API 12F tank: Minimum Temperature Limit

[AK8824]

Dear Forum Members,

Up to what minimum design metal temperature an API 12F tank can be used? I have a vendor offering API 12F tank to be used in Alberta (-45°C).

Any help would be appreciated.

Thanks.

AK

 

[IFRs]

Your concern is brittle fracture leading to failure. The shell is limited to 1/4" thickness and A36, A283-C and A285-C for API 12F tanks ( and a small range of sizes ). I would use the API 650 toughness chart as a guide to start. Hmmm - it shows that these materials are unsuitable without further testing. To use one of these materials, you have to require a toughness test at the low design metal temperature ( for API 650 this is 15 DegF above the lowest one-day mean temperature but you can choose a lower temperature if you want ). I would not be surprised if the material exhibited adequate toughness, but if not, use A516-60 or other similarly tough steel (which is pre-qualified as acceptable without further testing by the chart in API 650 for your temperature and thickness), and invoke section 12F 4.1 which allows variance in materials with approval of the owner.