Asphalt Base under Tank

[dik]

We have a 100' dia steel tank sitting on an asphalt base. The asphalt mix design that has been submitted is a good quality mix and ample for the loading.

Are there any special API requirements that the asphalt has to meet?

Thanks, Dik

 

[fegenbush]

So long as the foundation meets the recommendations in B.4.1.1 of API 650 and the customer has approved the use, I see no additional requirements for asphalt base.

 

[dik]

Thanks... The API requirments for an asphalt base don't have any special requirements?

I reposted the query in the Structures... and was just going to RF this post...

Dik

 

[SJones]

Before you steam ahead with asphalt, from a corrosion control perspective, has API RP 651 been referred to?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[dik]

Steve... what does API 651 have to say about the use of asphalt. We didn't do the design of the system, and I was asked a question about the ashpalt mix. It's a good mix, and is used for 'containment' but, I'm not familiar with the use of this material as a tank base. There should be no corrosion issues, and it should act as an 'impervious' layer...

Dik

 

[SJones]

That's the point: it also renders the soil 'impervious' to cathodic protection current should it be needed to control corrosion of the tank bottom.

API RP 651, 5.3.6 Continuous Asphalt Pad

"............Asphalt degrades with time.......allowing corrosion to occur.......In fact, deteriorated asphalt may shield cathodic protection current......"

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[dik]

Thanks Steve... I'm going to suggest the asphalt be removed... with a sand bed and membrane.

Dik

 

[IFRs]

It's not too unusual to use a bituminous asphalt cap on top of structural fill for under large oil tanks in the Houston area - they do with apparent long term success under residual fuel oil tanks that are heated to 140 DegF or so.