July 2016, Vol. 71 No. 7


NASSCO Standard Bearers: Andy Drinkwater

NASSCO just completed its 40th anniversary and continues to set standards for the assessment and rehabilitation of underground infrastructure. As the association continues its phenomenal growth, this series profiles those who have made significant contributions and impacted the continued acceptance and growth of trenchless rehabilitation methods. This is a bi-monthly installment in a series of articles exploring the history of NASSCO through the eyes of industry leaders.

This month, NASSCO honors Andy Drinkwater, a long-time WRC civil engineer who was instrumental in transforming a WRc publication into the basis for NASSCO’s PACP. This first-person story by Drinkwater describes his career and initial work on bringing PACP to the United States.

I started my civil engineering career in the city engineer’s department of the city of Manchester, England, a large city with a current population over 2.5 million. As a graduate, I spent time in the various engineering sections and found that drainage was by far the most interesting – every problem was different and most needed to be thought through. You simply couldn’t just refer to a design manual.
My experience while with Manchester’s drainage department included learning an extensive amount about drainage systems, both large and small, city center and residential, design and operation.

Nearly 35 years ago, I took the knowledge gained from my years at Manchester and began working for WRc [Water Research Center] where I initially worked on flow surveys and hydraulic modeling of sewer systems.

The WRc is based in Swindon, England, about 60 miles west of London, where much of my current focus includes applied research for water companies in the United Kingdom (UK) regarding FOG and wet wipes. Considerable research has been done on both of these topics. In the case of wipes this has been necessary because manufacturer tests that conclude the wipes are “flushable” do not translate to real-life sewer environments. This leads to blockages and has become such a concern that it is now leading to an ISO technical specification on the flush-ability of wet wipes. I serve as the UK technical lead expert who liaises with quite a number of people around the world on this subject. It is proving to be quite an interesting project, although I often think I must have done something terribly wrong in a previous life to be spending my days studying the topic of baby wipes!

Other areas of my work include serving as an expert witness. When something has gone wrong in a sewer system, pumping station or treatment facility, which may have led to flooding or other problems, I often get called in as an independent investigator to work out what caused the failure. Quite often the culprit is FOG and wet wipes, so my responsibilities are very much related. The greatest take-away from these failure issues is to better understand what went wrong and share information regarding what we can all learn to prevent them from occurring again in the future. The key to unlocking some of these mysteries is the accurate and effective inspection of sewer systems, specifically the CCTV recording of both sewer conditions and operational features.


At WRc we develop manuals and standards, one of which is the Manual of Sewer Condition Classification, which covers how to code a CCTV survey in a sewer or drainage system. While the classification is designed for the UK market, it is widely used worldwide. Identifying a need to address the unique sewer conditions within North America, Mike Burkhard, who was NASSCO’s executive director at the time, contacted WRc in 1999 about developing a coding system specific to this region, which would later be known as the Pipeline Assessment and Certification Program, or PACP.

At Mike’s request, that year I traveled to the U.S. with a colleague to better understand the unique contributors to sewer conditions that were, up until then, somewhat unfamiliar to us. Some examples included the use of Orangeburg pipe, which is not used in the UK, as well as different pipe material types which result in different failure mechanisms.

Additionally, the extreme temperatures experienced in Florida and California are not experienced in the U K; therefore, specifications at the time did not address hydrogen sulfite attacks in concrete sewer systems when the temperature exceeded 20 or 25 Celsius, or 70 to 80 degrees Fahrenheit. In helping to develop PACP, we also had to convert everything to the imperial system since the UK specifications were based on metric measurements.

I returned to the UK full of new knowledge about North American sewer system conditions and developed a presentation addressing coding of these conditions, which my colleagues and I presented to NASSCO in Atlanta on Sept. 11, 2001. During the presentation one of the people I was presenting to, who incidentally I had worked with many years earlier in Manchester, nudged me and said “Something big is happening in New York. We may need to stop the presentation.” I had no idea what he was talking about, but soon the entire world was informed about the tragedy. A few days later, I was on the first flight that was allowed to return to the UK from Atlanta.

Since then, PACP has been fully developed and used successfully throughout North America. I have kept very much in contact with NASSCO, and have had the pleasure of working with the last three executive directors, starting with Mike, then with Irv Gemora and Ted DeBoda.

In order to keep pace with continually changing conditions and technologies, PACP has been modified over the years and WRc has been very much involved in those modifications. Our involvement was heightened with the recent release of PACP Version 7. We were asked by Ted (DeBoda) to take a comprehensive look at the program. He wanted to make sure it had as much integrity as possible to ensure NASSCO’s mission to set standards for the assessment, maintenance and rehabilitation of underground infrastructure was maintained. We evaluated the entire program and, while we did not find any errors, we did find a number of things that were slightly inconsistent and addressed those inconsistencies to improve PACP even more.

Standards are an international issue. That is why we are asking NASSCO to return the favor and provide input as we update some of our manuals, including our Drain Repair book and Sewerage Risk Manual for the North American market, both of which will benefit greatly from the information and experience of NASSCO. Providing healthy infrastructures to our local communities is where it begins; coming together to ensure global integrity and healthy water and wastewater systems for people everywhere is where organizations like WRc and NASSCO can make the greatest impact.


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