Tank bottom / foundation interface water ingress protection

[FrCivEng]

I am looking for API Std or RP requirements regarding tank bottom / foundation interface water ingress protection in order to specify criteria for a durable protection.
Could somebody help me ?

 

[FTank]

If this is an API 650 field erected tank, crown the center to the outside as the standard recommends in Appendix B.
This will assist in drainage. If you have an tank bottom annular ring, make sure you are specifying a concrete retaining ring.
Also, select a contractor that has experience in construction of tank foundations and pads.

 

[uncletank]

Hi,

Additional to FTank's comments above, if you use a cone down foundation you can install tell-tale leak detection pipes in the foundation (in accordance with Appendix I, and as long as the pipes are kept free from debris and dirt any water underneath the tank should drain via the leak detection system.

Further to that I am not aware of any API standard or RP requirements but generally we ensure that the tank foundation is sufficiently above the compound floor (i.e. 0.3 - 0.5m above the main compound).

The other thing is to seal the floor plate projection (chine plate) to the foundation. There are a number of products on the market for this i.e. Shell Tixophalt, SikaTank, etc. We generally use Tixophalt, and paint it with an aluminium reflective paint to prevent it from prematurely failing due to UV.

There are also other products such as the Denso "Tank Boot" systems. However we have found that these systems tend to hold dirt and moisture unless they are regularly cleaned.

 

[FrCivEng]

Thanks a lot for your help.
In the mean time I have found an answer for the protection in API 650 11th Ed Art 5.4.5 and Fig 5.5 and for the sealing in Appendix B Fig B.1;
Regarding the protection system, I am more looking for an aluminium drip ring protection fitted outside on the shell about 0,15 m above the annular bottom plate, removable without any damage, it is more expensive but gives a better protection of the whole outside bottom plate and concrete annular ring, easily inspectable and more durable