wet mineral wool insulation 2

[pmover]

short of contacting mineral wool insulation mfg's...

in the event of mineral wool insulation becoming wet, does the insulation retain insulation properties once the insulation is dried?

frankly, how is insulation dried with 0.032" lagging applied? i suppose completely removing the lagging & insulation from equipment and then reapply the insulation & lagging. it seems to me that handling wet insulation is fruitless as the weight of water in the insulation will damaged the insulation. also, seems cheaper and more effective in replacing wet insulation that trying to dry it. actually, cheaper to provide a barrier to prevent moisture from contacting the insulation.

thanks!
-pmover

 

[quark]

I faced this problems many times. I never checked the insulation properties but I did check the skin temperature of lagging before soaking and after drying conditions. There was no substantial change.

My problems was with steam lines and what I used to do was to remove the lagging and let the moisture evaporate. My energy losses might have equalled the reinsulation cost but time was the factor for me(and I had enough boiler capacity)

I too feel reinsulation would be a better solution.

Regards,

 

[EdStainless]

If there is no visible mechanical damage to the insulation (crushed or torn) then it is probably very similar to new. Often when insulation gets wet it compacts and that does reduce its properties.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[25362]

Considering the case when mineral wool is used to insulate hot (piping) surfaces, upon becoming wet, after the rain, or otherwise wetting factor, ceased, the heat from the hot surfaces would evaporate the water, and the redried insulation would recover its insulating properties. This is claimed by mineral wool suppliers. Nevertheless, my views concur with Quark's experience and advice.

 

[pmover]

fyi, the insulation surfaces are large & flat, not piping insulation and operating temps are < 400 degF. wetting is due to rainfall and dew - new equipment not being protected. i know, covering insulation is dirt cheap and a preventitive act, but contractor seems to believe that wetted insulation is not a signficant issue as wetted insulation can be dried and original properties retained. common sense construction practices (i.e. protecting new equipment) appear not to be in contractor's mind.
oh, insulation mfg claims insulation is water repellant. however, i believe that is the case for an uncut insulation board. once cut, that cut portion of insulation no long has water repellant capabilities.
otherwise, thanks for the responses.

-pmover

 

[rmw]

If the wetted insulation compacts due to its wet weight then the R value is reduced. Edstainless so noted.

It is not the mineral wool per se that does the insulating, although mineral wool does have insulating qualities, it is the air trapped by the loosely "woven" mineral wool or similar material (fiberglass, etc.,) that gives you the insulation value.

Therefore if it compacts, you have less air trapped, and less effective insulation.

You just reminded me, I have mineral wool in the attic. It is time to go up with a yard rake, and fluff that stuff up.

rmw

 

[MikeHalloran]

The fibers used in high temperature insulation batting and cloth do not naturally stick to each other. They are coated with organic 'binders' to provide coherence for handling in manufacturing and installation. Acrylonitrile is one common binder.

When the insulation is first seriously heated, the binders burn off, and the fibers are thereafter just sort of sitting there, in the installed position. Attempts to remove and reinstall used insulation are generaly futile, because the fibers are no longer bonded.

Given the relatively low operating temperature stated, even a factory 'burn in' might not remove the binders, unless they did an elevated temperature test. If the binders have been removed or weakened, then rain could easily dislodge the insulation fibers, and drying won't restore the fibers to their original positions and the insulation won't be properly effective ever again.

If the insulation had never been heated after installation, then the rain should not permanently affect its insulating properties, unless the particular binders used are water- soluble.

I'd be inclined to ask the insulation mfgr for some assurance in writing, and to soak a small sample in a pan of water and see what happens.

I'd also be inclined to find out if the contractor was _contractually_ obligated to protect the new equipment. Okay, that would be just morbid curiosity on my part; if lawyers get involved, they will read his contract very carefully.




Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA