Corrosion Allowance

Sachin,

Corrosion Allowance consideration is normally based on the following.

Material Selection, Working environment and exposure limits.

Most of the companies have established rules based on past experience. Most importantly previous inspection records in regard to corrosion occurances under similar condition will provide you a good guideline for you to setup your limits. You got to consider those and also some info from the below refered codes can be of some help to you.

Guidelines & Data from NACE / API 579 (Fitness for service), API 574 (Inspection Practices for Piping System Components), API 571 (Damage Mechanisms Affecting Fixed Equipment in the Refining Industry), etc. etc.

See the following CR4 Threads:

- Corrosion Allowance for Service Pipe Line

- Corrosion Allowance

- Corrosion Allowances for Equipment and Pipes

- Corrosion Factor for SA516 Gr 70

- Corrosion Rate of Carbon Steel Plate

Corrosion allowance is defined after you've made a corrosion assessment and material selection of the plant or item. you've to define through calculation or literature data the corroison rate and then calculate the necessary CA for the design life of the plant or item

http://www.hse.gov.uk/comah/sragtech/techmeasmaterial.htm

S.