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Emerson Bettis GVO-C Series, Руководство по безопасности Sil

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SIL Safety Manual

SM-025-GVO Rev. 0

 

November 2017

19

Section 8: Periodic Test and Maintenance Requirements

Periodic Test and Maintenance Requirements

8.5 

Partial Stroke Diagnostic Coverage / Test Coverage

Considering the application of the above described Partial Stroke Test procedure, for all 
automatic methods indicated, the “Diagnostic Coverage” can be considered >90%.

In case of manual procedure the “Test Coverage” shall take into account also the test 
imperfection and the reliability/competence of the operator.

8.6 

Periodic Maintenance

GVO-CLP-SR/FS actuators are designed to operate long-term in heavy-duty operating 
conditions, without maintenance needs. Periodicity and regularity of inspections is 

particularly influenced by specific environmental and working conditions. They can be 

initially determined experimentally and then be improved according to actual maintenance 
conditions and needs.

Anyway every two years of operation an inspection is required: for the relevant procedures 
please refer to GVO-CLP-SR/FS Use and maintenance manual (Emerson document MAN 
617_GVO Section 5).

Содержание Bettis GVO-C Series

Страница 1: ...SIL Safety Manual SM 025 GVO Rev 0 November 2017 Bettis GVO C Series Pneumatic Actuators GVO CLP SR FS SIL Safety Manual ...

Страница 2: ......

Страница 3: ...ection 5 Service Condition Limitations limitation of use Section 6 Expected Time Section 7 Failure Modes and Estimated Failure Rates Section 8 Periodic Text and Maintenance Requirements 8 1 General 13 8 2 Full Stroke Test Proof Test 13 8 3 Diagnostic Coverage Proof Test Coverage 15 8 4 Partial Stroke Test 16 8 5 Partial Stroke Diagnostic Coverage Test Coverage 19 8 6 Periodic Maintenance 19 Sectio...

Страница 4: ...This safety manual provides essential information necessary to design install verify and maintain a Safety Instrumented Function SIF utilizing Emerson Actuator Series GVO CLP SR FS This manual provides necessary requirements for meeting the IEC 61508 2010 Sections 1 to 7 or IEC 61511 functional safety standards ...

Страница 5: ...ented Function safety function with a specified safety integrity level which is necessary to achieve functional safety and which can be either a safety instrumented protection function or a safety instrumented control function SIL Safety Integrity Level discrete level one out of a possible four for specifying the safety integrity requirements of the safety functions to be allocated to the E E PE s...

Страница 6: ...s de energized The choice of the safety function to be implemented is responsibility of the system integrator GVO CLP SR FS actuator is intended to be part of the final element subsystem as defined per IEC 61508 2010 The achieved SIL level of the designed function must comply with the project specification and must be submitted to the system integrator The final control element subsystem needs to ...

Страница 7: ...pringcartridgeandamountingpedestal complete with a joint for the coupling to the valve stem of actuator output stem The valve is actuated in opening and in closing position by the actuator pneumatic cylinder in onedirectionandbythespringunitintheotherdirection Theoutputthrustofspringunitcan be downward or upward according to valve operation requirements spring to open spring to close direct acting...

Страница 8: ...pen close chamber of the pneumatic cylinder the cylinder pistonstrokecausestheactuatoroperationandtheconsequentvalvemovementtotheopen close operational position and at the same time compresses the spring Upon a demand the instrument air is discharged from the open close chamber of the cylinder the actuator performs the closing opening operation driven by the spring and the valve moves from the ope...

Страница 9: ...ic override including an additional hydraulic cylinder with manual pump and distributor With reference GVO CLP SR FS actuator the mechanical manual override can be done with three configuration depending of the actuator size The use of a manual override is not recommended in a SIL classified application as it results in a bypass of the safety function In case the manual override is used the follow...

Страница 10: ...tions Table 1 MHW Manual Hand wheel MHP Manual Hydraulic To ensure that the hand pump has been correctly disengaged after a manual override operation the following test shall be completed restore the manual lever to remote position verify the functionality performing a test from remote control es partial stroke test ...

Страница 11: ...pected Lifetime Section 6 Expected Time Actuators lifetime strongly depends on operating conditions and on construction materials For normal service conditions the expected lifetime of Emerson GVO CLP SR FS actuators can be estimated in approximately 25 years with planned maintenance ...

Страница 12: ...all failure rates and failure modes of GVO CLP SR FS actuators According to D 2 2 of IEC 61508 2 2010 Annex D the estimated failure rates of the failure modes that result in a failure of the safety function are quoted in the following table Table 2 Failure modes and estimated failure rates GVO CLP SR FS actuators series Failure mode according to ISO 14224 Estimated failure rate 1 h Failure to clos...

Страница 13: ... performed to satisfy the PFDAVG value The Full Stroke Test frequency has to be defined by the final integrator according to the PFDAVG value to be achieved Full Stroke Test procedure 1 Operate the actuator to perform No 2 complete open close cycles operate the actuator to perform a full stroke 2 Checkthattheactuatoroperatesthevalvecorrectlyandwithintherequiredoperating times e g checkautomaticall...

Страница 14: ... Input Module Analog Input Module included in the Logic Solver 3 Application SW function to compare the actual trend with the one stored during SAT Case B use of a PST device 4 Limit switches box or 4 20 mApositiontransmitter 5 PST device with integrated SW function 1 Limit switches box with visual indication 2 Skilled and trained personnel Time necessary to reach the final position As above 1 Chr...

Страница 15: ... the major failure modes of the main components In case of manual procedure the detectable failure modes are the same as per automatic procedure The test coverage is lower than the one for automatic mode due to the human factor The manual procedure cannot be considered as diagnostic 8 3 Diagnostic Coverage Proof Test Coverage Considering the application of the above described Full Stroke Test proc...

Страница 16: ...n close cycles to verify the correct functioning of the actuator valve assembly 2 Verify that the partial stroke manoeuvre was performed correctly and within the expected time 3 Inspect the actuator components for any leakages internal and external The procedure can be performed manually or automatically In the following for both cases the following points are listed Parameters to be measured Inst...

Страница 17: ...ional b Measurement of cylinder chamber pressure as function of time c Verification of final position achievement in the established maximum time 3 By means of a manual PST system manufactured by Emerson slightly different sys tems can be available please make reference to the documentation of the specific project Table 5 Quality Instruments equipment Automatic Procedure Manual Procedure Linear po...

Страница 18: ... Component Detectable failure modes Automatic Procedure Manual Procedure Spring Cartridge Spring Breakage Weakened Worn Sticking As per automatic procedure Spring Flange Breakage Head end flange bolts Breakage Unscrewing Spring Rod Breakage Spring Container Total Breakage O Rings Breakage External leakage Pneumatic Cylinder Piston Sticking As per automatic procedure Notes The ones listed above are...

Страница 19: ... the test imperfection and the reliability competence of the operator 8 6 Periodic Maintenance GVO CLP SR FS actuators are designed to operate long term in heavy duty operating conditions without maintenance needs Periodicity and regularity of inspections is particularly influenced by specific environmental and working conditions They can be initially determined experimentally and then be improved...

Страница 20: ...nual SM 025 GVO Rev 0 20 Section 9 Classification Classification Section 9 Classification GVO CLP SR FS actuators are classified as Type A devices according to 7 4 4 1 2 of IEC 61508 2 2010 for use in low demand mode applications ...

Страница 21: ...10 MRT MRT Section 10 MRT The MRT of the device is 24 hours NOTE The MRT is estimated considering that the required spare parts are available on site and considering the availability of skilled personnel for maintenance equipped with adequate tools and materials ...

Страница 22: ...g components of the pneumatic cylinder and so according to definition 3 6 13 of IEC 61508 4 they cannot be used for the calculation of the SFF hence λS 0 for each type of Single Acting actuator For this reason according to definition 3 6 15 of IEC 61508 4 we have SFF 0 without external diagnostic tests SFF 0 with external diagnostic tests carried out according to definition 3 8 7 of IEC 61508 4 an...

Страница 23: ...matic Capability The systematic capability of GVO CLP SR FS actuators is 3 This systematic capability is guaranteed only if the user 1 uses the actuator according to the instructions for use 2 uses the device in appropriate environment limitation of use For the definition of systematic capability see 3 5 9 of IEC 61508 4 2010 ...

Страница 24: ... anyautomaticdiagnostics average repair time and the specific failure rates of all products included in the SIF Each subsystem must be checked to assure compliance with minimum hardware fault tolerance HFT requirements 2 When using a Emerson GVO CLP SR FS actuator in a redundant configuration a common cause factor of 5 should be included in the Safety Integrity calculations 3 Any failures that are...

Страница 25: ......

Страница 26: ...ongmeadow Business Estate East P O Box 6908 Greenstone 1616 Modderfontein Extension 5 South Africa T 27 11 451 3700 EUROPE Holland Fasor 6 Székesfehérvár 8000 Hungary T 36 22 53 09 50 Strada Biffi 165 29017 Fiorenzuola d Arda PC Italy T 39 0523 944 411 www emerson com bettis 2018 Emerson All rights reserved The Emerson logo is a trademark and service mark of Emerson Electric Co BettisTM is a mark ...

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