Home and Building Care and improvement Tips
Low density polyurethane injection
When we thermally insulate a building we can find facades that have air chambers filled with a previous insulation based on fibers or glass wools or mineral wools, but that is insufficient or has suffered wear over time. In this case we can inject open cell low density polyurethane, which compresses these wools, improving that existing insulation, reducing the energy losses or gains and the polluting emissions of that building.
Inject rigid polyurethane foam on the façade is a very effective insulation solution. Polyurethane can be injected into a double- leaf facade, which can be made of brick, concrete, cement, laminated plaster, metal or wood, as long as it has a space between the outer and inner walls (air chamber). The polyurethane is injected in the form of liquid foam in the air chamber of the façade, expanding inside and forming rigid open cell foam of great insulating capacity and very low density.
It is an avant-garde system of insulation by injection polyurethane in air chambers, with low density polyurethane foam, with very good thermal conductivity, which thanks to its foaming capacity guarantees an exceptional distribution in the air chambers.
In the practice of our profession, roughly and normally, in Spain we can see that before 1979 the air chambers are empty, without isolation. From 1979 to 1995, approximately, they are filled with thin plates where insulation can be insufflated or injected. And since 1995 can be found or chambers filled air with mineral wool or rock or other materials, which remain centimeters to fill, or well chambers completely filled air but whose isolation can also be improved, for example, polyurethane foam, because even in these last cases, the foam will compress the insulating material up to 80 percent, leaving a gap to improve it
What is polyurethane?
Polyurethane is the insulation obtained from the chemical reaction of two products: (derived from sugar cane) and isocionate, derived from petroleum, which at a certain pressure and temperature (38-50º) when combined produce polyurethane, insulation plastic.
Polyurethane cannot be considered natural, but it is recyclable and respectful with the environment.
Insulation Material Installation Services providers uses the technique of injection of polyurethane only in front air chambers and the product we use is from the manufacturer Dow.
The characteristics of the injection polyurethane foam are the following:
- Low thermal conductivity 0.038 w / m * k, similar to that of rock wool
- High thermal resistance
- Low fire behavior: Euro class E
- Low acoustic performance (50% of open cells)
- Under specific heat: 650 joules
- Low thermal gap (up to 6 hours in thicknesses of 200 and 250 mm)
- Hydrophilic: good behavior against water or humidity
- The application technique for this foam is injection. This system can be installed in areas where there are cavities with a minimum thickness of 20 mm for proper installation.
- It is good for the summer heat.
Advantages of injected polyurethane:
- Improves thermal behavior and comfort by eliminating infiltrations of outside air
- Reduces airborne noise from the outside, thanks to its structure of open micro cells
- Guarantees the total filling of the air chamber, adapts to any geometry and does not suffer settlements over time.
- The adhesive nature of the polyurethane makes it possible to consolidate both sheets of the facade
- The polyurethane does not proliferate fungi or microorganisms and is an innocuous material with a long life and useful life exceeding 50 years
- Regarding its application, logically, does not diminish the living space, since it is injected into the interior of the air chamber and, therefore, its installation does not create inconvenience to the user.