1、BS EN 13077:2008ICS 13.060.20; 23.060.99; 91.140.60NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDDevices to preventpollution by backflowof potable water Airgap with non-circularoverflow (unrestricted) Family A Type BThis British Standardwas published under the
2、authority of the StandardsPolicy and StrategyCommittee on 31 July 2008 BSI 2008ISBN 978 0 580 56793 3Amendments/corrigenda issued since publicationDate CommentsBS EN 13077:2008National forewordThis British Standard is the UK implementation of EN 13077:2008. Itsupersedes BS EN 13077:2003 which is wit
3、hdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee B/504/4, Backflow Prevention.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Use
4、rs are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 13077:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 13077June 2008ICS 13.060.20; 23.060.99; 91.140.60 Supersedes EN 13077:2003 English VersionDevices to preven
5、t pollution by backflow of potable water - Airgap with non-circular overflow (unrestricted) - Family A - Type BDispositif de protection contre la pollution de leau potablepar retour - Surverse avec trop-plein non-circulaire (to-tale)- Famille A - Type BSicherungseinrichtungen zum Schutz des Trinkwas
6、sersgegen Verschmutzung durch Rckflieen - Freier Auslaufmit nicht kreisfrmigem berlauf (uneingeschrnkt) -Familie A, Typ BThis European Standard was approved by CEN on 29 May 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
7、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 CEN Management Centre or to any CEN member.This European Standard exists in three official versions (Engl
8、ish, 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 CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, C
9、yprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOM
10、IT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13077:2008: EBS EN 13077:2008EN 13077:2008 (E) 2 Contents Page Forew
11、ord3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Designation 6 5 Symbolization.6 6 Materials .7 7 Requirements.7 8 Marking (not required for site constructed products) .12 9 Technical documents 12 Annex A (informative) Relationship between h and l for air gap Fami
12、ly A, Type B with rectangular overflow 13 Annex B (normative) Alternative overflow arrangements.14 B.1 General14 B.2 Horizontal overflow arrangement.14 B.3 Letterbox overflow extension arrangement15 BS EN 13077:2008EN 13077:2008 (E) 3 Foreword This document (EN 13077:2008) has been prepared by Techn
13、ical Committee 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 December 2008, and conflicting national standards shall be with
14、drawn at the latest by December 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 13077:2003. Compared
15、 to the previous edition of the document the following changes have been made: a) definitions in Clause 3 revised; b) Annex B on alternative overflow arrangements added; c) editorial errors corrected. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the foll
16、owing countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Repub-lic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sl
17、ovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 13077:2008EN 13077:2008 (E) 4 Introduction In respect of potential adverse effects on the quality of water intended for human consumption, caused by the product covered by this European Standard: a) this European Standard provides no i
18、nformation as to whether the product may be used without restric-tion 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, existing national regu-lations concerning the use and/or the characteristics of this product re
19、main in force. BS EN 13077:2008EN 13077:2008 (E) 5 1 Scope This European Standard specifies the characteristics and the requirements of air gap with non-circular overflow (unrestricted) Family A, Type B for nominal flow velocity not exceeding 3 m/s. Air gaps are devices for protection of potable wat
20、er 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 physico-chemical characteristics of materials of construction used for the purpose and application to ensure compliance with this Eu
21、ropean Standard during normal working use. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated refer-ences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any ame
22、ndments) 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 document, the terms and definitions given in EN 1717:2000 and the following apply
23、. 3.1 air gap with non-circular overflow (unrestricted) Family A, Type B (“AB“ air gap) permanent and vertical distance between the lowest point of the inlet orifice and the critical water level, and whose overflow is non-circular in design NOTE See Figure 1 for the design principle. Figure 1 Design
24、 principle 3.2 spillover level level at which water will start to overflow the receiving vessel with all outlets closed BS EN 13077:2008EN 13077:2008 (E) 6 3.3 critical water level physical or piezometric level of the liquid reached in any part of the appliance 2 s after closing the water inlet star
25、ting from maximum level 3.4 dimension h height between the spillover level and the critical level NOTE See 7.4 for measurement and calculation. For example, see Annex A. 3.5 maximum level highest water level H reached above the spillover level with flow rate Q applied and all outlets closed 3.6 diam
26、eter of feed pipe (bore D) maximum internal diameter (or calculated from the equivalent cross sectional area) found within the last metre of the supply pipe or the DN of the inlet connection 4 Designation An air gap with non-circular overflow (unrestricted) Family A, Type B is designated by: name; r
27、eference to this European Standard, i.e. EN 13077; family and type; denomination (see 3.7 DN or D). EXAMPLE Air gap, EN 13077, Family A, Type B, DN 15. 5 Symbolization The graphic representation of the air gap with non-circular overflow (unrestricted) Family A, Type B is as follows (see Figure 2). F
28、igure 2 Graphic symbol BS EN 13077:2008EN 13077:2008 (E) 7 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, shall sat
29、isfy the European Standards and national acceptance criteria and/or national restrictions for use currently in force in EU and EFTA. They shall be compatible among themselves and with the water supplied and with the fluids or substances that can come into contact with them. There are no special requ
30、irements 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 three parts: water inlet device; receiving vessel (container); non-circular overflow. 7.2 Wat
31、er inlet device Every float-operated valve or other device, which controls the inflow of water to a receiving vessel, shall be securely and rigidly fixed to that vessel. Every feed pipe supplying water to such a valve assembly or other device shall be fixed in its position to pre-vent it from moving
32、 or buckling. The feed pipe, inlet device and its outlet shall not come into contact in any way with a product from down-stream; it shall always be above level H (see Figure 3). When maintaining the maximum flow rate at normal operating conditions, if contact is observed between the upstream compone
33、nts and the liquid in the receiving vessel due to splashing, foaming or turbulence, the air gap shall be increased to a point where no contact is observed. BS EN 13077:2008EN 13077:2008 (E) 8 Key A air gap (distance) D internal diameter of feed pipe (bore) H maximum level 1 feed pipe 2 feed orifice
34、3 receiving vessel 4 spillover level 5 optional warning pipe 6 Uw 5h 7 critical water level (distance h) Figure 3 Air gap with non-circular overflow (unrestricted) Family A, Type B 7.3 Overflow arrangements The overflow arrangements shall be of non-circular design, shall discharge immediately into f
35、ree air and shall be totally unobstructed. For air gaps Family A, Type B the critical water level shall be established and the air gap distance measured from the lowest point of the water inlet to the critical water level (see 3.3). The height of the overflow arrangement Ow is 2D + h and never less
36、than 20 mm (see Figures 4 and 5). BS EN 13077:2008EN 13077:2008 (E) 9 Key 1 Cw 5 h 2 Ow 2D + h and never less than 20 mm 3 l 10 h Figure 4 Rectangular overflow arrangement Key 1 Cw 5 h 2 Ow 2D + h and never less than 20 mm 3 l 10 h Figure 5 Letterbox overflow arrangement For multiple inlets D is the
37、 largest feed pipe bore diameter. NOTE There is no relationship between the maximum water level and the top most level of the overflow arrangement. An additional circular warning pipe can also be fitted if required. BS EN 13077:2008EN 13077:2008 (E) 10 7.4 Air gap distance 7.4.1 Single supply For ai
38、r gaps Family A, Type B the critical water level 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). The distance A is 2D and not less than 20 mm and h is determined either by: a) measurement of the depth of wa
39、ter above the spillover level of the overflow arrangement, 2 s after the inflow equal to Q = 0,14D2in litres per minute 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 bore of the inlet, (see 3.6) and with all out-lets including o
40、ptional warning pipe (except the overflow arrangement) closed, based on velocity of 3 m/s, or the maximum recommended flow rate for manufactured appliances, when the flow rate is higher than Q; b) calculating the depth of water above the spillover level of the overflow arrangement using the followin
41、g equation: 323143,310=lQh (1) where Q is the inflow in litres per minute at 3 m/s (Q = 0,14 D2); l is the width of the overflow arrangement in millimetres. The calculation is only valid where: width (l) is greater than or equal to 10 h at the spillover level; crest thickness of the overflow arrange
42、ment (Cw) is less than or equal to 5 h; upstream face of the overflow arrangement (Uw) is vertical to a depth greater than or equal to 5 h; the depth of the overflow arrangement or notch (Ow) is greater than or equal to 2D + h and never less than 20 mm. When the overflow is not rectangular in design
43、 it shall satisfy air gap dimension A by test; see 7.4.1 a). 7.4.2 Multiple supplies In the case of multiple feed pipes to a single vessel having a non-circular unrestricted overflow, the distance of the air gaps for the potable water supply shall be dimension A above the critical water level. The c
44、ritical water level (3.3) shall be determined 2 s after stopping the inflow with all feed pipes discharging at an individual in-flow calculated at Q = 0,14D2 in litres per minute. If the flow rate Q cannot be achieved, apply a dynamic pres-sure of 1 MPa (10 bar) on all inlets. No feed orifice shall
45、be less than distance A above the critical water level. For calculating air gap distance A, use: =22 DA (2) BS EN 13077:2008EN 13077:2008 (E) 11 7.4.3 Backflow/back pressure If the receiving vessel can be subject to positive pressure backflow, it is important that the inlet orifice is posi-tioned so
46、 that the ascending/returning backflow fluid cannot contaminate it. 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 shall not compromise the overflow arrangement is incorporated, i.e. no
47、n-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 meas-ured horizontally and vertically downward. 7.5 Verification 7.5.1 General Verification can be achieved by calculation or by measure
48、ment. 7.5.2 Procedure for verification by measurement (see 7.4.1 a) and 7.4.2) a) Sequence of test: 1) Close all outlets (except the overflow). 2) Identify D. 3) Calculate Q. 4) Apply flow rate Q and maintain maximum water level. 5) Note contact with inlet device(s) during filling and at maximum lev
49、el. 6) Stop flow rate Q. 7) After 2 s establish distance h. 8) Measure air gap distance between distance h and the lowest point of the feed orifice. b) Requirements: 1) No contact is possible between the receiving vessel fluid and the inlet device(s). 2) The height Ow shall be 2D + h and never less than 20 mm. 3) The air gap distance A shall be 2D and never less than 20 mm. 7.5.3 Procedures for verification by calculation See 7.4.1, b). BS EN 13077:2008EN 13077:2008 (E) 12 8 Marking (not required for site
