Performance Based ApCommissioning Tests for Elec Systemsproach to BMS Solutions

Performance based Performance based approach to Burner approach to Burner Management System Management System (BMS)(BMS)

Performance based Performance based approach to Burner approach to Burner Management System Management System (BMS)(BMS)Shirish Ratnaparkhi, CFSE

Emerson Process Management

International Safety Conference October 12-13

IIT Gandhinagar

[File Name or Event]Emerson Confidential27-Jun-01, Slide 2

Boiler Safety is the oldest topic!Boiler Safety is the oldest topic!Boiler Safety is the oldest topic!Boiler Safety is the oldest topic! Handled since 17th Century, much before other

major industries existed! NFPA, ASME codes evolved to address boiler

safety in 1896, followed by Safety Standards ANSI / IEC / ISA codes in 1989 until 2001.

Process Safety Management was practiced, but mostly based on prescriptive standards.

There is a thin line difference…….


A thin line differenceA thin line differenceA thin line differenceA thin line difference Process Safety Management (PSM) is a major

change in approach – it introduced a Risk Assessment.

However, though almost a correct approach, it is not complete in itself, since it was still based on established prescriptive standards.

It can not demonstrate the “performance” of the Safety System implied.

There is a thin line difference between PSM and FSM! Functional Safety Management…..


Functional Safety ManagementFunctional Safety ManagementFunctional Safety ManagementFunctional Safety Management At first place, nobody ever asked a question – How

much safety do I need? Safety Life Cycle (SLC) approach as per IEC /

ANSI / ISA standards was first introduced coupled with numeric evaluation of “everything”

It addressed “Random failures” for the equipment and “Systematic failures” for design, engineering, and commissioning processes! Again very much numerically…..

FSM is the great way to go ahead in coming future….. Also for Boiler Safety.


Chemical, Life Sciences, Oil & Gas and Refining sectors world-over have picked up FSM by now to

a great and noticeable extent.

They are on the way to master it.

Now is the time that Boiler Safety be based on the same techniques.

Will have to deal with the myths.


Accidents in boilersAccidents in boilersAccidents in boilersAccidents in boilers


Major attributesMajor attributesMajor attributesMajor attributes Operational mistakes – and system allowed it to

happen ! Manual override / bypasses. Inadequate specifications while engineering the

Safety Systems Over emphasis on redundancy of “Safety

Controller” and lack of attention to field devices PSM is followed, however performance unknown Incomplete hazard analysis and underestimation


Traditional way of FSSS / BMSTraditional way of FSSS / BMSTraditional way of FSSS / BMSTraditional way of FSSS / BMS– Pre-defined “prescriptive architectures” like TMR-

DMR-QMR. It’s time to come out.

– Specifications still “suggest” fixed ALL-THREE combinations.

– Three transmitters, three Input cards, three processors, three output cards, three relays and sets of contacts, and surprisingly a single valve.

– Suppliers are obliged to provide ALL-THREE combinations without any analysis.

– With all this implemented, no-one is sure what SIL has been achieved! Or what was wanted at first place..


What was actually needed?What was actually needed?What was actually needed?What was actually needed?A Safety Instrumented System (SIS) optimally designed with

a known Risk Reduction configured SIF by SIF in

accordance with Functional Safety Management in place

as per IEC 61508 / 61511

Optimum Safety could be achieved


Furnace Safeguard and Supervisory Furnace Safeguard and Supervisory Systems (FSSS)Systems (FSSS)Furnace Safeguard and Supervisory Furnace Safeguard and Supervisory Systems (FSSS)Systems (FSSS) Boiler protection system (BPS)

– Emergency shutdown to create MFT

– Shutdown of one fuel / section

– SIFs are identified after thorough HazOp and SIL assigned, performance known.

Burner Management System (BMS)– Safety critical interlocks: Permissive and Trips

– Entire sequencing by SIS

– Performance evaluation of these BMS Safety Functions is possible


It’s all about APPROACH!It’s all about APPROACH!It’s all about APPROACH!It’s all about APPROACH! Words versus Numbers….!!!!!!! So far the rules and guidelines were “described”

in words. They are important but not enough. Performance of a Safety instrumented function

can be “calculated” and gives a TRUE picture than a “prescribed” function.

Think OPTIMUM SAFETY

OPTIMUM SAFETY


Complete Numerical approach….Complete Numerical approach….Complete Numerical approach….Complete Numerical approach…. Probable Loss of Life Probable Injuries Unmitigated Risk Risk Target RRF SIL Mission Time Start-up Time Repair Time Demand Frequency

Device Failure Rate Diagnostic Coverage Diagnosis Frequency Safe Failure Fraction Proof Test Interval Common cause Factor HW Fault Tolerance Test Coverage factor PFDavg on demand ROI


A special note on BMS: Option-1A special note on BMS: Option-1A special note on BMS: Option-1A special note on BMS: Option-1Consider wiring the common IOs between BMS and BPS to BMS system. If the BMS system is capable of executing the Sequence logic, it is highly recommended that this should be preferred.


A special note on BMS: Option-2A special note on BMS: Option-2A special note on BMS: Option-2A special note on BMS: Option-2Consider wiring only those signals to BMS, which contribute into the Start-permissive and the trips as per the HAZOP. Engineer the Sequence control in BPCS and a Safety critical sequence monitoring in BMS.


ConclusionsConclusionsConclusionsConclusions Boiler Safety is critical. It followed the established

standards so far and new methods of performance based standards are available.

BMS can also be analyzed SIF by SIF and the SIL ratings can be allocated and obtained. This way, optimum safety and availability can be realized.

Inadvertent cost due to lack of numerical analysis can be saved and the Optimum Safety can be obtained.

Experts from various fields in Process Industry can contribute a lot towards fulfillment of establishing best practices using Performance based standards for BMS and boiler safety.


ReferencesReferencesReferencesReferences Wisconsin Boilers Inspectors Association: Accident tracking site for

worldwide accident events in Boilers.

http://www.thewbia.com/membership_info.php

Report on the investigation of the starboard boiler explosion resulting

in one fatal and one serious injury on board the Liquid Natural Gas tanker – Hilli, Grand Bahama Shipyard, Freeport, Grand Bahama. 10 October 2003.

www.maib.gov.uk/cms_resources/Hilli.pdf ISA-TR84.00.05-2009, Guidance on the Identification of Safety

Instrumented Functions (SIF) in Burner Management Systems (BMS): ISBN: 978-1-936007-41-7

http://www.thewbia.com/membership_info.php

http://www.maib.gov.uk/cms_resources/Hilli.pdf

Thank you.Thank you.Thank you.Thank you.

Take home:Take home:Optimum Safety for BMSOptimum Safety for BMS

Performance Based ApCommissioning Tests for Elec Systemsproach to BMS Solutions

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