In the Field
Tank 111 project recognized for excellence

Alyeska Pipeline Service Company encourages long-term improvements to Trans Alaska Pipeline System (TAPS) operations and maintenance procedures by encouraging workers to improve work techniques and then celebrating outstanding environmental, health and safety performance.

Consequently, the Tank 111 project team recently received the President's Award for Excellence in Environment, Health and Safety for its safe and responsible replacement of two 48-inch tank valves at Pump Station 1 in 2003.

Tank valve replacements are complicated and hazardous procedures that are especially difficult at Pump Station 1 because of its accumulation of pyrophoric materials. These chemicals can spontaneously ignite in air that is colder than about 113F (45C) when they are rubbed or scratched. Pyrophoric hazards increase with concentration and Pump Station 1 is more susceptible to accumulating the materials than the rest of the pipeline because pyrophoric materials do not survive in an atmosphere with oxygen. Pump Station 1 is the only pump station that runs with basically zero oxygen concentration.

The project team mitigated Tank 111's unique safety risks by developing innovative techniques for draining tanks and monitoring their atmosphere.

All tanks must be drained before valves can be replaced. The Tank 111 project team developed a special circulation flow method for draining the tank to remove pyrophoric materials and reduce the risk of a pyrophoric reaction. The technique produced the cleanest tank crews have seen upon initial entry.

The team replaced and moved the Tank 111 valve to improve safety and give work crews easier access to complete future tank maintenance. It also developed and designed a specific testing skid for monitoring the tank atmosphere while the tank is in the explosive range for drain down and refill procedures.

The Tank 111 project was successfully completed without any injuries, equipment damage or environmental incidents. And Alyeska has adopted the new Tank 111 monitoring system to improve safety for all future TAPS tank valve replacements.