Bedding Anatomy 103: Foam Used In Mattresses
Volume 143 NO.1 January/February
Furniture World Magazine
This installment of Furniture World Magazine’s Better Bedding and Mattress Sales series will expand upon information presented in the last two issues on mattress construction. In the July/August installment we looked at how retail sales associates can successfully introduce information on mattress specifications and technologies into their presentations. The ups and downs of innersprings were presented in the October/November issue. If you missed these or any of the previous eight articles in this widely read series, please visit www.furnin fo.com/ series/ bedding.
By Russell Bienenstock
Useful Empty Spaces
Now we will take a close look at foam, the most common bedding component found in retail furniture and bedding specialty stores.
Lao Tzu pointed to a metaphysical truth when he wrote in the Tao Teh Ching, “Thirty spokes share the wheel's hub; It is the center hole that makes it useful. Shape clay into a vessel; It is the space within that makes it useful. Cut doors and windows for a room; It is the holes which make it useful.
Therefore profit comes from what is there; Usefulness from what is not there.” Though certainly stretching his words too far toward the mundane, we might consider that like the doorway or the pitcher refered to above, what all foams have in common are the empty spaces within. Foam is filled with tiny air bubbles that make it both useful as well as profitable.
As defined by Merriam Webster’s Dictionary, foam is “a material in a lightweight cellular form resulting from introduction of gas bubbles during manufacture”. We might add that the gas bubbles can either be introduced physically or be the result of chemical reactions during the foam making process.
Foam: An Exciting Material
What is your favorite kind of foam? Is it the kind that rises from the pounding Pacific surf or above a cold glass of beer? If you are in the furniture business, probably not. Furniture World’s editors would like to assume it’s the kind that helps our customers to get a good night’s sleep. Foam is a wonderful material, and unless you’ve been taking zzz’s in your bedding department for the past decade or so, you must know that recent innovations in foam technologies have driven the rapid growth in mattress sales. Foam advances have opened up myriad possibilities for retailers and consumers.
Does your customer prefer bouncy? Show them latex. Do they like that sinking feeling? Memory foam might be for them. Hot? Add some gel to that foam! Foams allow for infinite variety as they are mixed, matched and engineered to achieve nuanced support and comfort. The quality and amount of foam in a mattress also greatly affects its price, quality and durability. That’s why knowing a bit more about these materials allows store buyers to buy better, and retail sales associates to serve customers more authoritatively.
Within each mattress category there is wide variation in the thickness of foam used, its density and composition. This goes a long way toward explaining why two similar looking foam mattresses can vary so widely in retail price point.
Foam Basics Density & IFD
Allen Platek, Vice President Marketing at Sealy notes that, “For most consumers foam is foam and, unless retailers educate them about the quality of foams that are being used in their mattresses, customers may end up with products that perform poorly and get body impressions. Without guidance, many people choose a foam mattress simply based on its thickness without considering its quality.”
W. Brent Limer, National Product Manager, Hickory Springs Bedding Products suggests that retail buyers and sales associates should, therefore, take the time to learn some foam basics. “Foams are pretty simple until you get into specialty foams and even those can be understood by knowing about density and IFD.
“Density,” he says, “tells about a foam’s durability. Its indentation force deflection (IFD) tells you about its firmness. Basically IFD measures how much the foam is pushing back at certain depths as it is compressed.”
“Typically measured at 25 per cent compression using a four inch thick sample,” clarifies PFA’s Bob Luedeka, “IFD is the number of pounds required to compress a four inch thick sample, one inch; 25 per cent of its height using a 50 square inch indenter plate.”
Continues Brent Limer, “Foam density is measured in pounds per cubic foot, so, if you have one pound per cubic foot, the density is lower than if you have foam with a density of 1.8 pounds per cubic foot. Density does not affect the feel. The feel is determined by the IFD. Density does affect longevity.
“Also, the more material that is stuffed into a cubic foot, the more it costs, so the only reason to use lower density foam is to hit lower mattress price points.
“For mattresses with a solid foam core,” he continues, “manufacturers may use foam that has around a 30 IFD. What’s needed in a foam core is a higher IFD, and as foam gets closer to the top of the bed, the IFD comes down. If there are multiple comfort layers, the IFD comes down to the 10 or 12 or 15 range. Foam used for edge support with foam encased innersprings typically has a 45 or 50 IFD so that it holds the innerspring in the encasement and is firm enough to support a person sitting down on the edge of the bed.”
“What’s interesting about IFD and what most sales associates and buyers don’t realize,” adds Bob Muenkel, Director of Sales Education & Development at Serta International, “is this. They normally believe that the denser the foam, the firmer it is. Most will automatically assume that a 1.5 density foam is firmer than a 1.2, but that’s not necessarily true. It’s definitely heavier if you were to weigh it, but it’s the IFD that determines firmness. Foamers can actually change their formulations to create a higher density foam that feels softer than a lower density foam.”
Types of Foam
Now that we’ve discussed the basics of foam density and firmness, let’s take a closer look at foam types.
“There are three types of polyurethane foams used in bedding today,” explains Bob Luedeka, Executive Director of the Polyurethane Foam Association, Inc. (PFA). “The first is conventional foam that’s plain old garden-variety foam. The second type found in the marketplace is high resilience foam, nicknamed HR foam. There used to be a whole lot of it in the bedding industry, but not so much now. The third type, viscoelastic, is also called memory foam, which is sort of an oxymoron. It’s the opposite actually. Memory foam is very slow recovery foam.
Polyurethane Mattress Foams
“The higher the density of conventional polyurethane foam, the better you’re going to do in terms of support and durability,” elaborates Luedeka. “And, durability in the mattress business means minimizing body impressions and maintaining firmness. The higher the density, the greater the probability that you’re going to have good life from the product, plus minimal compression set (the tendency of foam to lose height as it is used). High-density foam also help to maintain original firmness and can provide quick height recovery, so when your customers get up in the morning their mattresses spring back to their original shapes.
“HR foam has been supplanted by higher density conventional foams and memory foam or viscoelastic, the technical name for it. HR foam was really good for bedding because it had an ability to be very soft yet very supportive. With conventional foam, even at high density there is a limitation as to the amount of support that can be generated. On the other hand, HR foam can have proportionally more support and still be soft on the top. The reason for this is that HR foam has an irregular cell configuration. High resilience, foam springs back very quickly, has good ball rebound, great comfort and support, too.”
We asked Bob Luedeka to give Furniture World readers some background on how polyurethane foam came into the bedding marketplace. “Polyurethane foam,” he responds, “first got its foot in the market as a replacement for latex. Many early polyurethane products were stiff and boardy. They didn’t work well in furniture, but they did serve a purpose in bedding where people liked firmer feels in beds.
“In the early 1960s, new catalysts were introduced that allowed polyurethane foam using a continuous production process rather than batch pouring, and this allowed the development of new polyols that expanded its range of densities and firmness. This put a lot of comfort into the product. Polyurethane certainly got the attention of the nation’s largest retailer, Sears Roebuck.”
According to Luedeka, the market for solid core polyurethane foam mattresses grew rapidly through the latter part of the 1980s with Sears leading the way. Then the trend began to swing the other way when Sears decided to turn over its bedding departments to national brands that de-emphasized solid polyurethane foam mattresses.
“After that,” continues Luedeka, “everything became pretty quiet with foam core bedding, but an awful lot of polyurethane foam began to go into innerspring models as high profile mattresses became more popular. The thickest innerspring coil you can put in a mattress is about five-and-a -half inches high. To create a mattress that is 14, 15, 16 or 17 inches thick, upholstery materials must be added. Originally this extra material was mostly conventional polyurethane foam, and the bedding business absolutely skyrocketed.”
Adds Sealy’s Allen Platek, “What happened in the industry at that time is what I call the arms race. Manufacturers of beds built thicker and thicker and thicker mattresses largely by putting in more foam.”
Polyurethane Mattress Foam Quality
Furniture World asked Sealy’s Allen Platek to talk about indicators of poor quality in conventional polyurethane foams. He replied, “Consumers who have done any work on the Internet know that body impressions in these thick mattresses are a big issue. And, today RSA’s are conscious of that. They shy away from selling those 16, 18 and 20 inch beds and, over the past four or five years, we’ve started to see beds skinnying down again.
“The vast majority of the foams we use in our products are polyurethane foams. We don’t use any urethane foam with less than a 1.2-pound density. A lot of manufacturers out there are using one-pound foams. I’ve even seen them as low as 0.9-pounds. And, with a density that low, you’re just going to get an inferior product that breaks down over time.
“Also,” he says, “we stress that we don’t use any convoluted foams in the upholstery layers. Convoluted foam, commonly known as Egg Crate® foam, is a product that’s generally used to add profile to a bed at lower cost. A bedding manufacturer can take a three and a half inch slab of polyurethane foam and make five inches of foam out of it by convoluting it. The result is five inches of profile for the cost of three-and-a-half. It is a very weak profile because over time that convoluted foam smashes down and results in a body impression.”
“Regarding convoluted foam,” Bob Luedeka told Furniture World, “manufacturers talk about comfort padding. They say the Egg Crate-type design is there to cuddle customers. They explain about posturization, with more foam (fewer dimples) at the center, then under the head and feet, giving more support. Technically that’s correct because there could be more foam for support in the center than at the ends. In most cases though,“ he continues, “it’s more of a visualization of comfort thing. But, there are some companies that have used convoluted foams effectively to create products that have a very good feel.”
“Another indicator of poor quality,” says Sealy’s Allen Platek, “is beds that incorporate thin layers of polyurethane foams. We see the better bedding companies are using fewer and thicker layers of polyurethane foams.
“The analogy I use,” he continues, “is this, you’d have no trouble bending a stack of 150 sheets of aluminum foil. They’re all very thin. But if I handed you a half inch thick piece of solid aluminum, you probably couldn’t bend it. And the same thing applies with foams. More thin layers can shift in a bed, bunch up and nest into each other. When I see all those different layers it’s a red flag that there may be a problem with body impressions in the future.”
Viscoelastic Foam Used In Bedding
As was noted previously, viscoelastic foam, known as memory foam or simply visco, is a form of polyurethane foam that has slow recovery characteristics. “About 2001, says Bob Luedeka, “we started seeing a big move in viscoelastic production volume. Today, essentially every foam producer in the United States makes a viscoelastic foam with most of it going into the bedding market. It is typically a high density product, meaning the density is greater than two pounds and can run up as high as five or five-and-a-half pounds. It is characterized by slow recovery that is sensitive to heat, an ideal product for mattresses because as the foam begins to warm up it becomes even better at distributing weight. In doing so it relieves pressure points over the entire surface of the body, particularly under the places where weight is most concentrated. Someone sleeping on memory foam leaves a body impression in the top of the bed, but then, after a few hours, the foam recovers and looks normal again. Part of this is the result of temperature change. Typically memory foam may feel a little bit stiff when a consumer first lies down, but as it begins to warm up, it really contours well. Because it’s typically a high-density product that has many of the same type of characteristics as an HR foam, it delivers a lot of support.
““Prior to PFA, when I was working with the marketing team of Union Carbide, viscoelastic foam was first introduced. Efforts were made to quilt mattresses with it. It was so soft and so slow in recovery some thought it would make a great quilt backing. But that idea didn’t fly because quilting machine needles stuck in it. In the beginning, many visco mattresses were made of 100 per cent viscoelastic foam that has a very high support factor that won’t allow a sleeper to bottom out. These mattresses were not nearly as thick as some of the products we see today. They had a lot of give to them and sleepers would sink into them as if it they were on a waterbed. Manufacturers soon discovered that they could place layers of viscoelastic foam over a high-density conventional foam core in the center, and that worked well.
“Viscoelastic foam can be formulated in many different ways. The trick is to get slow recovery when you compress it and then remove the compression and this needs to work over a range of temperatures.”
Furniture World spoke further with Sealy’s Allen Platek about foam cores in memory foam mattresses. “Most people,” Platek said, who own memory foam beds actually think their entire bed is memory foam. They don’t realize that there’s a six-inch polyurethane base under that memory foam. The cores in most memory foam mattresses are solid blocks of polyurethane. In upper end memory foam mattresses, you’ll see an engineered core.”
“What makes visco, visco, is its high density. You can’t have a low density visco,” adds Brent Limer. “You might see a two and a half pound density visco, maybe a two pound, but it won’t have its characteristic slow recovery. We make it up to five pounds, which is a very high quality visco. It is more expensive than conventional polyurethane foam because of higher pounds per cubic foot. A five pound density visco foam will have five times as much material as a one pound polyurethane.”
We asked Serta’s Bob Muenkel to comment on the variation in quality of viscoelastic foams used in mattresses.
“There is a broad spectrum of memory foams out there both in terms of look, feel, quality and even how it’s made,” he noted. “Memory foam can be either more towards the closed cell or an open cell variety. Closed cell means that the foam contains tightly packed cells that have a tendency to feel and sleep warmer. Open cell memory foam is definitely more common and more expensive. Open cell memory foam allows the air more freedom to move in and around. This creates a plusher type material and a lot more airflow. And that airflow is the key agent for removing and dispersing excess body heat.
“My rule of thumb is that memory foam should be at three-pound density or greater. Higher density is typically better. But here’s an odd thing. Sometimes a mattress can have only a half-an-inch of memory foam, and you’ll still get some benefit.
“There’s just a huge range of product that’s out there,” he adds, “ from the commodity-type memory foams which might be lower density closed cell formulas all the way to the premium product, higher-density and more open cell formulas. In my personal opinion, the branded memory foams are much better than the commodity Memory Foams that are out there.”
Sealy’s Allen Platek agrees. “The thing about visco,” he says, “is that a consumer can buy a visco bed from $499 all the way up to $8,000. Because of visco’s success, we’ve seen a deluge of very cheap imports. And, it’s easy for customers to ask themselves, ‘Why spend $3,000 when I can have a memory foam bed for $499?’’
Given the price differential, we asked our experts to identify some of the characteristics of poor quality memory foam.
Bob Luedeka explains, “It would not be desirable to have very fast recovery or recovery time that sped up a lot over time. In other words, you wouldn’t want your customer to receive a new mattress that had showroom-like slow recovery and felt great, and then, perhaps a year later, to have it lose that property and become faster in terms of its recovery with time under the same temperature conditions. If visco is too low density it could have less support than higher density foams. Higher density can give it guts underneath in terms of better support.”
So, can retailers easily tell the difference between good and poor quality visco?
Luedeka continues, “There was discussion about developing a definition and possible performance standards. This wasn’t pursued because these foams are used in all kinds of different applications, not just in bedding. If a manufacturer is going to use it as a solid core then they need to use something that has a lot of durability and offers a lot of support. If they are going to use a two-inch layer on the top, then that property isn’t so important. In applications such as industrial shock absorption or as a recoil pad, completely different properties may be needed.”
In the March/April issue of Furniture World Magazine, our Better Bedding and Mattress Sales series will continue with a look at more mattress components, gels and Latex, materials that are showing exceptional sales growth at retail.
Russell Bienenstock is Editor-in-Chief of Furniture World Magazine, founded 1870. Comments can be directed to him at firstname.lastname@example.org.
Read other articles by Russell Bienenstock