UPC Code update & ASSE scald awareness

committee update

By Ron George,CPD,
President, Ron George Design & Consulting Svcs.

The International Association of Plumbing & Mechanical Officials (IAPMO) held their 2012 Uniform Plumbing Code (UPC) and Uniform Mechanical Code (UMC) technical committee meeting May 2 – 4, 2011, in St. Louis. The committee listened to public comments and held discussions on code changes proposed in the monograph for the 2012 UPC and UMC.

June 8 is the final closing date for all technical committee ballots, including receipt of vote changes based on re-circulated comments. August 22 is the due date for distribution of the Report on Comments (ROC). Final changes should be ready at IAPMO’s annual Education and Business conference, technical meeting convention in San Antonio September 25 – 29, 2011. The 2012 editions of the codes are nearing completion of the three- year revision cycle and should be available near the end of the year.

Highlights of the public comments in St. Louis included many changes to conform to IAPMO’s new manual of style, which should help establish a consistent style and format throughout all of the uniform codes. The manual of style addresses the structure of uniform codes that includes the physical layout of the documents, a new numbering system and chapter sequences.

Changes submitted by a code correlation task group included many editorial changes to the manual of style changes as well as many technical changes. Proposed plumbing code changes dealt with issues such as air admittance valves, manifold systems sizing, vacuum waste drainage systems and product standards. The mechanical code hearing addressed concealed gas piping, gas purging during piping installation and HVAC unit refrigerant gas port security caps to prevent vandalism and abuse.
During the plumbing code discussions, there was also debate about referencing plumbing product standards in the body of the plumbing code versus listing the standards in the back of the code. There were two sides to the debate. A few inspectors and contractors said that they do not want to be bothered with keeping track of standards, purchasing standards books and looking up the “alphabet soup of standard letters and numbers.” They just want to see an IAPMO mark on the product, which indicates IAPMO approval. They seemed to prefer that all of the standards be listed in Chapter 14, “Referenced Standards,” which is located in the back of the code. There was some discussion about whether everything listed in chapter 14 was mandatory in the code. Someone commented that there would be inherent problems with relying on an IAPMO mark, because everything that has an IAPMO mark is not necessarily accepted in the code.

Those taking the opposite view included manufacturers, design professionals, contractors and some inspectors. They want to see each standard number and title referenced in the body of the code, in the section where the standard applies.

The standards require that products be marked with the standard that the product conforms to so that an inspector can look at a product and verify that it is installed in accordance with the proper code section. For example: There are numerous mixing valve standards; each one has a unique application that is described in the title and scope of the standard. The standard for shower valves for bathtub/shower combinations requires that they conform to ASSE 1016, Performance Requirements for Automatic Compensating Valves for Individual Showers and Tub/Shower Combinations. Because the standard addresses valve usage for individual showers or tub/shower combinations, ASSE 1016 mixing valves cannot be used as master mixing valves at a water heater. Some styles are pressure-balance type only; they have no thermostatic element and would be inappropriate for a master mixing valve application.
Other standards include the following: Shower valves for gang showers should comply with ASSE 1069, Automatic Temperature Control Mixing Valves. Master mixing valves located near a water heater or source of hot water should conform to ASSE 1017, Temperature Actuated Mixing Valves for Hot Water Distribution Systems. Local mixing valves near the point of use should meet the requirements of ASSE 1070, Performance Requirements for Water Temperature Limiting Devices.

Just listing the standards in the table at the back of the code with the standard language that states that “the product shall comply with the nationally recognized standard listed in chapter 14" could mean that a mixing valve could be misapplied but still have a standard number that is listed in the applicable section of the code. All mixing valves have the IAPMO mark on them. Unless the inspector is knowledgeable about the scope of each standard, it is not possible to determine which standard should apply, because there is no direction in the code.

The debate was lively and included several attempts to revise Chapter 14 by making the entire chapter mandatory, in lieu of listing the standards in the appropriate code sections. It was pointed out that there are numerous standards and guidelines in chapter 14 that are not consensus standards, so that would create a problem. The debate ended with a recommendation for an ad-hoc committee on product standards to review where the standards should be listed. If you are interested in serving on the ad-hoc committee, please contact IAPMO.

IAPMO hires new director of standards development

IAPMO has hired Abraham I. Murra as director of standards development. Mr. Murra recently worked at the Canadian Standards Association (CSA) as a project manager, where he managed 16 national and bi-national committees of more than 300 professional volunteers to develop and maintain technical standards for plumbing products.

I had a chance to spend some time with Mr. Murra at an ASME/CSA joint meeting in Phoenix in January. He is a pleasure to work with, and he has a passion for his work. Recently, Murra led committees developing standards on water conservation, water reuse and wastewater. He is a civil engineering graduate of Universidad de los Andes in Bogotá, Columbia, and he also holds a Master of Civil Engineering degree from Cornell University in Ithaca, New York. He will oversee development and maintenance of IAPMO’s plumbing standards, property and installation standards and IAPMO Guide Criteria.

ASSE scald awareness committee addresses water heater thermostats

The American Society of Sanitary Engineering produced the first white paper on scalding hazards associated with low flow showerheads last year. The committee has now moved on to the next white paper. This paper, which should be nearing completion by the end of the year, will address the inability of the water heater thermostat to accurately control hot water temperature,

Although water heater manufacturers are recommending that installers set thermostats at 120 to 125 F, most of them ship the water heaters at lower temperature settings. This is because of lawsuits that the water heater manufacturers have had to deal with because of scalds.

Scald injuries are very preventable. We have the technology to prevent scalds with proper hot water temperature controls. We just do not have the teeth in the codes when it comes to existing installations. Existing systems are not required to be upgraded to meet the current code because of two factors. One is cost: Building owners do not want to be forced to spend the money. The other issue is education: Most people do not understand the dangers associated with hot water scald injuries in systems without compensating type shower valves or master mixing valves.

Plumbing design professionals often recommend that hot water systems be designed with higher storage temperatures to reduce the threat of Legionella bacteria growth in the hot water tank; they recommend reducing the hot water delivery temperature to a safe temperature with the use of a master thermostatic mixing valve. Hot water systems are generally designed and water heaters are generally sized to store hot water at 140 F or higher. When the thermostat is set at a lower temperature, the water heater has a reduced capacity to deliver hot water. Lower thermostat settings can also cause condensation in a water heater. When maintenance workers lower the water heater thermostats, it is common for users to run out of hot water during peak periods, which leads to complaints. When, to address the complaints, the thermostat is re-adjusted to a temperature above 120 F, the heater usually delivers water at very hot temperatures to unsuspecting bathers or users.

Water heater thermostats were never intended to provide precise temperature controls. For example, the thermostat dial calibration test of ANSI Z21.10.1-1998, which is the applicable standard for gas-fired water heaters, allows the temperature to vary significantly above or below the thermostat setting. I have talked to water heater manufacturers who indicated that the controls can vary as much as 15 to 18 degrees F above or below the thermostat set point. I have witnessed temperatures 35 degrees above the set point at the water heater outlet. This is because the thermostat is inserted into the lower portion of a water heater tank, where the cold water inlet is located. This is done so the controller can anticipate the need for hot water, sense the incoming cold water and turn the burner on before the heater runs out of hot water. The thermostat turns “on” and “off” the fuel supply to the water heater. There is no way that the control device in the bottom of a heater can sense the temperature leaving the top of the tank. Testing has shown that, when a water heater thermostatic element is set at 120 F, the burner stays on until the water around the thermostat element near the bottom of the heater reaches about 135 F. (See Figures 1 2)

The maximum temperature limit test of ANSI Z21.10.1 gas water heater standard allows the outlet water temperature of the water heater to rise 30 degrees F above the thermostat setting. This provision accounts for the phenomenon known as “stacking” or “layering” of hot water in the top of a water heater. Hot water rises to the top of the water heater, due to recurring short duration heating cycles caused by a frequent number of small quantity hot water uses.

Although the above example addresses gas water heaters, this phenomenon can also occur in other types of storage water heaters. So, at the top of a water heater that is theoretically set for 120 F, the temperatures can easily reach 165 F. The ASSE scald awareness task group is in the process of developing a white paper to put this information into laymen’s terms so that the entire plumbing industry and the general public can understand the issue.

This scald hazard issue was recently moved up in priority on the list of topics to be addressed when the State of North Carolina allowed an exception to the code that does not require an ASSE 1016 type pressure balancing or thermostatic type shower valve for showers if the water heater thermostat is set at 120 F. Numerous comments from code consultants, industry experts and manufacturers were sent to North Carolina during the review period. Ultimately, the committee chose to allow the amendment, which would allow a builder to save a few bucks on every home, in lieu of choosing safety for their constituents. I was told that there was a significant representation of home builders on the committee that made the decision.

Ron George is president of Plumb-Tech Design and Consulting Services LLC. He has served as chairman of the International Residential Plumbing & Mechanical Code Committee. Visit www.Plumb-TechLLC.com, email Ron@Plumb-TechLLC.com or phone 734/755-1908.