IEC 61770 pdf download.Electric appliances connected to the water mains – Avoidance of backsiphonage and failure of hose-sets
1 Scope
This International Standard specifies requirements for appliances for household and similar purposes to prevent the backsiphonage of non-potable water into the water mains. It also specifies requirements for hose-sets used for connecting such appliances to the water mains that supply water at a pressure not exceeding 1 MPa. NOTE 1 Examples of similar purposes are the installation of appliances in canteens, restaurants, launderettes and communal flats. NOTE 2 This standard does not apply to – appliances used for dry cleaning; – appliances for medical purposes; – appliances intended for industrial purposes; – water heaters that are an integral part of the water supply system; – water coolers that are an integral part of the water supply system. NOTE 3 The connection of the appliance to the water mains may be temporary or permanent. NOTE 4 When reference is made to the water mains, water supplied from a cistern or similar system is also included. NOTE 5 Many countries have requirements concerning the prevention of contamination of potable water as a result of contact with unsuitable materials upstream of a backflow prevention device.
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 referenced document (including any amendments) applies. IEC 60730-2-8, Automatic electrical controls for household and similar use – Part 2: Particular requirements for electrically operated water valves, including mechanical requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. 3.1 potable water water which is obtained directly from the potable water mains and remains in a closed system up to the backflow prevention device 3.2 non-potable water water which leaves the closed system after having passed the backflow prevention device 3.3 backflow prevention device means to prevent contamination of potable water by backflow of non-potable water NOTE Examples are airgaps, dynamic backflow preventers and pipe interrupters.3.4 airgap unobstructed free distance between the water inlet or the end of the feed pipe and the critical water level NOTE A distance is considered to be unobstructed if the airflow into the feed pipe under vacuum conditions is not restricted by the construction of the appliance. 3.5 pipe interrupter device without movable or elastomeric parts, into which air can enter while water is passing through it 3.6 dynamic backflow preventer backflow prevention device which prevents backsiphonage by the use of moving parts 3.7 overflow means for discharging excess water from the appliance when the normal outlet is obstructed 3.8 maximum water level highest level of the non-potable water in any part of the appliance when it operates continuously under fault conditions 3.9 critical water level level to which the non-potable water is reduced from the maximum water level 2 s after water inlets have been closed 3.1 0 hose-set assembly consisting of a flexible hose and couplings and used for connecting the appliance to the water mains Note 1 to entry: Hose-sets need not be pre-assembled. Couplings may be removable with or without the aid of a tool. 3.1 1 detachable part part which can be removed without the aid of a tool
4 General requirements
4.1 Appliances shall be provided with a backflow prevention device. For appliances incorporating a water softener located upstream of an airgap or pipe interrupter, a dynamic backflow preventer shall be incorporated upstream of the water softener. Other components presenting a potable water hazard, such as dispensers for adding cleaning, rinsing, softening or similar agents to the water, shall not be located upstream of the backflow prevention device. Pipework containing potable water located upstream of a backflow prevention device shall not pass through non-potable water in the appliance.
IEC 61770 pdf download
