43 of 124  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 08: Electrical Works  Measuring principle shall be ultrasonic waves. Process temperature shall be 1 to 50 °C (34 to 122 °F). Sensor  shall be designed with wiper and operating pressure shall be at 0,0 to 0,3 bar (0 to 4.35 psi) pressure. Measuring  range shall be between 0.3 to 10.0 m (1.0 to 32 ft.).  The sensor is factory calibrated delivered. The speed of sound is adjustable and pre-programmed for the  application water. The optical signals are continuously monitored and checked for plausibility. Discrepancies  are reported via error messages by the transmitter. Maximum measured error 35 mm at 3.0 m. Protection type:  For transmitter IP67 for sensor IP68. EMC compatibility; Interference emission and interference immunity  complies with EN 61326: 2005, Namur NE 21:2007  8_Vol3_d4 3_Section 8 electrical works_en_GIR rev6.doc  8.8.15 Pressure Transmitter Pressure transmitters shall be installed to measure the pressure where necessary as industrial type and LCD  screened.  • It is the pressure transmitter with ceramic sensor which operates with capacitive principle, and is  designed to measure gauge or absolute pressure of the gas, steam or liquids used in the process.  8.8.14 Level switches  8.8.13 Secondary Clarifier Level Measurement  Materials: Sensor: ABS and epoxy plastic  Wiper: Rubber  Device’s standard sensitiveness will be 0.5%. Measurement range of the devices for each individual installation shall be selected considering the minimum  and maximum operating and testing pressures can be read without any fault  Level switches shall be provided for measuring of high and low alarm levels and for control of drain pumps.  High-level alarm for the reservoir shall be with a level switch.  The level switches shall be the floating type with a built-in changeover contact system.  The contact system shall be casted in a polypropylene housing in protection class IP68.  A mercury free contact system is preferred.  Cables from the level switches shall be connected via junction boxes provided with terminals.  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, IP67 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 (±0.2%) 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 150 meters. The Contractor must ensure that each equipment complies with the requirements and especially stoppage distance,  angle, and conicness of the heat dissipated must be taken into consideration.