alevinemi,
I wanted to know if there was a difference, primarily in durability between various pocket-coil innerspring components
Yes there is. But this isn't usually the weak link within a mattress. Depending upon the number of springs, methods of joining, fabric used (you seem to be curious in marshall springs), gauge of steel, tempering, arrangement, actual coils (revolutions) and so on, there will certainly be variations in spring unit durability. But the better segments from various manufacturer's lineups meant for adult use will typically outlast any foams placed upon them and provide good support/alignment for average BMIs and somatotypes. Specific needs or larger individuals will place more demands upon all componentry, at which point spring unit choice can be even more important for applicability and durability.
I've seen many of the manufacturers use the Leggett and Platt Quantum Edge component - either Bolsa or Combi-Zone. I can't always get a straight answer on what gauge of steel this uses, and it seems to vary by retailer. Not all Bolsas us the same steel, evidently, but the L&P units seem to range from about 14 to 17 gauge.
The gauge of steel works in combination with such things as the number of springs, arrangement, zoning, and diameter to provide overall support and alignment. The same designs can be made with different gauges to achieve different feels. A lower gauge doesn't necessarily mean a less durable product. As an example, I have a line of mattresses using the Quantum Edge with a thinner gauge of steel in the Quantum Edge than within the middle of the mattress, but the perimeter springs are smaller in diameter, at a higher concentration, and wound with a different coil structure, and they provide a firmer and more durable surface than what is in the middle of the mattress (which is still quite high quality). Conversely, you could have a basic 650 or so queen unit using a thicker 13 gauge steel at a lower profile with not as many coils that could actually be quite a bit less supportive by comparison even though it was using thicker gauge steel. So there's quite a bit that goes into overall durability of an innerspring unit, but exact testing data is something that is more technical in nature and not generally made public by the innerspring companies, as again the spring units don't tend to be the weak link within a mattress, much of the "wearing out" of a mattress will be sure to uppermost materials, much of the data is considered proprietary and even if it was disseminated it wouldn't be in a format that would make much sense to the general public. Manufacturers or knowledgeable retailers are usually a good source for comparing different spring units and relating the differences from one to another. Even if they don't know the gauges of steel and some spring units can be considered similar in the level of quality/durability, there may be differences in response curves/zoning that they can relate to help see if a particular unit is more appropriate for certain applications versus another.
I've found that the non-big-name manufacturers that don't use this unit have heavier gauge steel - usually from about 13 to 15 gauge. I'm assuming they manufacture their own coils or have a different supplier. I haven't checked the big names like sealy/simmons/serta.
There are other suppliers for marshall/pocketed spring units domestically, but Leggett and Platt is by far the largest supplier. There's over 500 different mattress manufacturers out there, and the gauge of steel used varies considerably, and very few manufacture their own innersprings. Most mattress companies actually create nothing but the finished products and are assemblers, sourcing foams, springs, and covers from suppliers. Of course, some of those materials are proprietary to specific mattress companies to provide them exclusivity.
Here's a listing
of a few of them that may be of interest to you.
Is one unit particularly better than another in terms of durability? I know that the innerspring isn't usually the weakest link in durability, but I'll be buying an innerspring/latex mattress, so all the components are high durability...
Latex can be a great choice for a comfort material. For the spring unit, in general take care to avoid very low spring counts. I don't like to paint with too broad of a brush, but I have seen a recent "flooding" of imported units (Far East) at some really low prices, and I have not been impressed with the quality of many of these units, so I would be extra careful if you are looking at something like that. Aside from that, take a look at any special features (zoning, edge reinforcement) that may be useful to you and I would rely upon guidance from a good manufacturer or retailer.
Jeff Scheuer, The Beducator
Beducation / Mattress To Go