Petroleum Aboveground Storage Tank Cleaning Procedures
Posted on Fri, May 21, 2010 @ 10:16 AM
By Craig Childres, Director of Business Development - Petroleum & Energy
Aboveground storage tanks are large steel cylinders that are used to store petroleum products. Periodically either due to regulatory inspections requirements, a change of product within the tank or needed repairs, petroleum aboveground storage tank requires cleaning. Cleaning of petroleum aboveground tank should be performed by highly trained crews with the necessary experience and certifications. Below is a general guide to cleaning AST's
For all daily site work, crews must be TWIC certified, be current with all trainings and maintain proper insurance. The crew should perform a daily on-site safety meeting covering all of the possible related safety issues. This meeting will be documented and a representative of the owner should participate. The crew needs to obtain the necessary work permits from the owner and go through the lock-out tag-out on the tank each day. The isolation of the piping and valves associated with the aboveground tank should have occurred and tank ventilation should be in place prior to the crew arriving at the site. The crew should verify that all blinds and blanks are in place and set up a safe and secure work area including a decontamination area. A site specific Health & Safety Plan (HASP) needs to be prepared followed and maintained at the work site.
The tank cleaning crew, consisting of a minimum of three people and all the proper equipment vacuum truck for product removal, support trucks, pressure washers confined space entry/rescue gear, supplied air (SCBA) system, and proper PPE will be needed. The crew will set up the confined space entry equipment around the tank using the front manway as the only entry and exit manway into the tank. An approved and properly calibrated air monitoring meter should be used to evaluate the atmosphere in the tank and the tank should be continuously vented throughout the cleaning process. The entrant crew will enter the tank and work the recoverable product with squeegee's to the vacuum truck hose placed in the center of the tank. Using the pressure washer, the entrant/crew will water wash the interior floor and wall usually to the first weld ring. Larger aboveground tanks are worked in quarters so as not to contaminate an area already cleaned. The vacuum truck will be used to remove the water rinse/sludge and to transport all wastes offsite for disposal/recycling. Once the tank is completely cleaned, a Gas Free/Safe for Hot work can be issued by a Certified Marine Chemist.