HAZOP_GUIDE_BRITISH_STANDARD_IEC_61882_2001

Input activity source destination state 1 close valve

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Unformatted text preview: Destination State 1: Close valve 1. Charge in C1 1. Transfer charge via T1, D1 and C2 Characteristics: 2. Transfer charge via T4 and R to ground Low side of valve 2. Low side charge to ground 3. Control opening via T1 and T4 from ground Signal from controller T1, T3 and T4 Voltage Capacity 2. Control signals to T1, T3 and T4 C1 and converter 1. Power to power side of valve 4. Isolated via T2 5. Prevent overcharge via T3 Overcharge to ground 6. Pevent reverse flow of charge via D2 Power side of valve 1. Discharge power side of valve 1. Isolate from C1 and converter via T1 Power side of valve and C2 Ground Characteristics: 2. Transfer power charge via D2 and T2 Signals from controller T1, T2 and T4 State 2: Open valve Voltage Capacity 2. Control signals to T1, T2 and T4 48 84 84 3. Transfer any charge of valve via D3, D4 and R 4. Isolate low charge side of valve via T4 © BSI 28 1002−80ISB © 1002−80 ISB August 2001 Licensed Copy: Puan Ms. Norhayati, Petroliam Nasional Berhad 4397000, 01 October 2003, Uncontrolled Copy, (c) BSI STUDY TITLE: P IEZO VALVE CONTROL SYSTEM Drawing No: 6 8812 E I2:C100 © BSI 28 August 1002−80 ISB © 2001 Table B.5 – E xample HAZOP worksheet for piezo valve control system SHEET: 1 o f 3 REVISION No.: DATE: TEAM COMPOSITION: D evelopment engineer, System engineer, Quality manager MEETING DATE: 0 4.11.97 Part considered: State 1: System closes valve Design intent: Transfer a defined quantity of electrical charge to the piezo actuator to close the valve at a defined time Element Guide word Deviation Possible causes Consequences Safeguards Comments Actions required Action allocated to Input: Charge in C1 NO No charge; including don ’ t transfer Power outage No flow via C2 into piezo valve None Situation not acceptable High-level alarm J. Smith Failure of converter Fault in C1 T1 is permanently closed T2 is permanently open Valve does not close; permanently open Reactive material running into the vessel Test routine Design change required T1 faulty – D iode D1 with open circuit; no current flows – 79 – Diodes (D1, D3) failure: – D iode D3 shortened; shortcut via D4 to low side of piezo valve or via R to ground C2 faulty Broken wires R faulty T3 faulty 49 94 BS IEC 61882:2001 T4 faulty Licensed Copy: Puan Ms. Norhayati, Petroliam Nasional Berhad 4397000, 01 October 2003, Uncontrolled Copy, (c) BSI BS IEC 61882:2001 E I2:C100 6 8812 50 05 Table B.5 ( continued ) STUDY TITLE: P IEZO VALVE CONTROL SYSTEM Drawing No: SHEET: 2 o f 3 REVISION No.: DATE: TEAM COMPOSITION: D evelopment engineer, System engineer, Quality manager MEETING DATE: 0 4.11.97 Part considered: State 1: System closes valve Design intent: Transfer a defined quantity of electrical charge to the piezo actuator to close the valve at a defined time Element Guide word Deviation Possible causes Consequences Safeguards Comments Actions required Action allocated to Input: Charge in C1 MORE More charge than defined Charge in C2 too high Piezo valve closes earlier than defined Flow meter shows too high quantity; transistor T3 discharges piezo valve; Situation not acceptable Consider high level alarm Peter Peterson Situation not acceptable Alarm J. Smith Faulty converter Transistor T1 does not close in time Damaged piezo valve None shown C2 faulty AC/DC converter delivers too high voltage Faulty protection T3 LESS Less charge than specified Insufficient capacity exists; Insufficient charge in C2 Faulty insulation of cable; charge disappears Charge in C1 Valve closes later than specified T1 closes too early T2 is partly open None – 99 – Transistor T1 does not close in time © BSI 28 August 2001 1002−80 ISB © Licensed Copy: Puan Ms. Norhayati, Petroliam Nasional Berhad 4397000, 01 October 2003, Uncontrolled Copy, (c) BSI STUDY TITLE: P IEZO VALVE CONTROL SYSTEM Drawing No: 6 8812 E I2:C100 © BSI 28 August 1002−80 ISB © 2001 Table B.5 ( continued) SHEET: 3 o f 3 REVISION No.: DATE: TEAM COMPOSITION: D evelopment engineer, System engineer, Quality manager MEETING DATE: 0 4.11.97 Part considered: State 1: System closes valve Design intent: Transfer a defined quantity of electrical charge to the piezo actuator to close the valve at a defined time Element Guide word Deviation Possible causes Consequences Safeguards Comments Actions required Action allocated to Input: Charge in C1 AS WELL AS T1 as well as T2 is open Less charge to C2 Uncontrolled chemical reaction None shown Small differences may be acceptable Alarm J. Smith Valve does not close Reactive material runs into the reaction vessel Test routine Reset Define acceptable differences – 0 11 – BS IEC 61882:2001 51 15 BS IEC 61882:2001 6 1882 Ó I EC:2001 B.6 – 53 – Oil vaporizer Licensed Copy: Puan Ms. Norhayati, Petroliam Nasional Berhad 4397000, 01 October 2003, Uncontrolled Copy, (c) BSI Interlock shuts main valve TCV I-5 TSH FAL Vaporized oil Heating coil TE FC FE FCV Interlock shuts main valve TCV I-4 Liquid oil Firebox Burners PSHH Natural gas PRV Pilot valve PV Main valve TCV TC IEC 456/01 Figure B.4 – Oil vaporizer The oil vaporizer consists of a furnace containing a heating coil and burners, which are fired by natural gas. The...
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This note was uploaded on 09/15/2011 for the course ECON 102 taught by Professor Calvin during the Winter '11 term at Oxford Brookes.

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