ASHRAE Journal - May 2009 - 74

Arrhenius and the Mayor By Joseph W. Lstiburek, Ph.D., P.Eng., Fellow ASHRAE I None of this is a surprise to folks who know and love water. It does not seem to be a problem with the folks living there n a strange world with strange connections, one of the since gangster Bugsy Siegel kicked Las Vegas into the big strangest connections of all exists among Jan Laverty Jones, time in the late 1940s. But it has been, and continues to be, John Rushworth Jellicoe, British dreadnoughts, German a huge problem with hot water heaters. Hot water heaters in U-boats, and Svante Arrhenius. Las Vegas fail faster than almost anywhere else—often in Our story starts with a politician taking a shower in a new only three to five years. home in Las Vegas in the mid 1990s and ends with tens of The hot water heaters fail from the precipitation of those thousands of houses with leaks and litigation. Our story takes pesky carbonates in the water. Now, other places also have a detour to the Great War* and one of the most famous naval lots of carbonates, but not lots of dissolved oxygen, and engagements that almost didn’t take place and an not lots of other neat stuff in the water as in underappreciated and much maligned national Las Vegas. The precipitation of the carbonates hero. Along the way we become reacquainted is much faster in Las Vegas hot water heatwith one of the greatest minds of all time—so ers than elsewhere. This results in the sort of great that the physicists and chemists both claim unintended consequences that leave your head him as one of their own. spinning. The water heaters are, in essence, Jan Laverty Jones buys a new house in Las pretty effective water-purifying systems, which Vegas and is incensed that it takes five minutes take dissolved minerals out of the water. The for hot water to get to her shower. She becomes minerals of interest happen to be calcium and furious when the builder says that he is not magnesium. Remember this for later. responsible and that’s the way that it is. Unlike The problem of failed hot water heaters in Las most new homeowners with a grudge, she hap- Photo 1: Jan Laver ty Vegas is simply accepted. You move to Las Vegas, pens to be the mayor (Photo 1). In a move that Jones, mayor of Las Vegas and live with the fact that you must replace your would make Boris Yeltsin proud, she decrees that from 1991 to 1999. Photo hot water heater every couple of years. It is anall new houses must have hot water recirculation courtesy of the Berkeley noying, but not a big deal. Everyone goes through systems. OK, it wasn’t a decree. It was a bylaw Daily Planet. it. The water heaters are all located in garages. change. But, you get the idea. Never mind the They are easy to replace. There is no real collatenergy implications of this decision. This was the 1990s. Who eral damage to worry about. Las Vegas lives with a system of cared about energy back then? The implications of this deci- disposable water heaters. Think of it as a “hot water tax” that is sion haunt Vegas homeowners and home builders to this day. almost unique to Las Vegas. What is the big deal about hot water recirculation systems? Home builders, in their continuing efforts to reduce their They have been around a long time. We know how they work. costs and improve their production efficiencies, began to replace We know about the energy penalties. Well, Las Vegas is dif- traditional copper-based piping systems with cross-linked polyferent, as we all know. But, the difference I am referring to is ethylene (PEX) water supply piping. PEX has a lot going for the water, not the other stuff. The water in Las Vegas, when it. It does not corrode, is chlorine-resistant, it does not develop coupled with hot water recirculation systems and the type of pinhole leaks, has fewer fittings, connections, and elbows. Did plumbing system that became common in the home building I mention the part about the fewer fittings, connections, and industry around then, makes for an interesting study of physics, elbows? Home builders began to use PEX systems almost chemistry, and unintended consequences. everywhere, including Las Vegas. Las Vegas has lots of sulfates and carbonates and a high pH With PEX systems the fittings and couplings are almost in its water, along with lots of chlorides and fluoridates. The universally brass. Brass, which is a metallurgist’s dream, is sulfates and carbonates and high pH come from nature; the a magnificent alloy of copper and zinc. But to the British chlorides and fluoridates come courtesy of the Las Vegas water Grand Fleet and its commander John Rushworth Jellicoe department. And, for reasons not well-understood, Las Vegas (Photo 2), admiral and hero of the British Empire, brass water has lots of dissolved oxygen. is a nightmare. * This was before we started numbering them. The first World War was thought to be the war to end all wars. 74 ASHRAE Journal ashrae.org May 2009

ASHRAE Journal - May 2009

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