OVER THE YEARS as a licensed master plumber, I have always honored the credo under which plumbers operate, that being, "Plumbers protect the health of the nation." It has just stuck with me, even though I am no longer actively involved with the plumbing trade. It's kind of like a moral duty. We were put here to do a job, and that's one of the jobs I am going to have to continue to do while I am still on the face of the earth. Protect the health of the nation.
Enter Dave Yates, a man who is passionate about his duty of protecting the health of the nation. One of the first times I had the opportunity to watch Dave in a public speaking engagement was in Sacramento, Calif., at a Radiant Panel Association conference. Dave was wearing a tall chef's hat. You know, the one that looks like a white salt shaker sitting on his head, and I thought to myself, "What's this guy cooking up?"
Dave started talking about the job of the plumber through the years from ancient Rome to present day, and the fact that plumbers had fought and won the war with most waterborne pathogens. Keyword most.
Dave was concerned with the often allowed"open, direct, combination" hydronic heating system. This is a system whereby the water that is used for washing and bathing is the same water that is flowing through the space-heating system. On first glance, it sounds like a reasonable use of equipment, unless you consider the fact that the water stagnating in the heating distribution system during the summer and during long non-use periods becomes water of questionable character. This water is the perfect petri dish for growing the omnipresent bacteria known as Legionella Pneumophila, also known as Legionnaires' disease.
I had actually installed one of these open and direct systems in my own house in an entrepreneurial convulsion one weekend back in the early ‘90s. I wanted to experience radiant floor heating first hand so I could better communicate the comfort factor to my customers, and this seemed like the easiest way to accomplish this feat. More on this experiment later. Back to Dave's speech.
These bacteria hide inside hardened cysts.
Dave talked about how the lower operating temperature required by radiant floor heating systems was in the ideal range for bacterial amplification. He went on to explain that the plastic tubing typically used for HRF systems was the ideal feeding and breeding ground for the bacteria because it could sit stagnant for long periods of time. It allowed oxygen to pass through the walls of the tubing, it harbored food (bio-slime, rust and scale) and it fell within the perfect temperature range (55° to 130°F) of maximum growth potential.
In the crowd were numerous HRF contractors, a few of whom would have loved to lynch Dave right there on the spot. I thought I was going to have to stand up and help rescue Dave if these people were to rush the stage. It was pretty obvious that these contractors were making a living installing these less-than-desirable open combination systems.
Calm ensued. Dave has a great way of being able to control the crowds. He went on to explain the research that he had done and the effects and potential health issues of continuing to do what the code authorities had allowed to be done under the current plumbing codes. He talked about proven methods of bacteria reduction and elimination. One proven method known to almost all of mankind, is thermal sanitization, i.e., simply raising the water temperature high enough and long enough to kill the bacteria with heat. Another method is to expose the bacteria to a copper/silver ionization process, and the last is to bombard the bacteria with high-frequency ultraviolet light waves, exposing them to all the methods of sanitization. It seems that these bacteria hide inside hardened cysts that act as armor, protecting them from the usual battery of disinfectants (chlorine) normally used in water treatment. He went on to explain that in order for chlorine to be effective it would need to be increased by a factor of 10,000 times, which would most probably create other health issues, as well as causing possible damage to the piping distribution system and, in my estimation, would render the water nearly impossible to drink from a taste standpoint. As a side note, many private individual well systems are not required to maintain a chlorine sanitization system at all.
He stated that at temperatures below 55°, another omnipresent amoeba would consume the bacteria, but that above that temperature, the Legionella turned the tables and consumed the amoeba.
So, it seemed pretty obvious that, based on currently available, proven and tested technology, that the only good way to keep the bacteria at bay is to take away all the things that it needs to survive — which is virtually impossible to do — or else cook the little critters to death.
Tune in next month as we continue our journey to the center of the pipe. Until then, Happy Safe Water Hydronicing.
Mark Eatherton is a Denver-based hydronics contractor. He can be reached via e-mail at [email protected] or by phone at 303/778-7772.