Disturbing study

Out of all systems we touched during our deep energy retrofit, the domestic hot water plumbing revealed the most unexpected surprises and opportunities – and as it now turns out, potential risk.

An article published in Environmental Science: Water Research & Technology by William J. Rhoads, Amy Prudena and Marc A. Edwardsa states:

“This study raises concerns with respect to current green water system practices and the importance of considering potential public health impacts in the design of sustainable water systems.”

(Environ. Sci.: Water Res. Technol., 2016,2, 164-173)

The researchers point to increased residence time of water in plumbing systems that have been built with water conservation (i.e. low flow fixtures) and efficiency in mind to get their green building credits. To quote hot water guru Gary Klein:

“…the rules for sizing the piping do not have a way to account for these lower flow rates and fill volumes. On top of that, standard engineering practice is to add a safety factor on top of the calculated design. The result of this tension between the plumbing code, engineering practice and water use efficiency has the effect of dramatically increasing retention time in the piping.”

That increased retention – or – residence time comes with risks:

“Concentration of 16S rRNA and opportunistic pathogen genus level genetic markers were 1–4 orders of magnitude higher in green versus conventional buildings.”

(Environ. Sci.: Water Res. Technol., 2016,2, 164-173)

A write up of the study was published in Chemistry World.


Let’s unpack this by taking a step back:

Thanks to Gary Klein, we have an efficiently structured plumbing system that maximizes energy, water and material conservation.

Well – maximizes with a lowercase “m” because the Chicago Plumbing Code got in the way. ½” is the smallest fixture branch (or twigs) size that is allowed (Chapter 18-29-604.5 Size of fixture supply). Yet the combination of our structured plumbing system and low flow fixtures validates 3/8″ fixture branches (twigs) and fixture supply lines, which would help keep excessive residence time at bay. This is a matter of right sizing the piping for fixture branches (twigs) and fixture supply lines to match the flow rate of the fixture they serve. Gary Klein puts it this way:

“lower flow = smaller water volume to deliver = smaller pipe sizing”

The 3/8″ fixture branches (twigs) may be unimaginable in Chicago, but other places have caught on to the smaller pipe sizing principle, as I found out when visiting my friend Oliver in Sweden.


I have come across a lot of bitching and moaning about the Chicago Building Code and inspections. Yet I learned to appreciate the code and the inspection through the process of our deep energy retrofit. Even if some things seem cumbersome and over the top, it is with our safety and welfare in mind. And the plumbing code is unambiguous about it:

“18-29-101.3 Intent: The purpose of this chapter is to provide minimum standards to safeguard life or limb, health, property and public welfare by regulating and controlling the design, construction, installation, quality of materials, location, operation, and maintenance or use of plumbing equipment and systems.”

Chicago, I am glad you watch my back! Except that sometimes you don’t. Sometimes the world is moving faster than you are. And everything having to do with green building is picking up speed every year. That includes encouraging developments in water conservation and low flow fixtures. I am sure ½” fixture supply pipes once were a rock solid safety standard – before the emergence of low flow fixtures. But these days… As Gary Klein points out:

“Reducing flow rates without reducing pipe volume is a recipe for disaster, as the study points out.”

Will I swap out all of our low flow fixtures with regular ones? Nope, not yet. And Gary gave me a little peace of mind:

“You actually were able to reduce the volume [and residence time] by the way you did the [structured] plumbing.”

Dear Chicago: I would appreciate it if you would live up to your health and safety intent. Take note of the study “Survey of green building water systems reveals elevated water age and water quality concerns” and adjust the plumbing code to allow smaller pipe sizes. Stay abreast of the green building developments, and in the process keep us safe – keep watching our backs!

Related posts:

ERV croaked – Part 4a

I am having fun with my sequential blog post titles … maybe to compensate for the inconvenience of having a sequential problem with our Energy Recovery Ventilator (ERV).

Both of our ERVs (both RecoupAerator by UltimateAir) have been running flawlessly for the past two years. But earlier this month, our 1st floor ERV showed symptoms that were reminiscent of the problems we had during the winter of 2013/14 with our basement unit.

When we ran the ERV, the building cooled down rather quickly. That indicated that something was amiss with the heat exchanging process. Based on our past experience, I knew that there were two probable causes:

  1. The enthalpy wheel stopped running.
  2. One of the blower motors and/or control boards croaked.

Well, it took no time at all to determine that it was the motor and/or control board. I made a quick call to UltimateAir and a few days later we received the replacement parts. It was time to start tinkering again:

I have a suspicion that the problem may lay with the heat sink on the control board. Two years ago, when I went through the same process in the basement, I noticed that the replacement board had a significantly bigger heat sink than the original board. I also recall vaguely that Matt at UltimateAir pointed out that the board on our 1st ERV may give us the same problem.


Or was it the fibers from the enthalpy wheel that started clogging the impeller that did the motor in? I am curious to know that the experts at UltimateAir think.

On a side note – this blog begins to pay off! Because everything is documented, it’s easy to look up a problem of the past to remind myself on how to fix things – like the ERV.

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Windy windows with a warp

I bought our 1st floor windows locally, at Newtec Windows & Doors at 36th Street and Kedzie here in Chicago. I liked their pricing. But first and foremost, I liked their specs. Their awning and casement windows in the 1400 Series are advertised as almost airtight. What I don’t like is that the casements I bought have major air leaks and that the service response by Newtec is painfully slow (and that is putting it politely).

It was about a year ago when I ran into trouble. Once it got cold and windy outside, I noticed drafts around our casement windows, which should not have been there at a specified air leakage of 0.02 cfm/sf.

Newtec Windows & Doors attempted to fix the leaks twice to no avail. The service visits were followed by two inspections by the company owner with his product suppliers. The verdict each time was that the casements had a very slight bow to them at the corners.

window-36 window-37

If I measure the gap between the sash and casement where it closes and seals properly, I get a reading of 1/16 inch. Toward the corners, where the casement bows out, the gap widens to ? inch. At this point the casement doesn’t press into the rubber gasket of the sash anymore, thus the air leak.


Putting a straight edge along the casement bottom is another way to reveal the bowing and the subsequent widening gap.

The vinyl profiles of the 1400 Series are manufactured by Rehau. During the last inspection (March 2015) the Rehau representative recommended that we replace the existing gaskets with new ones that would bridge the gap and provide the required air seal.

Ten months later, I finally got Newtec to come out to install the new gaskets – but it took some serious nagging!

The service technician pulled the old gaskets out, installed the new gaskets…

window-39 window-40

… and the windows were leaking air like they did before.

The old and new gaskets have an identical profile. To bridge and seal the gaps at the corners, the new gasket would need to have a profile at least 1/16 inch deeper – demonstrated here by squeezing the gasket.


Now that we have exhausted the gasket option, I wonder what is next. Replacing the bowed casement portion of the windows with one that is straight? But what I wonder about even more is when I will see the next effort to fix this by Newtec Windows & Doors.

Related posts:

Inspecting windows

Adjustment attempts

Checking on casement corners

1st floor replacement windows

The world of windows


Access enclosure – priming

I had one last little step left on the roof access: Priming the fiber cement board.

While reading through the product specifications of the fiber cement board, I noticed the recommendation to paint it with an exterior grade primer after installation to add to its weather resistance.

Easy! I got a gallon of low VOC primer. Not so easy: We, or for that matter Harold our friend, had to wait for a day warm enough to put the primer on. But we got lucky!


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Access enclosure – vinyl siding

Well, the north wall of the access enclosure got exciting with a mural in the making. When it came to the west wall, I was able to stick with my original plan – vinyl siding.

Don’t get me wrong – I don’t have my eye on vinyl siding because I love it. But it is a material that is fairly easy to purchase on the reuse market. And as I am still in pursuit of “reduce, reuse and recycle” as much as possible, vinyl siding appeared to be a good match.

Because I did start looking for reclaimed vinyl siding early on, I found the perfect batch for my job at the Rebuilding Exchange. And what makes this whole deal even sweeter is that I got it for less than half the price compared to new siding.


I never had installed vinyl siding before. But thank God for YouTube. Shannon, a charming Canadian builder, has a great tutorial that got me into the terminology and the installation process.

I started with the J-channels and flashing around the door and along the roof edge. That actually took a while. The installation of the actual siding panels proceeded rather quickly in comparison.

With the vinyl siding on the west wall, I completed the weatherizing of the roof access – almost…

Related posts:

Access enclosure – fiber cement board

Access enclosure – house wrap

Access enclosure – fire wall

Provisional plywood

Porch roof level