SIL Certified Overfill Prevention Systems

risknowlogy 2016-02-09

There are many tank farms around the world. You would think that tank farm operators would, from a business point of view, not be interested in overfilling a tank. How is is that good for business? Yet, today, many tank farms still have very poor tank level management systems and procedures in place. They are not in a position to manage overfilling properly and in a safe manner.

The last couple of years we have seen a few very bad tank farm accidents:

In all four cases the tanks where poorly equipped, poorly maintained and had poor safeguards – if they had safeguards in the first place. The tanks all had instrumentation installed but all of that does not help much if it is not maintained in the right manner and when there are no additional safeguards in case of equipment failures. In case of Buncefield for example, the level switch had failed and was already out of service for one month. In Bayamón, the level measure device had failed and it took months to repair them. See the video at the bottom.

These companies did not do proper risk assessments. Had they done this, they would not only have realised that an explosion is bad for business, but that it also injures and kills people, destroys the environment and ruins their reputation in the market.

Thank Farm Explosion CPC

Because of the history of tank farm accidents, the industry and legislation in these countries are not sitting still. If companies do not learn from each other and keep having the same kind of problems, then standards are created that support industry in implementing safety solutions. Nowadays, in the tank farm business the IEC 61511 and API 2350 standards apply. In countries like the UK and India these standards and the methods they advocate, like HAZOP and LOPA, have now become mandatory.

Also legislation does not have a ‘wait and see’ attitude. Legislation might move slow but when industry cannot fix their own problems, legislation steps in. And once it is there, it is not removed very quickly. In India and the UK the accidents have caused legislation to take action and tank farms are now obliged to follow safety standards and implement state of the art safety solutions.

Overfill Preventions Systems

One of the most effective safety solutions against overfilling of a tank is an Overfill Prevention System. There are two types of systems:

  1. Manual Overfill Prevention Systems (MOPS)
  2. Automatic Overfill Prevention Systems (AOPS)

The first system depends on an operator closing the valve after an alarm is generated due to overfilling. This solution requires not only a well designed alarm system but also correct procedures and training for the operator for when the alarm goes off. The second system takes care of overfilling by automatically stopping the flow into the tank when a certain level is reached. Needless to say also this system needs to be well designed.

Both the MOPS and AOPS needs to be designed according to IEC 61511 and/or API 2350 according to where the tank farm is located. Building an Overfill Prevention System that works is not so difficult. But making it in a way that it is compliant with the standard, and you can proof that, turns out to be a big challenge for most companies. This is where our certification services can help you. Whether you are an End User, an EPC, or a System Integrator independent certification proves that you did your work in compliance with the standards.

Install Certified Overfill Prevention Systems

Risknowlogy certifies Overfill Prevention Systems according to IEC 61511 and/or API 2350. We certify not only the design, but also the manufacturing process and the site installation. In case a manufacturer makes multiple designs then a certificate can be issued for each design. The end user can then select the desired design and ask the manufactured to build it. To make sure the Overfill Prevention System is manufactured according to the certified design, we certify the manufacturing process including FAT and iFAT. Some end users hire installation companies to install the Overfill Prevention System. To make sure that the certified manufactured solution is installed correctly in the field, and also works, Risknowlogy offers Site Certificate. In practice this means we verify that the installed Overfill Prevention System is the one that was manufactured including SAT.

Risknowlogy Certified Overfill Prevention System exist at 20+ tank farms in 4 different countries.

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CAPECO did not have a Certified Overfill Prevention Systems