APPENDIX 1 – Example Format for Hazards and Effects Register
APPENDIX 2 - Risk Assessment Matrix and Guidance on its use
APPENDIX 3 - Hazard HierarchyINTRODUCTION General requirements for the Hazards and Effects Management Process (HEMP) exist in EP2005-0300 Volume 3. This guide supplements these requirements and is intended for the layman who is expected to carry out HSE risk assessments as part of managing workplace activities. It sets the standard for HAZID exercises onshore and offshore and replaces the document ‘Guidance on the use of Activity Risk Assessments’ Document No. NS/OOP/NF/NF/GOXX/01560/G1 now withdrawn. 1.0 PURPOSE OF THIS DOCUMENT This document has, as its purpose, the objective of assisting readers to participate in or lead high quality HAZIDs that identify and develop practical HSE risk management measures in the workplace. In addition it provides clear and current guidance on the correct format and use of terminology for Hazard Identification Studies (HAZIDs) wherever they are carried out. ....
Successful HSE HAZID and risk assessment exercises require an in-depth understanding of the meaning and relationships of the following terms.
A Hazard is any situation with the potential for harm to People, Environment, Assets and Company Reputation. (Normally represented as P E A R).
Hazards are rarely simple events or activities but often involve energy (potential, kinetic, chemical, biological etc.), which is being used / released in a planned and controlled way. It is release of this energy in an unplanned or uncontrolled way that permits a Top Event to occur.
MAJOR ACCIDENT HAZARD
A Hazard which has a Consequence of 5 for impacts on People, Environment, Asset or company Reputation when assessed on the Risk Assessment Matrix (RAM).
A Threat is any factor that can release a hazard in an unplanned or uncontrolled way.
Threats abound in most workplaces ranging from corrosion, erosion and dropped objects through to lack of operator competence, poor communications and ineffective management. Effective identification and management of THREATS is critical in order to prevent the unplanned or uncontrolled release of a Hazard, which may lead to a Top Event.
A Threat Control is any system whether ‘hard’ (e.g. pressure safety valve) or ‘soft’ (e.g. maintenance procedure) implemented to prevent a Threat from being successful and releasing a Hazard.
Threat Controls range from an appropriate choice of materials of construction, through to using specialists to carry out a job to ensure the right level of competence. Any individual Threat is normally managed with more than one Threat Control so that if one Control fails it does not necessarily result in a Top Event.
A Top Event is the first thing that happens when a Threat is successful and a Hazard is released.
Top Events occur when Threat Controls fail and allow a Threat to succeed in releasing the Hazard. Very simply put, Top Events are Hazard release events but are often confused with Consequences and sometimes with Hazards. If detected early enough Top Events may not have the opportunity to escalate into further Consequences that may be significant.
Consequences may develop if nothing is done when the Top Event occurs.
Top Events frequently escalate into Consequences. Recovery Measures are aimed at reducing Consequence development and returning the situation to a point where the incident is considered over. Consequences always have a defined area of impact for risk assessment purposes. These impacts are People, Environment, Asset and Reputation. The severity of a Consequence is assessed on a scale of 0 to 5 using the Risk Assessment Matrix.
Recovery Measures are any ‘hard’ (e.g. fire water system) or ‘soft’ (e.g. emergency response procedure) response implemented to prevent escalation of a Top Event into Consequences.
Consequences could be a fire hence passive/active fire protection measures are typical Recovery Measures. Other examples of Recovery Measures are emergency shutdown and blowdown.
· Hard recovery measures are physical measures, systems or arrangements.
· Soft recovery measures are procedures, permits and other management measures employed for Hazard management purposes.
Likelihood is a measure of the chance that the Threat will be successful in releasing the Hazard and of the Top Event and subsequent Consequences occurring. Likelihood is assessed using a scale of A– E on the Risk Assessment Matrix
The combination or product of the Likelihood of an HSE related Hazard release (Top Event) with the Consequences if it was released.
AS LOW AS REASONABLY PRACTICABLE (ALARP) RISK
This is the point at which any further measures to reduce the Likelihood of a Hazard release (Top Event) and/or the Consequences, involves cost/effort disproportionate to the risk reduction that could potentially be achieved. It can be viewed as application of the Law of Diminishing Returns.
This is the risk that remains when all practicable Threat Control and Recovery Measures have been taken.
RISK ASSESSMENT MATRIX
A simple tool used by a HAZID Team for carrying out Qualitative Risk Assessments. (See Appendix 2)
Correctly applied the Hazards and Effects Management Process (HEMP) is very effective for identifying the systems, actions and responsibilities necessary to reduce workplace activity HSE risks to a level that is ‘as low as reasonably practicable’ (ALARP).
A HAZID models the HSE risks in the workplace and uses defined terms in an organised way to achieve this objective. It asks ‘what could fail’, ‘how could it fail’, with what likelihood and ‘what are the consequences of the failure’?
It is important that the HAZID technique is followed in a structured, systematic way so that the HAZID ‘map’ produced is a good model of the workplace ‘territory’, consequently helping us to identify and hence be able to manage HSE risks. It follows the simple Hazard management sequence of Identify, Assess, Control and Recover.
Hazards and Effects Management should be a routine part of all workplace activities to ensure HSE risks are maintained at levels that are ‘as low as reasonably practicable’ (ALARP). The word Risk however, is a complex term and to be understood and used effectively it needs to be broken down into its two component parts.
The two components of Risk are Likelihood (of a Top Event) and Consequences (of a Top Event) - Remember: a Top Event is the unplanned or uncontrolled release of a Hazard.
LIKELIHOOD X CONSEQUENCES = RISK
When carrying out a Hazard Identification Exercise (HAZID) the overall HSE risk picture may sometimes seem confusing. In practice the process is very simple:
· What is the source of HSE risks? – Hazards
· What can release a Hazard? – Threats
· What can prevent a Threat being successful? – Threat Control
· If Threat Controls are successfully implement what is achieved? – REDUCED LIKELIHOOD of a Top Event
· If Threat Controls fail what occurs? – Release of the Hazard and a Top Event
· What could happen after a Top Event? - Further escalating events called Consequences (for People, Environment, Asset and company Reputation)
· How do we get things back under control? – By putting in place Recovery Measures
· If Recovery Measures are successfully implemented what is achieved – REDUCED CONSEQUENCES from a Top Event
REDUCED LIKELIHOOD X REDUCED CONSEQUENCES = REDUCED RISK
Prevention (Threat Control) measures reduce Likelihood and recovery measures reduce Consequences. For good HSE performance our priority should always be prevention, but to also plan for recovery (e.g. try to avoid having an accident in your car but in case you do, always wear your seat belt).
When it is judged that there is little more we can practicably do to reduce Likelihood or Consequences we describe the (remaining, but much lower) residual HSE Risk to be ALARP.
When assessing risks the Shell Risk Assessment Matrix is used (see Appendix 2). Although qualitative in nature it does encourage consistency in risk assessment. Note that ‘High, Medium and Low’ are inadequate terms, are too subjective for risk assessment purposes, and should not be used.
The Shell Risk Assessment Matrix works by assessing the level of Likelihood (designated by a letter A-E) of the Threat being successful and allowing the Hazard to be released, and the level of Consequences to People, Environment, Asset and Reputation (designated by a number 0-5) if the Hazard was released.
Likelihood combined with Consequences gives a measure of Risk e.g. B5 or C4.
Any Hazard assessed with a Consequence of Level 5 on the Risk Assessment Matrix e.g. B5 is defined as a Major Accident Hazard. These Major Accident Hazards are further analysed using a Tool known as a Bow Tie or Cause-Consequence diagram but this is a more advanced technique normally employed in an HSE Case.
Identification of Hazards is made easier with the use of a Hazard Heirarchy (see Appendix 3), which is a standardised comprehensive list of generic hazards.
The HAZID Facilitator should ask the question ‘do we have this type of Hazard present, and if so where?’ In practice many of the Hazards associated with the activities being assessed are often well known.
When assessing a Hazard for potential Consequence (using the Risk Assessment Matrix) it must be assessed assuming that no hazard management measures (Threat Controls, Recovery Measures etc.) are in place.
Once the Hazards connected with the particular activity have been identified and Threat Controls/Recovery Measures agreed then the HAZID Team should ask the question ‘what more could we do?”
If reducing risks still further involves disproportionate cost/effort with minimal effect on the Likelihood or Consequences of a Top Event then the risks are usually judged to be as low as reasonably practicable (ALARP) and acceptable for the activities planned.
HAZID information needs to be captured in a clear, unambiguous format, called an Hazards and Effects Register, so that Threat Controls and Recovery Measures can be attributed to the Threats and Consequences they manage. A very effective format for doing this was developed for the Soroosh and Nowrooz HSE Cases and is recommended for general use (see Appendix 1).
When the Hazards and Effects Register is complete it conveys a full picture of what Hazards are present and for each identifies how it will be managed by the use of Threat Control and Recovery Measures. Attributing responsibilities to the Threat Control and Recovery Measures in the Register permits it to be used as a management tool for managing workplace activities planned with ALARP HSE Risks.
Although Hazard management measures for Threats and Consequences can be grouped together they are usually split between hard and soft types.
The Facilitator of a HAZID team should be thoroughly conversant with the terms and relationships in this document and be able to keep the team focused on their use and the application of the Risk Assessment Matrix and HAZID terminology.
This helps prevent Top Events being misidentified as Hazards. This type of error robs us of the opportunity to identify Threats and Threat Controls and makes it difficult to show whether the Hazard Management Measures we have are suitable and sufficient in reducing the likelihood of a Top Event.
TRIC is simple and useful workplace Hazard aide memoire that prompts Supervisors and their work teams to think about hazard management in the workplace. TRIC support the Permit to Work (PTW) process and assists in providing the information required on the PTW safety check sheets.
Completing a TRIC uses all the principles above but in this case each TRIC focuses on a specific work activity. Each activity is simply broken down into sequential tasks and the Hazards within each task examined to see whether they will be effectively managed. The TRIC format facilitates this for the work team.
Caution – TRIC HSE terminology is not consistent with the HEMP definitions above. The relationship between TRIC and HEMP terms are detailed below for clarity.
TRIC Terminology HEMP Terminology
Control Measures Threat Controls and Recovery Measures
What could go wrong? How could Threats be successful?
What would the effects be? What would be the Top Event and potential Consequences?
How can hazards be prevented? How can hazards be eliminated or
How can hazard releases be prevented?
Hazards and Effects Management Process – General requirements EP2005-0300 HSE manual, Volume 3 HEMP Requirements, Tools and Techniques.
+ نوشته شده در جمعه هفتم فروردین ۱۳۸۸ساعت 9:10 توسط امیر زارعی |
اساتید محترم ، دانشجویان گرامی ،همکاران محترم شاغل درواحدهای صنعتی خواهشمند است نظرات خود را دررابطه با این سایت و سایت مدیریت مهندسی ایمنی وبهداشت حرفه ای کردستان برای ما ارسال کنید و اگر مطلب علمی وجدیدی دارید برای ما ارسال نمایید تا با اسم خودتان در این سایتها درج نماییم.بدون شک پربارنمودن این وبسایت بدون کمک شما امکان پذیر نخواهد بود اگر چه من تمام سعی و کوشش خود را خواهم نمود.
آدرس وبسایت مدیریت مهندسی ایمنی و بهداشت حرفه ای http://amirsafety.blogsky.com
ایمیل حهت ارسال مطالب :firstname.lastname@example.org
منتظر مقالات و مطالب علمی شما هستم .
مدیرسایت امیر زارعی
عناوین مطالب وبلاگ
|نوشته های پیشین|
بهداشت حرفه ای
وسایل حفاظت فردی
استاندارهای ایمنی وبهداشت حرفه ای و محیط زیست
قوانین کار وتامین اجتماعی
مدیریت مهندسی ایمنی وبهداشت حرفه ای (منبع این سایت)