Existing Equipment and NACE Compliance

The question relates to the compliance of a 1953 swab tank made of rolled 1/2-inch plate A283C with NACE MR0175. Section A2.1.6 requires stress relief and a maximum hardness of 22 HRC for rolled or deformed material. The tank is 84 in. in diameter and rated for 100-psi service, but there is no documentation regarding the heat treatment of the plate after welding. However, the material meets the A283C requirements, and ultrasonic testing shows no issues. The customer seeks to determine if the tank is suitable as a NACE MR0175/ISO 15156-compliant material based on its long life, performance, and mechanical data.

Responsibility of Equipment User

The answer from the ISO 15156 Maintenance Panel cannot provide advice on the tank’s suitability for sour service, as it is the responsibility of the equipment user to evaluate the material’s suitability and NACE MR0175 compliance. The user should consider NACE MR0175/ISO 15156-2 Table 1 for permitted exclusions and NACE MR0175/ISO 15156-1 Clause 6.2 d) for guidance on the fitness for purpose evaluation of materials in existing equipment.

ISO 15156-1 Clause 6

This inquiry pertains to NACE MR0175/ISO 15156-1 Clause 6.

Reference: ISO 15156