Abstract

With the increasing use of ALARP principles in oil and gas safety studies to reduce the tolerable risks to As Low As Reasonably Practicable level, there is a need to understand the use of those principles with respect to (a) the level of uncertainty of data and (b) the risk criteria. Because of the level of uncertainty of data it becomes unclear which tool to be used for ALARP demonstration. As far the application of numerical risk criteria is concerned, it is not always correct in some cases. Thus the demonstration of ALARP and the risk criteria used should be justified by the categorization of risk which may be qualitative, semi-quantitative or quantitative, and the available data. For quantified risks, the intensification of ALARP demonstration will depend on the available data and the level of risk reduction to be achieved. Overlooking of such issues could lead to either inadequate analysis or over-analysis of risk resulting in companies burdened with extra cost for implementation of recommendations.

This paper suggests a structured methodology for the ALARP demonstration and its 'level of intensification', to address the issues stated above. Examples from previous risk assessment studies undertaken for various oil and gas companies have been taken and the proposed methodology is applied in the management/ALARP demonstration of both acceptable and tolerable risks. In the end, the paper demonstrates the benefits of using the proposed methodology.

The paper also addresses some common misconceptions regarding the ALARP principle.

Abbreviations Used

ADNOC Abu Dhabi National Oil Company

ALARP As Low As Reasonably Practicable

CBA Cost Benefit Analysis

DA Decision Analysis

DF Disproportionate Factor

EMBOT Extended Modified Bow-Tie Analysis

HSEIA Health, Safety and Environmental Impact Assessment

HSEMS Health, Safety and Environmental Management System

IAD Intensification of ALARP Demonstration

MBOT Modified Bow-Tie Analysis

QRA Quantitative Risk Analysis / Quantified Risk Assessment

RRM Risk Reduction Measure

Introduction

This paper addresses process related risk management by application of ALARP demonstration. In order to address the topic, i.e. ALARP Demonstration and its Level of Intensification, this paper begins with an explanation of the ALARP principle. It highlights some of the principles outlined by Health and Safety Executive (HSE), UK. Some misconceptions on the application of ALARP are also discussed.

The paper outlines two problems faced during an ALARP study, namely, uncertainty of data and risk criteria. The points to be kept in mind while assessing such problems are discussed. Hence an assessor may find this useful while dealing with risks to be reduced on the principles of ALARP.

The paper suggests that the application of ALARP demonstration tools and methods should depend on the categorization of risk. The tools used to demonstrate ALARP will vary depending on the level of risk reduction as well as the expression of risk (qualitative / quantitative). Hence the term 'intensification' is used for the assessor to know if a justified level of demonstration is being sought for the appraisal of risk reduction options. Thus the question 'how deep to dig' should be answered before proceeding with the demonstration.

Some examples of the demonstration tools have been included but these are not intended to be prescriptive.

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