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.