Backflow Prevention. ASHRAE : American Society of Heating, Refrigeration and Air- Conditioning Engineers

Transcription

1 Backflow Prevention ASHRAE : American Society of Heating, Refrigeration and Air- Conditioning Engineers Dubai, April 12 th, 2016

2 Watts Water overview Mission To improve comfort, safety, and quality of life for people around the world through our expertise in a wide range of water technologies. To be the best in the eyes of our associates, customers, and shareholders. 2

3 Industry Leading Brands 3

4 SOCLA, Key numbers 4, facilities (France and Germany) 74, M 2014 annual sales 300 employees Customers worldwide 4

5 Presentation description Backflow Prevention This presentation serves as an introduction to further the understanding of the basic principles of backflow, various hydraulic systems used to protect the environment from contamination of potable water sources. 5

6 Presentation description After this presentation, you will be able to perform the following tasks: Explain the basic concepts and definitions of backflow Identify the risks and select the means to prevent pollution Understand basic types of hydraulics equipment that control backflow 6

7 Presentation Outline Scope of Standard BS EN1717 Introduction : what is a Back Siphonage Pressure Backflow? Determination of fluid categories which are could be in contact with potable water Determination of installation characteristics How to determine the protection units Matrix of protection units Protection devices to prevent pollution by backflow Guide table 7

8 Protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow BS EN1717 : Scope The standard deals with the means to be used to prevent the pollution of potable water inside premises and general requirements of protection devices to avoid pollution by backflow. The hygiene protection specifications of this standard are applicable to all the standards for systems or appliances connected to the private supply system for water intended for human consumption This standard specifies the minimum requirements for product standards of protection units. The product standards are used to detail product specifications. In the absence of a product standard, this standard is used as a reference in order to draw up a specification for the products out of new development. 8

9 Backflow Prevention Water installations, due to their design or construction shall not be liable to generate pollution of public, or private potable water supply system by residual matters, harmful water or any undesirable substance. 9

10 Analysis method of the risks at the point of use and choice of protection A backflow of fluid in a potable water supply system can occur by: 10

11 Back siphonage Back siphonage: by a partial vacuum (drop in pressure) in potable water supply system (due for example to the bursting of pipe, the operation of a booster pump, excessive water demands in a part of the system, water taken for emergency use from a hydrant) 11

12 Pressure backflow Pressure backflow: by a back pressure originating in a non-potable system in which the pressure exceeds the pressure in the potable water system. 12

13 Determination of fluid categories which are or could be in contact with potable water Fluid representing a human health hazard due to the presence of microbiological or viral elements Fluid representing some human health hazard due to the presence of one or more toxic or very toxic substances (1) or one or more radioactive, mutagenic or carcinogenic substances Fluid representing some human health hazard due to presence of one or more harmful substances (1) Fluid presenting no human health hazard. Fluid recognized as being fit for human being, including water taken from a potable water distribution system, which can have undergone a change in taste, odour, colour or temperature (heating or cooling) Water to be used for human consumption coming directly from a potable water distribution system (1) The boarder between Cat 3 and Cat 4 is in principle LD50 = 200mg/kg body weight in reference to the EU Directive 93/21 EEC dated of April 27th,

14 Determination of the installation characteristics Pressure: define whether the protection point (existing or foreseen) or failing this, the point of connection of the apparatus is subjected to atmospheric pressure (p=atm) or to a pressure exceeding atmospheric pressure (p>atm) The situation will be p=atm if the protection point (existing, foreseen) or, failing this, the point of connection of the apparatus to the potable water network is located above the Maximal operational level. The situation will be p> atm if the protection point (existing, foreseen or, failing this, the point of connection of the apparatus to the potable water network is located this maximal operational level 14

15 How to determine the protection point? RT1b RT1d EA RT1a EA RT1c RT1: sanitary or alimentary purpose RT2: technical purpose (HVAC) RT3: fire protection RT4: watering purpose (irrigation) RT5: specific purpose (industrial activities, Laundromat, car wash, ) RT1e EA EA RT2 RT3 RT5 EA EA EA EA EA EA EA N P N B RT4 N B : «branching» level Public potable water system Private potable water system N E N P : «branch pipe» level N E : «equipment» level N E N E 15

16 Matrix of the protection units appropriate to fluid categories BA Fluid category BP with controllable reduced pressure zone CA Fluid category 1 2 BP with different non controllable pressure zones Covers the risk Covers the risk only if p = atm does not cover the risk EA / EC Fluid category Fluid category Controllable antipollution check valve EB / ED Non controllable antipollution check valve Only for certain domestic use Covers the risk Covers the risk only if p = atm does not cover the risk HA Fluid category Fluid category Hose union BP HD Hose union anti vacuum valve Covers the risk Covers the risk only if p = atm does not cover the risk 16

17 Antipollution check valve type EA Many water suppliers are now requiring containment at the water meter as a condition for the water user to receive or continue to receive the public water supply. 17

18 Hose Union Backflow Preventer type HA Backsiphonage protection Non-continuous pressure Non-testable 18

19 Hose Union Backflow Preventer type HA Normal Flow FLOW 19

20 Hose Union Backflow Preventer type HA Backsiphonage 20

21 Hose Union Backflow Preventer type HA 21

22 Backflow preventer with different non controllable pressure zone type CA Backsiphonage and backpressure protection Continuous pressure Non-testable Occasional water discharge 22

23 Backflow preventer with different non controllable pressure zone type CA Static Flow 57psi 60psi 52psi 23

24 Backflow preventer with different non controllable pressure zone type CA Normal Flow 56psi 60psi FLOW 60psi 57psi 51 psi 52psi No more than 25psi of loss at rated flow 24

25 Backflow preventer with different non controllable pressure zone type CA Backsiphonage 0psi 60psi 52psi 51 psi 25

26 Backflow preventer non controllable type CA Backsiphonage and backpressure protection Continuous pressure Non-testable Occasional water discharge 26

27 Backflow preventer with different non controllable pressure zone type CA Protects against backpressure and back siphonage SUPPLY WATTS AUTOMATIC FEED VALVE DRAIN BOILER AIR GAP RETURN Residential Boiler Installation 27

28 Backflow Preventer with controllable reduced pressure zones type BA Backsiphonage / backpressure protection Continuous pressure Occasional water discharge Install above grade and allow space 60psi for normal testing and maintenance Typical Use: Everywhere Check with local Authorities 56psi 51 psi 28

29 Backflow Preventer with controllable reduced pressure zones type BA Static Flow 57psi 60psi 60psi 56psi 52psi 51 psi 29

30 Backflow Preventer with controllable reduced pressure zones type BA 56psi Dynamic Flow FLOW 60psi 60psi 56psi psi psi 30

31 Backflow Preventer with controllable reduced pressure zones type BA Backsiphonage 0psi 60psi 56psi 52psi 51 psi 31

32 Guide table to determining the fluid category from which protection is required 60psi 56psi 51 psi 32

33 Water main protection is our daily concern 60psi 56psi 51 psi 33