Industrial Process Control: Standards

1. Industrial Process Control:Standards Nikhilbinoy.C Assistant Professor, ICE Department, N.S.S. College of Engineering, Palakkad.

2. Purpose • To establish a uniform mean of designating instruments and instrumentation systems used for measurement and control.

3. Scope • General • The procedural needs of various users are different. The standard recognizes these needs, when they are consistent with the objectives of the standardly by providing alternative symbolism methods. • A number of examples are provided for adding information or simplifying the symbolism as desired.

4. Scope • Application to Industries • Chemical. • Petroleum. • Power generation. • Air conditioning. • Metal refining.

5. Scope • Application to Work Activities • Design sketches. • Teaching examples. • Technical papers, literatures, and discussions. • Instrumentation system diagrams, loop diagrams, logic diagrams. • Functional descriptions. • Flow diagrams: • Process. • Mechanical. • Engineering. • Systems piping (process) and instrumentation. • Construction drawings. • Specifications, purchase orders, manifests, and other lists.

6. Identification of the System

7. Each instrument may be represented on diagrams by symbols. • Instrument or function to be identified is designated by an alphanumeric code or tag number. • The symbols may be accompanied by a tag number. FV101

8. Identification of the System(Tag Number) Instrument Identification or tag number TIC103

9. Identification of the System(Tag Number) Loop identification TIC103

10. Identification of the System(Tag Number) Loop number • First number is used to identify the loop. • The succeeding numbers is the serial number of the instrument in a particular loop. TIC103

11. Identification of the System(Tag Number) Function Identification • Function of the instrument is identified. TIC103

12. Identification of the System(Tag Number) First letter • Identifying the measured or initiating variable. • May have a modifier is intended to represent a new and separate measured variable. TIC103

13. Identification of the System(Tag Number) Succeeding letters • Identifying the function performed. • Second letter is used for the readout or passive function. • Third letter is used for the output function. • The succeeding letters may have a modifier to identify a separate function. TIC103

14. Function Identification

17. Symbols The symbols are intended to depict instrumentation on diagram and drawing.

18. Instrument Line Symbols WS SS HS GS ES NS IA PA AS Instrument supply or connection to process Air supply Instrument Air Electric Supply Gas Supply Hydraulic Supply Nitrogen Supply Water Supply Plant Air Steam Supply The supply level may be added to the instrument supply line. E.g:- AS-100; ES-24DC Undefined Signals Pneumatic signal Electric Signal Hydraulic Signal Capillary Tube Internal system link (s/w or data link) Mechanical link Electric binary Signal

19. General Instrument or Function Symbols Primary Location Normally Accessible to Operator Field Mounted Auxiliary Location Normally Accessible to Operator Discrete Instruments IP1 Shared Display Symbol Size may vary according to the user’s needs and the type of document. Abbreviations of the user’s choice such as IP1 (Instrument Panel 1), IC2 (Instrument Console 2), CC3 (Computer Console 3), etc. may be used when it is necessary to specify instrument or function location. Computer Function Programmable Logic Control

20. General Instrument or Function Symbols Primary Location Normally Accessible to Operator Field Mounted Auxiliary Location Normally Accessible to Operator Discrete Instruments Shared Display Computer Function Programmable Logic Control

21. General Instrument or Function Symbols Primary Location Normally Accessible to Operator Field Mounted Auxiliary Location Normally Accessible to Operator Discrete Instruments Normally in accessible, or behind-the-panel devices or functions may be depicted by using the same symbol but with dashed horizontal bars. Shared Display Computer Function Programmable Logic Control

22. General Instrument or Function Symbols Primary Location Normally In-accessible to Operator Field Mounted Auxiliary Location Normally In-accessible to Operator Discrete Instruments Shared Display Computer Function Programmable Logic Control

23. Control Valve Body Symbols Three Way Valve General Symbol Angle Four Way Valve Butterfly Globe Valve Rotary Valve Diaphragm Valve

24. Actuator Symbols Diaphragm, spring opposed or unspecified actuator Diaphragm pressure balanced Rotary motor (shown typically with electric signal may be hydraulic or pneumatic) M

25. Actuator Symbols D Digital Spring opposed single acting Double acting

26. Actuator Symbols S Solenoid E/H Electrohydraulic I/P TY Valve actuator with attached electro pneumatic converter

27. Actuator Symbols For pressure relief or safety valve only Hand actuator or hand wheel

28. Symbols for Self Actuated Regulators, Valves and Other Devices Automatic regulator with integral flow indication FICV FI Indicating variable area meter with integral manual throttle valve Upstream alternative Downstream alternative Restriction orifice (orifice plate, capillary tube, or multistage type, etc.) in process line FO

29. Symbols for Self Actuated Regulators, Valves and Other Devices Restriction orifice drilled in valve (instrument tag number may be omitted if valve is otherwise identified Flow slight glass, plain or with paddle wheel, flapper etc. FG Flow straightening vane (use of tag number is optional. The loop number may be the same as that of the associated primary element) FX FO

30. Symbols for Self Actuated Regulators, Valves and Other Devices Hand control valve in process line Hand actuated on-off switching valve in pneumatic signal line HS 002 LCV Tank Level regulator with mechanical linkage HV

31. Symbols for Self Actuated Regulators, Valves and Other Devices Pressure reducing regulator, self contained with hand wheel adjustable set point PCV PCV PDC Pressure reducing regulator with external pressure tap Differential pressure reducing regulator with internal and external pressure taps

32. Symbols for Self Actuated Regulators, Valves and Other Devices Back pressure regulator, self contained PCV PCV PDC Back pressure regulator with external pressure trap Pressure reducing regulator with internal outlet pressure relief valve, and optional pressure indicator

33. Symbols for Self Actuated Regulators, Valves and Other Devices PCV PCV Pressure relief or safety valve, general symbol Pressure relief or safety valve, straight through pattern, spring or weight loaded, or with internal pilot Vacuum relief valve, general symbol

34. Symbols for Self Actuated Regulators, Valves and Other Devices PCV Pressure and vacuum relief valve, spring or weight loaded, or with internal pilot Vacuum Pressure

35. Symbols for Actuator Action in Events of Actuator Power Failure Two way valve, fail open Two way valve, fail closed Three way valve, fail open to path AC A B C

36. Symbols for Actuator Action in Events of Actuator Power Failure D Four way valve, fail open to paths CB and DA A B C Any valve, fail locked (position does not change) Any valve, fail indeterminate

37. Primary Element Symbols AIT 001 AIT 002 Dual analysis indicating One burner ultra-violet flame detector connected to analog type flame intensity indicator BI 002 BE 001

38. Primary Element Symbols BE 001 BE 002 Two burner flame rod sensor connected to common switch BS 003 S Television camera and receiver to view burner flame TV BG 003 BT

39. Primary Element Symbols Orifice plate with flange or corner taps connected to differential pressure type flow indicator FI 005 FE 002 VC Orifice plate with vena contracta taps

40. Primary Element Symbols Orifice plate with vena contracta, radius, or pipe taps connected to differential pressure type flow transmitter FT 008 Venturi tube

41. Primary Element Symbols Variable area flow indicator FI 017 Flow element with connection for controller FE 017 FC 018

42. Primary Element Symbols FT 017 Flow element integral with transmitter FE 005 Vortex sensor

43. Primary Element Symbols FE 029 Flow nozzle Indicating wattmeter connected to pump motor JI 001

44. Primary Element Symbols Clock KI 001 Time schedule controller, analog type, or self contained function generator KC TIC

45. Primary Element Symbols VI 001 VI 006 Mechanical analysis in three planes VXT 002 VYT 003 VZT 007 VXI 004 VYI 005 VZI 008

46. Primary Element Symbols 1-0 JI 001 Self contained on-off room thermostat actuating circulating pump motor Cascade control: flow controller set by level control SP LC 104 FC 100 FT

47. Primary Element Symbols Differential temperature indicator TT 101 TT 102 TDI 103 FT 101 FR 104 Flow ratio controller with two pens to record flow FFC 103 FT 102 FR 105

48. Primary Element Symbols FT 101 Flow ratio controller with one pen to record flow ratio FT 101 Mass flow computation performed by mass-flow computing relay ‘FY’ having linear inputs for pressure and temperature and a non-linear input for flow GS FIC 111 FY FFC 103 FT 101 PT 201 TT 117 Mass Flow

49. Primary Element Symbols Flow transmitter with external temperature compensator TT 300 FT 400 FY TRC 302 Pressure balanced valve

50. Primary Element Symbols TSL 301 PSH 501 TSL 301 PSH 501 M FY M FIC 404 FIC 404 Flow control loop that may be blocked by interlock actuated by either low temperature or high pressure