International Plumbing Code Archives - Roger W. Griffith, P.E.

Careful! The Wrong Showerhead May Scald You

January 7, 2019 by Roger Griffith Leave a Comment

If not specified and installed correctly, showerheads can cause scalding!

Currently, standard shower valves and showerheads have a minimum flow rate of 2.5 GPM. There are water-saving shower valves and showerheads available with lower flow rates. WaterSense showerheads are rated at 2.0 GPM. There are also showerheads available that have 1.5, 1.0, and even 0.5 GPM flow rates. These various options for minimum flow rates in shower valves and showerheads create an opportunity for misapplication and dangerous results.

When the flow rate of a showerhead is less than the minimum flow rate of the corresponding shower valve, the potential for scalding increases for the following reasons: [Read more…]

Roger W. Griffith appointed to ICC Plumbing/Mechanical/Fuel Gas Code Action Committee

January 27, 2017 by Roger Griffith Leave a Comment

Roger W. Griffith has been appointed to the Plumbing/Mechanical/Fuel Gas Code Action Committee (PMGCAC) of the International Code Council (ICC). The role of this code committee is to review and propose revisions to the International Plumbing, Mechanical, Fuel Gas, Private Sewage Disposal, and Swimming Pool and Spa Codes and the International Residential Code, chapters 12 through 33, which covers the mechanical, plumbing, and fuel gas systems in residential occupancies. I am honored to be appointed as a member of this committee for the upcoming 2018 – 2019 code development cycle.

These important codes define how mechanical, plumbing, and fuel gas systems must be designed and installed to protect the health, safety, and welfare of the public.

Are Thermal Expansion Tanks Needed With Tankless Water Heaters?

June 21, 2015 by Roger Griffith 9 Comments

Thermal expansion tanks are typically installed in conjunction with storage water heaters, but are they needed with tankless water heaters? This issue can sometimes be overlooked. Let’s look at the specifics. [Read more…]

Thermal Expansion Tanks: Part 1 – The Need

June 20, 2015 by Roger Griffith 5 Comments

When are thermal expansion tanks needed and/or required in plumbing systems?

When heated, water expands. We know that. When water is heated in a water heater, the water expands, if possible. But what happens when water is heated in a water heater and there is no hot water usage?

This can occur after a period of showering/bathing during peak times followed by a period of no hot water usage. For example, evenings are a time when there is hot water usage for showering followed by a period of no usage while people are sleeping during the night.

During peak usage times, hot water stored in the water heater is distributed to the end-users, and cold water fills the water heater. The cold water in the tank is then heated, but when there is no subsequent hot water usage, the heated water has no room for expansion. If there is no place for the expanded water to go, the pressure in the system increases significantly. This leads to one of two possible scenarios:

[Read more…]

What’s Wrong With This Picture?

September 18, 2014 by Roger Griffith Leave a Comment

If you stay in this business long enough, you see a bit of everything. Notice the water heater’s T&P valve in the above photograph. The T&P valve discharges vertically up. What’s wrong with that?

There are many specific code requirements (13 to be exact) for the discharge piping from water heater T&P valves (Ref: 2012 International Plumbing Code 504.6). This installation violates requirements 8 and 9, which are:

8. Not be trapped.

9. Be installed so as to flow by gravity.

Obviously, with this incorrect installation, the discharge cannot flow by gravity. Also, water can fill and remain in the discharge pipe. Over time, stagnant water that remains in the discharge pipe can corrode the pipe and cause it to fail.

This is just a reminder. During field inspections, check the discharge pipe to verify code compliance.

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