Laserfiche WebLink
® WorleyParsons <br /> resources&energy <br /> DCS superimposed on the valve analog output. Valve position feed back for process <br /> control use will be hard wired. <br /> 5.6.7 Instrument Tubing and Installation <br /> Tubing used to connect instruments to the process line will generally be 1/2 inch diameter, <br /> 0.049 inch wall (minimum) seamless 316 stainless steel for primary instruments and <br /> sampling systems. <br /> Instrument tubing fittings will be the compression type. One manufacturer will be selected <br /> for use and will be standardized as much as practical throughout the plant. <br /> Differential pressure (flow) instruments will be fitted with five-valve manifolds. Three- <br /> valve or two-valve manifolds will be specified for other instruments as appropriate. <br /> Instrument installation will be designed to correctly sense the process variable. Taps on <br /> process lines will be located so that sensing lines do not trap air in liquid service or liquid <br /> in gas service. Taps on process lines will be fitted with a shutoff (root or gauge valve) <br /> close to the process line. Root and gauge valves will be main-line class valves. <br /> Instrument tubing will be supported in both horizontal and vertical runs as necessary. <br /> Expansion loops will be provided in tubing runs subject to high temperatures. The <br /> instrument tubing support design will allow for movement of the main process line. <br /> 5.6.8 Field-Mounted Instruments <br /> Field-mounting instruments will be of a design suitable for the area in which they are <br /> located. They will be mounted in areas accessible for maintenance and relatively free of <br /> vibration and will not block walkways or prevent maintenance of other equipment. <br /> Field-mounted instruments will be grouped on racks. Supports for individual instruments <br /> will be a prefabricated, off-the-shelf, 2-inch pipe stand. Instrument racks and individual <br /> supports will be mounted to concrete floors, to platforms, or on support steel in locations <br /> not subject to excessive vibration. <br /> Instruments will be freeze protected by utilizing heated "hard box" type enclosures as <br /> required. <br /> Individual field instrument sensing lines will be sloped or pitched in such a manner and be <br /> of such length, routing, and configuration that signal response is not adversely affected. <br /> Liquid level controllers will generally be the non-indicating, displacement type with <br /> external cages. <br /> 5.6.9 Instrument Air System <br /> Lodi Energy Center 3.5- 12 LEC AFC <br /> 071608 Rev.A <br />