Material change to a safety case

Offshore Information Sheet No. 3/2011

Issued February 2011



This sheet provides further guidance on what constitutes a material change revision to a safety case.


Guidance regarding material change safety case revisions is contained in paragraphs 200 – 204 of 'A guide to the Offshore Installations (Safety Case) Regulations 2005' HSE publication L301. However, it has become apparent that some duty holders are continuing to have difficulty in deciding whether certain changes to a safety case are material.

Further guidance

A material change is one that is likely to change the basis on which the original safety case was accepted. In other words changes that merit reappraisal of the risk control arrangements, whether or not they require the adjustment of measures to be taken.

In practice, safety case revisions are likely to be considered material if they have the potential to affect the major accident risks or their controls, either directly or indirectly.

Examples of direct effects are:

  • modifications or repairs to the structure, plant or equipment,
  • an increase in hydrocarbon inventory,
  • new technology, processes or operational complexity,
  • new types of combined operations, or new activities in connection with an installation,
  • new operational risk controls.

Examples of indirect effects are:

  • new ownership or operatorship, introducing a change in the management system,
  • a major change of contractor, and
  • extension of the use of the installation or its components beyond the original design life.

N.B. These are examples only and do not limit what might constitute or contribute to a material change in any particular safety case revision.

The guidance to the Offshore Installations (Safety Case) Regulations 2005 (booklet L30) advises that duty holders must decide, in the light of all circumstances, what constitutes a material change for their installation and safety case. They are, however, encouraged to discuss prospective changes with HSE if they are in any doubt.

Way forward

HSE may challenge a duty holder's decision as to whether revisions to a safety case constitute a material change. HSE can also at any time call in a safety case for inspection, and have powers to direct a revision.

HSE will then assess the revisions and decide whether they can be accepted and any proposed changes implemented. Duty holders are encouraged to engage early with their HSE focal point inspector, to minimise the risk of delays or complications in the process.

HSE's assessment and acceptance decision will relate to the proposed material change. However, it may be appropriate to take into account the impact that such revisions have on other parts of the safety case.

The Offshore Installations (Safety Case) Regulations 2005, regulations 14 and 15.


1. A guide to the Offshore Installations (Safety Case) Regulations 2005 L30 Third edition HSE Books 2006 ISBN 978 0 7176 6184 8. Back

This information sheet contains notes on good practice which are not compulsory but which you may find helpful in considering what you need to do.

Updated 2021-02-12