The ABC of Foam: A Guide to Foam Terminology

As the UK’s largest foam supplier, dedicated to delivering top-quality foam solutions for a multitude of applications, we want to make sure that you’re completely in the know when it comes to purchasing foam.

If you’ve ever found yourself puzzled by foam industry jargon or wished for a glossary that demystified all those technical terms, we’ve got something you’ll want to read.

Today, we’re going to break down a whole host of foam-related terminologies and abbreviations. You may have heard some of these in conversation before but might not fully have understood what they meant. With this guide to foam-related words, hopefully, that will be a thing of the past!

And don’t forget, our experts know all there is to know about foam and we’re always happy to answer any questions you may have. If you’re unsure about something or just want to find out more about our products, please feel free to get in touch.

Types of Foam

There are loads of different types of foam out there and this can sometimes cause confusion if you’re unsure which type is best suited to your project. Here, we’ll explore some of the most popular types of foam and explore what it is they do.

Open-Cell Foam: A type of foam where the cell walls, or surfaces of the bubbles, are broken and air fills the spaces in the material. This makes the foam softer and more flexible.

Closed-Cell Foam: A type of foam where the cell walls are intact, causing the foam to be more rigid and resistant to fluids, chemicals and more.

Polyurethane Foam (PU): A versatile and popular type of foam that is used in a wide variety of applications, including mattresses, furniture and various types of insulation.

Ethylene-Vinyl Acetate (EVA): A type of closed-cell foam known for its durability and flexibility, commonly used in sports equipment, footwear, costume making, prop making and more.

Acoustic Foam: A special type of foam used to control echoes and background noise in a room. Its open-cell structure is designed to absorb sound waves and minimise sound wave reflections that cause interference.

Convoluted Foam: Also known as Egg-crate foam. This is a foam that has been processed with a special machine that presses a pattern of bumps into one or both sides of the foam. The result is similar to the shape of an egg crate.

Recon Foam: Made from recycled scraps of foam that are bonded together to create a new recycled product. This is a durable foam often used in floor underlay, sports equipment and heavy-duty seating. Also known as reconstituted foam or chip foam.

Viscoelastic Foam (Memory Foam): A popular foam, often used in the manufacturing of mattresses and cushions to increase comfort. Viscoelastic refers to the foam’s ability to slowly return to its original shape after being deformed.

Antistatic Foam: A foam engineered to exhibit antistatic properties to help reduce or eliminate the build-up of static electricity. This is often used to store or package sensitive electronic equipment.

HLB Packaging Foam: A type of packaging foam with a high load bearing (HLB) capacity. It can offer additional protection to various items and can be cut to create foam packaging inserts.

Plastazote: An advanced type of closed cell foam blown with nitrogen. Manufactured by Zotefoams PLC and part of the Azote range which also includes Evazote and Supazote.

Reticulated Foam: A fast drying foam with wide open cells that allows water to rapidly drain through it. Has a visible mesh-like structure. Popular for making outdoor cushions and boat cushions. See also Quick Dry Foam.

Class 0 Foam: A type of acoustic foam with superior fire resistance. Manufactured to meet Class 0 requirements and often used in the construction industry.

Upholstery Foam: A generic term used to describe various types of polyurethane foams used for upholstery purposes.

High Density Foam (HD): A type of foam that has a high weight per cubic foot, often used in upholstery for its durability and support. A high density does not necessarily correlate with the firmness of the foam.

Acoustic Treatment Terms

We’ve already covered acoustic foam which is used to provide sound treatment for various types of indoor spaces. However, there are plenty of terms linked to this type of foam that you might not be aware of.

Noise Reduction Coefficient (NRC): A scaled representation of the amount of sound energy absorbed upon striking a particular surface ranging from 0 – 1. An NRC of 0 indicates perfect reflection whereas an NRC of 1 indicates perfect absorption.

Decibel (dB): The unit used to measure the intensity of a sound.

Frequency: The number of cycles of a wave that pass a certain point in each period of time. In acoustics, frequency is often measured in Hertz (Hz). Different frequencies correspond to different perceived pitches.

Hertz (Hz): A unit of frequency representing one cycle per second. In the context of acoustics and sound absorption materials like foam, it denotes the pitch of the sound that the material can effectively absorb. Lower frequencies correspond to a lower pitch (bass sounds), while higher frequencies correspond to a higher pitch (squeaky sounds).

Bass Traps: These are specialised panels that absorb low-frequency sound, preventing the bass from bouncing around the room. They are commonly placed in the corners of a room, where low frequencies tend to build up.

Studio Foam: A general term for the foam used in studios for sound absorption. It comes in various styles including wedge, pyramid and egg-crate profiles.

Pyramid Foam: A type of acoustic foam where the surface has been shaped into a pattern of pyramids.

Wedge Foam: A type of acoustic foam that has a surface pattern consisting of a series of protruding triangles in a wedge-like style.

Soundproofing: The process of preventing sound from entering or leaving a certain space.

Sound Absorbing Foam: Another name for acoustic foam, a specialised foam designed to absorb a percentage of sound wave energy to improve room acoustics.

Units of Measurement

In order to determine its properties and suitability for various jobs, foams are tested under a variety of circumstances. There are many units of measurements used to describe each type of foam to help explain the benefits they offer.

Indentation Load Deflection (ILD): Also known as Indentation Force Deflection (IFD), it measures the firmness, comfort, or support level of foam by determining how much force is needed to make a 25 percent indentation on a 4-inch thick foam sample. ILD is often used in the mattress industry and is expressed in pounds force (lbf).

Tensile Strength: A measurement of a foam’s ability to resist tearing. It is usually expressed in pounds per square inch (psi) or kilopascals (kPa).

Compression Set: A measure of the extent to which foam retains its shape after being compressed. It is expressed as a percentage, with lower percentages indicating better recovery.

Air Flow: A measure of the breathability of a foam, determined by the amount of air that can pass through it. It is often measured in cubic feet per minute (CFM).

Cell Size: A measure of the size of individual cells or bubbles in the foam structure, often stated in pores per inch (ppi). Smaller cell size can lead to higher strength and hardness, while larger cells can improve flexibility and shock absorption.

Density: A measure of the foam’s weight per cubic foot. This is often used to determine the durability of the foam, where low density foams will generally have shorter life expectancies when compared to high density foams. This is not an indication of how firm the foam is.

Have A Foam Question? Get in Touch

If you’ve got a foam-related question, we’ll be happy to help you. Our team of experts can provide a greater explanation of each type of foam we offer as well as the most common applications.

We always try to keep things clear and simple for our customers but don’t forget to use this guide if there are any words you’re not quite sure about.