Moisture in the insulation and walls (insulation)

[Christophe]

Topic divided: https://www.econologie.com/forums/conseils-p ... t9951.html

But at what% humidity is said that insulation does more useless?

Very good question ... in fact, I have no idea ... help

But knowing that the moisture range of use in materials is frankly weak:

Measuring range: 1 to 45% wood and other materials from 0.1 to 2.4%

Well, it does not have to be huge as a value ...

You should start by testing glass wool or new rock, I do not have on hand damage ... Well I'll take my moisture meter the next time I go in a brico!

Ah I wood wool panels installed 2010. Will test at different locations with this moisture: https://www.econologie.com/shop/humidime ... p-128.html

[dedeleco]

It's not complicated to an order of magnitude estimate, Water conducts heat in proportion to the amount impregnating the insulating !!
Taking the conductivity of still air in wool and that of water and which replaces that air proportion is calculated !!
water 0,6 0,0262 air W / m ° C
23 report so the isolation is divided by 2 for 1 / 23 = 4%

Pressing well to bottom, we see out 4% water !!
This is a very noticeable humidity

Check values ​​!! I could be wrong !!
http://en.wikipedia.org/wiki/Thermal_conductivity

Any conventional air condensation or addition with 50 60 to% humidity at 20 ° C, in this glass wool 10 ° C or less, give a much higher humidity, measured in these real conditions with cold. !!
While the insulation is completely destroyed !!
This is the reason a vapor barrier without any hole !!
Any roof leak more wet !!

[Christophe]

Mmm I take the method but I do not understand at all after ???

23 report therefore insulation is divided by 2 to 1 / 23 4% =

??

It is necessary to make a mass calculation of the water contained in the insulation according to the volume of the insulation to obtain an average "degraded" conductivity ... no?

Well I measured the moisture in wood wool we installed a few months ago: 0.63% with the meter: https://www.econologie.com/shop/humidime ... p-128.html

Measurements made in the room where there is the washing machine (but no clothes dryer).



A look at a cinderblock in the same room: 0.39%



I also measured in the same room, a block ytong / cellular concrete:



And plasterboard:



You want me to measure other materials and we make in a subject? Because the subject is important ...

[dedeleco]

I present some thoughts:
This device measures the moisture with which physical method ??
It feels that it is by conductivity ?? with two tips ??

There are direct special sensors of the humidity of the air in contact, for electrical capacity ,, other by absorption of microwave (more accurate, except metals), etc ..
Moisture is a complex topic!
http://fr.wikipedia.org/wiki/Humidit%C3%A9
http://www.omafra.gov.on.ca/french/crop ... rt08a2.htm
http://blog.trotec.com/fr-fr/instrument ... es-chapes/
see :
http://www.inforenovateur.com/document/ ... ygrometrie

I think we can make mistakes without realizing it.
The humidity of the ambient air is typically at 50 80% relative humidity in our region!
While this device does not measure the humidity, the less%. !!

My question physicist, it measures what, how !!

I feel that this is the volume fraction of liquid water in the material, not vapor in the air ??

Sure, https://www.econologie.com/shop/humidime ... p-128.html
it says that information for this device:

Measure electrical resistance

therefore measuring the electrical resistance of the material decreases with humidity.
I ask the question, is the relation resistance towards humidity is the same for different materials?

The water resistance is a function of its ion content i.e. of the amount of dissolved salts !!
Also, if the material contains salts, the measurement will be distorted, with lots of salt, the actual amount of water will be lower than that measured !!
For example, if the house is near the sea with sea spray that pass under the tiles (even 500m sea), glass wool handles salt and false measurement, and more become hygroscopic loads of moisture from the air and becomes naturally non-insulating (such as salt leaky) !!
Cements are not all the same, the wood can contain more or less of salt!
If the insulation has been contaminated by salt water, the device will give more water in reality !! A check with various salts.
If water is in packets or drops that will not affect the resistance will be higher than if they touch (percolation) and therefore can be wrong.
It takes place the device perpendicular to the wood fibers !!
https://www.econologie.com/shop/file/Notice_dvm125.pdf

It's very complex, such as physical measurement !!

I personally think that the measure strongly pressing a liter of insulating out all the water is also valid:
4% gives 40cm3 is much !!
Below is 10% 100cc / liter, it would be good to compare this direct method to that of Velleman, to appreciate Errors!
The method of heat to 80 or 100 ° C to extract all the liquid water and condensed by cooling is the best yet simple to calibrate and realize mistakes as possible!
Finally measure the thermal conductivity of a sample is as simple, not too much heat because the water evaporates quickly. !!
A heated probe a little into the insulation and measuring the cooling rate of change of the insulation is a simple way to measure and reliable, in my opinion. This type of device does not have the usual air except thermo-differential analysis for chemistry, so sophisticated. !!
Yet the very low current price of microprocessors makes this possible for not more than the thermal resistance.
It would be useful for monitoring insulation in situ, whatever their condition, dry, wet, damaged, etc ..

On the other hand, it would be good to test the quality of the vapor barrier in situ, in cold weather with the Velleman, because then the insulation going from 20 ° C to 0 ° C from one side to the other, must have much more moisture condensed on the portions at T <10 ° C as soon as the slightest draft of air coming from regions at 20 ° C !!
It would measure the importance of the vapor barrier seal !! Often forgotten in the homes of more e10 to 15 years with insulation placed anyhow !!

.

[chatelot16]

I have a much older this kind of humidimetre wood model

it does not just measure resistance, because it gives almost the same moisture as the tip is planted just a little, or bottom!

ca if measured resistance ca depandrait completely Contact!

but alas I have not understood the principle of exact measurement: ca me would seem more logical to measure a coefficient of capacitance loss ... but it can be measured as a ratio parameter PLUSIEUR

my apareil has a tuning knob to select the type of wood, it does not exactly give the same moisture if gasoline is changed: proof that the principle of measurement is not indepandant of materials, so can be completely wrong with of different materials too

[Christophe]

dedeleco is quick to criticize now I find ...

Well no this device does not measure the air, the measurement in the air (without contact of the tips) gives 0.0% so there is indeed a "correction" ...

By the way, do we speak in voluminal or mass%?

I presume mass but given the diversitée densities ...

[chatelot16]

I personally think that the measure strongly pressing a liter of insulating out all the water is also valid:
4% gives 40cm3 is much !!

no you just press hard he will not leave a drop

hysical the measurement reference is weighing a sample, the heat over 100 ° C to dry and weigh the dry weight: If ca 4% of lost weight is that there 4% water

there are special balance board with heating for drying and measuring the weight at the same time: we see that drying is finished when the weight no longer decreases

I did some testing and drying is slower than thought: with a large enough sample for a sufficient balance to the gram, drying in the oven at 150 ° C takes hours and hours

I made faster with a trebuchet which measures milligrams: ca lets take a smaller echantilon that dry faster


No he has no reason for a material in air has 50% moisture also take 50% humidity

1kg air has 50% moisture does not contain 0.5kg water! the definition of moisture in the air is completely different: the air 50% relative humidity contains 50% of the amount of water that contain pourait before being saturated: as the maximum amount water has saturation varies with the temperature the same air with the same amount of water see its relative humidity decrease if the temperature increases

the moisture content of a material does not change with temperature: it only drops if the water comes out!

[Christophe]

1kg air has 50% moisture does not contain 0.5kg water! the definition of moisture in the air is completely different: the air 50% relative humidity contains 50% of the amount of water that contain pourait before being saturated: as the maximum amount water has saturation varies with the temperature the same air with the same amount of water see its relative humidity decrease if the temperature increases

Quite and saturation is around the 30 m3 grams (tropical conditions), for details see mollier diagram: https://www.econologie.com/forums/humidite-c ... t5928.html

the moisture content of a material does not change with temperature: it only drops if the water comes out!

Well that of the air if: it decreases with the temperature ... by definition (which you have given) since the hot air can contain more water, therefore with a fixed amount of water, hot air is less humid than cold air that would contain the same amount of water. But the air tends to self-saturate with water all the time ... if a "source" is present.

So for a material as an insulator that contains a lot of air ... the question can be asked.

I think it's time to create a new specific topic.

[chatelot16]

It's not complicated to an order of magnitude estimate, Water conducts heat in proportion to the amount impregnating the insulating !!
Taking the conductivity of still air in wool and that of water and which replaces that air proportion is calculated !!
water 0,6 0,0262 air W / m ° C
23 report so the isolation is divided by 2 for 1 / 23 = 4%

it's much more complicated than that!

eg pure glass wool absolutely not absorb water: measuring the glass moisture is useless

but if there is condensation of water on the fiber this water will evaporate on the hot side by taking heat, condense on the cold part in aportant there heat, and return to the hot end by capillary action, the steam system is capable of carrying a grnde amount of heat! is the big loss due to humidity

this moisture can disappear or appear quickly, it is not the quality of the insulation that is in question

or the isollant is concerned, is when there is room: when it contains too many diverse dust can contain soluble matter in water and hygroscopic that hold moisture, which never dry up

the new glass wool will remain dry even with a bumper slightly porous steam, dining eve glass wool will always wet in the same condition that it will dry wrapped in plastic and ventilated by air dehydrated!

the same phenomenon is known for laundry: clean clothes dryer quickly, a clothes dryer full of sweat slowly, or even not dry at all, it attracts moisture from the air!

[chatelot16]

thank you to have carried all this in a special issue humidity!

I just said that the measure of moisture of the glass glass wool is useless

and measuring the moisture in the air that is in the glass wool or something else is useless either: this air asks only circulate

measuring the amount of water contained in 1kg wool already seems to me more interressante: mean that the measure of a humidimetre wood?

put about wool 1kg in a bag in canvas metalique, weigh, dry in the oven reweigh 150 °, and loss of weight will give the humidity

but this does not say why wool is wet: this is because the current condition is moistened and what was dry on its own, or is it because she is too dirty and never dry?

Btw ca makes me doubt on the calculation of breathable wall, or moisture has to go without condense: if the calculation is just when everything is new, is what remains of the dust with more?

he must invent a washing machine rock mineral wool or anything else, for reuse in bulk then?