Re: GBlist: Ventilation per John Bower

Hal Levin (hlevin@cruzio.com)
Tue, 18 Mar 1997 17:20:27 -0800

At 04:53 PM 3/18/97 -0800, John Salmen wrote:

>Pat Ballentine wrote:
>> I'm agreeing with John and adding my thoughts along those lines about
>> "breathing Walls" Have I missed something here? I am refering to the
>> rammed straw/clay walls (Robert Laporte) If air flows through the
>> walls, doesn't that amount to a filter you could never clean? Isn't the
>> straw a food source for microrganisms?

John wrote:
>There are a lot of assumptions being made about the nature of materials
>that are standing in the way of informed practice. We basically do not
>know enough about materials to dismiss the potential of any mediums
>ability to 'respirate' effectively. As I see it some of the potential
>(if any) of breathable wall research is going to be largely based on a
>materials innate or enhanced ability to mitigate toxins. One example
>that comes to mind is the salmonella studies where the bacteria was
>introduced to a plastic and a wood cutting board surface - after 30min.
>the bact. was absent from the wooden cutting board and was still going
>strong 24hrs later on the plastic.
>
What is the conclusion or implication you draw from the experiment?
Do you use wood or plastic? Where did the salmonella go to if they were no
longer present on the wooden cutting board? The air? Other food being
prepared on the board?

BTW - I avoid meat, including poultry, thereby reducing my potential
exposure considerably, regardless of the material from which my cutting
boards are made. I also do a lot for the environment, perhaps more than I
can do by consulting on environmentally responsible building practices,
since the production of meat is so land and water and nutrition intensive
relative to what it yields and compared with other nutritional sources. I am
always amazed to be at meetings of "green" architects and see them order and
consume huge hunks of dead animals. Did I fail to offend anyone yet? Let me
know and I am sure I can think of something.

[snip]
>
John wrote:
>Metal ducts and filtration membranes are not innately 'clean' surfaces,
>however bright and shiny they might be but their manufactured surfaces
>are quite conducive to pathogenic activity (I read recently that some
>surgical scalpels are being made from flint knappings and a microscopic
>enlargement of the steel versus sheared stone surface was a good
>illustration of why)
>
Metal products (including some ductwork, I suspect) are often coated
albeit thinly with oil. This can result in more rapid accumulation of
particles which in turn can act hygroscopically and serve as nutrients for
microbial contaminants. When you buy aluminum foil, one side is shiny and
one is dull. I believe the shiny side is coated with oil.

Hal Levin <hlevin@cruzio.com>

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