Hi Minneasota,
I would keep in mind that different types of latex have a different “feel” and some (like Talalay) are more resilient than others (there is more about the difference between Dunlop and Talalay in post #7 here for example) and that different latex designs can also have a very different feel as well depending on the type of support core, the design and firmness of the latex comfort layers, and the type of cover and quilting in the mattress. In general though latex is a more resilient or “springy” material than other types of foam that are used in comfort layers. There are also latex/innerspring hybrids that have some of the “feel” of an innerspring (which is generally a support layer and much of what you feel on an innerspring mattress will be in the comfort layer materials not necessarily the innerspring) and use latex comfort layers so I wouldn’t necessarily make a decision about a whole category of mattresses based on testing only one of them.
The bottom line though is that I would choose a mattress that is a good match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) and used the type of support components and comfort layers that you tend to prefer because all materials will have lower quality and less durable versions and higher quality and more durable versions.
I would also make sure that no matter where you are buying a mattress that you know the specifics of all the materials inside it so that you can make sure there are no “weak links” and can make more meaningful comparisons with other mattresses. I would never buy any mattress where you didn’t have all the information you need to make an informed choice and meaningful comparisons regardless of which manufacturer or retailer you were dealing with.
You can read a little more about fire barriers in this article and in post #2 here but I wouldn’t have any “safety” issues with an inherent rayon/silica fire barrier.
I’m surprised that they weren’t familiar with CertiPur but this may have just been the salesperson you were dealing with.
I think you may have already seen this already based on your comment about My Green Mattress but just in case you haven’t post #2 here has links to most of the better posts and topics about children and mattresses that may be helpful when you are buying a mattress for a child. They also include more information and some links to good sources for children’s mattresses.
There are three different types of foam which are polyfoam, memory foam, and latex foam. Out of these, most people wouldn’t have any any issues with using polyfoam in a childs mattress as long as it was either CertiPur certified or was made in North America (see the guidelines in this post). I also wouldn’t have any issues with using any type of latex foam. I would however tend to avoid memory foam for children (especially younger children) both because the odds are higher that some people may be more sensitive to memory foam than polyfoam or latex and also because it is a softer material that may not be firm enough or “motion friendly” enough to be the best choice for younger children so this may be what you are referring to. Any polyfoam can be made in softer or firmer versions regardless of its density so with polyfoam density is only about quality and durability not about firmness or toxicity. Latex is also available in a wide range of firmness levels.
Finding out the foam densities “should be” the job of the retailer you are dealing with and if they don’t know they should be the ones calling their factory. In some cases factories will only provide this information to their retailers becasue they aren’t set up to deal with customer enquiries. Unless there is a very compelling reason that you are interested in a particular mattress that would justify the efforts involved to find out for yourself what a retailer should be finding out for you … I would tend to avoid it. If it was me I would make it clear that if they couldn’t find out the information I needed to make an informed choice (even if they had to pass the request up the “chain of command”) that there was no chance that I would be buying a mattress from them.
There is more about the most important parts of the value of a mattress purchase in post #13 here but as long as I knew the quality of the materials inside any mattress I was considering so I could identify any weak links and make more meaningful comparisons between mattresses this wouldn’t matter as much to me. To some degree this would be true of most manufacturers because they would rarely make every component in their mattresses and would order them from other suppliers and then put the mattress together in their own factory. To me the “bottom line” about how the mattresses compare is more important than the steps that went in to making the mattress.
As you know I have many reference posts that I link for most questions so I don’t have to retype the answers to each one but I certainly don’t get tired of answering questions as long as I know they are helping people to make better choices
Phoenix