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Practice title

Barrier Effectiveness through Management of Process Safety Critical Equipment

Brief overview of the practice

1. Introduction

Process Safety and Risk Management(PSRM) when applied robustly will reduce the likelihood of any catastrophic event. Located amidst a densely populated community, Tata Steel realised the importance of strong Process Safety and Risk Management (PSRM) in 2006 to address the process related risk and avoid any loss of containment. Following the acquisition of Corus by Tata Steel in 2007 the knowledge sharing across the group has been a significant benefit as process safety was also high on Corus agenda.

‘Excellence in Process Safety Risk Management’ was identified as one of the key safety strategies for achieving the Tata Steel corporate objective of ‘Committed to Zero’.

A firm foundation in Process Safety & Risk Management (PSRM) has been established across Tata Steel but in pursuit of making process safety a ‘way of life’, the Centre of Excellence (C0E) concept was undertaken in two manufacturing units in FY16 and in three more manufacturing units in FY17 at Jamshedpur works. Inculcating Process Safety as way of life, has not only reduced the likelihood of a catastrophic event but has also provided business results in terms of reduction in breakdown time leading to increase in production. Looking at the results Tata Steel Management has decided to extend the Centre of Excellence (CoE) concept in eight more departments in FY19.

As we undertook the CoE journey, we used the following three simple questions at all levels of our organisation to test our strength:

Ø Do we know what can go wrong?

Ø Do we know what barriers we have to ensure that it doesn’t go wrong?

Ø Do we know that our barriers are effective and working properly?

We have different Hazard Identification and Risk Assessment tools to address the first question like HAZOP, LOPA, SIL, QRA etc.

To answer the second & third questions Identification, tagging & management of Process Safety Critical Equipment(PSCE) practices had to be established.

2. Process Safety Critical Equipment

Process Safety Critical Equipment is an individual piece of equipment, a control system or an individual protection device which in the event of single point failure

Ø  could cause or contribute substantially to a major accident hazard

or

Ø  Directly cause an accident that results into harm to people, property or environment

PSCE form components of the barrier & thereby ensures barrier effectiveness.

PSCE are identified on the criterions as mentioned

1.     Consequence based

2.     Preventive & mitigative

3.     Prescriptive

2.1 Identification

Consequence based process safety critical equipment

Equipment whose failure may result in, allow, or contribute to the following events that could result in death or major irreversible health effects, significant property damage, or significant environmental impact.

Ø  The loss of primary containment of a hazardous substance

Ø  The release of chemical energy generated within the process (e.g., deflagration, detonation, and uncontrolled reaction)

Following are examples of consequence based process safety critical equipment (but are not limited to)

Ø  Process vessels, reactors

Ø  Storage tanks

Ø  Process equipment (e.g., Receivers, day tanks, distillation vessel/ column, centrifuge, filters, heat exchangers, condensers, dryers, milling equipment, blenders, grinders, mixers, sifters, granulators etc.)

Ø  Pumps and compressors

Ø  Piping system- Piping system include valves, transfer hoses, sight glasses, expansion bellows, flanges and piping-support systems

Ø  Valves and fittings in hazardous substance services

Preventive & Mitigative type process safety critical equipment

Equipment which prevent or mitigate the consequences of hazardous events that could result in death or major irreversible health effects, significant property damage, or significant environmental impact.

Following are examples of preventive & mitigative type process safety critical equipment (but are not limited to)

Ø  Safety Instrumented system

Ø  Process alarm & associated controls

Ø  Emergency shutdown systems

Ø  Reaction quenching system, dumping system, emergency cooling system or a similar emergency process shut off/ control mechanism.

Ø  Fire protection systems installed to mitigate consequences of PSM-related hazardous events (i.e., sprinklers, deluge systems, fire water supply, storage, pumping, and piping-distribution hydrant systems)

Ø  Explosion-suppression systems, Explosion relief panel/ flaps

Some e.g. of passive mitigation system

Ø  Secondary containment systems (e.g., dikes, sumps, process sewers, or waste-collection systems) and jacketed piping systems intended to contain hazardous substances

Ø  Fire and blast walls

Ø  Electrical and instrument installations in an electrically classified hazardous area. (e.g. flame proof, intrinsically safe electrical equipment and instruments)

Prescriptive type process safety critical equipment

Equipment which are prescribed as PSM critical as per regulatory norms          

Ø  Pressure relief valves, rupture discs, other relief devices and the other upstream or downstream vent systems, Flaring system

Ø  Flame arrestors located in process vents and emergency vents

Ø  Pressure vessels

Ø  Safety interlocks that are designed to prevent process safety incidents, including sensors, logic solvers, and final control elements.

Ø  Emergency devices, including process shutdown and isolation systems as far as they are preventing PSM-related hazardous events or mitigating the consequences of such events.

2.2 Tagging

To control risk in the tolerable region effectiveness of PSCE is a must. The identified PSCE’s on the above criteria are tagged as “S” in SAP Plant Maintenance (PM) system. Once tagged, maintenance plan for the equipment is uploaded along with measuring points, to measure the effectiveness of equipment. Maintenance plan/actions are identified from Standard Maintenance Practices- SMP’s based on RAGAGEP

2.3 Management

Specific provisions have been made in the SAP PM system. However, it should be remembered that if personnel are unable to carry out maintenance task on PSCE, they are not going to prevent or manage an incident. This is especially critical for all High hazard operations.

The SAP PM system recognises the importance of maintenance on PSCE to address the following key items

1.   Maintenance procedures addressing specifically PSCE’s

2.   Prioritising inspection, maintenance and testing of PSCE’s over other equipment’s

3.   A requirement that ensures the drawings and manuals of PSCEs are up to date and available

4.   PSCE’s failures are highlighted in the incident reporting system for high visibility

5.  

The maintenance plans of PSCE’s are tracked on monthly basis through PSM dashboard & reviewed by leaders

Fig1: PSM Dashboard

6.   Maintenance plans/barrier effectiveness is also ensured through barrier management line walks.

Fig2: PSCE Management & Life cycle

Living the safety and health principles

Steel making being a hazardous process and making this high hazard operations safe is a challenge. Implementation of Process Safety and Risk Management (PSRM) to enable effectiveness of barriers through PSCE has shown results to provide confidence to management as well as to employees that Excellence in safety and health supports excellent business results.

Management is responsible for providing the adequate resources, motivation, and discipline to ensure that process safety is deployed through management of PSCE. Weekly and monthly reviews of PSM dashboard has ensured that the top events do not occur and even if it happens the event is mitigated to have least impact on people, property & environment.

Fig3: PSM critical parameters, design deviation of Top Pressure of Naphthalene.

Fig3: Monthly deviation of Top Pressure of Naphthalene.

Impact on metrics

Process Safety has brought cultural change in thinking of the employees toward the hazard identification & risk assessment. As part of the Process Safety Journey the departments identify PSCE, (whose failure may lead to a process incident) and they are tagged in SAP system with their maintenance plan. Special attention is provided to these equipment and employees who do maintenance work on these equipment’s. Barrier Audits are also conducted to check the healthiness of these critical equipment.

As a result, failure of these critical equipment has reduced making the plant safer and reducing the breakdown time thus providing the departments with more production time.

Some of the benefits of PSCE management are:

§  Drive Business Competitiveness

§  Less number of Process Incidents

§  Standardization, Leverage and Sharing

§  Cost Reduction & Sustainability Control Plans

§ 

Fig4: Number of A category incidence & its result in production at LD#1

Fig5: Availability of Desulphurisation unit at LD Shop#2