ILD vs Thickness - confused ?
- Thread starter zzzombie
- Start date
For all intensive purposes:
Resiliency = Elasticity
Regular PU foam itself actually has poor elasticity compared to natural rubber foam. Memory foam (even though ironically called visco-elastic) is virtually no elasticity.
This information from the PFA is really only explaing how ILD or IFD by itself means almost nothing.
The foam itself is not becoming any softer or firmer after being cut or being made in any different thickness. What they are testing is how much resilience there is in the foam at a certain % of height compression. So they are using the same exact recipe of foam for these IFD values and using different thicknesses of foam but yet they are compressing the foam to completely different amounts since they are compressing the foam a certain amount of height based on %.
So they are compressing a 4" thick sample only 1", they then measure the force required to do so. When they are compressing the 8" thick sample they are compressing 2" of the height and then measuring the force required. I would be willing to bet a large amount that the difference in ILD or IFD between both samples if the 4" thick sample was also compressed 2" would be very similar, probably with 5% of error.
It is for this very reason that ILD's and IFD's alone are really not the best means of comparing one foam to another, especially when comparing one latex to another. IFD does not translate directly into higher resiliency/elasticity which really is the paramount measurement of rubber foam in particular. The purer the product generally the better the elasticity will be. ILD's and IFD's are really only good enough to give a baseline to go on. They definitely are not the sole descriptor of quality
Resiliency = Elasticity
Regular PU foam itself actually has poor elasticity compared to natural rubber foam. Memory foam (even though ironically called visco-elastic) is virtually no elasticity.
This information from the PFA is really only explaing how ILD or IFD by itself means almost nothing.
The foam itself is not becoming any softer or firmer after being cut or being made in any different thickness. What they are testing is how much resilience there is in the foam at a certain % of height compression. So they are using the same exact recipe of foam for these IFD values and using different thicknesses of foam but yet they are compressing the foam to completely different amounts since they are compressing the foam a certain amount of height based on %.
So they are compressing a 4" thick sample only 1", they then measure the force required to do so. When they are compressing the 8" thick sample they are compressing 2" of the height and then measuring the force required. I would be willing to bet a large amount that the difference in ILD or IFD between both samples if the 4" thick sample was also compressed 2" would be very similar, probably with 5% of error.
It is for this very reason that ILD's and IFD's alone are really not the best means of comparing one foam to another, especially when comparing one latex to another. IFD does not translate directly into higher resiliency/elasticity which really is the paramount measurement of rubber foam in particular. The purer the product generally the better the elasticity will be. ILD's and IFD's are really only good enough to give a baseline to go on. They definitely are not the sole descriptor of quality
Good post Eagle....and yes I believe that is the standard size piece that they use for those measurements. So long as all companies subscribe to testing the ILD on the same size foam then they are atleast comparable figures.
I for one am a small government person. Having said that, I must say, I believe untill the federal government steps in and requires all mattress manafactures to subscribe to a clear and understandable standard label that decribes much more than the current "Law Label" we will just have to guess regarding what we are actualy purchesing. The "Nich Market Manfactures" as I like to call the online small manafactures of latex mattresses, subscribe to a much more clear code of conduct because the internet traffic can compare the different companys products, (if we will read the websites carefully).
Untill then,... we will all just have to keep our guard up!!
Untill then,... we will all just have to keep our guard up!!
eagle2 wrote:
I for one am a small government person. Having said that, I must say, I believe untill the federal government steps in and requires all mattress manafactures to subscribe to a clear and understandable standard label that decribes much more than the current "Law Label" we will just have to guess regarding what we are actualy purchesing. The "Nich Market Manfactures" as I like to call the online small manafactures of latex mattresses, subscribe to a much more clear code of conduct because the internet traffic can compare the different companys products, (if we will read the websites carefully).
Untill then,... we will all just have to keep our guard up!!
For sure good labeling would be a useful government function. I think the labeling of food products has definitely been beneficial to consumers. I think the same would apply to mattresses. Part of making a economy run efficiently and for the benefit of its citizens is to have as much useful information as possible in order to make informed decisions.
I for one am a small government person. Having said that, I must say, I believe untill the federal government steps in and requires all mattress manafactures to subscribe to a clear and understandable standard label that decribes much more than the current "Law Label" we will just have to guess regarding what we are actualy purchesing. The "Nich Market Manfactures" as I like to call the online small manafactures of latex mattresses, subscribe to a much more clear code of conduct because the internet traffic can compare the different companys products, (if we will read the websites carefully).
Untill then,... we will all just have to keep our guard up!!
For sure good labeling would be a useful government function. I think the labeling of food products has definitely been beneficial to consumers. I think the same would apply to mattresses. Part of making a economy run efficiently and for the benefit of its citizens is to have as much useful information as possible in order to make informed decisions.
I totally agree, and if I ever have time I'm going to write Certified Letters to my Congressmen/women about this. I suggest you all do the same.
I think the mattress companies should be required to divulge to the consumer on a ticket attached to the mattress, the type of springs, the gauge, how many layers of foam or other substances, in what order (bottom to top or vice versa), and what ILD and types of foams are present. I don't really think that would be too much to ask.
The mattress guy who used to come here, Alexander, said people do not really want to know. My argument is that people will LEARN to want to know! I'm sure people didn't really "want to know" what was in their food, at first, either, but now a lot of people care a lot. There are always those who don't care that much. But especially on a big ticket item like this where you spend about 1/3 of your life using it, I think people need to know. And I think memory foam should have to be regulated not to off-gas toxic chemicals. If they can't make it without doing that, then they should be forced to stop making it.
I'm "small government" in many cases, but I think Big Government should sometimes step in, when prudent, to provide knowledge (labeling in this case) and standards to protect the people.
I have started to sell water filter systems and I did a whole lot of research before deciding to do so. What I found out is that there are regulations but the regulations are not strong enough to prevent a lot of unscrupulous manufacturers from making unfounded claims for their filters. But at least there are a couple of non-profit testing services and certification services (one is the NSF - the National Sanitation Foundation), which does idependent lab testing and surprise visits to factories to insure an NSF-Certified For Health Standard 53 filter system does indeed filter the contaminants the company says it does. The military and others use NSF-Certified filters for their water filtering services. I think many other industries could benefit from this type of independent testing and monitoring. For example, some monitoring and certification service - government or independent - should make sure mattresses meet certain standards and divulge what is in their mattresses, and that those claims are honest. The "NMF" (the National Mattress Foundation, we could call it) would allow an NMF Seal only if they honestly divulge the materials in their mattresses and attach that label with the "NMF" seal, to the mattress!
I think the mattress companies should be required to divulge to the consumer on a ticket attached to the mattress, the type of springs, the gauge, how many layers of foam or other substances, in what order (bottom to top or vice versa), and what ILD and types of foams are present. I don't really think that would be too much to ask.
The mattress guy who used to come here, Alexander, said people do not really want to know. My argument is that people will LEARN to want to know! I'm sure people didn't really "want to know" what was in their food, at first, either, but now a lot of people care a lot. There are always those who don't care that much. But especially on a big ticket item like this where you spend about 1/3 of your life using it, I think people need to know. And I think memory foam should have to be regulated not to off-gas toxic chemicals. If they can't make it without doing that, then they should be forced to stop making it.
I'm "small government" in many cases, but I think Big Government should sometimes step in, when prudent, to provide knowledge (labeling in this case) and standards to protect the people.
I have started to sell water filter systems and I did a whole lot of research before deciding to do so. What I found out is that there are regulations but the regulations are not strong enough to prevent a lot of unscrupulous manufacturers from making unfounded claims for their filters. But at least there are a couple of non-profit testing services and certification services (one is the NSF - the National Sanitation Foundation), which does idependent lab testing and surprise visits to factories to insure an NSF-Certified For Health Standard 53 filter system does indeed filter the contaminants the company says it does. The military and others use NSF-Certified filters for their water filtering services. I think many other industries could benefit from this type of independent testing and monitoring. For example, some monitoring and certification service - government or independent - should make sure mattresses meet certain standards and divulge what is in their mattresses, and that those claims are honest. The "NMF" (the National Mattress Foundation, we could call it) would allow an NMF Seal only if they honestly divulge the materials in their mattresses and attach that label with the "NMF" seal, to the mattress!
It is so sad to me that I actually agree with you Jim. I mean it is actually quite ridiculous that it should get to that point, but it IS at the point where it would be very beneficial to many people if companies had to arbitrarily be more transparent in what they are selling.
Look at any other major retail product and the competitiveness in the specs and details....go and shop for a car, a TV, a high end reciever for a stereo, a computer, a cell phone, a digital camera, companies are inherently transparent with most of the specs and are always constantly trying to out do each other on it. The mattress world is sometimes becoming about the specs, but not the same kind of full disclosure, its never the full story, its cherry picked information that is presented to people. Bottomline is this...if a company does not list publically what their product is, there is a reason they are taking steps to conceal that info...and its not about competitive issues.
Look at any other major retail product and the competitiveness in the specs and details....go and shop for a car, a TV, a high end reciever for a stereo, a computer, a cell phone, a digital camera, companies are inherently transparent with most of the specs and are always constantly trying to out do each other on it. The mattress world is sometimes becoming about the specs, but not the same kind of full disclosure, its never the full story, its cherry picked information that is presented to people. Bottomline is this...if a company does not list publically what their product is, there is a reason they are taking steps to conceal that info...and its not about competitive issues.
We also vote with our buying power. Don't buy the garbage from companies that won't be honest with you. We all have experience with these mattresses now don't we? All of us here?
How did we get on this subject from ILD and thicknesses? What is the conclusion to that question. Is a 3" 42 ILD latex the same as a 6' 42 ILD???? Because I would rather buy 3" over a 6" anyday. Easier to move around if you know what I mean
How did we get on this subject from ILD and thicknesses? What is the conclusion to that question. Is a 3" 42 ILD latex the same as a 6' 42 ILD???? Because I would rather buy 3" over a 6" anyday. Easier to move around if you know what I mean
Leo...I believe that yes the actual pieces you would be buying would be somewhat comparable in firmness between the either one of these pieces. They are realistically all made from a 6" piece of whatever ILD they claim it is, and then cut them down to size after. So the foam itself would be the same.
jimsocal wrote:
I totally agree, and if I ever have time I'm going to write Certified Letters to my Congressmen/women about this. I suggest you all do the same.
I think the mattress companies should be required to divulge to the consumer on a ticket attached to the mattress, the type of springs, the gauge, how many layers of foam or other substances, in what order (bottom to top or vice versa), and what ILD and types of foams are present. I don't really think that would be too much to ask.
Jim, I agree with the concept of full disclosure. Sadly I think the only way that is going to happen is if the "S" brands & their lobbiests write the bill. The "S" brands, a.k.a. "mattress mafia" are self serving weasles just like congress.
On topic with ILD vs thickness goes, maybe we need to start paying attention to foam density (LB/cu-ft), of latex. A good portion of the toppers out there are being cut from 6" cores.
I totally agree, and if I ever have time I'm going to write Certified Letters to my Congressmen/women about this. I suggest you all do the same.
I think the mattress companies should be required to divulge to the consumer on a ticket attached to the mattress, the type of springs, the gauge, how many layers of foam or other substances, in what order (bottom to top or vice versa), and what ILD and types of foams are present. I don't really think that would be too much to ask.
Jim, I agree with the concept of full disclosure. Sadly I think the only way that is going to happen is if the "S" brands & their lobbiests write the bill. The "S" brands, a.k.a. "mattress mafia" are self serving weasles just like congress.
On topic with ILD vs thickness goes, maybe we need to start paying attention to foam density (LB/cu-ft), of latex. A good portion of the toppers out there are being cut from 6" cores.
From my limited understanding
ILD/IFD measures the stiffness/firmness of the foam by indicating the amount of pressure requiredto compress a specimen of specific dimensions by a particular fractional depth (typically 25% or 65%). Implicitly the actual depth of compression is dependent on both the thickness of the specimen and the target fraction (e.g. 2%5 of 4" is 1" and 25% of 8" is 2"). Everything else being constant, reducing the thickness of the specimen would effectively reduce the actual target depth but also reduce the volume of material available to resist the applied force. Thus the relationshipis not really linear (there are conversion charts), but effectively the required force is reduced giving a lower measured ILD. It is better to have the dimensions of the specimen used during the test to enable a fair comparison. I dont think the [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]ASTM D 3574 standards of test measurements are mandatory.[/FONT]
Resilience of a foam is measured using the dropped ball test and is a measure of the elasticity/springiness of the foam. Standard PU foam has low resilience, HD is about 30-40%, Lux/Evlon is about 40-50%, HR is about 50-60% and latex is usually greater than 60%.
A related measure is the compression set which measures the amount of 'permanent' deformity after the foam has been under compression for a sustained period. Low values are good and is slightly correlated with resilience and density
Density is probably the most reflective of durability. Denser products (of same material) tend to maintain their specifications longer.
ILD/IFD measures the stiffness/firmness of the foam by indicating the amount of pressure requiredto compress a specimen of specific dimensions by a particular fractional depth (typically 25% or 65%). Implicitly the actual depth of compression is dependent on both the thickness of the specimen and the target fraction (e.g. 2%5 of 4" is 1" and 25% of 8" is 2"). Everything else being constant, reducing the thickness of the specimen would effectively reduce the actual target depth but also reduce the volume of material available to resist the applied force. Thus the relationshipis not really linear (there are conversion charts), but effectively the required force is reduced giving a lower measured ILD. It is better to have the dimensions of the specimen used during the test to enable a fair comparison. I dont think the [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]ASTM D 3574 standards of test measurements are mandatory.[/FONT]
Resilience of a foam is measured using the dropped ball test and is a measure of the elasticity/springiness of the foam. Standard PU foam has low resilience, HD is about 30-40%, Lux/Evlon is about 40-50%, HR is about 50-60% and latex is usually greater than 60%.
A related measure is the compression set which measures the amount of 'permanent' deformity after the foam has been under compression for a sustained period. Low values are good and is slightly correlated with resilience and density
Density is probably the most reflective of durability. Denser products (of same material) tend to maintain their specifications longer.