BS EN 14897:2006 pdf download – Water conditioning equipment inside buildings — Devices using mercury low-pressure ultraviolet radiators — Requirements for performance, safety and testing
4 Requirements
4.1 General The treatment of water with the UV device shall yield a reduction equivalent fluence of at least 400 J/m 2 (40 mJ/cm 2 ), at a wavelength of 254 nm in the defined operational range.
4.2 Radiation chamber The radiation chamber is made of corrosion resistant and UV resistant materials. Materials and substances used shall be suitable for contact with drinking water.
NOTE Product intended for use in water supply systems should comply, when existing, with national regulations and testing arrangements that ensure fitness for contact with drinking water. The Member states, relevant regulators and the EC Commission agreed on the principles of a future unique European Acceptance Scheme (EAS), which would provide a common testing and approval arrangement at European level. If and when the EAS is adopted, European Product Standards will be amended by the addition of an Annex Z/EAS under Mandate M/136, which will contain formal references to the testing, certification and product marking requirements of the EAS. The mechanical design and the construction shall comply with the relevant requirements for the pressure present. Direct or indirect leaking of radiation from the radiation chamber to the environment with a wavelength below 400 nm shall be avoided. Radiation chambers shall be constructed in a way that they are easily serviceable. For UV disinfection devices, the radiation chamber shall be provided with a sensor for a representative irradiation measurement. The location of the sensor shall be designed so that the irradiation measurement is not disturbed by gas bubbles or sediment deposits.
4.3 Low-pressure mercury UV lamps In order not to produce ozone, only lamps with a radiation range above 240 nm shall be used. At the line of 254 nm shall be 85 % of the total radiation intensity in the UV C range at the mercury resonance. Lamp(s) shall be marked with a designation of type. Only those lamps used for the type test shall be used in the UV device. The UV lamp(s) shall be approved for the device by the manufacturer or be equivalent to the approved type used at the type test.
4.4 Electrical
4.4.1 General For the electrotechnical design of UV devices, the relevant EC Directives and CE marking requirements shall be accomodated. Compliance with these EC Directives is a requirement of this standard.(see [3])
4.4.2 UV disinfection devices Controller The UV disinfection device shall be equipped with a controller, which provides the following functions:
when switching on the device, the signal for the waterflow shall be delayed until the minimum irradiance is reached;
operation and failure of the electrical function of each lamp shall be indicated;
operation beyond the permissible limits of operation shall be indicated and a signal shall be provided which allows the waterflow to be stopped; Sensor For the measurement of the irradiation, a sensor shall be provided to ensure disinfection under consideration of possible changes in water UV transmittance and lamp performance. Requirements for the device sensor are given in Annex A. Where national regulations apply, a sensor and monitoring window may have to fulfil certain requirements. NOTE An example for a monitoring window is shown in Annex C.
4.4.3 UV bactericidal treatment devices The UV bactericidal treatment devices shall be equipped with a controller, which provides the following functions:
operation and failure of the electrical function of the lamp(s) shall be indicated;
general malfunction signal shall be provided. The following functions shall be displayed:
device in function;
service time of the UV lamps.
4.5 Performance
The UV device shall apply a reduction equivalent fluence of at least 400 J/m 2 at the end of the lamp service life for the specified flow rates and UV transmittance values. The performance is evaluated with a type test for which the manufacturer shall provide information in accordance with Annex D.
4.6 Labelling The information to be given on a nameplate, which shall be permanently fixed to the UV device and be legible when installed, shall be in accordance with Annex E.