42 of 124  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 08: Electrical Works  Level transmitters shall be provided for non-contact continuously measuring of liquid levels. Maximum  measuring range shall be suitable max. 30 m. Measuring principle shall be operating based on the time-of-flight  method. The sensor shall be suitable for installation in wastewater/sludge and the sensor house shall be made of  316 L or similar material. The housing shall be in protection class IP68. Common communication protocols and  interfaces  such as 0/4...20 mA and Ethernet or 0/4…20mA/HART shall be integrated. The compensation shall  be electronic. The accuracy of the level measuring system shall  as a minimum be 2 mm of the full scale. The  full scale shall be selected according to the location of the level measuring. Device shall have an integrated  overvoltage protection. Detector will be appropriate to be mounted in an open or covered tank and completely  covered and protected against water that may reach on itself  IP68 rate protected from environmental effects.  Control units must have independent balancing features between zero and certain interval and its output must be  between (4-20 mA) as proportional with the level. General accuracy of the measurement device  must not be  higher than (±2 mm) of the measurement device level indicator. The connection between the detector and  control units must be shielded type cable that is available in the market and equipment must be able to operate  with cables up to 60 meters. Material process connection shall be PVDF. Antenna diameter shall be in 40 mm  and its shape shall be horn antenna.  8.8.12 Hydrostatic Level Measurement  Level transmitters shall be provided for continuously measuring of water levels and for control of the  machinery.  Analogue level measuring shall be based on the hydrostatic measuring principle based on the pressure  generated by the height of a liquid column. The pressure acting on the pressure-measuring cell built-in the  sensor shall be converted into a level-proportional electrical signal. The sensor shall be suitable for installation  in wastewater/sludge and the sensor house shall be made of 316 L or similar material. The housing shall be in  protection class IP68. The level transmitter shall provide the PLC with a 4-20 mA level proportional signal and  additionally provide the sensor with the necessary power supply. The transmitter shall automatically  compensate for the atmospheric pressure. The compensation shall be electronic. The accuracy of the level  measuring system shall as a minimum be (±0.2%) of the full scale. The full scale shall be selected according to  the location of the level measuring. The linearity shall be better than 1%. It shall be possible to change the full  scale for the sensor by using a special programming device connected to the sensor. Device shall have an  integral overvoltage protection. Alternatively  level measurement  will be performed by contact free  echo time  measurement device that operates at ultrasonic frequency at locations where required. Equipment will transmit the vibration that is reflected to the detector from the surface of the liquid that is being  measured. Equipment will be consisted of separate control system and a detector that has transmitter and  receiver. Equipment will be provided with automatic temperature balancing mechanism and will comply with the  approved design for operation under defined weather conditions. 8_Vol3_d4 3_Section 8 electrical works_en_GIR rev6.doc 