Page 549 - Marine Structural Design

Chapter 29 Risk Assessment Methodology 525

acceptance is applicable to risk to personnel, environment, and assets. Trbojevic (2002)
illustrated the use of the ALARP-principle in design.

V (Lower tolerability limit)
Acceptable risk

Figure 29.5 The ALARP-Principle

29.3.4 Comparison Criteria
This type of criteria is suitable in more limited studies that aim at comparing certain concepts
or solutions for a particular purpose with established or accepted practice. The criteria are
suitable in relation to operations that are often repeated such as drilling and well interventions,
heavy lift operations, diving, etc. The use of the comparison criteria requires that the basis of
the comparison be expressed precisely.
The formulation of the acceptance criterion in this context may be that the new solution shall
not represent any increase in risk in relation to current practice.
Examples of comparison criteria are:
Alternative design (or use of new technology) for fire water system shall be at least as safe
as conventional technology
The risk level for the environment shall not be higher compared to the existing solution
Alternative solution shall be at least as cost effective as the established practice
This type of risk acceptance criteria is also suitable for risk to personnel, environment, and
assets.

29.4 Using Risk Assessment to Determine Performance Standard

29.4.1 General
LR (1 999) published guidelines for classification using risk assessment techniques to
determine performance criteria. The risk assessment methodology used in LR (1 999) is similar