A106 pipe

Date 06-06-2003 23:02

At the refinery where I am presently working, I noticed a 6" A106 pipe being used to supply steam for a turbine. Curiously I read the specs on the turbine as to steam pressure and super heat temps for this unit.
After reading steam pressure at normal operating conditions of 700psi and heated to 700 degrees F, the pipe material used somewhat suprised me. I thought for sure the plant would use chrome in this case, but the pipe turned out to be carbon steel.
My question is, what are the limits A106 pipe is capable of as far as pressure and temperature are concerned and can this pipe be used as a shell for a steam boiler not to exceed its designed specifications?

By Niekie3 (***)

Date 06-07-2003 18:26

Hi Skip

According to Appendix A of ASME B31.1, (Power piping code) A106 can be used up to 800°F. It would be difficult to tell you if your particular application is correct, because it obviously depends on the material grade (A,B or C), the pipe diameter and pipe schedule.

Just to give you an idea: If you had a 6" pipe, schedule XXS of A106 Gr. B, it could take a pressure of 3844 psi at a temperature of 700°F, while a Sch 40 pipe could take around 990 psi at the same temperature.

The short answer is that you can use A106 at the temperatures and pressures you were mentioning.

Hope this helps

Regards
Niekie Jooste
Fabristruct Solutions

By G.S.Crisi (****)

Date 06-09-2003 12:52

Niekie's opinion is correct for Power Piping, i.e., piping to be used in a power plant.
Skip, however, works for an oil refinery, and in this case, at the option of the Owner, the piping of the refinery's power plant may be designed to ASME B31.3 "Oil refinery and chemical plant piping", which is less stringent than B31.1.
Back in my days of project engineer, I took part in the design and construction of more than one oil refinery, petrochemical and chemical plants, including its power plant, having as Engineer such prestigious companies as Lummus, M.W. Kellogg, Mitsubishi, Badger, Krebs etc.
Sometimes, at the Owner's option, the piping was designed to ASME B31.1, and sometimes to B31.3.
Now, we can safely assume that if A-106 is suitable for Skip's service under B31.1, it will be also under the less stringent B31.3.
Giovanni S. Crisi
Sao Paulo - Brazil