overflow arrang
36、ements The overflow arrangements shall not be less than 19 mm internal diameter. The overflow arrangements shall include an air break prior to any connection to a drain. An air break to drain shall comply with the requirements of EN 1717, excluding W.Cs. 7.4 Air gap distance 7.4.1 Single supply For
37、air gaps family A, type G the critical water level (h) shall be established and the air gap distance A measured from the lowest point of the water inlet to the critical water level (see Figure 3). For air gap distances see Table 1. The air gap can be determined by one of the following methods: a) h
38、is determined by test measurement of the depth of water above the spillover level of the overflow 2 s after the inflow equal to Q = 0,14 D2in l/min has stopped or, a dynamic pressure of 1 MPa (10 bar) has stopped if the flow rate Q cannot be achieved. Where D is the inlet bore (see 3.8) and with all
39、 outlets (except the EN 14623:2005 (E) 9 overflow) closed, based on a velocity of 3 m/s, or the maximum recommended flow rate for manufactured appliances when the flow rate is higher than Q; b) in the case of a pipe or valve not greater in size than 15 mm (G), by measurement of the air gap distance
40、A from the lowest point of the feed orifice and the centre line of the overflow pipe. Table 1 Air gap distance Pipe/valve size (inch/metric) Distance A (mm) DN 15 (G ) 20 mm DN 20 (G ) 25 mm DN 22 (G ) 2 D 7.4.2 Multiple supplies In the case of multiple feed pipes to a single vessel having an overfl
41、ow, the distance of the air gaps for the potable water supply shall be dimension A above the critical water level. The critical water level (3.3) shall be determined with all feed pipes discharging at an individual inflow calculated at Q = 0,14 D2. If the flow rate Q cannot be achieved, apply a dyna
42、mic pressure of 1 MPa (10 bar) on all inlets. No feed orifice shall be less than distance A above the critical water level. For calculating air gap distance A use =22 DA 7.4.3 Backflow/back pressure If the receiving vessel can be subject to positive pressure backflow, it is important that the inlet
43、orifice is positioned so that it cannot be contaminated by the ascending/returning backflow fluid. When the air gap is part of an installation which can generate positive pressure backflow it is essential that a means of limiting the flow rate to a rate which will not comprise the overflow arrangeme
44、nt is incorporated, i.e. non return valve fitted upstream of the pressurisation unit. Potable water inlets shall terminate at a higher level than non-potable inlets and never closer than 2 D measured horizontally and vertically downward. 7.5 Verification 7.5.1 General Verification can be achieved by
45、 test or by measurement. 7.5.2 Procedure for verification by test See 7.4.1 (a) and 7.4.2. a) Sequence of test close all outlets (except the overflow); identify D; calculate Q; apply flow rate Q and maintain maximum water level; note contact with the outlet of the inlet device(s) during filling and
46、the maximum level; EN 14623:2005 (E) 10 stop flow rate Q; after 2 s establish distance h; measure air gap between distance h and lowest point of the feed orifice. b) Requirements: no contact between the receiving vessel fluid and the outlet of the inlet device(s); measured air gap shall meet the req
47、uirements of dimension A (see Table 1). 7.5.3 Procedure for verification by measurement (single supply only) a) Sequence of measurement see 7.4.1 (b). b) Requirements measured air gap shall meet the requirements of dimension A (see Table 1). 8 Marking (not required for site constructed products) Eac
48、h appliance incorporating an air gap with minimum circular overflow (verified by test or measurement) family A, type G shall be clearly and permanently marked and accessibly visible. Marking shall indicate: a) manufacturers brand or logo; b) letter indicating family and type of air gap; c) denominat
49、ion (DN or D); d) reference to this European Standard. Following information to be given where possible: e) reference (type or model, etc.); f) serial number. 9 Technical documents The manufacturers documentation shall include the appropriate installation requirements to ensure the air gap is not compromised, including positive pressure backflow. blankBS EN 14623:2005BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body resp
