Retiring value for a 12" pipe with nominal wall thickness 14.27mm

You need to specify the design pressure and temperature and exact grade of steel and then refer to the applicable piping code, perhaps ASME B31.3.

Hi The thickness for a required design pressure is calculated as t= PD/2S where t is the thickness P is the design pressure D the Nom diameter of the pipe S is the Specified Min yield Strength of the the material. Its obvious that the design pressure is higher than the operating so the pipes are capable of handling the operating pressures for longer time. Sometimes on the design thickness there is a corrosion allowance of 3mm, but then that depends whats gonno flow through the pipe.

Hi,

I would accept the pipe as long as its thickness equals or exceed the minimum design wall thickness. Otherwise you must replace it or repair it (if possible and economically cheaper than replacement).

Kind regards

If it is carrying water --- 0