It has become apparent that some duty holders and/or their QRA consultants have been calculating Temporary refuge impairment frequency (TRIF) for normally unattended installtions on a yearly basis, then factoring the frequency for the level of occupancy of the installation (i.e. number of days/hours the NUI is attended).
This Semi Permanent Circular (SPC) provides guidance for inspectors on the approach to take to determine whether duty holders have addressed the actions required by the Offshore Installations (Safety Case) Regulations 2005 (SI 2005/3117) and the Assessment Principles for Offshore Safety Case Assessment.