Hazard identification, risk assessment and control measures for

1、HAZARD IDENTIFICATION, RISK ASSESSMENT AND CONTROL MEASURES FOR MAJOR HAZARD FACILITIESBOOKLET 4 TABLE OF CONTENTS TOC o 1-3 t 2nd Heading,2 1Who is this booklet for? PAGEREF _Toc200338788 h 32What does the booklet aim to do? PAGEREF _Toc200338789 h 33Hazard identification, risk assessment and contr

2、ol measures introduction PAGEREF _Toc200338790 h 34Hazard identification PAGEREF _Toc200338791 h 3The importance of getting the hazard identification right PAGEREF _Toc200338792 h 4Features of HAZID PAGEREF _Toc200338793 h 5Hazard identification processes and techniques PAGEREF _Toc200338794 h 8Revi

3、ew, revision and typical problems PAGEREF _Toc200338795 h 145Risk assessment PAGEREF _Toc200338796 h 16Risk assessment aims PAGEREF _Toc200338797 h 16Examples of risk assessment methods PAGEREF _Toc200338798 h 236Control measures PAGEREF _Toc200338799 h 32Introduction PAGEREF _Toc200338800 h 32What

4、is a control measure? PAGEREF _Toc200338801 h 32Understanding control measures PAGEREF _Toc200338802 h 34Selecting and rejecting control measures PAGEREF _Toc200338803 h 38Additional or alternative control measures. PAGEREF _Toc200338804 h 39Defining performance indicators for control measures PAGER

5、EF _Toc200338805 h 41Critical operating parameters PAGEREF _Toc200338806 h 44Involving employees in control measures PAGEREF _Toc200338807 h 45Control measures within the safety report and SMS PAGEREF _Toc200338808 h 45Reviewing and revising control measures PAGEREF _Toc200338809 h 46SMS - A suggest

6、ed combination of key elements PAGEREF _Toc200338810 h 471Who is this booklet for?This booklet has been produced for employers in control of a facility that has been classified by Comcare as a major hazard facility under Part 9 of the Occupational Health and Safety (Safety Standards) Regulations 199

7、4.2What does the booklet aim to do?This booklet provides guidance on key principles and issues to be taken into account when conducting an effective hazard identification and risk assessment at a major hazard facility (MHF) that is subject to Commonwealth legislation. It also describes the type and

8、nature of control measures that the employer in control of an MHF should consider. These processes should be consistent with the safety management system.This booklet is a guide to the intent of the Regulations but employers in control of an MHF should refer to the Regulations for specific requireme

9、nts. In addition, this booklet refers to hazard identification and risk assessment techniques that may be appropriate for MHF purposes (and described in the facility SMS refer to Booklet 3) but these may not be the only techniques in use at a facility, other techniques include job safety analysis an

10、d task analysis.3Hazard identification, risk assessment and control measures introductionHazard identification (HAZID) and risk assessment involves a critical sequence of information gathering and the application of a decision-making process. These assist in discovering what could possibly cause a m

11、ajor accident (hazard identification), how likely it is that a major accident would occur and the potential consequences (risk assessment) and what options there are for preventing and mitigating a major accident (control measures). These activities should also assist in improving operations and pro

12、ductivity and reduce the occurrence of incidents and near misses. There are many different techniques for carrying out hazard identification and risk assessment at an MHF. The techniques vary in complexity and should match the circumstances of the MHF. Collaboration between management and staff is f

13、undamental to achieving effective and efficient hazard identification and risk assessment processes.4Hazard identificationThe Regulations require the employer, in consultation with employees, to identify:all reasonably foreseeable hazards at the MHF that may cause a major accident; andthe kinds of m

14、ajor accidents that may occur at the MHF, the likelihood of a major accident occurring and the likely consequences of a major accident.4.1The importance of getting the hazard identification rightMajor accidents by their nature are rare events, which may be beyond the experience of many employers. Th

15、ese accidents tend to be low frequency, high consequence events as illustrated in Figure 1 below. However, the circumstances or conditions that could lead to a major accident may already be present, and the risks of such incidents should be proactively identified and managed.Figure 1: HAZID focus on

16、 rare eventsHAZID must address potentially rare events and situations to ensure the full range of major accidents and their causes. To achieve this, employers should:identify and challenge assumptions and existing norms of design and operation to test whether they may contain weaknesses;think beyond

17、 the immediate experience at the specific MHF; recognise that existing controls and procedures cannot always be guaranteed to work as expected; andlearn lessons from similar organisations and businesses.Some significant challenges in carrying out an effective HAZID are:substantial time is needed to

18、identify all hazards and potential major accidents and to understand the complex circumstances that typify major accidents;the need for a combination of expertise in HAZID techniques, knowledge of the facility and systematic tools;the possibility that a combination of different HAZID techniques may

19、be needed, depending on the nature of the facility to ensure that the full range of factors (e.g. human and engineering) is properly considered;obtaining information on HAZID from a range of sources and opinions; andensuring objectivity during the HAZID process.Comcare must be satisfied that hazard

20、identification has been comprehensive and the risks are eliminated or controlled before granting a licence or certificate of compliance to operate an MHF. 4.2Features of HAZIDComcares expectations and some important features of HAZIDComcare will expect:a clear method statement or description of the

21、HAZID process, defining when it was conducted, how it was planned and prepared, who was involved and what tools and resources were employed; that the HAZID process was based on a comprehensive and accurate description of the facility, including all necessary diagrams, process information, existing c

22、onditions and modifications; andthat the overall HAZID process did not rely solely on data that was historical or reactive and that employers ensured that predictive methods were also used.The HAZID process must identify hazards that could cause a potential major accident for the full range of opera

23、tional modes, including normal operations, start-up, shutdown, and also potential upset, emergency or abnormal conditions. Employers should also reassess their HAZID whenever a significant change in operations has occurred or a new substance has been introduced. They should also consider incidents,

24、which have occurred elsewhere at similar facilities including within the same industry and in other industries. Refer to the guidance material for Safety Safety Report and Report Outline guidance material (booklet 4) for the definition of significant change.Involving the right peopleAn effective HAZ

25、ID process is dependent upon having the right people participating in the process. The employer should:involve Health and Safety Representatives (HSRs) in selecting staff to participate in HAZID;involve HSRs in determining if the HAZID techniques are suitable for the staff selected;ensure participan

26、ts understand the relevant HAZID methods so that they can fully participate in the process; andbe alert for hazards that can be revealed by the combination of knowledge from specialists in different work groups.Features of a HAZID processThe following aims to demonstrate the main features of a HAZID

27、. Although the HAZID process chosen by employers must suit the circumstances of the MHF, the features noted below are generally applicable to all processes. Preparation: Prior to commencement of the HAZID, the following steps should be completed:Agreement on the purpose and scope of the HAZID;Approp

28、riate personnel and HAZID tools identified;Sufficient resources and time allocated;Clearly defined reporting processes and study boundaries according to the purpose and scope;Appropriate background information and studies collated, such as historical incident data;An agreed interpretation of major a

29、ccident that is consistent with the Regulations and relevant to the facility.System description: At the commencement of the HAZID, the complete system of assets, materials, human activities and process operations within the boundaries of the study should be clearly defined and understood, taking acc

30、ount of the original design, subsequent changes and current conditions. Typically, the system should be divided into distinct separate components or sections to enable manageable quantities of information to be handled at each stage. Systematic evaluation and recording: The HAZID should move progres

31、sively through the system, applying the HAZID tools to each component or section in turn. All identified hazards and incidents should be recorded in some way. (See Figure 16 in this booklet for some examples of how hazard registers may be configured.) A checklist of guidewords, questions or issues s

32、hould be considered at each stage. Some key questions and issues could be:What is the design intent, what are the broad ranges of activities to be conducted, what is the condition of equipment, and what limitations apply to activities and operations? What are the critical operating parameters? What

33、process operations occur, and how could they deviate from the design intent or critical operating parameters? This should consider routine and abnormal operations, start-up, shutdown and process upsets.What materials are present? Are they a potential source of major accidents in their own right? Cou

34、ld they cause an accident involving another material? Could two or more materials interact with each other to create additional hazards?What operations, construction or maintenance activities occur that could cause or contribute towards hazards or accidents? How could these activities go wrong? Coul

35、d other hazardous activities be introduced into this section by error or by work in neighbouring sections of the facility?Could other materials, not normally or not intended to be present, be introduced into the process?What equipment within the section could fail or be impacted by internal or exter

36、nal hazardous events? What are the possible events?What could happen in this section to create additional hazards, e.g. temporary storage or road tankers?Could a particular section of the facility interact with other sections (e.g. adjacent equipment, an upstream or downstream process, or something

37、sharing a service) in such a way as to cause an accident?Past, present and future hazardsTo identify all hazards, the HAZID will need to consider past, present and future conditions, hazards and potential incidents. Past incidents, at the MHF or similar facilities, provide an indication of what has

38、gone wrong in the past and what could go wrong in the future.A wide range of hazards and potential incidents will be present in the facility. New hazards and incidents could be created in the future as a result of planned or unplanned changes. The management of change process described in the SMS sh

39、ould identify new conditions during the planning of modifications or new activities. This should then trigger further HAZID studies and risk assessments, with the identification of control measures as appropriate. Figure 2 below illustrates the range of tools that can be used to identify past, prese

40、nt and future hazards.Figure 2: Past, present and future hazards4.3Hazard identification processes and techniquesHAZID techniquesThe flowchart below summarises all the steps needed in a HAZID process and how those steps relate to one another.Figure 3: HAZID processExamples of HAZID TechniquesHAZOPHa

41、zard and Operability Study (HAZOP) is a highly structured and detailed technique, developed primarily for application to chemical process systems. A HAZOP can generate a comprehensive understanding of the possible deviations from design intent that may occur. However, HAZOP is less suitable for iden

42、tification of hazards not related to process operations, such as mechanical integrity failures, procedural errors, or external events. HAZOP also tends to identify hazards specific to the section being assessed, while hazards related to the interactions between different sections may not be identifi

43、ed. Therefore, HAZOP may need to be combined with other hazard identification methods, or a modified form of HAZOP used, to overcome these limitations.Equipment failure case definitionThis method is a systematic approach to defining loss of containment events for all equipment within the study bound

44、ary. Process flow and equipment diagrams are studied systematically, and all equipment is assigned appropriate loss of containment scenarios, such as pinhole leaks, according to design, construction and operation. This form of hazard identification may be necessary for many major hazard facilities,

45、to avoid missing potential scenarios, but is not sufficient on its own because it does not consider specific causes or circumstances. Therefore, this technique should only be used in combination with other techniques for MHF purposes.ChecklistsThere are many established hazard checklists which can b

46、e used to guide the identification of hazards. Checklists offer straightforward and effective ways of ensuring that basic types of events are considered. Checklists may not be sufficient on their own, as they may not cover all types of hazards, particularly facility-specific hazards, and could also

47、suppress lateral thinking. Again, this technique should only be used in combination with other techniques for MHF purposes.What-If TechniquesThis is typically a combination of the above techniques, often using a prepared set of what-if questions on potential deviations and upsets in the facility. Th

48、is approach is broader but less detailed than HAZOP.BrainstormingBrainstorming is typically an unstructured or partially structured group process, which can be effective at identifying obscure hazards that may be overlooked by the more systematic methods.Task AnalysisThis is a technique developed to

49、 address human factors, procedural errors and man-machine interface issues. This type of hazard identification is useful for identifying potential problems relating to procedural failures, human resources, human errors, fault recognition, alarm response, etc. Task Analysis can be applied to specific

50、 jobs such as lifting operations, moving equipment off-line or to specific working environments such as control rooms. Task Analysis is particularly useful for looking at areas of a facility where there is a low fault-tolerance, or where human error can easily take a plant out of its safe operating

51、envelope. Failure Modes Effects Analysis (FMEA)FMEA is a process for hazard identification where all conceivable failure modes of components or features of a system are considered in turn and undesired outcomes are analysed. This technique is quite specialised and may require expert assistance.Failu

52、re Modes Effects and Criticality Analysis (FMECA)FMECA is a highly structured technique that is usually applied to a complex item of mechanical or electrical equipment. The overall system is described as a set of sub-systems and each of these as a set of smaller sub-systems down to component level.

53、Individual system, sub-system and component failures are systematically analysed to identify their causes (which are failures at the next lower-level system), and to determine their possible outcomes, which are potential causes of failure in the next higher-level system. This technique is quite spec

54、ialised and usually requires expert assistance.Fault Tree and Event Tree AnalysisFault Trees describe loss of containment events in terms of the combinations of underlying failures that can cause them, such as a control system upset combined with failure of alarm or shutdown and relief systems. Even

55、t trees describe the possible outcomes of a hazardous event, in terms of the failure or success of control measures such as isolation and fire-fighting systems. Fault tree and event tree analysis is time-consuming, and it may not be practicable to use these methods for more than a small number of in

56、cidents. Historical records of incidentsDatabases of incidents and near misses that have occurred are a useful reference because they give a very clear indication of how incidents can occur. Employers should consider site history, company history, industry history and possibly even wider sources of

57、historical information for this purpose. Examples of major accidents and the role of multiple factors in those accidentsTexas City, USA, 2005. An explosion at a large refinery killed 15 workers and injured over 170 others. Equipment upgrades and SMS elements including process safety information, com

58、munications and training were targeted for improvements following the incident. Total cost of plant upgrade reported to be 1 billion dollars over 5 years.Longford, Victoria, 1998. Two workers were killed and eight others injured in an explosion at a gas processing plant. As a result, many elements o

59、f the SMS were targeted for improvements including process safety information and communication of critical safety information.Pasadena, USA, 1989. A fire and a series of explosions at a refinery complex resulted in 23 fatalities. Inadequate and unofficial isolation procedures, together with human e

60、rror induced by poor ergonomics played a role in causing the accident. The loss of life and scale of damage were increased due to poor plant layout and subsequent damage to fire-fighting systems. Piper Alpha, UK, 1988. The accident was triggered by a small leak in a condensate pump system, which by