What is one approved method of overfill prevention for tanks?

• A. 80% full automatic shut off
• B. 90% full automatic shut off
• C. 95% full automatic shut off
• D. 99% full automatic shut off

Answer: (C)

One approved method of overfill prevention for tanks involves using a 95% full automatic shut-off system. This level of fill is widely recognized as an effective measure to prevent overfilling because it provides a sufficient margin of safety between the tank's full capacity and the point of potential overflow.

Setting the shut-off mechanism at 95% ensures that there is still some headspace in the tank to accommodate any expansion of the liquid due to temperature changes, which can occur in storage tanks. This approach helps to minimize the risk of spills and leaks, thereby protecting the environment and adhering to safety regulations.

Using lower percentages, such as 80% or 90%, may not provide an adequate buffer against overflow risks, particularly when accounting for variabilities in the storage process or conditions. Conversely, setting a threshold too high, like 99%, could lead to unnecessary operational delays and might not address safety concerns effectively. Thus, the 95% full automatic shut-off is the most balanced and practical solution in the context of tank overfill prevention.