COMMISSIONING FOR FLOATING ROOF SEAL

[mustafa2014]

Dear all, Good day,

I would to ask about the rim space > recently our maintenance team has installed a new seal for external floating roof, my question is that when they opening the fire water on a rim space, the water
came in to the tank through the seal? is that accepted? if yes how much should be the amount? is there any reference to that?. our tank is an API650.

 

[IFRs]

Hard to say. The seal(s) should be tight but are not impervious. A small amount of water may be acceptable. There should be no visible gaps. A wiper seal in the downwards position will allow more water than the same in an upwards configuration. A shoe seal should not leak through the fabric vapor barrier. If the fabric is filled up, it might pull the shoe away from the shell. The fabric splice may be leaking. At vertical butt welds, there may be an unavoidable gap that would let water through. A liquid-mounted seal would be the tightest but may still leak a little at shell butt welds. Water blasted at the seal will produce more leakage than a slow application. Applying the water to the tank shell might find its way past the seal(s). A secondary seal should shield the primary from exposure. Need more information: tank construction, seal(s) type (pictures or drawings would help), tank size, how was the water applied. There is no seal testing criteria other than visible gaps that I am aware of.