Major accident hazard (MAH) pipelines: Notification

This page summarises the information required on MAH pipeline Notifications. It tells you what Notification is and when it is required. Further details are given in HSE's Guidance A guide to the Pipelines Safety Regulations 1996.


The Pipeline Safety Regulations 1996 (PSR) place a duty on operators of MAH pipelines to provide certain information to HSE at various stages in the lifecycle of a MAH pipeline.

These duties are covered in the following Regulations:

These requirements only apply to MAH pipelines.

Submission of Notifications

From the 3rd January 2012 you can send your notifications to HSE electronically using our online notification system.

If you have any questions or wish to send your notification/s by post or e-mail.

Regulation 20: New MAH Pipelines

Regulation 20 requires that the construction of a new MAH pipeline should not start until the operator has notified HSE at least six months prior to the start of construction. PSR Schedule 4 lists the particulars required which includes the name and address of the operator. This notification may form the first contact between the pipeline operator and HSE for that pipeline. The intention is that this notification should be made at the 'end of the concept design' stage and hopefully before major expenditure has been committed to by the dutyholder. Operators often approach HSE in advance of regulation 20 requirements to discuss plans and designs; we welcome this early and productive dialogue.

If an operator is in any doubt as to whether HSE is aware of its identity and/or its MAH pipeline(s) it should contact us (see full Notification addresses.

Multiple Construction Sites: under regulation 20 if construction of a MAH pipeline occurs at more than one location (eg onshore, offshore or a combination of both) and in more than one stage, notification to HSE should occur at least 6 months before the first stage begins. An example is where a pipeline bundle intended for offshore use is constructed on land and is then taken for final assembly and connection to an offshore installation. Construction of the pipeline under these circumstances is deemed to start at the first stage on land, not at the subsequent phase offshore.

Regulation 21: Notification before use/re-use

Under regulation 21 HSE requires 14 days' prior notification of the intention to bring a MAH pipeline into use so it has the opportunity of a final inspection before a dangerous fluid is first introduced into the pipeline.

This regulation also applies where a pipeline is to be brought back into use after it has been taken out of commission (other than where the circumstances were routine maintenance, planned or emergency repair).

PSR Regulation 22(1): Change of MAH Pipeline Operator

The operator of a MAH pipeline may change at any time throughout the life of a pipeline. Under regulation 22(1) any change of operator must be notified to HSE within 14 days of the change.

If a pipeline is transferred from one operator to another, there must be sufficient information passed to the new operator so that all the relevant duties can be complied with. The onus is on the new operator to ensure that it has sufficient information to comply with PSR and to enable proper decisions to be made about the integrity and safety of the pipeline.

Regulation 22(2): Other Cases

Regulation 22(2) requires notification in other cases. The notification period for this Regulation is at least three months. Regulation 22 concerns significant changes to the pipeline which can affect the level of risk. Examples include:

HSE Addresses

Please note that this e-mail should only be used for MAH Pipeline Notifications. Any other enquiries received will not be responded to via this e-mail account.

Scotland and Scottish waters

Health and Safety Executive
Hazardous Installations Directorate
Gas and Pipelines Unit
Lord Cullen House
AB25 3UB

E-mail: [email protected]

Rest of GB, territorial waters and UK continental shelf

Health & Safety Executive
Hazardous Installations Directorate
Gas and Pipelines Unit
Rosebery Court
Central Avenue
St Andrews Business Park

E-mail: [email protected]

Updated 2021-06-16