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® WorleyParsons <br /> resources&energy <br /> In general, temperature instruments will have scales with temperature units in degrees <br /> Fahrenheit. Exceptions to this are electrical machinery RTDs and transformer winding <br /> temperatures, which are in degrees Celsius. <br /> Dial thermometers will have 4-1/2 inch-diameter (minimum) dials and white faces with <br /> black scale markings and will be every-angle type and bimetal actuated. Dial <br /> thermometers will generally be visible 10 feet from an operator's normal stance at floor <br /> level (viewing area) and will be resistant to plant atmospheres. <br /> Temperature elements and dial thermometers will be protected by thermowells except <br /> when measuring gas or air temperatures at atmospheric pressure. Temperature test points <br /> will have thermowells and caps or plugs. <br /> Thermowells for dial thermometers and filled system instruments will be purchased with <br /> the instruments to assure proper fit. Thermowells will be constructed of stainless steel <br /> except where conditions warrant the use of main line class material. <br /> All thermowells will be drilled barstock(not built-up type). <br /> Threaded and socket weld thermowells will have lagging extensions when used with <br /> insulation for high temperature. Consideration will be given to thicker insulation in cold <br /> services. <br /> In general, RTDs will be dual 100-ohm platinum three-wire circuits (Rloo/Ro-1.385). The <br /> element will be spring-loaded, mounted in a thermowell, and connected to a cast iron head <br /> assembly. However, RTDs associated with multi-variable transmitters will be four-wire. <br /> Thermocouples will be type K dual element, ungrounded, and spring-loaded. For general <br /> service, the materials of construction will be dictated by service temperatures. <br /> Thermocouple heads will be the cast type with an internal grounding screw. If a <br /> thermocouple is inaccessible, the leads will be brought to an accessible junction box. <br /> "Face" gauges in high vibration areas will be liquid filled and include a vibration snubber. <br /> 5.6.4 Level Instruments <br /> Reflex-glass or magnetic level gauges will be used. Level indication for corrosive service <br /> (if required) will use devices other than reflex-glass gauges. Level gauges for high- <br /> pressure service will have suitable personnel protection. Transparent type gauge glasses <br /> will be used up to 600 PSIG. <br /> Gauge glasses used in conjunction with level instruments will cover a range that includes <br /> the highest and lowest trip/alarm set points. <br /> Level transmitters for measuring the level in storage tanks vented to atmosphere (e.g., <br /> condensate storage tank) will generally be the flanged differential pressure type and will <br /> Lodi Energy Center 3.5 -8 LEC AFC <br /> 071608 Rev.A <br />