No shutdown required for tee and flare line repair

A northwestern refinery discovered a 4" x 4" hole in a 24-inch flare line where it teed into the flare stack.

Because hazardous flare gases were being released to the atmosphere, immediate repair was imperative.

Plant maintenance personnel were able to effectively patch the hole temporarily. Further inspection, however, showed that area of the line and stack might have been weakened by corrosion, thus, raising the possibility of additional leakage.

Personnel from Team's leak repairs division were contacted by plant officials.

Team recommended a perimeter seal enclosure for the tee. The tee enclosure would permanently seal and strengthen the weakened area and serve as a long-term repair. Further, Team technicians pointed out the repair could be made without a shutdown.

Plant officials agreed to the plan.

Recognizing the difficulties associated with both the measure-up and the installation of such a large enclosure, Team's leak repair technicians contacted Team's safety and engineering departments as well as the company's technical support center.

Because of their proximity to poisonous flare gases, Team technicians were required to be in full one-piece acid suits with air-supplied respiratory equipment (Level A protection).

Additionally the tee was located approximately 40 feet above ground inside the flare structure. Consequently, safety lines and harnesses had to be used.

Further, the line and stack area to be measured had several stub outs protruding from it. The close proximity of this and other flare structures, plus hot steam lines, required very precise and cautious measurements by Team's technicians.

The measurements were obtained safely and forwarded to Team's engineering design department.

A three-piece, 24-inch enclosure was designed by Team engineers to fit the tee. The enclosure was eight feet long and weighed 2,800 pounds.

Team's manufacturing center hot-shotted the enclosure's pieces to the refinery. Once the pieces were onsite, Team technicians - with the help of construction cranes - fitted the three-piece enclosure over the tee and line.

The perimeter seal was then bolted permanently over the tee, sealing and strengthening the designated area of the line and stack.

Normal operations were maintained throughout the repair, and the customer saved the cost of a shutdown.