ALARP , risk assessment

ALARA and ALARP are commonly used acronyms in risk assessment and reduction activities. ALARA stands for as low as reasonably achievable, ALARP is short for as low as reasonably practicable. Although now broadly used, ALARA originated in the atomic energy field. This is taken from the Reference Library, Glossary of Terms at www.nrc.gov. 

A safety management risk assessment techniqne that is used to define and control the hazards associated with a process, job, or procedure. The Job Safety Analysis ensures that the hazards involved in each step of a task are reduced to as low as reasonably practical (ALARP). The assessment starts with a summary of the entire job process. The job is broken into smaller steps and listed in a tabular form. The hazards for each step are then identified and listed. This is repeated for each step in the process and a method of safe work is identified. It may be also called a Job Hazard Analysis (JHA). See also As Low As Reasonabfy Practical (ALARP). 

It is suggested that the four components of the Accident Tetrahedron may be considered as a new concept of separate lines of defence or layers of protection when considering ALARP Justifications, all of which must be considered during risk assessments. Further research is recommended on the costs of mitigation methods across the four areas of the tetrahedron. A specific retrospective application would also have benefit. 

Several depictions of the ALARP concept begin with an inverted triangle, the purpose being to indicate that the risk is greater at the top and much less at the bottom. Figure 6.2 shows the concept combined with the elements in the risk assessment matrix. 

Table 8 Is based on HSE s Guidance on ALARP decisions in control of major accident hazards (COMAH) SPC/Permissioning/12. Note that a scenario-based risk assessment with a single fatality is not the same as an Individual Risk calculation. 

The UK Health and Safety at Work Act 1974 defined the concept of as low as reasonable practicable (ALARP). The ALARP principle is based on reasonable practicability, which simply means that hazard controls are implemented to reduce residual risk to a reasonable level of practicality. For a risk to be considered ALARP, it must be demonstrated that the cost in reducing the residual risk further would be grossly disproportionate to the benefit gained. Therefore, a risk assessment is conducted, and a cost-benefit analysis performed to determine how far to carry the hazard control. Of course, the challenge is deciding what is practical (e.g., cost, effort, time) balanced with how much benefit of lower residual risk the hazard control brings. Unfortunately, there is no standard method to demonstrate that the hazard control trade-off will meet ALARP. However, some of the following have been successfully used ... 

Many industries will justify the ALARP level with a quantitative risk assessment of how it will impact societal risk. In other words, how many additional lives are saved with this hazard control This application is very common in the United Kingdom especially in rail safety but highly controversial in the United States. But this is changing to some extent in the United States. Trade-off benefits in pollution control in some industries are now using the ALARP method (Figure 2.2). 

Following the discussion of the DBA, the probabilistie risk assessment (PRA) and severe accident analysis are described in subsections 5.4 and 5.5. The PRA and severe aceident analysis seek to demonstrate that the numerical risk to operators and members of the public are acceptably low, and serve as an input into the ALARP assessment in Chapter 8. 

Safety aspects of front end engineering design (FEED) QRA = quantified risk assessment ALARP = as iow as reasonably practicable. 

The following risk assessment involves testing the proposal to fit mandatory automatic floatation equipment to the skids of helicopters against the principles outlined in this book and to apply the ALARP principle to the findings. 

Apportionment of Safety targets and quantification of requirements. To demonstrate that the risks resulting from the changes to the railway are tolerable, ALARP and no greater than the level of risk in the current Railway System, quantitative risk assessments are carried out, and a set of requirements related to the new hardware system constituents have been quantified. 

Figure 8. An example of the roll function in time domain and ALARP risk evaluation criteria applied for the assessment of safety of a ship in damaged conditions.

An example of application of the ship performance data regarding the ship roll function in time domain and ALARP risk evaluation criteria for assessment of a ship safety in damage conditions is presented in Figure 8. The vertical axis in Figure 8 regards the angle of heel in degrees and the horizontal axis concerns the time in seconds. 

The Risk Assessment Matrix (RAM) is coimnonly used to map the various risks associated with a system under stu. As indicated in Fig. 2 the matrix shows a scale for increasing likehhood of a particular event and the other scale shows the severity of the consequence for that particular event. The yellow area of the matrix, as low as reasonably practical (ALARP) to indicate the level used as the limit for which risks should be mitigated. Each company should define the ALARP region in their RAM. Qualitative values from A to E are assigned for likehhood (equivalent numerical values from 0 to 5 are also used to estimate a risk index value). For Tambaredjo, the risks indices numbered in Table 2 are shown in Fig. 2. Risks 1 to 3 require further considerations. 

In the risk assessment, the assessors could have failed to identify shortcomings associated with the controls measures that were in place. In other words, the risks were considered to be controlled ALARP when, in fact, shortcomings existed and additional controls should have been recommended. 

Early safety and health assessment will not only benefit from the safety and health performance but also contribute to lowering the overall plant costs (Edwards and Lawrence, 1993 Kletz, 1998 Shah et al., 2003). Besides, the cost of fixing a problem (e.g., making changes or modifications on the process) is lower when done at the earlier phases of the process lifecycle. Analyses made by Kletz (1988) revealed that the cost increases tenfold as one progresses through each phase. This is because hazard and risk assessments will eventually lead to decisions that require necessary preventive actions to either eliminate or reduce the hazards and risks as low as reasonably practicable (ALARP). The decisions cover diverse elements including alternative process routes, plant layout, and plant... 

NOTE The examples below are not meant to be complete ALARP assessments, but may be taken as indicative of the concept of use. The risk situations considered may be chosen as required and could even be different phases of the same procedure. 

Part Two The claim for completeness of assessment and risks being ALARP can be made providing it can be demonstrated through evidence that all four areas of the accident tetrahedron have been equally assessed to a degree appropriate to the credible accident scenarios developed. The greater the risk of the credible accident, the more evidence in all four areas is required. For additional probity of the claim, independent assessment may be taken. It must also be shown that further reduction in risk is not reasonably practicable. 

Requirements 1 to 7 can be met by the application of either qualitative or quantitative hazard and risk analysis techniques as per part 5 of the Standard. The example to date has applied a quantitative analysis employing a number of techniques. In terms of qualitative assessment, an "unlikely failure but with "catastrophic outcome represents an extreme risk necessitating "necessary risk reduction and application of ALARP (as low as reasonably practicable), good practice and continuous risk reduction principles... 

Petroleum Institute (API) developed their Recommended Practice 75 (RP 75), which recommended that offshore facilities develop a Safety and Environmental Management Program (SEMP). Like a safety case, RP 75 is mostly nonprescrip-tive. However, it makes extensive reference to industry standards (mostly from the American Petroleum Institute), and so it is perceived as being considerably more prescriptive then the safety case approach. Nor does RP 75 require that a formal assessment of acceptable risk (ALARP) be determined. 

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