A bridge too far

Doug Woodbridge looks at the application of RFID (Radio Frequency Identification) in Personnel Location Awareness and Personnel on Board (POB) control

Knowing where your personnel are when it counts really matters when it comes to offshore oil and gas facilities.

In 1988, the Piper Alpha oil platform inthe North Sea caught fire and exploded. Piper Alpha remains the world's worst offshore oil disaster and has been the catalyst for many changes in regulations and legislation leading to a greater overall focus on safety in the Oil and Gas industry. Evidence of this has been the ever increasing importance of the location awareness of personnel and the implementation of enhanced safety precautions. For example, POB (Personnel on Board) counts are carefully managed and Muster drills are now carried out weekly to ensure, should the worst happen, everyone is prepared and has the best chance of survival.

Hess Corporation is operator of South Arne, one of Denmark's most significant fields. The facility is located approximately 150 miles west of Esbjerg in the Central North Sea. The South Arne Complex comprises the main South Arne Platform bridge-linked to an adjoining drilling platform. Where two or more offshore installations are bridge-linked, it is important to ensure that at any time the population of each installation does not exceed the number of lifeboat seats available on that installation.

Previously, control of POB on-board the South Arne platform used a manned, paper-based, bridge control system involving a person permanently stationed at the bridge-link taking counts of those crossing between the drilling and production platforms. In an effort to improve safety by reducing the risk of human error Hess took the decision to invest in an electronic solution.

Upgrading the POB system on South Arne was important for Hess so they would know at all times those on-board and, in an emergency, be 100% confident that all personnel could be safely evacuated using the facilities available.

To address this requirement, S3 ID supplied an Automated Bridge Portal with 'Traffic-light' Control and a remote alarm system in the South Arne Central Control Room to warn of exceeding the maximum POB. Moving away from the manual system provided an additional benefit for Hess, as it saved the cost and bed-space of having two people offshore just to monitor the bridge.

Giving the green light for safety S3 ID's 'Traffic light' technology uses RFID Personnel Tracking Tags which are automatically read by the Bridge Portal and POB system. This replaced the manual paper-based alternative and now monitors the movement of personnel across the bridge-link between South Arne and the Drill platform. Simple, visual and highly effective, the 'Traffic light' system automatically ensures that the maximum POB is not exceeded.

Safety Procedure All personnel are required to wear an individually Identifiable RFID active transponder tag. As a member of personnel passes the bridge portal, their unique Intrinsically Safe (IS) RFID tag is read by the bridge-mounted Ex certified reader unit, which is configured with four antennae to enable the reader unit to detect the presence and direction of travel of the transponder tags. These are worn by all platform personnel crossing the bridge - i.e., whether they are entering or leaving the installation. Their identity is captured by the system and the installation POB count automatically updated. This is then compared against the maximum allowed POB number.

As the person is entering the facility they see in front of them a 'traffic light'. If the system calculates that the maximum POB count for the installation they are about to enter is not exceeded by their presence, then this will light 'Green' to advise that it is safe to proceed. However, if their presence brings the total POB over the safe limit, then the red or 'flashing yellow' for some clients, will illuminate cautioning them that they should not proceed further and should leave. If they continue, a hardwired alarm contact signalling 'maximum POB exceeded' is triggered which is connected directly to the platform ICS system.

Two PTS client workstations, one located in the South Arne Heli-Admin and the other on the Drill/Hotel platform display an operator interface. A graphical display shows current POB for the both the South Arne platform and the Drill/Hotel. Both PTS workstations are attached to a PTS tag allocator. This enables transponders to be allocated to personnel on arrival at the platforms.

Conclusion Electronic Bridge Controls provide an enhanced level of safety and security for personnel by removing the human risk element (as far as possible) and improving communication ensuring maximum POBs are not exceeded.

Doug Woodbridge is head of sales & marketing at S3 ID.