Comments on PHMSA's Proposed Integrity Verification Process (IVP) for Oil and Gas Pipelines
Haggag, F.M., "Comments on PHMSA's Proposed Integrity Verification Process (IVP) for Oil and Gas Pipelines," Public Comments to PHMSA, ABI® Services LLC.
These public comments to PHMSA were submitted in response to the proposed Integrity Verification Process (IVP) published in 2013 following the catastrophic San Bruno, California pipeline explosion of 2010 — an incident that cost PG&E more than $2 billion, resulted in several fatalities, and destroyed many homes.
The San Bruno accident had a simple root cause: the operator increased transmission pressure beyond the strength capability of an undocumented pipeline due to increased customer demand. In response, PHMSA proposed requiring all U.S. pipeline operators to document the basis used to establish each pipeline's MAOP.
Haggag's comments compare three approaches to material verification for undocumented pipelines: destructive coupon testing (expensive, requires shutdown and repair), hydrotesting (pressurizing with water to 110–120% of MAOP), and in-situ ABI® testing.
The comments detail specific disadvantages of hydrotesting in-service pipelines: it requires multiple excavations and access points, storage and disposal of contaminated water, disruption of transmission service, and — critically — it can grow subcritical cracks to near-critical sizes during the test. Additionally, hydrotesting undocumented pipelines presents a catch-22: the initial water pressure depends on yield strength, which is unknown without grade certification. If the guessed value is too high, the pipe will bulge or leak.
Notably, PG&E conducted 95 successful hydrotests in 2011–2012 based on yield strength values measured from in-situ ABI® tests — demonstrating ABI®'s accuracy and value in guiding hydrotesting programs. The cost of ABI® testing a 100-mile pipeline segment is estimated at 10–30% of the cost of hydrotesting the same segment.