Devices to prevent pollution by backflow of potable water - Controllable backflow preventer with reduced pressure zone - Family B - Type A

This document specifies the field of application, the dimensional, the physico-chemical, the design, the hydraulic, the mechanical, and the acoustic characteristics of controllable backflow preventers with reduced pressure zone Family B Type A.
This document covers controllable backflow preventers of Family B Type A, with reduced pressure zones, intended to prevent pollution of potable water by backflow, caused by backsiphonage or by backpressure.
It is applicable to controllable backflow preventers in denominations DN 6 up to DN 250.
It covers controllable backflow preventers of PN 10 that are capable of working without modification or adjustment:
-   at any pressure, up to 1 MPa (10 bar);
-   with any pressure variation, up to 1 MPa (10 bar);
-   in permanent duty at a limited temperature of 65 °C and for maximum 1 h at 90 °C.
It specifies also the test methods and requirements for verifying their characteristics, the marking and the presentation at delivery.

Sicherungseinrichtungen zum Schutz des Trinkwassers gegen Verschmutzung durch Rückfließen - Systemtrenner mit kontrollierbarer druckreduzierter Zone - Familie B - Typ A

Dieses Dokument legt den Anwendungsbereich, die maßlichen und physikalisch chemischen Anforderungen, die Anforderungen an die Konstruktion, die hydraulischen, mechanischen und akustischen Anforderungen für Systemtrenner mit kontrollierbarer druckreduzierter Zone, Familie B, Typ A fest.
Das vorliegende Dokument gilt für Systemtrenner mit kontrollierbarer druckreduzierter Zone, Familie B, Typ A, die verhindern sollen, dass durch Rücksaugen oder Rückdrücken Wasser zurückfließt und dadurch Trinkwasser verschmutzt wird.
Es gilt für Systemtrenner der Nennweiten DN 6 bis DN 250.
Es gilt für Systemtrenner mit einem Nenndruck PN 10, die ohne Abänderung oder Nachstellung arbeiten:
-   bei jedem Druck bis 1 MPa (10 bar);
-   bei jeder Druckschwankung bis 1 MPa (10 bar);
-   unter Dauerbelastung bei einer Grenztemperatur von 65 °C und für maximal 1 h bei 90 °C.
Die Norm enthält ferner Festlegungen für die Prüfverfahren und Anforderungen zum Nachweis dieser Eigenschaften, die Kennzeichnung und den Lieferzustand.

Dispositifs de protection contre la pollution de l'eau potable - Disconnecteur à zone de pression réduite contrôlable - Famille B - Type A

Le présent document spécifie le domaine d'application, les caractéristiques dimensionnelles, physico-chimiques, de conception hydrauliques, mécaniques et acoustiques de disconnecteurs à zone de pression réduite contrôlable de Famille B, Type A.
Le présent document s’applique aux disconnecteurs de Famille B, Type A à zone de pression réduite contrôlable, destinés à empêcher la pollution de l’eau potable par retour d'une eau par contre-pression ou siphonnage.
Il est applicable aux disconnecteurs contrôlables de dénomination DN 6 à DN 250.
Il s’applique aux disconnecteurs contrôlables de PN 10 qui doivent pouvoir fonctionner sans modification ni réglage :
-   à toute pression, jusqu'à 1 MPa (10 bar) ;
-   pour toute variation de pression, jusqu'à 1 MPa (10 bar) ;
-   en service continu à une température limite de 65 °C et pendant 1 h au maximum à 90 °C.
Il spécifie également les méthodes d’essai et les exigences pour vérifier leurs caractéristiques, le marquage et la présentation à la livraison.

Naprave za varovanje pred onesnaženjem pitne vode zaradi povratnega toka - Sistemski ločevalnik z nadzorovanim območjem znižanega tlaka - Družina B - Tip A

General Information

Status
Not Published
Current Stage
4060 - Closure of enquiry - Enquiry
Due Date
08-Oct-2020
Completion Date
08-Oct-2020

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SLOVENSKI STANDARD
oSIST prEN 12729:2020
01-september-2020
Naprave za varovanje pred onesnaženjem pitne vode zaradi povratnega toka -
Sistemski ločevalnik z nadzorovanim območjem znižanega tlaka - Družina B - Tip A

Devices to prevent pollution by backflow of potable water - Controllable backflow

preventer with reduced pressure zone - Family B - Type A
Sicherungseinrichtungen zum Schutz des Trinkwassers gegen Verschmutzung durch

Rückfließen - Systemtrenner mit kontrollierbarer druckreduzierter Zone - Familie B - Typ

Dispositifs de protection contre la pollution de l'eau potable - Disconnecteur à zone de

pression réduite contrôlable - Famille B - Type A
Ta slovenski standard je istoveten z: prEN 12729
ICS:
13.060.20 Pitna voda Drinking water
91.140.60 Sistemi za oskrbo z vodo Water supply systems
oSIST prEN 12729:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 12729:2020
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oSIST prEN 12729:2020
DRAFT
EUROPEAN STANDARD
prEN 12729
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2020
ICS 13.060.20; 91.140.60 Will supersede EN 12729:2002
English Version
Devices to prevent pollution by backflow of potable water
- Controllable backflow preventer with reduced pressure
zone - Family B - Type A

Dispositifs de protection contre la pollution de l'eau Sicherungseinrichtungen zum Schutz des Trinkwassers

potable - Disconnecteur à zone de pression réduite gegen Verschmutzung durch Rückfließen -

contrôlable - Famille B - Type A Systemtrenner mit kontrollierbarer druckreduzierter

Zone - Familie B - Typ A

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 164.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12729:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 6

4 Denomination................................................................................................................................................... 7

5 Designation ....................................................................................................................................................... 7

6 Symbolization ................................................................................................................................................... 8

7 Physico-chemical characteristics .............................................................................................................. 8

7.1 General................................................................................................................................................................ 8

7.2 Materials ............................................................................................................................................................ 8

7.3 Surface coating ................................................................................................................................................. 8

8 Design .................................................................................................................................................................. 9

8.1 General................................................................................................................................................................ 9

8.2 Relief valve ........................................................................................................................................................ 9

9 Characteristics and tests ............................................................................................................................ 10

9.1 General.............................................................................................................................................................. 10

9.2 General tolerances ....................................................................................................................................... 10

9.3 Dimensional characteristics ..................................................................................................................... 11

9.4 Mechanical characteristics ........................................................................................................................ 12

9.5 Tightness characteristics ........................................................................................................................... 16

9.6 Hydraulic characteristics ........................................................................................................................... 19

9.7 Compatibility with the products used for shock disinfection of the networks ...................... 23

9.8 Acoustic tests .................................................................................................................................................. 24

10 Marking and technical documents ......................................................................................................... 24

10.1 Marking ............................................................................................................................................................ 24

10.2 Technical documents ................................................................................................................................... 25

11 Presentation at delivery ............................................................................................................................. 26

Annex A (normative) General Information for Coating ................................................................................. 27

Bibliography ................................................................................................................................................................. 29

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European foreword

This document (prEN 12729:2020) has been prepared by Technical Committee CEN/TC 164 “Water

supply”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12729:2002.
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Introduction

In respect of potential adverse effects on the quality of water intended for human consumption, caused

by the product covered by this document:

a) this document provides no information as to whether the product may be used without restriction

in any of the Member States of the EU or EFTA;

b) it should be noted that, while awaiting the adoption of verifiable European criteria, existing

national regulations concerning the use and/or the characteristics of this product remain in force.

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1 Scope

This document specifies the field of application, the dimensional, the physico-chemical, the design, the

hydraulic, the mechanical, and the acoustic characteristics of controllable backflow preventers with

reduced pressure zone Family B Type A.

This document covers controllable backflow preventers of Family B Type A, with reduced pressure

zones, intended to prevent pollution of potable water by backflow, caused by backsiphonage or by

backpressure.

It is applicable to controllable backflow preventers in denominations DN 6 up to DN 250.

It covers controllable backflow preventers of PN 10 that are capable of working without modification or

adjustment:
— at any pressure, up to 1 MPa (10 bar);
— with any pressure variation, up to 1 MPa (10 bar);

— in permanent duty at a limited temperature of 65 °C and for maximum 1 h at 90 °C.

It specifies also the test methods and requirements for verifying their characteristics, the marking and

the presentation at delivery.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 806-1, Specifications for installations inside buildings conveying water for human consumption —

Part 1: General

EN 1717, Protection against pollution of potable water in water installations and general requirements of

devices to prevent pollution by backflow

EN 10310:2003, Steel tubes and fittings for onshore and offshore pipelines — Internal and external

polyamide powder based coatings

EN 13828, Building valves — Manually operated copper alloy and stainless steel ball valves for potable

water supply in buildings — Tests and requirements

EN 14901, Ductile iron pipes, fittings and accessories — Epoxy coating (heavy duty) of ductile iron fittings

and accessories — Requirements and test methods

EN ISO 3822-1, Acoustics — Laboratory tests on noise emission from appliances and equipment used in

water supply installations — Part 1: Method of measurement (ISO 3822-1)

EN ISO 3822-3:2018, Acoustics — Laboratory tests on noise emission from appliances and equipment used

in water supply installations — Part 3: Mounting and operating conditions for in-line valves and

appliances (ISO 3822-3:2018)

EN ISO 6509-1, Corrosion of metals and alloys — Determination of dezincification resistance of copper

alloys with zinc — Part 1: Test method (ISO 6509-1)
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3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1717 and EN 806-1 and the

following apply:

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
controllable backflow preventer with reduced pressure zone-Family B-Type A
specific characteristics of this device called “BA”, are as follows:

• 3 pressure zones such that upstream p > intermediate p > downstream p (static no flow and under

1 i 2
water flow conditions);
• p − p > 14 kPa (140 mbar);
1 i

• connection from the intermediate pressure zone (p) to the atmosphere when p − p ≤ 14 kPa

i 1 i
(140 mbar);

• disconnection by venting the intermediate pressure zone (p ) to the atmosphere when p < 14 kPa

i 1
(140 mbar);
• a minimum set discharge flow (backflow rate);

• devices that allow verification in every zone of the disconnection and of the sealing of the protection

devices (check valves, discharge valve)
Note 1 to entry: see Figure 1
Key
1 upstream zone p
2 intermediate zone p
3 downstream zone p2
Figure 1 — Design principle

Note 2 to entry: For the purpose of this document, “controllable backflow preventer BA” is hereafter referred to

as “device”
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3.2
in line device

installed within the pipework where the downstream flow of water supplies one or more points of use

3.3
incorporated device
integrated in appliances e.g. cleaning apparatus, heating boilers
3.4
end of line device

installed at the end of the pipework at the point of use for a specific purpose e.g. filling heating system,

jetwasher machine, …
4 Denomination

For the purpose of this document for the devices the nominal size DN is a function of the minimum flow

rate given in Table 6.
5 Designation

A controllable backflow preventer with reduced pressure zone-Family B-Type A is designated by:

• its name;
• its family and its type;
• type of installation (in line, end of line or incorporated device);
• its denomination;
• its size of end connection;
• the material of its body;
• its surface finish (possible coating);
• the acoustic group I, II or nc (for DN ≤ 32);
• the reference to the present standard.
Examples for a designation:

Controllable backflow preventer with reduced pressure zone — Family B — Type A, in line, DN 32,

R 11/4 × R 11/4, bronze, I, EN 12729.

Controllable backflow preventer with reduced pressure zone — Family B — Type A, in line DN 100,

flanged, cast iron, epoxy coated, EN 12729.
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6 Symbolization

The graphic representation of the controllable backflow preventer with reduced pressure zone-

Family B-Type A is as follows (see Figure 2):
Figure 2 — Graphic symbol
7 Physico-chemical characteristics
7.1 General

The selection of materials is the responsibility of the manufacturer, provided they satisfy the following

requirements:
a) materials and coatings shall not contaminate the potable water;

b) in a technical document, the manufacturer shall state the nature of the materials and coatings used;

c) materials with inadequate corrosion resistance shall have additional protection;

d) the materials used shall be suitable for the temperatures specified in the tests in this document;

e) the materials, and in particular copper alloys, for which recommendations or international

standards exist, shall comply with the relevant European standards.
7.2 Materials

All materials in accordance with national regulations of the European Community and/or European

standards may be used.

Copper-zinc alloys containing more than 10 % zinc are subject to dezincification when submitted to

water capable of dezincification. In the countries where the use of products made of dezincification

resistant materials is required, the materials used shall guarantee a dezincification depth less than

200 µm in any direction. For this purpose, materials shall be tested in accordance with EN ISO 6509-1

and the product shall be marked in compliance with the indications according to Clause 10.

7.3 Surface coating
7.3.1 General

The outside and inside surfaces of the device may or may not contain a coating. Such coating shall not

impair the functional characteristics of the device.

The coating for protection of the basic material against corrosion can be either realized by epoxy

coating or by polyamide powder based coating.
7.3.2 Epoxy Coating

Epoxy coating shall fulfill the requirements as described in Annex A based on EN 14901.

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7.3.3 Polyamide Powder based Coating

Polyamide powder coating shall fulfill the requirements as described in Annex A based on EN 10310.

8 Design
8.1 General

a) The internal components of the device shall be accessible for inspection, repair or replacement.

These operations shall be possible on the installed device. Mandatory maintenance can also be

done by removing the device from the pipework for sizes DN ≤ 20. By design, the components shall

be able to be refitted at their initial place, without ambiguity (impossibility of reversal, interchange

of obturators, diaphragms, springs …). A visible mark is not sufficient;
b) the settings of the springs shall be fixed and not adjustable;

c) in line devices and incorporated devices shall comprise three pressure tappings, upstream,

intermediate, downstream, permitting periodic verification of the function of the device;

d) end of line devices shall comprise at least two pressure tappings, upstream and intermediate

permitting periodic verification of the function of the device.
They are placed:
• upstream of the first check valve;
• in the intermediate zone;

It shall be possible to vent the air which can accumulate inside the device at the highest point of the

device;

e) only the pressure of the water of the supply network can operate the control of the internal

components of the device;

f) possible additional control devices (electric, pneumatic, …) shall not adversely affect the backflow

protection function;

g) normally the device shall be installed horizontally. Devices DN ≤ 50 may, be installed in the

downward vertical orientation in accordance with the design of the valve and the manufacturers’

instructions while satisfying all the criteria in this document. If this orientation influences the

function of the devices the tests shall be carried out in all possible orientations.

8.2 Relief valve

The design of the relief valve operation shall be such that when the differential pressure over the

upstream check valve is less than 14 kPa (140 mbar) the relief valve shall be open to ensure positive

safety.

An internal vertical distance h, as shown in the figure x and y (in disconnected position) shall be

provided between the upstream check valve seat and the seat of relief valve:
• h ≥ 5 mm for DN ≤ 15;
• h ≥ 10 mm for 15 < DN ≤ 50;
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• h ≥ 20 mm for DN > 50.

In all the installation positions indicated by the manufacturer, any water retention shall not be possible

within the intermediate zone.

The cross sections of the passage orifices and of the pilot tube for operation of the relief device shall be

2 2

equal to or greater than 45 mm with DN ≥ 15, or 12,5 mm with DN < 15. No dimension for the

calculation of the cross section shall be less than 4 mm. The outside pilot tube shall be made so as not to

be subject to any permanent deformation or rupture under outside stresses.

An air break to drain shall exist between any waste drain and any means of collecting the discharged

water (floor, tundish, curb, sink).

The air break to drain shall meet the dimensional requirements as specified in EN 1717. This air break

to drain shall be:
• either directly incorporated into the device;
• or factory fitted;
• or supplied with the device,
• or guaranteed by the installation.

In the latter case, the relief orifice of the device shall permit, neither the fitting of a standardized

threaded pipe, nor the connection of a standardized pipe or shape, be it by glue, welding or interlocking.

If applicable on the dimension ‘’G” of the outlet of the air break to drain (see in EN 1717), it shall be

possible to fit a standardized drain pipe (Standard EN 1329-1 PVC compact and EN 1453-1 PVC with

structured walls).
9 Characteristics and tests
9.1 General

Performance tests shall be carried out on the device as installed in accordance with the manufacturer’s

technical documents, subject to dimension h being complied with.

If not specified, all tests shall be performed with water at an ambient temperature.

9.2 General tolerances
9.2.1 Tolerance of set parameters
In the absence of any particular specifications:
• flow rate and pressure: ± 2 % of the value specified;
• temperature:cold water: ± 5 °C of the value specified;
hot water: ± 2 °C of the value specified;
other values: ± 2 °C of the value specified;
10 %
• time of the value specified.
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9.2.2 Accuracy of measuring instruments

All the measuring instruments shall have an error limit of ± 2 % of the measured value.

9.3 Dimensional characteristics
9.3.1 Connections
The connection shall be in accordance with the relevant European Standards.
9.3.2 Pressure taps

The devices shall have one test port orifice per zone according to the indications as shown in Figure 3

and Table 1.

The bores for pressure taps shall have over their full length a minimum cross-section of 12,56 mm .

Their smallest dimension shall be not less than 4 mm.

The outlet of isolating valve shall be in accordance to the indications as shown in Figure 3 and Table 1.

Table 1 — Dimension of thread and test parts
DN Thread a
(designation in accordance with ISO 228-1) mm
≤ 15 G 1/8 or G 1/4 > 6,5
20 ≤ DN ≤ 50 G 1/4 > 6,5
> 50 G 1/2 > 13
Key
G Thread
a Test part
Figure 3 — Pressure tap orifice

These test ports shall be fitted with stop valves or other technical means for the verification of the

device e.g. fast couplings, removable plugs, …

If stop valves are fitted, they shall be in accordance with the following requirements:

• For devices DN ≤ 15 G 1/8 or G 1/4 connection female outlet;
• For device 20 ≤ DN ≤ 50 G 1/4 connection female outlet;
• For device DN > 50 G 1/2 connection female outlet.
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9.4 Mechanical characteristics
9.4.1 General

Examples shown in the figures are for guidance only. Laboratory equipment shall be designed to ensure

that the device can be tested in accordance with the requirement.
9.4.2 Mechanical resistance of the body under pressure
9.4.2.1 Requirement

There shall be no visual permanent deformation or rupture of the body or the internal parts of the

device.
9.4.2.2 Test method

Apply at the inlet of the device in increments of 0,1 MPa (1 bar) per 5 s an increase of the static water

pressure up to 2,5 times the PN, the value that equals 2,5 MPa (25 bar); hold this pressure for 5 min.

Observe the device and note any observations.
Verify that the device satisfies the requirement of 9.5.1.1.
9.4.3 Endurance
9.4.3.1 Requirement

a) The endurance test shall be done with the same sample that has been tested according to 9.6.1,

9.6.2, 9.6.3, 9.7.4 and 9.8. After performing the test according to 9.4.4.2 the sample shall fulfill the

requirements according to 9.6.1, 9.6.2, 9.6.3, 9.7.4 and 9.6.4;

b) There shall be no visible damages or deformation of the coating, and of components.

9.4.3.2 Tests
Test 1 — Behaviour at temperature.

Place the complete device for 72 h in an environment at a temperature of 65 °C, and at a relative

humidity of 50 ± 10 %.
Test 2 — Thermal shock.

Following the preceding test, put the complete device at the flow rate as given in the Table 4, supplying

it with water at 90 °C.

Once temperature reaches 85 °C at the outlet of the device, hold the flow rate for 60 min, and then

supply for 10 min with water at 15 °C.
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Test 3 — Mechanical endurance.
A Supply flow; maximum pressure of 0,3 MPa (3 bar) at zero flow
B Supply pressure: (1 ± 0,05) MPa (10 bar ± 0,5 bar)
C Supply pressure: (0,3 ± 0,03) MPa (3 bar ± 0,3 bar)
Key
valve with time control of opening and closing
adjusting valve
6 pressure gauge
Figure 4 — Endurance testing equipment

Following the preceding tests 1 and 2, submit the device placed in the testing equipment (see Figure 4)

+50
to 5 000 cycles at a temperature of 65 °C, each cycle comprising:

• Stage 1: Open valve 5 then valve 1, circulation at a flow rate as given in Table 2 at the value ± 5 %

for (6 ± 2) s;
• Stage 2: Close valve 5 then valve 1;
• Stage 3: Open valve 3, static pressure at 0,3 MPa (3 bar) for (6 ± 2) s;

• Stage 4: Close valve 3, open valve 4. Upstream drain for (6 ± 2) s (opening of the relief valve);

• Stage 5: Close valve 4;

• Stage 6: Open valve 5 then valve 1, circulation at a flow rate as given in Table 2 at the value ± 5 %

for (6 ± 2) s;
• Stage 7: Close valve 5 then valve 1;
• Stage 8: Open valve 2. Static pressure at 1 MPa (10 bar) for (6 ± 2) s;

• Stage 9: Close valve 2, open valve 4. Upstream drain (opening of the relief valve) for (6 ± 2) s;

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• Stage 10: Close valve 4.
The 5 000 cycles are broken down into seven periods as follows:
• 1 250 cycles;
• the device is at rest for 14 hours at ambient temperature;
• 1 250 cycles;

• the device is maintained under load at a static pressure of 1 MPa (10 bar) for 14 h at ambient

temperature;
• 1 250 cycles;

• the device is submitted for 14 h to an upstream pressure of 0,3 MPa (3 bar) and to a downstream

pressure of 1 MPa (10 bar) at ambient temperature;
• 1 250 cycles.
Table 2 — Nominal size versus endurance test flow rate
DN 6 8 10 15 20 25 32 40
Flow rate m /h 0,25 0,4 0,6 1,3 2,2 3,5 5,8 9
DN 50 65 80 100 125 150 200 250
Flow rate m /h 14 24 36 56 56 56 56 56

Perform test according to 9.6.1, 9.6.2, 9.6.3, 9.7.4 and 9.6.4 in the indicated sequence.

9.4.4 Torque test of Captive rotating Nuts and Bending Strength – Tightness of the Body

9.4.4.1 Requirement
a) After unscrewing, no visual damage of the nut shall be detected.

b) There shall be no rupture nor permanent deformation or leakage on the body of the device. The test

shall be carried out under the conditions defined in 9.4.4.2.
9.4.4.2 Test method

The device shall be fixed to the test rig, into operating orientation, as shown in Figure 5, swivel nut

connection shall be tightened with the torque specified in Table 3. Gradually apply torque to the captive

rotating nut/backnut until the tightening torque is reached and maintain it for a period of at least 1 min.

Once it is in water under pressure and without bending stress, the fitting shall be leaktight. In case it is

not leaktight, the tightening torque can be increased.

Apply a load W as shown in Figure 5 corresponding to the bending moment shown in Table 4 according

to the type of product (see 3.2, 3.3 and 3.4). Apply pressure up to 1,6 MPa (16 bar) with increments of

0,1 MPa (1 bar) per 5 s.

Maintain bending moment and pressure for 10 min. When calculating load W corresponding to the

bending moment, loads introduced by the piping and taps and any loads coming from the test apparatus

shall be accounted for.
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Table 3 — Torsional strength
Nominal size DN 10 15 20 25 32 40 50
Tightening torque (Nm) 30 60 75 100 125 150 150
Key
W load
1 isolating valve
2 pressure gauge
Figure 5 — Bending moment testing equipment
Table 4 — Nominal size versus bending moment
N 6 8 10 15 20 25 32 40
In line device 20 30 40 70 110 150 250 300
Bending
moment
End of line device 30 50 70 120 190 220
Incorporated device Not applicable
DN 50 65 80 100 125 150 200 250
In line device 500 750 950 1 300 1 800 2 400 3 800 5 500
Bending
moment
End of line device 300
Incorporated device Not applicable
Verify that the device satisfies the requirements of 9.4.4.1.
9.4.5 Reliability of isolation valves fitted to test ports (if applicable)
9.4.5.1 General

The following test shall only be performed if the isolating valves are not in accordance with the

requirements of EN 13828.
The isolation valves fitted to the pressure taps shall be easily manoeuvrable.

The isolation valves of flanged devices shall be operable by hand without additional tools.

The opening and closing positions shall be defined by mechanical stops.
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oSIST prEN 12729:2020
prEN 12729:2020 (E)
9.4.5.2 Operating torque
9.4.5.2.1 General

Before starting the test, one preliminary cycle shall be carried out. The valve shall then be left for 24 h at

ambient temperature.
The operating torque of the valve is measured
...

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