At the age of 12 I started my first “real” job, working for Dr. Neibert, DVM. I knew Doc from our visits with various pets and jumped at the chance to work with him. Although the bulk of Doc’s business dealt with house pets, farm calls were a regular occurrence and I looked forward to tagging along.
Cows are pigs! They’ll eat just about anything left lying around, including pieces of metal. As a result, it is sometimes necessary to “feed” them long, cylindrical, plastic-coated magnets, which gather these bits of metal during their progression through the digestive system. A hefty deposit ensured the farmers had enough incentive to sift through the rather ample supply of fertilizer and return the magnets.
In order to persuade the cows to open wide, one must first insert what looks like ice tongs (with rounded ends, not points) into their nostrils. These are tightened by pulling on the rope attached to the far handle, which slides through an open ring on the second handle (much the same way a dog’s choker collar works). Once inserted and snugged up, you pull the cow’s head upward and its mouth drops open.
The magnet is inserted past its tongue by means of a long stainless steel syringe-like plunger with rings for your index and middle finger and a sliding shaft with thumb ring that ejects the magnet from the tube.
On my first of many farm visits that required the application of “animal magnetism,” our patient was a rather large bull. In order to hold him in place for treatment, the farmer had placed a nice bowl of grain outside the bullpen and closed the bars around its neck, preventing the bull from retreating.
Doc demonstrated how easy it was to insert the nose tongs and instructed me regarding how to insert the magnet. He made it look so easy, I couldn’t wait to give it a try. Unfortunately, Mr. Bull had no intentions of allowing some snot-nosed kid any chance of looking good for the audience that had gathered. While the farmer and his family looked on in amusement, I attempted to insert the nose tongs. The bull simply turned his head.
Finally, Doc blurted out, “Yates, didn’t you ever hear the phrase, ‘grab the bull by the horns’?” as he walked up and wrapped his muscular arm around the bull’s horns, twisted its head to the side and deftly inserted the nose pincher. Stepping back, he removed them and once again handed them to me.
Not to be outdone, I surged forward; grabbed that bull by the horns and rapidly discovered my light weight was no match for what was now one very angry bull as he whipped his head side-to-side with me grimly hanging on! Being thrashed into the sides of the door was a quick lesson in humility.
Safe storage and delivery of potable hot water remind me of that bull. In spite of collective efforts among manufacturers, code officials, distributors, maintenance personnel, landlords and contractors to turn down water heater temperatures to 120°F, scalding cases continue to occur at alarming rates.
According to The American Hospital Association, more than 100,000 cases of scalding from hot water occur each year. The National Safe Kids Campaign indicates that 26,110 of those were children and that an average of nine children die from scalding-related injuries each year. Pretty dismal figures and, if you didn’t know better, you might think these high numbers were statistics of injuries from a war.
Take a close look at the accompanying chart showing the time-and-temperature relationship for scalding related injuries. That 120°F water doesn’t look so good anymore, does it?
If we add the variables for age, we find that infants are four times more susceptible to scalding because their skin is very thin and much more sensitive than adults or older children. While bathing, be it a kitchen sink or bathtub, by the time an adult reacts to an infant’s cry, even if you’re in the same room, it is often too late to prevent injury. Although infants and toddlers can readily sense pain from scalding, they don’t have the cognizance to know where that pain is coming from or how to move out of harm’s way.
As we age, we lose some of our ability to discern scalding temperatures or to react quickly to avoid injury. Illnesses such as diabetes adversely affect one’s sensory perception and there have been cases where diabetics have immersed themselves unknowingly into tubs filled with scalding water.
When someone slips and falls in a bath or shower, the natural reaction is to grab at anything within reach to attempt to avoid injury. More often than not, that instinctive move is directed at the faucet handle because that’s the one thing the bather has been accustomed to adjusting over the years. They grab the faucet without thinking and, in many cases, that results in an inadvertent adjustment to scalding water. In extreme cases, if the person is injured or loses consciousness after turning the faucet to hot while falling, the bather may not be able to escape.
Legionella bacteria growth becomes an issue too. Temperature ranges between 50°F and 133°F (in conjunction with a pH between 5 and 8.5, biofilms and stagnation) offer an environment conducive for Legionella. Legionnaires’ disease is contracted by inhaling bacteria-laden water mist.
The Centers for Disease Control and Prevention indicate that this strain of bacteria causes as many as 10,000 deaths per year. So, what’s the answer to safe storage, distribution and delivery of potable hot water?
The misconception has been that we either reduce the temperature even further at the heat source, as in nursing homes where water temperatures are kept at 105°F to 110°F (Legionella bacteria thrive best at these moderate temperatures, often resulting in positive tests and repeated attempts to eliminate the bacteria), or install a listed American Society for Sanitary Engineering Standard 1016 scald guard faucet at the point of use. Listed devices must be able to hold their set water temperatures within just a few degrees, typically plus or minus 3°F.
The full name of Standard 1016 is “Individual Thermostatic Pressure Balancing, and Combination Pressure Balancing and Thermostatic Control Valves for Individual Fixture Fittings.”
Three types of ASSE 1016 scald guard devices are listed: “P”, or pressure balancing; “T”, or thermostatic reacting; and “P/T,” representing those capable of reacting to both pressure and temperature fluctuations. All are equipped with field-adjustable limit stops that require the installer’s attention.
Although the “P” style valves perform well and maintain bather protection under most conditions, they are blind to temperature fluctuations. Why is that an issue you ask? For starters, what have homeowners been doing ever since they began getting new water heaters set at the factory for 120°F and they run out of hot water more quickly compared to their older model? They crank up the thermostat to increase the storage temperature, thereby extending showering times because that changes the ratio volume of hot-to-cold water mixing.
While that solves their short-term problem, it also inadvertently results in altering that previously set high limit safety stop in the P-style faucet. Do they know that or do their children understand the repercussions associated with the hotter water? Who is responsible? More often than not, economics have dictated the P-style valves are installed instead of the slightly more expensive T or P/T-style valves.
Another issue known as “stacking” can occur in any hot water storage vessel, wherein layers of hotter water can stack up like pancakes at the breakfast buffet. In fact, this is a fairly common occurrence brought on by intermittent draw or a dripping faucet that triggers the burner. The regulation governing hot water storage vessels of 75,000 Btuh or less (Z21.10.1) in residential models, allows for that stacked outlet temperature to be as high as 190°F!
So, what do responsible designers, code officials and installers need to do to ensure safe point-of-source, distribution and point-of-use potable hot water in residential, commercial and institutional systems? Tune in next month to explore more challenges we face and the set of guidelines that could well resolve this complicated issue.
Dave Yates owns F.W. Behler, a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at [email protected].