The International Code Council has issued the code change monograph for changes to the 2024 edition of the Plumbing, Mechanical, Fuel Gas and Fire Codes, as well as parts of the Building Code. The monograph can be downloaded by visiting

There are 147 changes to the Plumbing Code; 101 changes to the Mechanical Code; and a mere eight changes to the Fuel Gas Code. While the hearings are scheduled over a four week period of time, Plumbing, Mechanical and Fuel Gas code change hearings do not begin until the last week of April. The Fuel Gas Code change hearing will begin on Sunday, April 25, immediately followed by Plumbing Code changes. The Mechanical Code change hearing is not scheduled to begin until Wednesday, April 27. In order to participate, you must register with ICC for the hearings. You can either register to observe or register to testify.

While the hearings are virtual, the committees will actually be live at the ICC Central Regional Office in Country Club Hills, Illinois. The committee, ICC staff and moderators will all be operating from the office, while everyone else participates virtually. The hearings are scheduled to run from 9 a.m. to 7 p.m. CDT. However, the start on Sunday is always at 12 p.m. CDT.


Code change specifics

With the eight code changes to the Fuel Gas Code, the only excitement is a proposal to remove the requirement that all pipe hangers and supports be metal. The change would allow any hanger system for fuel gas piping. While this appears to be an “about time” code change, I’m sure we will probably hear about the need to have noncombustible pipe hangers. Every time I hear that argument, I wonder what good is a metal hanger when the wood holding the hanger is on fire?

For the plumbing code changes, I would lump the majority into one of three categories: New materials, backflow standards and fixture requirements. You actually have to search to find technical changes that may have an impact on plumbing system design.

There are new materials introduced during every code cycle. However, this cycle seems to have a significantly large number of new standards being introduced into the code. ASSE and others have proposed a number of changes to the backflow standards and other ASSE standards.

The plumbing fixture requirements include proposals for new categories of building to identify fixture requirements, new definitions of types of public toilet rooms and new privacy requirements for all gender toilet rooms. While it may not seem exciting, the discussion on fixture requirements and privacy are always invigorating at the code hearings.

The National Resource Defense Council (NRDC) has a proposal to mandate WaterSense showerheads. This would result in the showerhead flow rate dropping from 2.5 gpm to 2.0 gpm. While this is a good change in an effort to conserve water and energy, similar proposals in the past have received opposition from the manufacturing side of the industry. This change may receive more favorable consideration with all of the plumbing fixture manufacturers promoting their newer WaterSense showerheads. This simple change can have a serious impact on the sizing of hot water piping systems, as well as water heaters.

Another change impacting hot water is a proposal to mandate the sizing for hot water recirculation in accordance with the International Energy Conservation Code. While it would appear the Energy Conservation Code is always applicable, that has not been the interpretation with regard to hot water recirculation. This change is expected to get a lot of comments in light of all of the discussion of hot water temperature maintenance in relationship to Legionella and other bacteria growth.

Another proposal would mandate the height location of backflow preventers, which would require backflow preventers to be installed between 12 inches and 60 inches above the finished floor. The justification for the change is to provide access for periodic testing and maintenance. When similar changes have been proposed in the past, those opposed always asked what is wrong with servicing a backflow preventer on a ladder or an aerial platform? While the concept may sound good, it can create a design problem for many industrial locations.

The Healthcare Committee proposed a change that appears rather confusing, in my opinion. The change would require hand washing be provided to all dedicated hand washing stations. However, there is no mandate of hand washing stations. The change continues by allowing water colder than tempered water, followed by the next section that would require hot water. Again, it is a rather confusing code change.

I happen to be the proponent of the only change to sizing in either drainage or venting requirements. The proposal would introduce the revised bathroom group fixture unit value based on the research done by Tom Konen more than 25 years ago. I was asked last year why the IPC does not have the newer (as in the past 25 years) fixture unit values for bathroom groups. I traced the history and found that nobody had ever proposed the revised fixture unit values. As a result, I submitted the values developed by Tom in his memory.

Tom basically identified that families are getting smaller, and the number of bathrooms in a dwelling unit are increasing. This always reminds me of a high-rise building in which I was involved in the water piping design. The average unit had five full bathrooms. After occupancy, the average occupancy of each dwelling unit was 2.1 people. As a result, the fixture unit value needs to be adjusted to reflect the actual use of the fixtures. This is what Tom developed with his research.

The changes proposed to the Mechanical Code are predominantly related to the ventilation, exhaust and refrigeration sections. One of the few hydronic changes is a proposal to identify design limitations for radiant heating and cooling systems. Included within the proposal is a table that would limit the maximum length of a circuit. Reviewing the proposed values, I would identify the lengths as greater than what most of us design in our systems. For example, a 1/2-inch loop would be allowed a maximum circuit of 300 feet. The circuit is defined as the tubing from the supply to the return manifold.

With the hearings going virtual thanks to the COVID-19 pandemic, this provides a wonderful opportunity to participate in the hearings. I would encourage everyone to download the changes and review the impact they would have on your part of the profession. If you feel strongly enough, either pro or con, you have the ability to testify on any given code change.

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The views expressed here are strictly those of the author and do not necessarily represent PM Engineer or BNP Media.