ILD vs Thickness - confused ?
Mar 25, 2010 1:12 AM
Joined: Mar 2, 2010
Points: 27
FBM claimed in an older post that

"The 6" firm latex core cut in half is the 3" medium toppers. When you make them thinner they loose the firmness

 

According to PFA the statement appears true for PU foam

4.3 IFD varies significantly with foam thickness. On the exact same foam, the IFD increases as the thickness increases, as the following chart illustrates:

All samples are 20" x 20" x stated thickness.
Sample Thickness (inches)    IFD at 25% deflection (lbs/50 in squared)


4---------------------------28.0

5---------------------------31.0

6---------------------------34.5

7---------------------------38.5

8---------------------------43.0

 

Is this statement applicible to Latex ?

PU foam has High resiliance, latex has no resiliance.  Looking more for the facts than opinions.

 

Anyone ?

 

 

 

 

This message was modified Mar 25, 2010 by zzzombie
Re: ILD vs Thickness - confused ?
Reply #7 Mar 25, 2010 4:42 PM
Joined: Dec 17, 2009
Points: 850
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. 

Re: ILD vs Thickness - confused ?
Reply #8 Mar 25, 2010 6:15 PM
Joined: May 3, 2008
Points: 827
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 wink

This message was modified Mar 25, 2010 by Leo3
Re: ILD vs Thickness - confused ?
Reply #9 Mar 25, 2010 6:25 PM
Joined: Dec 17, 2009
Points: 850
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.
Re: ILD vs Thickness - confused ?
Reply #10 Mar 25, 2010 7:17 PM
Joined: May 3, 2008
Points: 827
Thanks Budgy!
Re: ILD vs Thickness - confused ?
Reply #11 Mar 25, 2010 8:40 PM
Joined: Mar 2, 2010
Points: 27
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.

This message was modified Mar 25, 2010 by zzzombie
Re: ILD vs Thickness - confused ?
Reply #12 Mar 25, 2010 10:15 PM
Joined: Aug 17, 2009
Points: 542
There is a formula for figuring ILD (AKA IFD) so that there is a consistency across differing thickness of latex. I feel confident that Latex Internatioal uses this formula when measuring there latex.
Re: ILD vs Thickness - confused ?
Reply #13 Mar 26, 2010 12:35 AM
Joined: Mar 25, 2010
Points: 1
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 ASTM D 3574 standards of test measurements are mandatory.

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.

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