Thank you RBean. Yes, I would certainly agree that regulations in general for single-family residential buildings tend to fall far short of what they should be in many areas.

I have little doubt that way too many elderly people living in single-family residential buildings in the US contract Legionella phenomena that is never traced back to the source in their home. After all, elderly people tend to die and often from phenomena. Gram-negative bacteria like Legionella also tends to be resistant to antibiotics, so this isn’t a bacteria to be trifled with...but in the US, this appears to be our current mode of operation.

However, some will tell you that we should not have any regulations or government at all. We should just trust in large companies and in the free enterprise system to take care of us. Having lived in Munich, Germany for six years and having traveled the world extensively, I can’t say that I found the highly regulated, socialism style of European government to be all that objectionable...although we would never personally give up our firearms! Quite the contrary, many European countries have spawned significant advancements in many fields that have resulted in their life expectancy rates significantly exceeding that of the US. So YES, I would personally vote to have Standard 188 apply to all buildings.

Listen to you guys go on!!
OP asks for evidence that open systems increase the risk of LD. You all agree that there is no evidence of that but you want to ban them anyway.
Let me paraphrase for you. I know there is no evidence that you committed murder but we are going to hang you any way 'cause we thing you might!!!

You would never personally give up your firearms but you will give up every thing else? Really?

You would personally vote for 188.

•••Note the part about an already chlorinated public water source still failing to kill the legionella •••

Are you personally prepared to take responsibility for the hundreds or thousands of deaths that will occur? As soon as you start chlorinating residential wells you will destroy most of the septic system in the country. Now you have lots of bad bacteria and parasite heading to the nearest river and aquifers. That ought to make LD look like a tempest in a teapot.

What is the net risk of chlorination in residential homes? Well based or in house based? What are the risks of off gassing or free gas in the home? I know from personal experience that a large number of wells are damage because of chlorine corrosion of the pitless adaptors or the well stem. When a pitless adaptor fails, the well stops working and you fix it. When the well stem corrodes no one knows until the well is contaminated.
What are the risks of system failure inside the home?
""The one thing that should be done is the pump tube should be replaced every six months, having one break and leak bleach everywhere could be a problem if replacement is not done regularly.""
Is this something we want everybody handling? Like there is no problem with spa treatment chemicals already?

What are the byproducts of chlorination? Why do we have to neutralize them when we use them in the final step of septic treatment? What happens to aquatic bacteria in our stream with the increase use of chlorine by unsophisticated people. Any chance that more elderly will die maintaining their systems then ever did from LD?

Chlorine is a very toxic substance in most of its forms. Just because a little might be good ---

Can you guarantee that there isn't or won't be chlorine resistant bugs? Will over use cause problems we have not even dreamt of yet?

•••We should just trust in large companies•••• Every time I see advocacy for more regulations, the first thing that comes to mind is "what big company is pushing this. How do they plan to capitalize on it?"

No, I like my drinking water fresh, so I would not use an open system to make it stale, but if you guys can't provide better evidence not to, I will defend OP's right to do it.

One last question. Does this thread reveal the split personalities of Borst?

After you’ve peeled yourself off the ceiling - spend some time reading The Canada Consumer Product Safety Act and understanding the fundamentals of the Precautionary Principle. Then since you’re from Alberta have a read of the Code of Ethics for members of ASET and APEGA and you may as well read the ASHRAE version as well.

Some days it would be nice to freely be supportive of issues without risking consequences but that’s not how it works in the professional world.

Here at Club Bean, we store city chlorinated water at 145F and mix down at fixtures.

As we said…some folks don’t want any regulations and will get openly hostile at the mere thought of such a thing and quickly demonize the person making such a suggestion…

As we indicated previously, there are health concerns with chlorination too. However, there are also good scientific data and methods to use chlorination with minimal health risks. If you don’t want to use the chlorination approach, there is always the socialistic European heat approach. Either way, it is still wrong to expose anyone to Legionella.

It has been awhile since my last visit here and I have enjoyed the reading. As a layperson (yes, a potentially dangerous position) I must admit, even after all the reading, to liking the simplicity of an open direct system. From the science I have read it appears that there is never Legionella found in fossil fuelled hot water heaters, nor in water heated to 140 degrees F. So, how about an open system using a NG condensing hot water tank (i.e.: Phoenix or Polaris), stainless pumps and all potable plumbing with water set to 140 F with a mixing valve for domestic water. We plan to be in the house for the next 20 years and I would absolutely separate the heating and domestic systems before selling simply by connecting a standard NG hot water tank. I get that there are other small design issues at play. The main concern seems to be health related and based on my understanding of the science using 140 F water in a NG appliance completely eliminates the health issue.

Correct me if I'm wrong guys, since it's been 5 years since I finished my house and haven't stayed on top of the code requirements since.

Isn't all this discussion about an open system somewhat moot? I ask that because, as I recall, the International Residential Code and International Plumbing Code expressly prohibit any cross connection allowing water in a heating system from entering a potable water system. Of course, if OP is not governed by either of these codes then he may be free to use an open system.

not correct that a 140 tanks solves all issues. the loop field is not maintained at that temp and provides a lot of potential biofilm, and 140 takes time to kill the germs, it's not a flash kill. Also, you just wasted a lot of money buying a condensing water heater and then setting it so hot it won't condense for 90% of your heat demands (10% being actual domestic draws).

also not correct that health is the only or even primary concern. System longevity is a much more common issue. Open systems have a LOT more avenues toward destruction. that is not a "small" design issue. if you want to avoid the potential for destruction without a heat exchanger, then you need to cripple the systems' flexibility, and overspend and over work yourself using fat pipes, and then get stuck using substandard or no balancing hardware. also not a "small" issue.

Long, short, middle: a one time insurance policy (heat exchange) protects everything from your family to your investment in the heating system and allows the system to be designed to perform properly without compromise. It's absolutely foolish to skip it. No amount of rationalization will make this otherwise.

You can choose not to wear seatbelts too. for most people it works out ok. but it's still a foolish thing to do. and if you're unlucky it'll cost you a lot more than the heat exchanger will.

not correct that a 140 tanks solves all issues. the loop field is not maintained at that temp and provides a lot of potential biofilm, and 140 takes time to kill the germs, it's not a flash kill. Also, you just wasted a lot of money buying a condensing water heater and then setting it so hot it won't condense for 90% of your heat demands (10% being actual domestic draws).

also not correct that health is the only or even primary concern. System longevity is a much more common issue. Open systems have a LOT more avenues toward destruction. that is not a "small" design issue. if you want to avoid the potential for destruction without a heat exchanger, then you need to cripple the systems' flexibility, and overspend and over work yourself using fat pipes, and then get stuck using substandard or no balancing hardware. also not a "small" issue.

Long, short, middle: a one time insurance policy (heat exchange) protects everything from your family to your investment in the heating system and allows the system to be designed to perform properly without compromise. It's absolutely foolish to skip it. No amount of rationalization will make this otherwise.

You can choose not to wear seatbelts too. for most people it works out ok. but it's still a foolish thing to do. and if you're unlucky it'll cost you a lot more than the heat exchanger will.

Precisely Rob, you need to treat (i.e., chlorinate, heat, or both) the ENTIRE system, for the REQUIRED TIME, at the REQUIRED FREQUENCY. Discussion of an open system should be moot.