Maximum rate of liquid level rise inside tanks with floating roof?

[dags76]

Hello. This question is also cross-posted over at the Mechanical Eng'g forum.

I work in a petroleum terminal and we have a concern about our floating roof tanks. We have a 40-ft diameter vertical cylindrical tank with external floating roof that receive product pumped from a marine vessel.

Is there a safe maximum allowable rate of liquid level rise inside a floating roof tank? Currently we observe a rate of about 8 meters per hour and we are concerned that this could lead to the tipping of the floating roof.

Thanks in advance for any reply.