If you write the codes or comply with the codes as an engineer, contractor or owner, pay attention to how the codes are argued and interpreted to protect the health and safety of people.
I recently concluded a domestic hot water scald burn case involving a student in a university dormitory tub-shower. The tub-shower valves installed throughout the dormitory were code-compliant valves when manufactured; the manufacturer confirmed that the valves were third-party certified to ASSE 1016 in 2001.
The university maintenance personnel admitted to removing the maximum-temperature limit stops, which is a safety device, from the tub-shower valves. With no temperature control devices downstream of the gas-fired, storage-type water heaters serving the multistory building, the likelihood that scalding hot water would flow from a showerhead while a student was showering was an omnipresent threat.
Yet, the university argued that it had no reason to suspect that anyone would ever be scalded in a shower because they were unaware of any student having complained of the water being “too hot” in the previous five years (an arbitrary look-back period, which is not relevant to the issue of whether a plumbing system is safe). However, a closer look at the records did show complaints of water too hot and numerous complaints of leaks followed by complaints of no hot water.
I was surprised when I read the university’s expert report defending the removal of the maximum-temperature limit stops from the tub-shower valves by the owner’s in-house maintenance personnel. The defense was based upon a university maintenance employee’s belief that the valves may have been installed before the university even purchased the building. At that time, the code did not require the installation of valves conforming to ASSE 1016, with the maximum-temperature limit stop adjusted to a temperature of no greater than 120 F.
The university’s expert further surmised that perhaps the valves were installed before the ASSE 1016 standard even had a provision for a maximum-temperature limit stop, which provision became part of the ASSE 1016 standard in 1988. The valve manufacturer, in this case, was ahead of the curve, having introduced its valve with a maximum-temperature limit stop in 1986.
Therefore, the defense argued that removing the limit stops violated no code as tub-shower valves with maximum-temperature limit stops weren’t even required to have been installed in the first instance. The defense further argued that with the limit stops removed, the tub-shower valve met the previous ASSE 1016 standard — the one introduced in 1973 did not contain a provision for maximum-temperature limit stops.
Note that the foreword of the 1973 ASSE 1016 standard admonishes any claim that a product meets the standard without third-party testing and certification. There is no evidence that this tub-shower valve with its maximum-temperature limit stop was ever tested and certified to this 1973 standard, even though the removal of the limit stop should not affect the other functionalities of the valve.
Although no record of the installation dates existed in the university’s records, the university was able to identify the model number of the valve and provide a photocopy of a specification sheet for the subject tub-shower valve, which showed evidence of being retrieved from a three-ring binder.
The specification sheet bore a date of 06/02; the valve manufacturer confirmed that there was no earlier specification sheet for that model of tub-shower valve. The valve manufacturer identified the model number for the subject tub-shower valve as included in the 2001 third-party testing and certification of its valves to the ASSE 1016 standard.
The defense concluded that the university maintenance personnel’s relatively recent removal of the safety device violated no code because maximum-temperature limit stops were not required by code some 30-plus years ago when the valve was alleged to have been installed.
International Plumbing Code Provisions
However, for many years, including the most recent effective version of the International Plumbing Code (IPC), there was a provision requiring that: “[a]ll plumbing systems, materials and appurtenances, both existing and new, and all parts thereof, shall be maintained in proper operating condition in accordance with the original design in a safe and sanitary condition.” I’d be curious to hear from others how they would interpret the later removal of a product’s safety device, although not required by the code in effect at the time of installation.
The defense had yet to contend whether any post-installation code required the university to install ASSE 1016 valves with maximum-temperature limit stops, both integral to the valve and field adjusted, per the manufacturer’s instructions, to limit the maximum setting of the valve to 120 F. The defense report concluded that no such code required any update to tub-shower valves, citing various code provisions regarding the lawfulness of existing installations (i.e., grandfather clauses).
In my opinion, having been involved for decades in writing, analyzing, interpreting and applying the various building codes, there should be no room to argue that any tub-shower valve installation without a maximum-temperature limit stop is “grandfathered” into a long-ago code. In nearly every building in America, tub-shower valves with integral maximum-temperature limit stops, field-adjusted to limit the maximum setting of the valve to 120 F, are code-required to have been or to be installed by now.
The reason is simple: With every installation of a water heater, either in new construction or as a replacement in an existing structure, tub-shower valves must be installed, re-adjusted or replaced with new, ASSE 1016-compliant valves. In this multistory dormitory building, several separate instances of gas water heater replacement were recorded.
All were performed when the local code in effect required the installation of tub-shower valves conforming to ASSE 1016 (that is, requiring integral maximum-temperature limit stops) and field-adjusted to limit the maximum setting of the valve to 120 F or less.
In existing structures, installing a new water heater is an alteration to a plumbing system; it can cause an existing plumbing system to become unsafe if the proper precautions are not performed. The installation of a new water heater affects the entire domestic hot water distribution system’s temperatures. The removal and replacement of a water heater require alterations to the fuel gas piping, the fuel gas vent piping and the water piping connections.
Installing a new water heater requires an assessment of the number and use of the fixtures to determine if the replacement water heater is of adequate size and fuel input capacity to meet the hot water needs of the consumers. Therefore, when a new or replacement water heater is installed, the existing plumbing fixtures, including shower and tub-shower valves, should be brought up to the current code to make the plumbing system safe. The applicable IPC provision is:
International Plumbing Code
“102.4 Additions, Alterations or Repairs
“Additions, alterations, renovations or repairs to any plumbing system shall conform to that required for a new plumbing system without requiring the existing plumbing system to comply with the requirements of this code. Additions, alterations or repairs shall not cause an existing system to become unsafe, unsanitary or overloaded.
“Minor additions, alterations, renovations and repairs to existing plumbing systems shall be permitted in the same manner and arrangement as in the existing system, provided that such repairs or replacement are not hazardous and are approved.”
International Fuel Gas Code Provisions
Additionally, with respect to gas water heaters, the International Fuel Gas Code (IFGC) specifically requires the scald protections of the IPC to be followed when installing a water heater. The applicable IFGC provision is:
International Fuel Gas Code
“624.1 General
“Water heaters shall be tested in accordance with ANSI Z21.10.1 and ANSI Z21.10.3 and shall be installed in accordance with the manufacturer’s instructions.
“624.1.1 Installation Requirements
“The requirements for water heaters relative to sizing, relief valves, drain pans and scald protection shall be in accordance with the International Plumbing Code.” (Emphasis added.)
I have always interpreted this provision in the IFGC to refer to the IPC’s requirement for anti-scald valves in showers, combination bathtub-showers, bathtubs and whirlpool bathtubs (i.e., both ASSE 1016 and ASSE 1070 valves). The applicable IPC provisions are:
International Plumbing Code
“424.3 Individual Shower Valves
“Individual shower and tub-shower combination valves shall be balanced-pressure, thermostatic or combination balanced-pressure/thermostatic valves that conform to the requirements of ASSE 1016 or ASME A112.18.1/CSA B125.1 and shall be installed at the point of use.
“Shower and tub-shower combination valves required by this section shall be equipped with a means to limit the maximum setting of the valve to 120 F (49 C), which shall be field-adjusted in accordance with the manufacturer’s instructions. In-line thermostatic valves shall not be utilized for compliance with this section.
“424.4 Bathtub and Whirlpool Bathtub Valves
“The hot water supplied to bathtubs and whirlpool bathtubs shall be limited to a maximum temperature of 120 F (49 C) by a water-temperature limiting device that conforms to ASSE 1070 or CSA B125.3, except where such protection is otherwise provided by a combination tub/shower valve in accordance with Section 424.3.”
The university interpreted this provision of the IFGC to refer to the IPC’s requirement for a tempering valve to limit the temperature of the hot water supplied to the potable hot water distribution system to 140 F for a combination potable water-heating and space-heating system.
A similar requirement for a tempering valve for combined systems where water greater than 140 F is required for space heating is contained in the International Mechanical Code (IMC); unfortunately, for many years, the IMC titled this provision as “scald protection.” I was present when the title of this provision was changed because this provision is not for scald protection. The title is now “temperature limitation.”
An ASSE 1017 valve is not an acceptable means for scald protection, and a hot water temperature of 140 F is not for purposes of scald protection. According to the Moritz & Henriques burn studies, at 140 F, it takes only three seconds for a serious, blistering, irreversible burn that will cause scar tissue in an adult male.
Rather, the requirements of a hot water distribution temperature of 140 F for combination potable water-heating and space-heating systems are based on other plumbing system design principles to ensure adequate hot water capacity and for the proper function of a water heater.
International Property Maintenance Code Provisions
Regardless of any debate over the obligations of a property owner to install and field-adjust ASSE 1016-compliant valves when installing a water heater, either in new construction or as a replacement in an existing structure, there is one code that repudiates any notion of “grandfathering” of noncompliant structures or premises — the International Property Maintenance Code (IPMC).
This code was not addressed by the university’s expert, though he alluded to it in his quotes of the local jurisdiction’s construction code, which specifically required compliance with the retroactive provisions of the “building code, fire prevention code, existing building code, and the property maintenance code.” Although the other named codes may have only some retroactive provisions, the entirety of the IPMC is retroactive.
Based upon the language of the IPMC, the installation of code-compliant ASSE 1016 valves, field-adjusted to limit the maximum temperature of mixed hot water flowing from bathtubs and showers to 120 F, is required of property owners regardless of whether any other alterations, additions or repairs to the domestic hot water (plumbing) system are made, and regardless of any other percentages of construction.
The IPMC contains several provisions concerning the need for current compliance with its mandates so that there cannot be any doubt that compliance with the current code is required. At the outset, the IPMC informs that:
International Property Maintenance Code
“101.2 Scope.
“The provisions of this code shall apply to all existing residential and nonresidential structures and all existing premises and constitute minimum requirements and standards for premises, structures, equipment and facilities for light, ventilation, space, heating, sanitation, protection from the elements, life safety, safety from fire and other hazards, and for safe and sanitary maintenance[.]” (Emphasis added.)
In further clarification of its mandate that compliance with the current code is required, the IPMC specifically directs property owners to make repairs to bring their structure or premises up to the requirements of the code provisions:
International Property Maintenance Code
“101.3 Intent.
“This code shall be construed to secure its expressed intent, which is to ensure public health, safety and welfare insofar as they are affected by the continued occupancy and maintenance of structures and premises. Existing structures and premises that do not comply with these provisions shall be altered or repaired to provide a minimum level of health and safety as required herein.” (Emphasis added.)
To avoid any further confusion as to whether the IPMC requires property owners to alter or repair their building’s “plumbing facilities and fixtures” in order to bring it up to the requirements of the current code provisions, IPMC Chapter 5, Plumbing Facilities and Fixture Requirements, mandates compliance with its requirements before a premise can be occupied by anyone:
International Property Maintenance Code
“501.2 Responsibility.
“The owner of the structure shall provide and maintain such plumbing facilities and plumbing fixtures in compliance with these requirements. A person shall not occupy as owner-occupant or permit another person to occupy any structure or premises which does not comply with the requirements of this chapter.” (Emphasis added.)
Chapter 5 also requires that the hot or tempered water supplied to bathtubs and showers (as well as other plumbing fixtures) be in accordance with the IPC:
International Property Maintenance Code
“505.1 General.
“Every sink, lavatory, bathtub, or shower, drinking fountain, water closet or other plumbing fixture shall be properly connected to either a public water system or to an approved private water system. All kitchen sinks, lavatories, laundry facilities, bathtubs and showers shall be supplied with hot or tempered and cold running water in accordance with the International Plumbing Code.” (Emphasis added.)
IPC Chapter 6
IPC’s Chapter 6, Water Supply and Distribution, discusses the materials design and installation of water supply systems, both hot and cold, in Section 601.1 (2009 International Plumbing Code), Section 607 and Section 607.1. They specifically defer to Section 424.3, Individual Shower Valves.
International Plumbing Code
“Section 607 — Hot Water Supply System
“607.1 Where required.
“In residential occupancies, hot water shall be supplied to all plumbing fixtures and equipment utilized for bathing, washing, culinary purposes, cleansing, laundry or building maintenance. In nonresidential occupancies, hot water shall be supplied for culinary purposes, cleansing, laundry or building maintenance purposes. In nonresidential occupancies, hot water or tempered water shall be supplied for bathing and washing purposes.
“Tempered water shall be supplied through a water temperature limiting device that conforms to ASSE 1070 and shall limit the tempered water to a maximum of 110 F (43 C). This provision shall not supersede the requirement for protective shower valves in accordance with Section 424.3.” (Emphasis added.)
Removing the maximum-temperature limit stops and, instead, trying to rely upon the water heater thermostat for scald protection is a dangerous practice. In this case, university maintenance personnel testified to its unwritten policy to set the water heater thermostats to 120 F.
With a thermostat setting of 120 F, the temperature of hot water leaving a water heater can, permissibly by standard, reach 150 F. However, there were several documented instances where the water heater thermostats were set to 140 F in this case.
The dangerous practices of university maintenance personnel and the conditions present in this domestic hot water system led to the serious scald burn injuries of a university student.
Original post: https://www.phcppros.com/articles/15031-the-importance-of-maximum-temperature-limit-stops
Installing a gas water heater as a DIY homeowner can be risky if not done correctly. Some of the highest risk aspects associated with DIY installation of a gas water heater include:
To minimize these risks, it’s always advisable to hire a professional licensed plumber to handle the installation of a water heater. They have the expertise, tools, and knowledge to ensure that the installation is safe, code-compliant, and free from the risks associated with DIY installation. Additionally, professional installation often comes with warranties and peace of mind.
A new water heater can potentially cause smelly water and a rotten egg smell in the hot water if there is an issue with the water quality of the water source.
Here are some reasons why you may experience a rotten egg smell in your hot water, especially after the installation of a new water heater:
It’s important to note that these issues can also happen in older water heaters as well, and not only in new ones. To address this problem, you should have a licensed professional inspect the installation, complete a water quality test, check for the presence of sulfur bacteria or high levels of sulfates, and test the water source. They will also check the anode rod and the plumbing. Based on their findings, they will recommend the necessary steps to eliminate the smell and prevent it from reoccurring.
NOTE: Water quality is a fluid and dynamic state that changes continually. As water quality changes, the needed solutions must also change and adapt if perfect water quality is desired.
When well water is present and/or iron-eating bacteria is present, an aluminum anode rod is typically considered to be a better option than a magnesium anode rod.
Here’s why an aluminum anode rod is considered to be a better option for homes with well water:
It’s important to note that even though aluminum anode rods are more resistant to corrosion in well water and water with iron-eating bacteria, it’s still important to regularly check and replace them to ensure that the water heater tank is protected. Additionally, you should consult with a plumber or water treatment professional to determine the best course of action for your specific well water or iron-eating bacteria situation.
Magnesium and aluminum anode rods are both used in water heaters as a means of protecting the tank from corrosion. However, they have some important differences as explained here.
Here are some important differences to consider regarding magnesium and aluminum anode rods in your water heater:
In summary, the main difference between magnesium and aluminum anode rods is that magnesium anode rods are more efficient in soft water and have a shorter lifespan, while aluminum anode rods are more efficient in hard water and have a longer lifespan. The choice of which one to use depends on the water hardness of the area and the budget.
When you have well water, your water heater and other water appliances require extra care to ensure that they function properly and last as long as possible.
Here are a few key things for owners of homes with well water to keep in mind:
By following these best practices, you can help to ensure that your water heater and other appliances are in good working order and that they last as long as possible. More importantly, you can ensure your family has safe healthy water for all your needs.
Hot water from the home's faucets and sinks can cause serious injury to members of the family. Underestimating the risks posed by burns and scalding wounds only makes members of the household more vulnerable to injury. The following facts about scalds and burns can help illustrate the dangers of improperly heated water in the home.
1. Kids and seniors face the highest risk
Seniors and kids under the age of 5 are especially vulnerable to serious scald injury. A thinner dermis poses an extra threat of deeper burns in children, while limited flexibility can sometimes put seniors in danger with regards to nearby hot water.
2. Overheated water is a common problem at home
Ironically, many homeowners that balk at the idea of burn-related injuries in the home are at the greatest risk. Over 40 percent of inspected urban homes were found to have water heaters set at or above 140 degrees. Setting water temperatures to 120 degrees will increase safety and heating efficiency simultaneously.
3. Serious burns can occur in seconds
Burn wounds caused by a home's water supply can occur quickly. In fact, 140 degree water can cause a third-degree burn after just five seconds of exposure.
4. Cool water is better than ice for temporary treatment
Resist your instinct to ice a serious burn or scald, as treating the injury with ice actually risks worsening the burn. A wet compress or a flow of cool water will do the trick until you can schedule a medical visit.
5. Scalding injuries are mostly preventable
While hundreds of thousands of scald wounds occur each year, 75 percent of burn injuries in children are preventable. Families taking a proactive approach toward preventing burn injuries will see rapid results in the form of fewer burn accidents.
6. Going tankless can eliminate scald injuries
Often performing maintenance on an aging water heater simply increases risks of a scalding accident. Electric tankless water heaters have more precise, reliable heat controls to help prevent burn injuries.
SOURCE: https://webflow.com/design/hot-water-safety
They get too hot, the water inside turns to steam. Steam takes up far more room than the water it once was, and the expansion rips the water heater apart. And make no mistake, there have been some spectacular water heater explosions. The MythBusters have addressed (if that’s the right word) this issue several times:
If this happens in your home you probably won’t show the same level of enthusiasm as these fellows, though. Here’s another less, ah, flamboyant link:
Water Heater Explosions – Should You Be Concerned? | Water Heater Hub
Naturally, there are safety devices to prevent this, mainly a thermostat to turn off the heat source (gas or electric) before things get anywhere near too hot. The next safety device is the T&P valve, the temperature and pressure valve, designed to open if the temperature or pressure gets too high. In order to make the video above, the MythBuster guys had to disable the thermostat and remove the T&P valve.
Of course, no homeowner would ever do that, but over time the T&P valve can get stuck, then fail when it is needed. It needs to be tested, maybe about once per year; if it keeps leaking after the test, have it replaced. There’s no end of websites discussing water heaters and required maintenance, just search “water heater t&p valve.” Here’s one chosen at random (NOT an endorsement!):
Water Heater Temperature & Pressure Relief Valve Discharge Pipe
Original reporting: https://www.quora.com/What-happens-when-a-hot-water-heater-explodes-why
Nine recently confirmed cases of Legionnaires’ disease in Hopkins, MN reminded me of an old blog post that I thought would make for a timely re-blog, along with some updated information. First, here’s the story about the recent cases in Hopkins: http://www.startribune.com/mdh-hopkins-warehouse-and-fountain-under-investigation-as-possible-source-of-legionnaires/393567731/. As mentioned in the story, Legionnaires’ disease resembles a severe case of pneumonia and is spread by inhaling the fine spray from water sources containing Legionella bacteria. In your home, the source of that bacteria could be your water heater, especially if you turn your water heater temperature down to the “vacation” setting when leaving for extended periods of time. The people who are most at risk for Legionnaires’ disease are those over 50, smokers, or those with certain medical conditions.
According to LegionellaPrevention.org, legionella bacteria can grow at temperatures from 68° F to 122° F, but the ideal growth range is between 95° F and 115° F. When it comes to preventing legionella bacteria growth, hot water is better. Legionella bacteria cannot multiply at temperatures above 122° F, and are killed within 32 minutes at 140° F. So crank up the water heater as high as it will go, right? No, of course not. That would create a scald hazard. Water heater manufacturers put a warning on water heaters saying the water temperature should not exceed 125° F to help prevent “severe burns instantly or death from scalds”. Their words, not mine.
So what’s the perfect temperature for your water heater?
Unfortunately, there’s no simple answer. The American Society of Sanitary Engineering Scald Awareness Task Group released a white paper many years ago on this topic, which essentially says that there is no perfect temperature to set your water heater to. Part of the reason is that traditional tank-style water heaters don’t keep the water in the tank at an exact temperature; there is a temperature “band” that tank water heaters maintain. At the beginning of a heating cycle, a water heater set to 120°-ish might start at 115° F, and might get up to 125° F at the end of its heating cycle. There’s more to it than just that, but the point is that water heaters do not produce constant temperatures.
If the water in a tank is kept below scalding temperatures, there is a potential for Legionella bacteria growth. Ideally, the temperature in a water heater tank should be cranked way up to 140° F or higher, but now we’re back to the scald hazard thing. One solution is to have a hot water tempering valve installed for the entire home.
This valve would be installed right at the hot water outlet of the water heater. It would allow the water heater to be cranked up to a scalding 140° F, which would be sufficient to kill bacteria and would extend the capacity of the hot water tank, while at the same time reducing the temperature of all of the hot water throughout the house. Click the following link for more information about these devices: http://media.wattswater.com/F-MXV.pdf . While these devices won’t guarantee safe water temperatures at every fixture, they’ll get you a lot closer.
If you want more hot water out of your water heater and you want to reduce the risk of Legionella bacteria growth, hire a plumber to install one of these mixing valves at your water heater and turn the temperature up on your water heater. I should also mention that point-of-use thermostatic mixing valves should ideally be installed at the faucets for the highest level of safety… but I’m pretty sure I’ve never seen a home fully outfitted with those.
