Refer Insulation

[SV THIRD DAY]

Originally Posted by s/v Jedi

This makes it only 10% better than the blue boards.

This happens all the time on chat forums...the answer is so simple that it gets missed in the huff, puff and bluster. Is 10% better or not why use something 10% worse than PolyIso?

Next up for scientific consideration...
Just how much of that first inch of PolyIso is REALLY seeing that lower temp and thus lowering it's R-value...ah...bingo and there is your science answer my friends. It also goes to show the danger is taking some web data and running with it without some real life test data to tell you if you are on track.

I'm not trying to be a smart ass (ok..maybe a little) but you know I could give all the raw testing data I have and it would still not be believed...so why bother. I've given a good summary of it and folks can take it or leave it. Again...why would I lie about something like this...sheesh...maybe I'm a Member of Big PolyIso?

[s/v Jedi]

Originally Posted by SV THIRD DAY

This happens all the time on chat forums...the answer is so simple that it gets missed in the huff, puff and bluster. Is 10% better or not why use something 10% worse than PolyIso?

Next up for scientific consideration...
Just how much of that first inch of PolyIso is REALLY seeing that lower temp and thus lowering it's R-value...ah...bingo and there is your science answer my friends. It also goes to show the danger is taking some web data and running with it without some real life test data to tell you if you are on track.

I'm not trying to be a smart ass (ok..maybe a little) but you know I could give all the raw testing data I have and it would still not be believed...so why bother. I've given a good summary of it and folks can take it or leave it. Again...why would I lie about something like this...sheesh...maybe I'm a Member of Big PolyIso?

First, it doesn't matter who you are or how many people believe you: when you make a scientific statement then you have to add the citation. I know everything there is to know about some geek networking tech but when I come without citations they kill me off as well. There is no logic in becoming excited or upset when asked for citations; it is the right thing to do with the scientific method. Your reaction to this is actually making people more suspicious; remember, like all of us and that building-science club, you are just a guy on the Internet as well

So yes, 10% better R-value is a better value. And yes, it may only be the first 1/8" or 1/4" of foam performing less for cold environments.... but that doesn't make the statement that polyiso performs less in cold environment bogus. It seems you now agree with me that yes it isn't a myth and does underperform, but only for the little thickness where the temperature is that low. This is what I posted earlier so we actually agree

The other poster (sorry, forgot who you were ) who posted to first use a different foam, then the polyiso seems to understand that as well and tries to improve by laminating different types of foam. I believe he wrote to use 1" while maybe 1/8" or 1/4" would suffice but he may be able to improve upon using only polyiso. If it is worth the effort is another thing but let's be clear about this: we're all half mad to even discuss this instead of sailing or snorkeling instead!

[SV THIRD DAY]

Originally Posted by s/v Jedi

but that doesn't make the statement that polyiso performs less in cold environment bogus.

YES...I stand by the use of the Term Bogus...why?
The question was, will using a layer of Blue Board and then PolyIso give you a better R-value result. The answer is NO...so the question/idea is indeed Bogus!

But you also have to understand how chat room rumors/myths go...I know because I take client calls about them all the time and spend quite a bit of time busting them. So when I see a Bogus idea...I have to call it out. Not dance around the head of a pin debating semantics. Semantics doesn't keep the beer cold or ice cream hard. People will take half the "truth" and run hog wild with it, I see it all the time.

See how it goes.

Originally Posted by s/v Jedi

The other poster (sorry, forgot who you were ) who posted to first use a different foam, then the polyiso seems to understand that as well and tries to improve by laminating different types of foam.

This again is totally Bogus.
But in the chat room world, this is exactly how myths get started and why I so strongly call them out as Bogus! You yourself admit that PolyIso would be about 10% better than blue board...but now you imply otherwise...see how the game goes and how the myths get going?

I see it all the time...like on the Defrost thread.
A poster falsely claims that frost is actually a GOOD Thing for your box and says it in a way that comes off as if he knows that he is talking about. I HAVE to call ******** on that (and I did it politely as I could) but myths like that actually get out there, add confusion to an easy issue, and lead folks astray when their dock expert quotes the internet expert.

Again...
What gain do I have in sticking with this and not just saying...yep...put 1/4" of blue board over your PolyIso and you will be better? That would be the path of least resistance, but it would also be WRONG. I gave a summary of the data, people can call me a liar or believe me...heck it won't change my life one bit.

When people call me up for water maker or refrigeration advice, they are talking to an expert on the subject mater and can then take it or leave it. But if they tell me I'm wrong in what I do for a living since I won't give them my back up engineering data...well...Amigo...I don't have the time nor energy to play the chat room games. Honestly, I've been around this chat room world enough to know just how the game goes of dancing on the head of the pin.

The bottom line, which is what matters:
You will not increase your R-Value by putting ANY thickness of Blue Board over your internal box layer of PolyIso.
To imply otherwise is simply BOGUS.

[Dsanduril]

So here's another study that says pretty much the same thing, but also backs up Rich's assertions.

http://www.pacificalliedproducts.com...oofing3016.pdf



This puts the crossover pretty close to freezing, which means that a hybrid refrigerator wouldn't likely perform any better than a pure polyiso. And Rich describes test conditions as 2/3 refrigerator, which says that a fair amount of the temperature exposure of the insulation would be expected to be at par values between the two types.

So, the question to me (because I don't have a combined fridge-freezer) is what happens in a pure freezer box where the entire interior surface temperature is kept down at 0F (-18C)? Sounds like the science posted would say a hybrid box would work better. Rich, have you tested as you posted with a pure freezer box? Maybe you don't consider that a typical use case so why spend the $, but some do have separate boxes, and I'd love to know the results.

[s/v Jedi]

Originally Posted by Dsanduril

So here's another study that says pretty much the same thing, but also backs up Rich's assertions.

http://www.pacificalliedproducts.com...oofing3016.pdf

Attachment 123639

This puts the crossover pretty close to freezing, which means that a hybrid refrigerator wouldn't likely perform any better than a pure polyiso. And Rich describes test conditions as 2/3 refrigerator, which says that a fair amount of the temperature exposure of the insulation would be expected to be at par values between the two types.

So, the question to me (because I don't have a combined fridge-freezer) is what happens in a pure freezer box where the entire interior surface temperature is kept down at 0F (-18C)? Sounds like the science posted would say a hybrid box would work better. Rich, have you tested as you posted with a pure freezer box? Maybe you don't consider that a typical use case so why spend the $, but some do have separate boxes, and I'd love to know the results.

I agree with your findings. The question is how much thickness of foam is required to get above the turn-around temperature? If that is very little, then there is little to win.

I now see how Rich is calling the lamination winning from straight polyiso "bogus" while I, and apparently others as well, thought he was calling that research bogus, which, as it turns out, is genuine. But now he is calling "bogus" again on something else with a heap of ranting about the Internet and "chat rooms" whatever that has to do with it; looks out of control to me

[a64pilot]

I can't find out much about Polyisocyanate board and moisture.
I can find it is about 5% moisture at time of manufacture but moisture content will vary upon environment, that even if its a clear sky night, you need to keep it under plastic if building a building.
Then seemingly a completely different comment about it being good as a moisture barrier.

I know any insulation is degraded if wet or has moisture, so is Polyiso hydroscopic, or hydrophobic?

[Dsanduril]

My understanding, and I'm not posting citations on this one, polyiso is a terrible moisture barrier, absorbs water, and otherwise behaves much like an open-cell foam. However, almost all polyiso is delivered foil-faced, and the foil face is an excellent moisture barrier. So, as delivered, if the edges are sealed (as Rich recommends - agree with him there) you can get a moisture resistant installation. But, if you leave the polyiso itself exposed, then you are asking for moisture trouble.

[SV THIRD DAY]

PolyIso has a rate of water ingress when placed in water of 1mm per year.
Unlike the Blue Board (which is hydrophobic) polyiso is not. So when using polyIso, you want to be sure to follow good practices of keeping a good vapor barrier in place. Putting foil tape on any cut edges of nicks in the foil barrier that comes standard with the PolyIso is required, at least in my book.

Air movement around and through the insulation is your worst enemy, since it will bring with it moisture. So attention should be paid to not just the inside liner material of your box, but also what's going on behind the insulation. That air needs to be sealed off as well.

[SV THIRD DAY]

We did do a series of test trials on a 5CF Freezer box, which would be HUGE on a cruising boat. I haven't looked at that data in a while, so I will have to go dig it up and see what we found....but my memory is that the PolyIso still "won". By winning I'm looking at total daily amp hours needed to keep the box at a stable operating temp.

Now with all of this dancing on the head of a pin, I must say this data really was for a world where a 125W solar panel was $1000 to $750. Now that solar has come down so much in price...does 10%...20%...or even 30% difference in power usage matter as much? We all know that your refrigerator/Fridge is the biggest power draw a cruiser has at anchor....but...is that becoming less and less important as solar arrays get bigger and bigger? To me with 1300W of solar and a 400AH LiFePO4 battery bank...I'm not as panicked with power usage as I was with a 250W solar array and 425AH of Lead Acid batteries.

My combined freezer and refrigerator now use a total of about 75AH per day. Would I freak out if that number when up to 100AH because I wanted to use Blue Board for it's properties rather than PolyIso? No...no not really. Now take it to 150AH and you get my attention!

I don't have any problem with using a single layer (say an inch) of blue board on the inside walls of your box and then following that up with as many inches of PolyIso as you can make fit. 4" would be minimal for a refrigerator and 5" for a freezer but this is also where reality comes in. We forget this because all (ok most) of us here are data and techy nerds. But the average cruiser isn't going to remake his box...it's too costly to hire someone to do it and most people don't want to tackle a job like this on their own. They are just going to live with whatever Amp draw their insulation gives them...heck I did when we went cruising on the first boat. There was no way I was going to rip up the galley.

On this boat now, I am about to start a rip up and total rebuild of the freezer. My plan is to use 6" of foil lined PolyIso, covered by the FRP wall panels sold at Home Depot...easy pleasy. I'm going after the most power efficient box I can, and I'm also a cheap liveaboard cruiser myself and I'm not going for spendy Vacuum panels etc. Easy is easy and I leave the science projects for the Lab, not my boat.

[a64pilot]

See Rich, what I'm contemplating is blue board on the bottom where I can put say three layers of it to raise the bottom as the wife has to use a stool to reach, and it's all I can do to reach the back corner, and use polyiso for the walls and ceiling, where I don't want to lose the space and less likely to have standing water.
Remember I have the 7 cu ft fridge and 7 cu ft freezer, that holds at 5 F freezer and 40 F fridge.
But the floor will have water on it, every time I defrost, and standing water will I believe eventually find its way in, so I think it prudent to use something waterproof.

On edit, this is inside of the existing factory box, I'm not going to rip out the box, I have way too many more pressing projects to tackle that.

[SV THIRD DAY]

Originally Posted by a64pilot

See Rich, what I'm contemplating is blue board on the bottom where I can put say three layers of it to raise the bottom as the wife has to use a stool to reach, and it's all I can do to reach the back corner, and use polyiso for the walls and ceiling, where I don't want to lose the space and less likely to have standing water.
Remember I have the 7 cu ft fridge and 7 cu ft freezer, that holds at 5 F freezer and 40 F fridge.
But the floor will have water on it, every time I defrost, and standing water will I believe eventually find its way in, so I think it prudent to use something waterproof.

I'm with you and would take the same approach given your situation.
I'm not Anti-Blue Board...it has it's handy good uses...I just didn't want people to get the impression that it can have a better R-Value. But for it's water repelling properties...it is a GOOD product to use.

[s/v Jedi]

Originally Posted by a64pilot

On edit, this is inside of the existing factory box, I'm not going to rip out the box, I have way too many more pressing projects to tackle that.

A64, here's a couple of pics from my project I did 12 years ago:

the plywood panels have fiberglass and epoxy; are glued to the foam and then fixed with epoxy fillets to each other and the side walls. It was then primed 3 times with 545 followed by two topcoats. no water can pass through. The bottom now has 13" blue board and the back wall 7" with the fridge on the other side.