Foam insulation is typically a low-density elastomer or polymer in the form of a thermal insulating foam that provides a thermal barrier around a component or between an interior space and a heat or cold source. It contains better insulating qualities (higher thermal resistance to heat flow known as R-value) than traditional fiberglass insulation due to its ability to block conductive, radiant and convective heat transfer. Many types also seal air leaks, provide sound reduction and protect against moisture.

Foam insulation is a relatively modern and improved substitute for rolls of traditional insulating products like fiberglass insulation. The U.S. military began using polyurethane-based spray foam insulation in the 1940s on airplanes and rigid foams were widely used for safety and insulation in cars starting in the 1960s, but foam insulation products did not begin to gain popularity in residential and commercial buildings until the 1970s.

Types

Foam insulation can come in the form of spray-on foams, rigid foam panels or custom pre-molded shapes. Types of foam insulation include:

• Closed cellular foams with interconnected cells or pores that are sealed off, making them impenetrable to moisture, an excellent sound barrier and have a higher R-value
• Open cellular foams with interconnected cells or pores that are not completely closed, which makes it more sponge-like and reduces noise. This type of foam also has a solid thermal and air barrier, although it is not an effective moisture barrier
• Flexible foams that absorb impact by bending or flexing without cracking
• Rigid foams made of a skeletal matrix that offers little or no flexibility
• Reticular foams that have a more open structure and a skeletal matrix composed of a network of interconnecting strands
• Syntactic foams consisting of microspheres or glass micro-balloons held together by a resin

 
The chemical compounds used in foam insulation were developed by scientists for their properties in thermal insulation, fire resistance, low density, durability and shock absorption. By installing a layer of foam insulation on or inside any surface, it creates a thermal envelope thanks to their relatively high R-value, which is the material's thermal resistance to heat flow. Thanks to the properties of these chemical compounds, foam insulation also reduces noise at a greater level than other insulating materials of the same thickness.

Spray foams work by using an A + B system whereby two components combine during application. A plastic or elastomer liquid resin is mixed with a catalyst or hardener upon application, which causes a curing process whereby the resin can expand to many times the size of its liquid form.

Features

Foam insulations vary by their level of thermal insulation, the amount of outside sound they block and whether they effectively block moisture. Foam offers these qualities better than traditional insulation products while also being lighter weight. They have varying degrees of fire resistance/retardant, chemical resistance, electrical insulation or a conductor of electricity and expand in the case of spray foams. In addition, foam has a tougher and higher density integral skin layer against a lower density core, is resistant to collapse when exposed to hydrostatic pressure and is weather and ultraviolet light resistant.

Many foam insulation products come in the form of relatively rigid, precut panels for easy installation in larger spaces. Molded foam insulation allows users to create a custom shape that can be used to insulate uniquely shaped components or spaces. Spray foam insulation can be used as an effective seal or filler for holes, particularly if it is moisture-proof closed cell spray foam. It is a more versatile product for use in tight or hard to reach spaces due to its expanding qualities.

Applications

While foam insulation is standard as a preferred insulation material for homes and other buildings, its use in buildings is more recent compared to its many other purposes. Some of traditional uses include:

• Aerospace and aircraft applications
• Automotive and other transportation applications like lightweight body panels, cushions and filtration
• Baffling to reduce the sloshing of fuel and volatile liquids whose movement during transportation can generate explosive fumes
• Furniture applications like seating, mattresses and pillows
• Commercial and industrial filtration systems in the case of open celled foams
• Heating, ventilating and air conditioning systems
• Marine applications, where products are used in ships or boats much how they are in cars or airplanes
• Sealing applications
• Packaging and casing applications 

Specifications

Foam insulation products have a number of specifications, but the most commonly referenced is the R-value. The higher R-value equates to a more efficient insulation. Foam insulations have an R-value of at least 4, although some are much higher. Other specifications of foam insulation include:

• Use temperature - Temperature range to which the material can be exposed
• Dielectric strength - Maximum voltage a material can withstand
• Tensile strength - Maximum amount of stress required to break the material
• Tear strength - How well material can withstand the effects of tearing
• Bulk density - Mass per unit of an area of the material
• Noise reduction coefficient - A rating based on the material's ability to absorb noise 

Material

 
While many chemical mixtures can be used to create foam insulation products, the most common materials used to make foam insulation include:

• Plastics or polymers like polyurethane, polyisocyanates, polystyrene (extruded, expanded, molded expanded and extruded expanded variants), and extruded ethylene copolymer, fluoropolymer, water-based latex, polyester, polyether, polyetherimide, polyimide, polyolefin, polypropylene, phenolic or silicone
• Metal or metal alloys
• Ceramics
• Plant-based materials like corn, fungi or natural rubber
• Elastomers or rubbers
• Advanced plastics like thermoplastic and thermoset plastic

Many spray or pourable foam insulation also uses an A + B formula where one of the plastics noted above acting as a casting resin is mixed with a catalyst or hardener to initiate a curing process.

Selecting

The type of foam insulation needed is highly dependent on the application intended for use. Foam in automobiles, boats and airplanes use specialized, rigorously tested products. In addition, foam insulation products for packaging are developed to maximize shock absorption and prevent moisture from damaging the packaged product. Consumers have a wider choice of materials from the traditional plastics to a newer range of plant-based packaging.

Building applications provide the greatest amount of choice in foam insulation with spray, rigid foam panel and molded products all potential solutions. Users can decide which option is best by evaluating the cost to the desired level of thermal insulation, noise reduction and moisture blocking.

Benefits

For the millions of people and businesses looking at foam insulation to insulate their homes or offices, foam insulation provides thermal insulation as much as 50% higher than traditional insulation products. Beyond their common use as thermal insulators, foam insulation provides a potential wealth of additional benefits including top-quality noise reduction in buildings, cars, ships and airplanes. Many forms block out moisture, which prevents mold and mildew and the ensuing rot they cause. Although, in the case of packaging, foam insulation has wicking qualities to keep moisture from the product it is protecting with its additional shock absorption qualities.

References

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Pittsburgh Corning | Grainger Industrial Supply | Elasto Proxy Inc.