Frequently-Asked Question FAQ #200

FAQ-200: PIC for lines with multiple possible MAOP

Question: Our company constructed a line many years ago with an MAOP of 1000 psi. Recently we extended the line and, expecting market growth, put in pipe with an MAOP of 1201 psi. But the only supply to the new segment is the old line. Can we look for HCAs in both segments using MAOP=1000 psi? If we do so, are we obligated to go through a derate/uprate procedure?

Answer: Under the circumstances described, the MAOP of the line is 1000 psi, governed by the capability of the most limiting component (the old line). Potential impact circles can be calculated using the 1000 psi MAOP. Use of the line at higher pressure would require that the line be uprated, in accordance with Part 192 requirements. The management of change element of the operator's integrity management program should require that HCAs be re-evaluated, using the new MAOP, prior to any such uprate.