Demarcation between FOD and OSD for inspection of stacked offshore installations

OC 18/7(rev2)

This OC provides guidance on an agreement between Field Operations Directorate (FOD) and HID Offshore Division (OSD) about operational responsibility for regulatory supervision of stacked offshore installations.


1 When not in use for exploration or production activities, mobile offshore installations (usually drilling rigs) are brought into sheltered waters. These may be into waters within the GB baseline (eg estuaries and firths) or within the territorial sea. Such installations are referred to as stacked; they are no longer "offshore installations" for the purposes of the offshore-specific regulations. While stacked the installations may undergo inspection, repair, refit etc. or simply care and maintenance. The baseline is the line from which the territorial sea is measured and usually equates with low water mark. The territorial sea extends 12 nautical miles from the baseline. (See FIC LCA 171 and the OSD Enforcement Manual).

2 When within the baseline, HSW Act and the relevant statutory provisions apply to a similar extent as they would to any vessel. When outside the baseline, but within the territorial sea, HSW Act and the relevant statutory provisions are applied by Article 8 of HSW Act (Application outside Great Britain) Order 2001. The activities to which HSW Act apply are limited and, with the exception of maintaining the vessel on station, those carried out by the marine crew of the vessel are not covered.

3 This OC outlines the allocation of responsibilities and working arrangements for regulatory supervision of stacked installations. It also confirms the circumstances in which installation owners will be subject to charges under the current Health and Safety (Fees) Regulations

Operational responsibility

4 It has been agreed that FOD is responsible for all inspection and enforcement of HSW Act and the relevant statutory provisions in relation to offshore installations, while they are alongside repair berths undergoing maintenance or repair work involving contractors. Such work does not link directly to the offshore safety case regime and is not chargeable to the owner or the operator of the installation.

5 OSD is responsible for enforcement of HSW Act and the relevant statutory provisions for activities on or in connection with installations that are moored in estuaries [such as the Cromarty Firth] or are otherwise within the limits of the territorial sea. Such activities are generally not linked directly to the offshore safety case regime and are not chargeable to the owner / operator of the installation (but see 6. below)

6 However OSD inspectors may need to visit an installation which has been stacked (alongside or otherwise), for example to follow up specific matters in relation to issues raised before the installation went into stack. Similarly, this could happen prior to mobilisation, before an installation goes to a working location on UKCS. OSD will have full operational responsibility when an installation is moved from any stacked position with a view to its being used as an offshore installation on the UK Continental Shelf. All such work has a direct link with enforcement of the safety case regime and is therefore chargeable.

7 The Maritime and Coastguard Agency (MCA) also have responsibilities in relation to stacked installations which will usually be ships as defined in the Merchant Shipping Act 1995 s.313. MCA's role is primarily to deal with the safety of ships (navigability, seaworthiness) and their crew (manning, qualifications, occupational health and safety). Thus MCA inspectors may also need to visit stacked installations. A Memorandum of Understanding (MoU) between HSE, MCA and the Marine Accident Investigation Branch describes the arrangements for effective coordination of each organisation's activities at the water margin and offshore. FOD inspectors should refer to file 780 and OC 780/1 for information on the MoU.

Liaison between FOD and OSD

8 Certain actions are essential to ensure the effective coordination of FOD and OSD activities in relation to stacked installations.

(1) Before undertaking visits to installations alongside repair berths for purposes described in para 6 above, OSD inspectors should liaise with the appropriate FOD group responsible for ship repair at the berth involved.

(2) FOD should copy to OSD any correspondence (including any Notices) sent to contractors working on installations at repair berths where it is likely that the contractor may remain on, and continue to work on, the installation when it is offshore. Any enforcement action proposed by FOD that relates to the structure or equipment which is part of the installation should, where practicable, be discussed with OSD, before action is taken.

(3) If during a visit to a stacked installation for reason of the type indicated in paras 5 & 6 above, an OSD inspector sees matters of concern involving a shore based contractor and it is intended to write to that contractor, or take formal enforcement action, a copy of the correspondence should be sent to FOD, for information.

(4) OSD will provide specialist assistance if required to FOD for investigations, especially in respect of serious and fatal accidents.

Date first issued: 30 April 2004

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Updated 2023-10-12