Areson A 106 -B is seamless C.S for high temperature use with no mandatory requirement of impact test. A 333-6 is seamless & welded pipe intended for low temperature use - even at sub-zero temperature with impact test becoming mandatory for the ordered pipe. If as a user, you intend to use the material at sub-zero temp, below 0 deg centigrade, then A 333-6 is to be considered for your service with impact tests meeting for this quality grade. Wall thickness calculation can be the same for both grades - A 106 Gr B or A 333 - Gr 6 depending on the service design pressure and design temperature. Wall thickness calculation is related to rated pressure and temperature. For 1" thickness, naturally this implies that the material is intended for higher pressure in the system. Hope this helps you C.V.Srinivasan Nishi Engineers Pvt Ltd India Feb 12,2008 E-mail: nishi@vsnl.com >Dear All, > >I've encounter specifiction from some of major oil company >that required the use of A106-B for <1" wall thickness and >A333-6 for >1" wall thickness and the minimum design >temperature is degC. Can anybody justify this requirement? > >As I know, the A333-6 common used for low temperature >application beow 0 degC. > >Areson