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Audit of safety systems at the Teesside terminal

On 20 May 2010, the Petroleum Safety Authority Norway (PSA) conducted performed an audit of safety systems at the Teesside terminal in the UK. The audit identified two improvement items related to emergency shutdown valves.

The audit was limited to areas under Norwegian jurisdiction, more precisely shutdown valves, metering system and four large crude oil storage tanks.

Unstabilised crude is imported to the ConocoPhillips terminal at Teesside, where the oil is stabilised and re-exported. In addition to stabilized oil, LPG is exported partially as pressurised liquids (hot products) and partially as cold products.

The audit activity is related to the PSA’s main priority “Technical and operational barriers”, and is part of the PSA’s audit plan for 2010.

The purpose of this priority is to draw attention to the fact that safety-critical barriers shall be maintained in a comprehensive and consistent manner, thus reducing the risk of major accidents to the greatest extent possible. Technical safety comprises central parts of the technical barriers (the safety functions), and safeguarding these is important to maintaining an acceptable risk level.

Proposition No. 110 to the Storting (Norwegian Parliament) (1972-1973), the treaty between Norway and the UK concerning the Ekofisk pipeline, Article 26, stipulates the Norwegian authority’s area of responsibility. The treaty also stipulates that uniform safety regulations shall be utilised.

The purpose of the audit was to confirm that ConocoPhillips Skandinavia AS plans, manages and carries out its activities at the Teesside terminal in a safe, prudent manner.

The audit at the Teesside terminal was carried out as planned. The result shows that the activities are managed in a satisfactory manner, within the technical area covered by the audit. Two improvement items relating to emergency shutdown valves have been commented on.

The PSA’s observations can generally be divided into two categories:
• Non-conformity: Related to observations where have identified breaches of the regulatory requirements
• Improvement item: Related to observations where we find deficiencies, but do not have sufficient information to be able to ascertain breaches of the regulatory requirements

Improvement items

Closing time for emergency shutdown valves
It should be clarified whether valves with an ESD function (barrier function) meet the functional requirements.

The ESD9 signal activates three valves; XHV11002, XHV11003 and XHV11004.
A review of maintenance history showed that valve XHV11002 had a closing time of 3.45 minutes. The typically closed within 45 seconds. Performance requirements had not been established for closing time or leak rates.

Verification of closing function XHV11001
During the audit, documents could not be produced to demonstrate that the valve (XHV11001) safeguards the barrier function.

Valve XHV11001 is difficult to function test while the installation is operational. Function testing is planned for valve XHV11001 in connection with the planned shutdown of the Teesside terminal this summer.
The PSA requests a copy of the results of this function test.

Other comments

The opening meeting
At the opening meeting, ConocoPhillips presented the installation’s safety management system, which is founded on guidelines from the Health & Safety Executive.

The control room
Verification was performed in the main control room. The ESD system and the process control system were reviewed and explained. The gas detection system was based on catalytic point detectors. Shutdowns take place following a vote, two out of three. The four crude oil tanks have level switches for high levels (three levels). If the level of two tanks is too high, a shutdown signal is sent to ESD9.

Passive fire protection
The crude oil tanks’ foundation was protected with a cement-based vermiculite coating from Mandoval.

Fire extinguishing systems
The pig launcher, metering station and crude oil tanks are protected by a deluge. The firewater coverage was recently verified to be adequate. Firewater monitors and hose stands are also in use.

The PSA conducted spot checks of performed maintenance. ConocoPhillips uses the maintenance administration system SAP. The PSA has no comments regarding the presented documentation.