ASTM 285 Gr.C vs. A36

[Jens12]

Hi,

our tank manufacturer wants to change the tank material from specified ASTM 285 Gr.C to ASTM A36. The affected storage tanks are atmospheric and on the one hand for PHC sludge covered by API 650, diameter from 2000 to 5500 mm and on the other hand water tanks covered by AWWA D100 from 5500 to 12500 mm.
As far as I know all the applicable codes deal with A36 but I'm not familiar if there are any restrictions for this material. Can anybody teach me ?

best regards
Jens Binder

 

[MJCronin]

Jens....

API-650 contains restrictions on the selection of tank materials based on the lowest ambient temperature expected.

API-650 requires the designer to specify a Minimum Design Metal Temperature (MDMT...which is the lowest expected one-day temperature for the site..plus 15F) and to base the material selection on the MDMT.

The purpose of this restriction is to prevent brittle failure of the tank due to usage bellow the NDT of the steel.

API-650 groups the materials based on MDMT. AWWA ( to the best of my knowledge) does not but is in the process of modification to adopt rules similar to API-650.

My opinion only....

-MJC