Plumbing Info

courtesy of The Safe Guardian, for Professionals Committed to Safety – April 1996
by Pat Higgins

The issue of tap water scalds demands the attention of everyone with in the plumbing industry. As a former hot water burn victim, I can attest to the pain of a scald. I was burned by hot water in a freak accident during my days as a journeyman plumber. I was fortunate: the burn required only that I spend one week with both of my hands wrapped in gauze “boxing gloves.” In addition, no scarring took place. Nonetheless, I will never forget that incident. It has made me an advocate for the improvement of plumbing codes and regulations to prevent future occurrences wherever possible.

Plumbing systems are designed to provide hot water to most plumbing fixtures, leaving our industry particularly vulnerable to tap water burn litigation. For years, plumbing codes were most vocal in requiring water at temperatures no less than 140°F and even hotter for commercial and sterilization applications.

Such terminology remains within today’s codes (though additional provisions have been added to the model code and some state codes to reduce the potential for scalding incidents). Further, the American Society of Plumbing Engineers reported their findings that temperatures over 140°F are required to prevent the growth of Legionella. At that temperature, scalds are almost instantaneous.

THE MODEL CODE APPROACH: Some 15 years ago, our firm began a crusade to reduce the potential for scalds and burns in plumbing systems. We suggested changes to the model codes, as most states were adopting them in one form or another. Due to concerns over minimum water temperatures to provide sanitary dish washing and to reduce bacteria growth in low temperature hot water systems, we advocated addressing hot water scalds by the following code provisions:

Hots on the left: When I first joined the plumbing trade, this adage was one of “three things a plumber must know,” along with “goodies flow downhill” and “Friday is payday.” All kidding aside, the standardization of cold and hot handle positions is very important to the safe use of plumbing fixtures and fittings especially for the young and the old.

For safety’s sake, the codes have made this orientation the norm. Valves that can be installed back to back should be readjusted to confirm that hot flow relates to the left side of the fitting once it has been installed.

Protective valves in the shower and the bath/shower area: All of the model plumbing codes have adopted this protective valve provision for these areas. Some have also applied the criteria to bathing vessels as well.

Thermal protective devices on instantaneous heaters: Some codes now require thermostatic protection in conjunction with instantaneous heaters. These devices reduce the exposure of the occupant to very hot water.

Thermal protection in public lavatories: Some codes have recognized the need for thermal control in unsupervised public lavatories especially when such fixtures are used by the young and the physically challenged.

MORE WORK IS NECESSARY: Although the model codes have made great strides in protecting against scalds, other issues still need to be addressed:

Proper water heater sizing to assure a lower temperature and a higher delivery capacity. Though accepted by some codes, minimum sizing criteria for water heaters have been rejected by others. That’s hard to believe especially when health, safety and public comfort are in question.

I will say it until I die: Do not install a low capacity heater and just “crank it up”! Such decisions border on lunacy.

Thermal protection in bidets: ‘Nuff said!

Relief valve reinspection: During a reinspection, the plumber should not only determine that the relief valve is functioning correctly, but also that the relief valve drain is properly installed. The drain should not:

  • have any traps;
  • have an outlet that can be easily plugged, capped or sealed;
  • be exposed to freezing;
  • flow uphill;
  • terminate where the steam or hot water discharge could burn or scald any building inhabitants.

Total home protection using master blender valves: A model code recently accepted this safety concept as an alternate to the protective valve requirement for the shower. While shielding all outlets within the plumbing system from excessively hot water, master blender valves do little to reduce potential pressure imbalances that could thermally shock the shower user.

I prefer the requirement for protective valves even with a thermally controlled water supply. The master valve must also meet minimum safety standards for hot water control and provide the necessary capacity to meet all flow demands with the building. The water heater thermostat should never be used as the sole hot water control for a building.

Additional work is required in the standards arena to clarify the requirements for master blending valves. A great deal of confusion attends this issue. No code permits the use of tempering valves to control hot water temperature. Only thermostatic valves can be used to control the upstream temperature for two handled valves.

The Tasks At Hand: The plumbing professional is getting mixed signals from the design industry regarding water heater outlet temperatures. Hot water must be provided to various plumbing fixtures. But even with additional protective criteria within the model and state codes, policing all plumbing installations to prevent further accidents is virtually impossible. Still, all of us can and must take a positive role in scald prevention.

First, review your local and state codes. Do they contain protective provisions for scald prevention devices? Have such requirements been amended from model codes by state revisions? How does your state code address the task list of code issues presented above? If protective devices and methods are not cited, how can they be added?

Second, we must educate our fellow plumbers and consumers about scald hazards. With so much litigation in our society, the professional plumber must maintain a high level of communication with both plumbing training schools and customers. Only then can he or she assure that health and safety issues are solved by education – not litigation.

Patrick Higgins is President of P.J. Higgins and Associates and former NAPHCC Technical Director. For the past fifteen years, his company has monitored Federal and state activities which affect the plumbing industry.

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