How to calculate the corrosion in piping

Material selection design basis

· Design Life

Design Life (DL) = 20 years for Equipment

= 10 years for piping, or

= Per Client’s requirements

· Corrosion Rate (CR) Estimation

CR = mils per year (mpy) or millimeters per year (mm/yr)

· Corrosion Allowance (CA)

CA = 1/16”, 1/8”, 3/16” or 1/4”

= 1.6 mm, 3.2 mm, 4.8 mm or 6.4 mm

Maximum CA = 1/4” or 6.4 mm

(Upgrade material if required CA is > ¼” or 6.4 mm)

CA = CR x DL

Corrosion Mechanisms in Petroleum & Chemical Industries

· Amine Corrosion

· Ammonium Bisulfide Corrosion

· Ammonium Chloride Corrosion

· Atmospheric Corrosion

· Boiler Feed Water /Condensate Corrosion

· Carburization

· Caustic Corrosion

· CO₂Corrosion

· Cooling Water Corrosion

· Corrosion Under-Insulation (CUI)

· Erosion-Corrosion

· Flue Gas Dew Point Corrosion

· Fuel Ash Corrosion

· Galvanic Corrosion

· Graphitic Corrosion of Cast Iron

· High Temperature H₂/H₂S Corrosion

· High Temperature Hydrogen Attack

Piping Design