On Sep 12, 12:41 pm, "Pete C." wrote:
Brent wrote:

On Sep 11, 11:30 pm, "Pete C." wrote:
Nick Mueller wrote:

Pete C. wrote:

An insulated container that is kept at a controlled interior temperature
will not experience this issue any more than a house maintained at a
controlled interior temperature will.

Sorry, wrong.
You do have a temperature gradient looking at a section through the wall. At
the place where the temperature drops below the dew-point, you'll get
condensation. Preferably, that happens within the insulation-material,
supposing it can retain and transport humidity. If that is not the case you
get condensation. And this will be exactly at the inside of the metal
container. Styrofoam and that stuff glued to the inside of a wall is *the*
*worst* you can do. Except you are out for mushrooms.

Moisture doesn't magically appear to condense, it has to come from
somewhere. Neither the steel container, not extruded polystyrene
insulation are permeable so nothing of significance is going to happen
in the space between them. The interior surface is very unlikely to be
at dew point in a conditioned space so nothing is likely to happen there
either.

The difference to a house is, that the dew-point is *in* the brick-wall (oh,
you know what this is? G) and the brick can transport humidity to the
outside, especially if there is a humidity-stopping layer (or not as good
transporting, or much longer distance) on the inside of the wall. You get a
much better climate and much less humidity this way. No dehumidifier
needed.

Again with the steel container, EPS insulation and FRP paneling you have
a triple layer vapor barrier. Moisture outside stays outside, moisture
inside stays inside (normal vents remove it).

The only
source of moisture in the container will be one human intermittently
working in it, something normal ventilation will readily handle.

Sorry, wrong again. Relative humidity is the point. Warm outside, cool
inside and you ventilate - moisture inside. Just have a look at the water
running out of A/Cs.

Look at moisture running out of an A/C after it has been running in an
enclosed space for a while, and dehumidifying the space. Unless you're
doing something really stupid to allow a lot of moisture into the space,
it will remain dry and the A/C will operate more efficiently since it
won't have the added load of condensing moisture out of the air as well
as cooling the air.

OK so in my situation i could use a little feedback here

there are 4 passive vents in the corners of my container

Same on my non insulated 40' container. It sits through new england
seasons and has yet to have a moisture problem inside.



i know i'l likely need to leave these vents through but they will
allow humidity to enter too

Loose those vents, they won't be adequate for your intended use. Install
"real" venting in the form of RV vents, regular roof vents, or similar.



Because of my Climate i know i will need both Heating and Air
conditioning

Nick's statements about the dewpoint are valid the Container cools
faster than the ambient air once the sun is down so it will draw dew
if it cools past the dewpoint i will need to seal the inside walls
with a vapor barrier that is a given and i will need ot take steps to
de-humidify the shop.

You *do not* need a vapor barrier, it will accomplish absolutely
nothing. A vapor barrier is used in residential frame construction
because the wall materials are all permeable, steel is *not* permeable,
nor is extruded polystyrene insulation, nor FRP paneling.

the AC itself I primarily use to drop the
humidity to make work bearable rather than needing the temperature
itself to dropit seems that using Styrofoam the possibly after the
electric is run to call in a sprayfoam guy to seal behind it.

Run electrical in surface mounted EMT conduit. See the great power
upgrade 2006 on my site:http://wpnet.usfor an example.

There is no reason to seal behind the polystyrene insulation that you
glue in place, other than for additional insulation and even that is
marginal. The cavities formed behind the insulation are sealed chambers
assuming you make proper use of the adhesive. None of the materials
involved are moisture permeable and the humidity in that chamber will
always be the same as the day it was sealed.



Should i fork over a little more for an AC to let it automatically run
to prevent condensation?

A separate dehumidifier if you find a need for it after you've completed
the rest and monitored it for a while. The separate dehumidifier will
function when heated in the winter to remove moisture tracked in from
snow on your boots.



Even if i'm not there if it senses that the dewpoint could be exceeded
it will trigger and dehumidify the shop?

Yes, separate dehumidifier. Before spending money on it however, spend
the $30 for a temp / humidity gauge with min/max and see what the spans
really are.



I'm investigating elsewhere too but there are no container conversion
experts local to me.

If i have to do something fancy to prevent condensation so be it, my
tools are worth an ounce of prevention and a few dollars of
dehumidifier runtime

Again, review what I've posted and just monitor to see if you have an
actual issue. Residential wood frames, plywood or OSB sheathing,
fiberglass insulation and drywall are all moisture permeable, steel, EPS
insulation and FRP panels are not.- Hide quoted text -

- Show quoted text -

Try to hang heating, A/C, dehumifier, dust control from the
ceiling....floor space is reserved for the heavy stuff.

TMT