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Safety Integrity Level Calculator

Data used in our online SIL calculator is based on reliability data (DU failure rates) made available through the PDS Data Handbook (2013) by SINTEF and the PDS Forum. You may order the full  PDS data handbook here.

The DU failure rates used in this calculator are also available in the Norwegian Oil and Gas Guideline 070 (NOG 070).



1. SIL calculations above are only for a single component/component group. Remember that SIL requirements apply to entire functions, not individual components/component group.

2. A common cause factor (Beta) of 5% is assumed for all device types for redundant configurations (1oo2, 1oo3 and 2oo3)

This risk calculator can be used to:

- calculate the probability of failure upon demand (PFD) for a given equipment based on available data in Norwegian Oil and Gas Guideline 070 (NOG 070) for different voting configurations

- calculate the PFD based on failure rate for your component (user entry) for different voting configurations and functional/proof test interval (user entry)

- calculate updated PFD and recommended test interval based on experienced failures for given equipment

- indicate the “SIL-capability” of the component based on the PFD; the quantitative SIL requirement.


User groups:

- functional safety engineers

- reliability engineers

- risk analysis experts

- technical safety