Boy Scout facility is a study in plumbing safety

There’s a new bathhouse in Central Pennsylvania that serves as model for Boy Scouts of America bath and shower facilities nationwide. The plumbing and mechanical contracting firm that designed and installed the domestic water system declared “a wholly plumbing war” on two fronts — Legionella bacteria and scalding — and won.

“Before the job began, we planned our attack carefully,” said Dave Yates, president York, Pa.-based F.W. Behler, Inc. According to Yates — a master plumber and scoutmaster — in addition to showering facilities at the BSA’s Camp Tuckahoe, ADA-compliant bathing areas would be needed and there were numerous sinks to plumb. A number of challenges arose: provisions for scald protection for diverse age groups with varying physical abilities; prevention of bacterial growth within the potable hot water system; energy conservation; and heating for the sections not winterized each year.

To begin with, said Yates, “A potable hot water system consists of three distinct parts: point of source, which is the water heater; the distribution system; and points of use, which are the individual faucets where people make contact with the hot water. Yates’ “assault” would assure protection on both fronts: protection from disease, and the risks of scalding. To do it right, it would be necessary to encompass all three parts — point of source, distribution and points of use — into one coordinated battle plan.

For starters, Yates installed a double-check backflow preventer on the building’s cold water supply, which is delivered from a gravity-fed well water storage tank with a atmospheric vent. “Once potable water enters the bath house, it can only leave by way of a faucet being opened,” added Yates. “This prevents any possibility of a sudden negative pressure if a main breaks or lower-elevation drainage point is opened while the system is down. Storage tanks are designed to withstand high pressures, but can be quickly damaged if a vacuum builds.”

Dave Yates, president of F.W. Behler. Inc., inspects the 100-gallon, 299,000-Btu Bradford White EF 99% efficiency water heater that provides domestic hot water at a set point of 160°F. Mixing valves and circulators eliminate scalding, while the unit provides sufficient hot water for space heating in sections of the bath house that remain open during winter months.

Yates chose a 100-gallon, 299,000- Btu Bradford White EF 99% efficiency water heater to serve as the domestic system’s point of source. Yates confidently set the tank’s storage temperature at an uncommonly high set point of 160°F — a sure bacteria cooker.

But before Yates set the water heater’s operating temperature, he verified that, in fact, the higher set point does not result in a significant increase in energy use. The result is a very slight increase in stand-by jacket heat loss. And he points out that the higher storage temperature also increased system capacity due to a lesser proportion of hot water being needed for mixing with the cold water.

“Another attribute is that there are no stack losses because the EF LP gas water heater is equipped with sealed combustion and uses both PVC exhaust and combustion air lines,” continued Yates. “We also liked that fact that it offered several venting options, electronic controls, four protective magnesium anode rods, a sediment reduction system and factory-installed dielectric fittings.”

But, clearly, the 160°F set point was way too hot for distribution outward to points of use. So a suitable means had to be included for managing the second stage of the potable hot water system battle plan. An ASSE-certified 1017 thermostatic mixing valve was added to the potable distribution piping and set to maintain a minimum of 133°F. A bronze circulator was incorporated to keep the distribution system constantly on the move while maintaining that 133°F throughout its course, which prevents stagnation. Legionella bacteria don’t stand a chance at these continuously-operating temperatures.

According to Yates, most of the piping in this open-framed building would be exposed and the high temperatures too closely approached the upper limits for rigid plastic lines.

The idea of PEX was considered but dismissed because the neatly installed lines would ultimately droop and twist. PEX-AL-PEX wasn’t available in the larger sizes they needed, so copper was clearly the best way to plumb lines that would remain in plain sight for years to come.

Another consideration in the potable hot water battle plan called for some measure at the many points of use. “Our age group of bathers would range from five to 90,” said Yates.

“The potential for scalding is high in a facility seeing such a diversity of hot water users. So we chose some heavy-duty ASSE-certified 1016 scald-guard devices offering temperature and pressure regulation for all shower heads and sinks.

“Our installation required mounting the shower faucets on solid block walls with a stainless steel shroud to conceal the piping,” he added. “For the sinks, the valves tucked up neatly under the bowls with 3/8" o.d. compression fittings.”

The contractor’s design/water heater check list Efficiency — BSA policy dictates that we use the earth’s resources responsibly. At 99% efficiency, the water heater chosen as the heart of this system does just that. As a bsa member & leader, the “leave no trace” admonition for outdoor activities and camping fits, too. Combustion is ultra-clean, and because it’s a sealed-combustion water heater, there’s virtually no stand-by heat loss. Reliability — As a long-time user of Bradford White products, I had a high level of confidence that this water heater would easily stand the test of time. While Tuckahoe isn’t on the other side of the earth, it’s not exactly next door either. So a product installed there must be reliable and perform as expected. Hundreds of bathers would rely on us to deliver hot water. Long-term reliability and safe operation — We needed consistent temperature storage and delivery over a wide range of use and demands. There would be single users, or hundreds of users in a relatively short time span. And in the winter, heating needs. This would be handled with a flat-plate HX (the bather load is sharply reduced in winter months, so the extra capacity was available for some hydronics). Longevity — Early in the design phase, an issue glared back at me from the drawings — a deadly one where combustion products are concerned! Initially, the pool equipment and chemicals were to be in the same room as the water heater. Yikes! Chlorine and hydrocarbons produce hydrochloric acid during combustion, which generates a real strong dose of acid rain that will greatly shorten the life of any combustion product. I insisted they incorporate a block wall from floor to ceiling to divide the pool stuff from our mechanical area. Sealed combustion — Having the combustion air and exhaust gases hard-piped to the outdoors with their terminations at the same level reduces stand-by losses by eliminating any natural draft that would strip away Btu’s. That also gave us the opportunity to get fresh air for combustion on the prevailing up-wind side of the roof, away from any stray pool chemical fumes.

All that remained was the heating issue. With more than half of the bath house being winterized annually, the Bradford White water heater would have more than enough excess capacity to power-up some hydronic units.

The solution for maintaining the domestic system’s integrity is quite simple. A stainless-steel heat exchanger was installed to isolate the potable and hydronic fluids. The potable side includes a bronze circulator that operates whenever there is a call for heating and without a check valve — gravity circulation takes over during idle times. Also, temperatures are constantly within the pasteurization range.

“The hydronic side is treated like any other heating system with a 30-pound relief valve, water feeder and expansion tank,” assured Yates. “Given that this is the lower of the two pressure zones, any leaks that might develop within the heat exchanger will result in the hydronic side’s relief valve leaking, alerting maintenance to the problem.”

The wall-mounted hydronic convectors each have their own thermostat, which allows for pumped zoning. No matter how frequently the doors are opened during wintry weather, each zone has the ability to maintain the desired indoor climate thermostat setting.

Chlorine treatment won’t suppress Legionella If you think chlorine is keeping our water safe from legionella bacteria, think again. Chlorine levels in typical potable water systems are 10,000 times lower than the levels needed to suppress these bacteria cultures. High chlorine concentration flushes of infected systems do not eradicate the bacteria and they typically return within a few weeks. Elevated levels of chlorine in potable water systems also create carcinogens. Chlorine dissipates in hot water and there’s pretty good evidence that it attacks both copper and certain types of PEX tubing. Legionella bacteria need just a few things to survive and thrive and not all need to be present at the same time: Aqueous environment pH between 5 & 8.5 Water temps between 55 and 133°F Biofilm Stagnation “And there’s the Catch 22,” said Yates. “If chlorine, our old reliable bactericide, isn’t effective against Legionella, and it isn’t, then what can we do? It seems painfully obvious that the solution lies in raising our hot water storage temperatures above 133°F. But that move, of course, increases the risk for scalding.” The solution applied here by Behler Inc. professionals accomplishes both antibacterial temperatures and scald protection.

The anti-scalding and germ-free warfare battle plan was 100% effective. Common-sense plumbing with safeguards for protection against scalding and disease has worked flawlessly. According to Yates, the additional time spent installing these products was negligible and their cost didn’t break the bank either. “It sure seems to me that the time has come for our National Plumbing Codes to enact rules that mandate these common sense safeguards. Our children and parents deserve nothing less.”