1、BRITISH STANDARDBS EN 14622:2005Devices to prevent pollution by backflow of potable water Air gap with circular overflow (restricted) Family A, type FThe European Standard EN 14622:2005 has the status of a British StandardICS 13.060.20; 91.140.60g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3
2、g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIBS EN 14622:2005This British Standard was published under the authori
3、ty of the Standards Policy and Strategy Committee on 26 January 2006 BSI 26 January 2006ISBN 0 580 47619 7National forewordThis British Standard is the official English language version of EN 14622:2005.The UK participation in its preparation was entrusted by Technical Committee B/504, Water supply,
4、 to Subcommittee 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 docum
5、ent may 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. U
6、sers are 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 chan
7、ge, and 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 dis
8、played in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14622May 2005ICS 13.060.20; 91.140.60Eng
9、lish versionDevices to prevent pollution by backflow of potable water - Airgap with circular overflow (restricted) - Family A, type FDispositifs de protection contre la pollution de leau potablepar retour - Surverse avec trop plein circulaire (limite) -Famille A, type FSicherungseinrichtungen zum Sc
10、hutz des Trinkwassersgegen Verschmutzung durch Rckflieen - Freier Auslaufmit kreisfrmigem berlauf (eingeschrnkt) - Familie A,Typ FThis 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 g
11、iving 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 versi
12、ons (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, Cypr
13、us, Czech 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 D
14、E NORMALISATIONEUROPISCHES 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 14622:2005: ELicensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontro
15、lled Copy, (c) BSIEN 14622:2005 (E) 2 Contents Page Foreword 3 Introduction4 1 Scope .5 2 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 Licensed Cop
16、y: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 3 Foreword This European Standard (EN 14622:2005) has been prepared by Technical Committee CEN/TC 164 “Water supply“, the secretariat of which is held by AFNOR. This European Standard shall be given the status
17、 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 the latest by November 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
18、following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, S
19、weden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (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
20、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, existing national regulations concerning the us
21、e and/or the characteristics of this product remain in force. Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 5 1 Scope This European Standard specifies the characteristics and the requirements of air gaps with circular overflow (restricted) fam
22、ily A, type F for nominal flow velocity not exceeding 3 m/s. Air gaps are devices for protection of potable water in water installations from pollution. This document applies to air gaps in factory assembled products and to constructed air gaps in situ, and defines the physicochemical characteristic
23、s of materials of construction used for the purpose and application 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 applie
24、s. For undated references, the latest edition of the referenced 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 purpos
25、es of this European Standard, the terms and definitions of EN 1717:2000 and the following apply. 3.1 air gap with circular overflow (restricted) family A, type F a permanent and vertical distance between the lowest point of the feed orifice and the critical water level or the top of the overflow hav
26、ing a circular overflow capable of draining the maximum inflow of water under fault condition NOTE See Figure 1 for 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 Licensed Copy: Wang Bin, na
27、, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 6 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 starting from the maximum level 3.4 dimension h height between the spillover level and
28、 the critical level 3.5 maximum level highest water level H reached above the spillover level under positive pressure fault condition with all outlets closed 3.6 splashing (requirements for protection) when maintaining the maximum flow rate at the maximum level if a contact is observed between the u
29、pstream component 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 3.7 diameter of feed pipe (Bore D) diameter D is the maximum internal diameter within the last metre of the supply device and the c
30、onnecting pipework or the DN of the inlet connection 4 Designation An air gap with circular overflow (restricted) family A, type F is designated by: name; reference to this European Standard; denomination (see 3.7 DN or D); family and type;. Example for a designation of an air gap with circular over
31、flow (restricted) Family A (A), Type F (F), DN 15 Air gap, EN 14622, Family A, Type F, DN 15 Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 7 5 Symbolization Figure 2 Graphic symbol 6 Materials The manufacturer shall state the type of materials
32、 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 satisfy the European standards and national acceptance criteria and/or national restrictions for use currently in force in E
33、U 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 requirements concerning the materials downstream of the atmospheric outlet opening provided they do not have any harmful effect o
34、n 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. 7.2 Water inlet device Every feed pipe, float-operated valve or other device which controls the inflow of water to a receiving
35、 vessel shall be securely and rigidly fixed to maintain the air gap. Every feed pipe supplying water to such a valve assembly or other device shall be fixed in its position to prevent it from moving or buckling. The feed pipe, the inlet device and the outlet of the inlet device shall not come into c
36、ontact in any way with a product from downstream, they shall always be above level H (see Figure 3). Submerged supply pipes to the inlet device are not permitted. Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 8 Key 1 Feed pipe 2 Feed orifice 3
37、 Receiving vessel 4 Spillover level 5 Critical level (distance h) 6 Overflow pipe 7 Air break to drain A Air gap (distance) D Internal diameter of feed pipe (bore) H Maximum level Figure 3 Air gap with circular overflow (restricted) family A, type F 7.3 Overflow arrangements The area of the minimum
38、cross section of the overflow pipe throughout its length shall be equal to four times the inlet pipes (D) cross sectional area. All circular overflow arrangements shall ensure an air break prior to any connection to a drainage system. An air break to drain shall be provided see EN 1717, Clause 9. 7.
39、4 Air gap distance 7.4.1 Single supply For air gaps family A, type F 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). The air gap distance A shall be 2 D and never less than 20 m
40、m and can be determined by one of the following methods: Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005 (E) 9 a) h 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
41、,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 3.7) and with all outlets (except the overflow) closed, based on a velocity of 3 m/s, or the maximum recommended flow rate for manufactured appliances
42、when the flow rate is higher than Q; b) by measurement of the air gap distance A from the lowest point of the water inlet device and the uppermost point of the overflow outlet bore. 7.4.2 Multiple supplies In the case of multiple feed pipes to a single vessel having a circular unrestricted overflow,
43、 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 dynamic p
44、ressure of 1 MPa (10 bar) on all inlets. No feed orifice shall be less than distance A above the critical water level. After calculations the distance A shall not be less than 20 mm. For calculating air gap distance A use =22 DA 7.4.3 Backflow/back pressure If the receiving vessel can be subject to
45、positive pressure backflow, it is important that the inlet 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 ra
46、te to a rate which will not compromise the overflow arrangement 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
47、.5 Verification 7.5.1 General Verification can be achieved by test or by measurement. 7.5.2 Procedure for verification by test See 7.4.1 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 w
48、ith inlet device(s) during filling and at the maximum level; 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: Licensed Copy: Wang Bin, na, Mon Apr 17 08:17:14 BST 2006, Uncontrolled Copy, (c) BSIEN 14622:2005
49、(E) 10 no contact between the downstream fluid and the inlet device(s); the air gap A shall be 2 D and never less than 20 mm. 7.5.3 Procedure for verification by measurement (single supply only) a) Sequence of measurement see 7.4.1 (b). b) Requirements the measured air gap shall meet the requirements of dimension A (see 7.4.1). 8 Marking (not required for site constructed products) Each appliance incorporating an air gap with circular overflow (restricted) family A, type F shall be clearly and p
