Polyurethane is a plastic material, which comes in a variety of forms that can be customised for rigidity and flexibility. It’s used in a variety of applications, including insulation of refrigerators/freezers, buildings, cushioning for furniture, motor vehicle parts, adhesives and coatings, composite wood panels and sportswear.
Kwikspace believes there’s no better alternative to polyurethane, for use in its prefabricated buildings. In fact, a specialised polyurethane foam (40 mm thick) is injected inside the Chromadeck steel Structural Insulated Panels (SIPs) that make up the walls and ceilings of their prefabricated building units. The foam is a significant factor in the safety, longevity and robustness of Kwikspace units.
The impressive benefits of polyurethane
The polyurethane foam utilised by Kwikspace delivers a number of advantages, including:
- High load bearing capacity, in both tension and compression.
- Under a heavy load, polyurethane changes shape, but returns to its original form once the load is removed. This is of particular benefit for mobile modular buildings, which need to withstand the rigours of relocation.
- Resists tears, chemical solvents, insects, mould and decay. “While polystyrene will suffer when subjected to harsh solvents, polyurethane is resistant to all chemicals,” explains Johan Liebenberg, Production Executive, Kwikspace. In addition, polyurethane is also safe, non-toxic and chemically inert.
- Superior fire retardation. “Polyurethane will remain mostly undamaged by heat until temperatures reach 700 °C, at which point the material begins to char. Polystyrene, by comparison, will melt at temperatures in the 200- to 300-degree range,” elaborates Liebenberg.
- Water resistance. Polyurethane foam remains stable (with minimal swelling) in water, due to its closed cell structure. This ability to resist water makes it a preferred choice for buildings that are exposed to a lot of moisture (e.g. ablution buildings).
- Good electrical insulation.
- Thermal efficiency which, in turn, reduces energy use. “The most cost-effective way to increase the energy efficiency of a building is to install good insulation in the walls and roofs. Energy consumption is reduced, which also reduces the carbon emissions that harm the environment,” notes Liebenberg.
- Insulation properties with a high R-value (a measure of thermal resistance). Polyurethane demonstrates about twice the resistance to heat than polystyrene. This means it has a resistance to extreme temperature and won’t degrade in harsh environmental conditions.
- Structural strength. During the manufacturing process, polyurethane is injected into Chromadeck rigidised panel sheets. It bonds to the sheets and adds additional strength to the panel. “This would not be possible with polystyrene panels, which are bonded together under pressure using an adhesive. This process has an increased risk of delamination of the polystyrene from the panel sheet over time,” adds Liebenberg. Even where panels are joined (by means of a male/female joint), the area around the joint can withstand high winds and driven rain.
- It offers excellent sound absorption.
- It makes for easy handling and assembly of panels, as well as rapid manufacture of units, since panels are ready for installation just 18 minutes after the polyurethane is injected into them (with no delays required for the foam to cure).
The effective application of polyurethane foam is one reason why Kwikspace prefabricated buildings deliver a minimum life of 20 years, and are SANAS-certified. Read more about our prefab building technology, here, or contact us to get more information.