Types of Insulation
When in 1937, Otto Bayer invented spray foam (polyurethane) by mixing isocyanate and polyol resin in small volumes, little did he know that he was about to revolutionize the packaging and insulation industry. Both chemicals have high reactive properties and when mixed with each other they expand up to 60 times the original liquid volume. The mixture can take the shape of the material to be packed, resulting in virtually zero air infiltration and thermal insulation. This completely envelops the material from heat and changing environmental conditions. Along with these properties, it also has a high value of thermal resistance. All these attributes make spray foam popular in the packaging and the insulation industry. Today there are a number of different types of insulation.
Cell insulating materials should be impermeable to airflow, durable over the lifetime of the building, and able to withstand the natural forces that act against them. Spray foam technology adheres to all these aspects and raises the standards of design and functionality of constructions.
Spray foam insulation can be categorized into two forms based on its density. These two forms are open cell foam and closed cell foam. Open cell foam is a spray foam that forms when water as a blowing agent mixes with isocyanate to produce carbon dioxide that fills all the cells of the spray foam. Since the water is mixed with isocyanate just before the application, the expansion of carbon dioxide makes the bubbles burst because of the pressure and the material looks spongy. Since the cells open upon application it has been given the name “open cell foam”.
Open Cell Foam
In open cell foam, the bubbles share walls with each other and the plastic component in the finished product is usually very low, which makes it really soft and airy. Most of it is simply carbon dioxide filled in cavities. Since it has water as a blowing agent, open cell foam is an inexpensive alternative for industrial insulating requirements. It is used as an insulator to save the building from heat, excessive cold and sometimes airy weather which produces noise. Open cell foam has more gas and less plastic. Hence the final product is low in density and weighs only 0.5 to 0.6 pounds per cubic feet.
This makes open cell foam beneficial when being used in open and wide spaces, as it can reach a huge area because of its light weight and low density. It is recommended for filling cracks, crevices, and in the places which are in the interiors of the house. A place like an attic of a house is a favourable space for the open cell foam spray.
Even though open call foam is not a vapour barrier, open cell foam acts as an irreplaceable air barrier when applied. It engulfs the air leakage in its gas pockets making it perfect for sound proofing and air proofing, especially in windy areas. This quality of pocketing air leaks also makes it an inexpensive alternative for energy efficiency by saving the energy spent in air conditioning. It keeps conditioned air where it should be - inside the building.
Closed Cell Foam
The formation of closed cell foam is similar to open cell foam. The only difference is the use of Enovate chemical also known as 245fa along with water as blowing agent. Since Enovate is a chemical which needs to be manufactured, it is expensive. This makes manufacturing of closed sprayed foam an expensive affair compared to open foam sprays.
The cell structure in close cell foam is independent of the other cells and these cells do not share a wall with any other cell. Closed cell foam is made of millions of tiny plastic closed cells filled with Enovate gas resulting in highly efficient insulating properties. It has density around 2 to 3 pounds cubic per foot. Closed cell foam shows higher thermal resistance as compared to open cell foam. This higher R value makes closed cell foam a better insulating material.
The high insulation value of close cell foam also makes it useful in packing fragile items such as glass items. It can easily adapt the changing environmental conditions while the product is transported or preserved at a place.
The applications of closed cell foam are not limited to wide spaces; it can be used as effectively in a shallow space too. As a building gets old it starts losing its nails and the basic tile structure of the roof. Closed cell foam can be used to restore the firmness of the hinges and roof as it is stronger than other alternatives like fiberglass.
Moisture permeability is also a huge area of concern for the builders and home developers. With the lowest rating of 1 perm for 2" of the depth of moisture permeability, closed cell foam offers a great solution. Problems such as mold formation, which are the results of humid weather, can be solved by using closed cell foam.
The moisture permeability of closed cell foam is so low that it can even be used at places that are frequently affected by floods. The closed cell foam prevents the penetration of the moisture to the core of the structure. It also dries itself quickly since the main component is plastic. Due to these properties, the construction industry considers closed cell foam spray a great value for the money.
The main parameters of comparison between open and close cell foam are its costs, air permeability, rate of insulation, moisture permeability, energy efficiency, and structural strength.
R-Values of Open Cell Foam and Closed Cell Foam
Within the two categories of spray foam there are additional types of insulation based on the heat resistance of the material. For instance, a ½ pound open cell foam spray weighs between .4 and .6 lb/ft3 when it is cured. It expands approximately 150 times its original volume and forms a semi-rigid structure. This cell foam has an R-value of about 3.5 per inch. R-value is a measure of resistance to heat flow through a given thickness of material. 2 lb closed cell foam weighs between 1.5 and 2 lb/ft3 when cured, expands to between 35 and 50 times its original volume, and forms a rigid structure. The 2 pound cell foam has an R-value of around 6 or greater per inch.
What are the Differences between Closed Cell Foam Spray and Open Cell Foam Spray?
Costs: Because of the procedure involved in the manufacturing process, there is a significant difference in the cost. The cost of closed cell foam is higher due to the use of Enovate. Since Enovate is a patented product and manufactured by only one company its prices are on the higher side. On the other hand, open cell foam uses water as the blowing agent, significantly reducing the manufacturing costs.
Air Permeability: It is a misconception that open cell foam requires a thickness of 5.5” to achieve air barrier status. Closed cell foam is considered as an air barrier at only 1” thickness. Open cell foam does not use CFCs or HFCs as blowing agents. Open cell foams that meet the ASTM E283 standards are equally good barriers as closed cell foams. They even increase the sustainability of the building.
The rate of insulation: The other factor that differentiates the open cell foam from closed cell foam is its rate of insulation. The rate of insulation affects the demand of the spray foam as an insulation solution irrespective of the pricing. The open cell foam has a large number of cells that are connected to each other with the shared walls. Water is as a blowing agent and spaces within the cells are filled with atmospheric air. Because of this open cell foam is affected by the change in external temperature. Even a minute change in the temperature over a small area can affect the overall temperature.
R-value of open cell foam is lower as compared to closed cell foam. As a result, open cell foam is a good insulator when the changes in the temperature are moderate. However, it cannot work as effectively when the changes in the temperature are drastic.
In closed cell foam, the cell structure has a large number of cells which are independent of each other. No two cells share a common wall in closed cell foam. This attribute makes it a highly efficient insulating product. Since no two cells are in physical contact with each other, aggressive temperature changes over a particular area have no effect on overall insulation. Thus high-quality insulation can be achieved with closed cell foam.
The difference in blowing agents of both the foam also affects the R or rate of insulation. In open cell foam, water reacts to form air between the cells. In closed cell foam, the blowing agent is Enovate which is highly reactive resulting in trapped Enovate gas bubbles. As a result, closed cell foam has a high insulation value of six. The R value of both open cell foam and close cell foam are unaffected by the factors like air pressure and temperature.
Although the open cell foam has lower R-values, it remains constant. Since the cells are filled with air, the R value does not change with time. For closed cell foam, the R value is higher at the time of application but degrades over time. This is because the trapped gas bubbles are replaced with atmospheric air reducing its insulating properties. At the time of application, the R-value of the closed cell foam can be increased by spraying multiple layers.
Moisture Permeability: Closed cell foams are considered as vapor impermeable and open cell foam are considered vapor permeable. Under right conditions, some water can move through the open cell foams.
Energy efficiency: Air leakage can lead to increased cooling and heating costs. Both open cell and closed cell foam spray are equally efficient in acting as an air barrier. But, open cell spray foams have added benefits of longevity. It is due to the same manufacturing process related problems that we have discussed.
Structural strength: Use of foam cells should complement the structural strength. Closed spray foam delivers additional strength to the structure because of its rigidity. It provides increased racking loads, compressive resistance to the structure. On the contrary, the open-cell foam provides structural flexibility. Open-cell foams are flexible and spongy thus they expand and contract with framing members thus providing a reliable air seal.
Being environment-friendly is also extremely essential. The open cell foam uses water which is a renewable source. The greenhouse gas emission is also lower for open cell foam as opposed to closed cell foam which uses Enovate as blowing agent. Open cell foam is also widely used for sound proofing.
Both open cell foam and foam closed cell provide a better insulation solution as compared to any other insulation technique like fibreglass and cellulose. The uses of both vary from place to place in accordance with the temperature requirements of the place. Spray foam has become a global phenomenon. Every day new techniques are being employed to provide clients a durable solution to their insulation problems.
To design and build a durable, safe, comfortable and economical building, airflow must be controlled. Uncontrolled airflow should be controlled as it impacts structural integrity, serviceability, indoor air quality and also the thermal energy performance. Performance optimization is achieved when systems and products work together to promote an energy-efficient environment. We provide the best solutions to ensure all these parameters are controlled.
Let SprayEz Meet your Home Insulation Needs
At SprayEZ, we provide both open and closed cell spray for various types of insulation requirements. SprayEZ is one of the largest suppliers and manufacturers of spray foam, dispensing equipment, and Polyurea in the world. We have a range of open cell foam spray, closed cell foam spray, and other do it yourself equipment that will help you insulate your homes and buildings. At SprayEZ we offer specially designed equipment that enables you to adjust for the higher heat and pressure needed for Polyurea with the ability to lower the heat and pressure for the needs of Spray Urethane Foam.
We understand that insulation requirements change from place to place. Thus, we offer customized solutions to our clients rather than providing generic solutions. Be it spray guns, closed cell spray, open foams, accessories or dispensing equipment, we at SprayEZ make finding the right product according to your requirements as easy as it can get. We also offer financing to make our products available to more people. Wherever you reside we have the products to suit your needs. Solvents, spare parts, spray foam guns, or SFT machines, you name it and we have it. We are one stop shop for all your insulation related needs. Be it dust, freezing pipelines or any other problem related to non-insulated housing structures, we have you covered.