For the construction phase of onshore plants, standardized acceptance criteria have never been developed within the Statoil Group or the Norwegian landbased industry, although project specific design acceptance criteria was developed prior to the construction of the onshore facilities on the western coast of Norway when developing the huge Troll field some years ago.

This paper focuses on the development process of such criteria for risk acceptance with an emphasis on the construction, commissioning and start-up phases.

The use of risk analyses in plant design, construction and operation is not only a legislatively based requirement in many European countries, i.e. Norway, but also offers a lot of advantageous features to the design process:

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    Identification of risk and implementation of risk reduction measures in a stage of the project when changes to design and lay out can be implemented relatively easily and with moderate cost compared with implementing the changes after the plant has been built.

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    Firm and objective decision making on the feasibility of implementing risk reducing measures compared with the rule based approach and above all, decision making based on intuition.

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    Often a variety of design options can be at hand if verified suitable by risk analyses compared with the rule based approach, which often offers a preset choice of design and construction solutions.

Risk based design and construction allows to a larger degree, tailor made design and construction solutions to be implemented compared with the rule based approach,

In addition, risk analyses can give a substantial contribution to effective implementation of the construction phase and limit the risk both to personnel and material assets.

In order to evaluate risk, risk acceptance criteria is often used and such criteria have been developed for the project, covering:

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    Risk both to employees and workers being present at site

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    as well as neighbours in the vicinity of the plant.

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    Risk to environment.

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    Risk to material assets.

Two sets of criteria have been established for the evaluation of risk to people, one quantitative set for the strategic assessment of technical risk that can be expressed mathematically and one set to be used when specific work operations or tasks are evaluated.

The later one is being performed by the qualitative use of a risk matrix, where every case can be represented by a frequency of occurrence and a consequence that indicates if the risk is intolerable, tolerable or that can be made tolerable if risk reducing measures are being introduced.

It is firmly believed that the technical risk management system in the this project, including the use of risk acceptance criteria, have been a valuable and decisive success factor in the design and construction of the new facilities.

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