Recording studios rely on acoustic treatments to control and enhance produced sounds inside the room. Acoustic treatments vary in form and material, and the most common of them all may have to be acoustic foams. You would hardly find a recording studio without them. From walls, floors, ceilings, to doors—almost every inch of its interior is covered in acoustic foam.
Because of their sound-absorbing capability, acoustic foams are installed to minimize noise, echoes, vibrations, and other unwanted sounds for the best acoustic experience. But the use of acoustic foam raises fire safety issues, as this material is said to be flammable. Is that true?
The answer is a mixed yes and no. Yes, because polyurethane, a typical component in acoustic foams, is combustible. But it’s also a no since most acoustic foams commercially sold are already treated with fire retardants, making them fire-rated. And if it’s made from melamine instead of polyurethane, it’s also non-flammable.
Not yet fully convinced? We’ll expound more on acoustic foam’s properties to see if it’s safe enough to use or would it only prove to be a fire hazard.
What Is Acoustic Foam Made Of?
Acoustic foam can be either made from polyurethane or melamine foam. But open-cell polyurethane foam is the more widely used material. Acoustic foams come in different shapes, colors, and sizes. They are usually cut into panels to fit any part of a room. Their surface features cone-like wedges that look a bit like those of an egg crate.
Does Polyurethane Make Acoustic Foam Flammable?
Since polyurethane is an organic product, it can easily catch fire when subjected to high temperatures. Polyurethane foam should still be regarded as flammable even if already treated with fire retardants.
Thus, you should handle the material with extra care to reduce the risk of fire-related accidents. When ignited, polyurethane foam burns quickly and releases irritating smoke and toxic gases, including carbon monoxide. Even this result alone seems this material unsafe and dangerous in case of fire.
Does MelamineMake Acoustic Foam Flammable?
Melamine foam has long been used as an effective soundproofing treatment. Naturally fire and heat resistant, this material is non-combustible and highly unlikely to burn when exposed to open flames.
What Does It Mean To Be A Fire-Rated Material?
Fire (or fire-resistance) rating is a measurement of how a material can withstand fire through a fire-resistance test. For acoustic foams, the ASTM E-84 test is conducted to evaluate flame spread and smoke development. From the results, the material will then be given classification, making it fire-rated.
What Should Be Acoustic Foam’s Fire Rating?
Depending on the material, the acoustic foam has two possible fire ratings. Polyurethane foam burns when subjected to fire but will eventually extinguish on its own. This makes it a Class C material, meaning you may only use it for low-occupancy areas.
Melamine foam is highly fire and heat resistant, which explains its Class A fire rating. Only Class A materials are permitted for use in public spaces.
What Is The Difference Between Fire-Resistant And Fire-Retardant?
Is it fire resistant or retardant? Similar as they may seem, these two terms don’t mean the same thing. Fire-resistant materials are manufactured to be non-flammable right from the start. They can self-extinguish and will not melt or drip even in the face of extreme heat.
Fire-retardant materials are not necessarily naturally non-flammable. They have been chemically-treated to burn slowly or self-extinguish when exposed to an open flame.
Do Fire Retardants Make Acoustic Polyurethane Foam Fireproof?
Fire retardants come both in powder form to be mixed with water or as a liquid to be coated or sprayed. These chemicals are capable of delaying the spread or decreasing the severity of a fire. That said, acoustic polyurethane foams with fire retardants are still not fireproof.
During a fire, they will still burn and eventually be put out slowly. But this feature is an advantage as it provides more time to potentially escape from a burning building.
How Does Acoustic Foam Work for Sound Treatment?
Acoustic foam eliminates background noise in a recording studio by reducing the amplitude of airborne sound waves. This unnecessary energy gets converted into heat.
Acoustic foam’s open cell structure stops the bouncing of sound waves on hard surfaces. This dampens the sound coming from nearby rooms.
How Does Acoustic Foam Absorb Sound?
Sound absorption involves trapping sound waves in the air. Then part of the absorbed energy is transformed into heat while some of it transfers to an absorbing object such as a microphone. This converted energy gets diffused and cancels out noise, and boosts other frequencies.
Sound waves can pass through any opening, however small they may be. That’s why it’s crucial to install acoustic foams properly. Having gaps in between foams reduces acoustic foam’s efficiency. It will not absorb sound as much and just reflect them instead.
What Is The Difference Between Sound Absorption And Soundproofing?
Acoustic foam is used for sound absorption but not for soundproofing. These two are often confused and assumed to be one and the same thing. Of course, that’s just not the case.
Simply put, sound absorption is all about absorbing sound to prevent it from bouncing back and forth into the room. This process eliminates background noise and echoes. Soundproofing totally blocks sound using thick and heavy materials. They usually have multiple layers to prevent sound from passing through.
What Makes Acoustic Foam Different FromRegular Foam?
You may think acoustic foam is just like any other foam. It’s easy to be mistaken for regular foam because they almost look and feel the same. But the difference lies on the inside. Acoustic foam is specially designed with enhanced built-in features, which that foam in your mattress doesn’t have.
Fire-Retardancy
Wiring, audio equipment, and other electronic devices inside a recording studio are prone to accidentally starting a fire. With these risks of exposure to high temperatures or open flames, fire retardancy is indeed an essential safety feature for acoustic foams.
Resilience
With people constantly walking back and forth inside a recording studio, anything could happen—bump into the wall, drop a piece of heavy equipment on the floor, and a whole lot of other minor accidents. So, it’s only fitting for acoustic foams to have the ability to withstand all kinds of damage and last for a long time.
Firmness
Acoustic or regular foam, firmness, or Indentation Load Deflection (ILD) is a feature to look out for. Acoustic foam’s customized firmness provides maximum sound absorption across all frequencies. A higher ILD means a firmer foam that absorbs more low-frequency sound, while a lower ILD means a softer foam that absorbs high-frequency sound. An efficient acoustic foam balances the two.
Cellular Structure
Acoustic and regular foam may have the same material, but they actually differ in structure. Foam consists of tiny cells. Their size, measured in Pores Per Inch rating (PPI), matters in a foam’s sound absorption property. Acoustic foam has a higher PPI than regular foam. And the higher the PPI, the more sound-absorbent the foam is.
Aesthetic
Physical appearance also emphasizes the difference between a regular and acoustic foam. A small dent on a bed mattress can be covered by sheets. But with acoustic foam, the same flaw will be noticeable in a foam-lined wall. Since acoustic rooms constantly evolve, products change just as fast. There’s a possibility that you won’t find a new acoustic foam replacement that matches the appearance of the old one, leading to an inconsistent look.
What Other Materials Can You Use For Acoustic Treatment Aside From Foam?
To choose the right material, you should have a basic understanding of how sound travels through the air and behaves when it arrives at a surface. Each material has its own approach to affecting a room’s acoustic environment. This way, you’ll achieve an effective acoustic treatment. Here are a few great options:
Acoustic Fiberglass
Fiberglass is probably one of the best acoustic treatments. It’s made out of compressed tiny glass or plastic particles. Acoustic fiberglass used for soundproofing is typically in the form of batts or rolls. It also comes in rigid boards that can be attached to foams or fabrics for customized acoustic treatments.
Wooden Acoustic Panels
Sound-absorbent wooden acoustic panels are usually perforated for sound diffusion. They lower down noise levels and reduce reverberation for better sound quality. These panels can be made from reclaimed wood, making it an eco-friendly alternative to acoustic foams.
Conclusion
Acoustic foam has earned itself the reputation of being an effective acoustic treatment. It has long been used as a sound absorber in recording studios. But concerns about potential fire risks can’t just be simply ignored. To acoustic foam being a fire hazard, it’s safe to say it isn’t because of its fire-retardancy.
But if you still don’t feel comfortable with using acoustic foams, you can still opt for other alternatives that are just as functional. In the end, it’s you who decides what you believe is safe or not. Either way, acoustic foam is a great choice.
