I'm not makiing any claims here, TexasICF. I linked to Rastra's performance claims. If you think the manufacturer can't use DBMS because it is not a massive system, I encourage you to take it up with the Federal Trade Commission. https://www.ftccomplaintassistant.gov/ Ditto for AAC. There is an advantage to doing it the right way, you see.

Hotbox test by ORNL of the Rastra block showed it to have a RValue of R-8.

For example, the Washington State Energy Code (2011+ Building Code Edition) requires R-21 in the walls for Zone1&2, they state: "prescriptive path R-values do not take thermal mass into account. R-values used to demonstrate code compliance is the tested “steady state” R-value without any increases for the potential benefit from thermal mass." They then list the 8" Rastra block as R-8, the Rastra 12" gets R-15 and the Rastra 14" get R-18. None of the Rastra blocks meet the R-21 minimum code. Yet, Arxx, Quad Lock, Nudura and others pass the R-21 code (11" ICF). PolySteel gets destroyed due to the thermal bridging of the steel inserts and only gets a R-12.

Rastra might have been a decent block back in the 1980's but today ICF technology has surpassed Rastra blocks and today's ICF blocks are way ahead what Rastra had designed back 3-4 decades ago. Rastra is not a mass wall.

Honeycomb concrete? No thanks, I will pass. Good luck getting consolidation in a honeycomb design.

Rastra had its fair share of legal trouble and many people are still having issues with the moisture problems. Rastra is not waterproof, quite the opposite is true, it soaks in any and all moisture and many homeowners continue to have issues with the walls and moisture. A Rastra wall must be handled like a wood frame wall, any and all moisture and water must be kept off of it and the wall must be allowed to vent and dry out.

No attachment strips. Their solution? Glue the drywall onto the wall:

No! Yo momma! Rastra only exists in this thread to demonstrate the right way to make mass effect claims. Dunno about Washington state. I had no problem in Pa. To repeat. Got nothing against ICF. Sitting in a house built on it. But IMHO the ICF industry's sales tactics are despicable.

BTW, I parged plaster directly onto the blocks for about $1/foot. No drywall necessary except on interior walls. My plasterer did a Venetian finish on both block and drywall. It is fabulous. We just slapped paint on the block in the garage and areas that won't be seen because of paneling and such. It is perfectly acceptable. Averaged out, I paid less than the 80 cents/sf that drywallers ask in this part of the world and got twice the result.

Posted By toddm on 15 Sep 2012 08:02 PM
Lbear, kindly link the detailedl spec sheets that cite DBMS and mass enhanced equivalent r values for ICF.

Energy Efficiency Data & Performance:
* Thickness of the EPS.………………………………………………… 2.625" / wall panel (5.25" total EPS thickness)
* EPS Steady State R-Value (thermal resistance of the material)…. R - 23 (R - 4.55 / inch @ 40 degrees Fahrenheit)
* CTL Group Thermal Resistance R-Value Calculation Report……. R - 23+ calculated in accordance with ASHRAE 90.1
* EPS K-Factor (thermal conductivity of the material)………………. K - 0.22 / inch @ 40 degrees Fahrenheit
* Air Leakage (infiltration rate).….…….……………………………….. 0.05 to 0.10 ACH (average air changes / hour)
* ORNL Thermal Mass Calculator Dynamic R-Value Equivalent…... Greater than R - 32

TECH DATA

Posted By toddm on 16 Sep 2012 07:32 AM
But IMHO the ICF industry's sales tactics are despicable.

No! Yo momma!

You should direct your disdain towards the wood frame insulation industry's sales tactics because they have so many false claims about their products and R-Value's that the FTC can't keep up with the complaints.

FTC VIOLATIONS

GBA R-Value Crooks


Despicable?  In regards to your personal attacks & name-calling, yes.

Gotta say that is one detailed spec sheet, Lbear. Either Fox did not do what Rastra did to develop DBMS numbers or it didn't like the result.

Speaking of despicable, I just read through the Washington state building code currently in effect (based on iecc 2009). First it specifically exempts log or solid wood houses thicker than 3.5 inches (!!!) Then it refers builders of nontraditional houses to an alternative compliance procedure using modeling software such as ..... DOE2. So, yes, PRESCRIPTIVE PATH r values can't use thermal mass (i.e. 2x6 framing and R21 fiberglass batts = good to go.) ALTERNATIVE PATH compliance can be whatever you want so long as DOE2 says it is equivalent. And, yes, serving up misinformation in order to sell ICF is despicable.

Posted By TexasICF on 15 Sep 2012 06:19 PM
Interesting jonr - any convection at all and r-value approaches zero. Which is part of its limitation. The other limitation is radiation.

Just curious, but what do you MEAN by that?

I was referring to the hot box test which does not allow convection. I believe the test as its defined is not a real world as it might be. I'm sure you've read David South's R-value Myth. If not and you are interested I'm sure I can track it down. The test is biased toward materials (eg fiberglass that perform better in the lab in absence of convection than in the real world. Regards.

Posted By TexasICF on 17 Sep 2012 01:29 PM
I was referring to the hot box test which does not allow convection. I believe the test as its defined is not a real world as it might be. I'm sure you've read David South's R-value Myth. If not and you are interested I'm sure I can track it down. The test is biased toward materials (eg fiberglass that perform better in the lab in absence of convection than in the real world. Regards.

There a much bigger difference between " almost zero" & real world performance than there is between an ASTM tested R & real world performance, even for the lowest density fiberglass (even if the test configuration overstates the latter.)  The denser & more air-retardent the fiber, the less of a difference it makes.

If jonr was talking about the convection effects on the oft-exaggerated R-value claims for interior & exterior air films we would probably all agree.

I've never been very impressed with David South's analysis or his presentation, especially since he completely ignores  the changes in R-value of polyurethane over temperature & humidity, and uses ridiculous straw-man parameters such as:

 "Consider the R-value of an insulation after it has been submersed in water or as a 20 mile-per-hour wind blows through it."  

If your attic or walls are submerged in water you've got bigger problems than R-value no matter what you use for insulation, and the pressures required to blow 20mph through a wall cavity or attic would rip most houses apart.

South's analysis of what happens to R-value with loose-fill in attic applications turns out to be simply DEAD WRONG if the loose fill fiber is cellulose rather than low-density fiberglass, and in fact even at open-blow ~1.2-1.5lbs density cellulose has a stabler R value than open cell or (his preferred) closed cell polyurethane foam, and RISES slightly at colder temps in a cold-side up configuration, where convection forces would predict a falling in-situ R-value (which IS the case if the loose fill insulation is fiberglass.) 

In any configuration or density the R value of cellulose doesn't rise as quickly with falling temp as EPS does, but neither does it lose it as quickly with falling temperatures.  (Cellulose doesn't lose anything LIKE 20% of it's R value when it rises from 40F to 75F average temp, but EPS does, yet the 40F number is oft quoted without comment or question.)

Anybody can kick around the deficiencies of low density fiberglass (and I can kick it with the best of 'em), but with David South it's all bald assertion & no data. Even if some of his generalizations approximate the facts in the lowest-density fiber products out there, his generalizations are way too broad and at odds with verifiable fact, particularly with higher-density fiber goods (be they rock wool, fiberglass, or cellulose.)  He seems to have made a career out of kicking the deadest-possible dead horse: Loose fill low density fiberglass.

The real data are available, and "...almost zero..." is as big a fairy tale as the myth South stridently attempts to dispel. (Even David stops the exaggeration at "...50 percent or more.")

[edited to add links]

Thanks for the temp R charts. Very interesting. I suppose the point I was making is that convection is not part of the R-value test. Jon is right convection plays havoc on real world R-value -- but not in the lab. If you drill a small hole through the test material (let's call it foam) and hot box it I don't think the lab R-value would change much.

On the other hand if put that same piece in your wall of your home what is the R-value in the area near the hole?

Convection within the fiber layer is fully accounted for in an ASTM C 518 test, but only at roughly 30F delta-Ts. In low-density fiber the internal convection rates increase with increasing delta-Ts, and even the average seasonal delta-Ts in colder US climate zones are greater than the ASTM tests.

A hole in the air barrier on the exterior side of a fiberglass insulated wall is not a convection issue, it's an infiltration issue. Convection forces may drive part of that infiltration, but that's not even the half of it- wind and air-handler driven pressure differences drive a lot more air through a wall cavity with leaky air barriers than convective forces. A hole on the interior side of a wall assembly won't affect the localized R value much if the exterior is tight, but can affect moisture transfer rates even at very low convection rates within the fiber.

The fact that low-density fiberglass installed in attics without a top-side air barrier (how big a hole is THAT?) while pretending for purposes of code compliance that it actually meets ASTM performance when installed that way is a loophole in the code big enough to drive a truck through. Yet cellulose installed with or without a top-side air barrier in an attic will still performs at it's ASTM tested values, winter or summer.

High density "cathedral ceiling" fiberglass or rock wool batts will come pretty close to hitting their ASTM performance too when installed perfectly, even in attic apps. It's really only the low-density straw man that is truly easy to kick the stuffing out of with arguments like that. Above some minimum density even fiberglass becomes sufficiently air retardent that the rated-R actually means something. Those goods are readily available but are not the standard low-cost most commonly used goods in barely-legal code-min tract housing.

But barely-legal code-min construction isn't really in the same market as ICF either. Performance builders & designers know (or should know) the performance difference between low-density and higher density fiber goods, and the importance of air-tightness to thermal performance, a factor sometime presumed in absence of measurable reality by SIP & ICF builders. (Just because it's easy to air-seal a SIP or ICF doesn't mean that it will automatically hit IRC 2012 levels of air tightness without attention to details.)

ASTM c518 is a steady state conduction test. Since it's used to measure conduction of many different material types - how do you account for either convection or radiation in the test?

Your perception of "conducted only" is at odds with what the test really does. ASTM C 518 is NOT a conduction test, it is a heat flux test between two plates at fixed delta-Ts, and is agnostic of the heat transfer method.

It will accurately measure the combined heat transfer via conduction, radiation, and convection within air-permeable insulations, and will accurately measure the combined heat flux at different air-gaps for radiant barriers, with results consistent with other methods of measuring the same.

ASTM C 518 does not and can not test the effects of infiltration in a building assembly.

BASF has come out with a new EPS design in that they inject integrated graphite into the EPS:

BASF neopor

The story goes that graphite reflects radiant heat which I'm sure it does. So does a thin layer of metal foil - remember the crazy claims of foil-faced insulation? 20% improvement on lower density EPS would be great if it actually works. I suspect this is gimmicky but could be wrong. Why not put graphite in drywall then?

If the EPS is covered with drywall I suspect that the drywall already reflected and\or absorbed most of the radiant heat already. Also the heat source itself is important. Forced-air systems for example do not have much radiant heat. Radiant ceiling or baseboard heat will have more.

I'd like to see real-world tests or at least an explaination of how much heat is actually radiated through typical wall covering such as 1/2" drywall, and what the heat source was. I suspect they did the measurements or calculations with raw EPS facing a highly radiant heat source. Guilty until proven innocent I guess.

FWIW Fox blocks has their energy stick which also has graphite...

The emissivity of graphite is 0.98, which is about the LEAST reflective sort of material that there is.   The emissivity of any bright aluminum is under 0.05- VERY high reflectance.

Graphite improve the performance of EPS, but the method by which it does that isn't related to it's effectiveness as a radiant-barrier- it's a radiant ABSORBER. The way this improves EPS performance is by blocking  & absorbing the portion of radiated heat that would otherwise pass unimpeded through the EPS (which is translucent in parts of the infra-red spectrum), and re-radiates it back from whence it came. This is very different from the way aluminum works (which truly reflect the IR photons rather than via absorption & re-emission.)  The market fluff is laughable, trying to have it both ways on the physics fundamentals:

"The graphite reflects and absorbs radiant heat and significantly improves insulation capacity." 

All materials both reflect and absorb radiant heat:

Graphite absorbs about 98%, reflects 2%.
Aluminum absorbs 2% reflects 98%, so they're just about the same, right?

But IF it works still counts more than HOW it works, eh?

In solid materials as dense as drywall essentially 0% of the heat transfer through the material is radiated, and over 99% of is conducted. Coating the surfaces of such materials with low-E materials such as aluminum has a thermal effect, but only if there its a very low density material (such as air, or vacuum) between it and the surface or object at a different temperature.  In low-density fiber insulation there is a radiated component, to the heat transfer between say, wallboard & sheathing, but it's pretty small compared to the conducted and convected fraction of the heat transfer.   In high-density fiber the radiated fraction truly miniscule- even smaller than the convected fraction which is also quite small.

Dana, good description. If they said "absorbs and radiates back" that would make more sense but only if you didn't have drywall ;)

You said 99% of heat is conducted in drywall so are you agreeing with me that the radiant aspects are nonsensical (or at least fishy) especially considering that drywall is in direct contact (conductive) with the EPS?

Sure an object can absorb heat in any way and then radiate that heat outwards, but I can't really see the graphite helping to do that to any noticeable effect.

Now for windows, not walls, where light (and other radiation) can escape to the outside that is a different story. Thus low-e glass etc.

So DOES this stuff actually help in the real world irrespective to HOW?

Radiant barrier foils in direct contact with dense materials on both sides have zero thermal benefit.

Graphite throughout the EPS foam may impede the heat tranfer between interstitial gaps or even from one side to the other of the closed-cell structures at the microscopic level. I haven't delved deeper into any theoretical basis for how it works, but I'll accept the ICC-ES testing data on it's performance. It's not being marketed as a radiant-barrier type material and it's performance is measured via standards consistent with ASTM C 518 that does not include or rely on beneficial air-gaps for performance. The labeled performance is a 10 year averaged value rather than an initial value (which may be higher.)

So, yes whatever they're doing with it makes a measurable difference. How it achieves that effect is opaque to this observer, and their marketing descriptions obscure rather than illuminate. It may be that graphite is reflective in a critical range of infrared where polystyrene is transparent or something or that there is a thin-film optical effect when applied at some average thickness to a polystyrene cell, or it could be something completely different. Whatever- they've been making it for 17 years now- if it wasn't performing as-labeled it's likely their competitors would be all over it by now. (And if it's soon to go off-patent you can bet their competitors will be getting into the game.)

Posted By TexasICF on 17 Sep 2012 04:59 PM
Thanks for the temp R charts. Very interesting. I suppose the point I was making is that convection is not part of the R-value test. Jon is right convection plays havoc on real world R-value -- but not in the lab. If you drill a small hole through the test material (let's call it foam) and hot box it I don't think the lab R-value would change much.

On the other hand if put that same piece in your wall of your home what is the R-value in the area near the hole?

There's been at least some systematic attempt to measure that effect, and the upshot is that with low-density fiberglass it becomes a somewhat lossy heat exchanger when the leakage as a random distribution of smaller holes. That's not as horrible as one might fear even at 10 pascals air pressure difference, (but obviously less than ideal.)