Optimizing PIR Insulation with VILPE Sense: Combating Moisture and Heat Accumulation
In some regions, PIR (polyisocyanurate) is a favored insulation material due to its thermal performance and fire resistance. Its low thermal conductivity provides energy efficiency, while its inherent fire resistance enhances building safety. However, PIR insulation is particularly sensitive to moisture, heat and thermal fluctuations, which can degrade its effectiveness and longevity. The VILPE Sense system addresses these vulnerabilities by detecting moisture levels within the insulation, ventilating and cooling the insulation layer as needed, thereby ensuring that PIR retains its high performance and durability over time.
PIR (polyisocyanurate) insulation is widely used in both Europe and the United States due to its thermal performance, fire resistance, and durability. In Europe, PIR insulation is integral to the construction industry, driven by stringent energy efficiency standards and regulations aimed at reducing the carbon footprint of buildings. The material’s high insulation value per unit thickness allows for thinner walls, providing more usable space without compromising energy efficiency. This makes it particularly popular in residential and commercial buildings where space optimization is crucial.
PIR insulation is a rigid foam insulation. It is a type of plastic derived from the reaction of polyol with MDI (methylene diphenyl diisocyanate) in the presence of a blowing agent. PIR foam consists of closed cells, which makes it resistant to water absorption (Walker and Pavía, 2015). PIR insulation has a very low thermal conductivity, typically around 0.022 – 0.026 W/mK (Filin and Filina-Dawidowicz 2021; Pásztory 2021). This means it provides excellent insulation with thinner layers compared to other materials. Also, PIR insulation has good fire resistance properties (Prałat, Ciemnicka and Jankowski, 2023). It chars and forms a protective layer when exposed to fire, which helps to limit the spread of flames and the release of toxic smoke (Bytskov, 2015). The disadvantages with PIR insulation are that it is often more expensive than other types of insulation like EPS or mineral wool. PIR insulation is also more sensitive to handling and installation as improper techniques can compromise its performance. It should be noted that PIR insulation material properties can show some qualitative variance depending on manufacturer and formula used. Qualitative variations for PIR materials have been documented for thermal properties (Prałat et al., 2023b), fire resistance (Wi et al., 2022), environmental impact (Fraska et al., 2023) and long-term integrity.
PIR Insulation and material aging
The thermal insulation capacity of PIR insulation degrades over time, particularly when exposed to significant temperature fluctuations and moisture (Tariku, Shang and Molleti, 2023). This has been observed in both field studies and laboratory conditions. Long-term thermal properties of PIR insulation have been extensively studied, indicating that thermal conductivity increases over time. However, these effects can be minimized with temperature and moisture management and proper installation techniques.
Temperature. PIR insulation is particularly sensitive to temperature fluctuations and especially high temperatures (Berardi and Naldi, 2017; Makaveckas, Bliūdžius and Burlingis, 2021). This degradation is primarily due to the penetration of air components, such as oxygen and nitrogen, into the insulation’s cell structure, a process that accelerates at higher temperatures. As temperature increases, the gas within the closed cells of the foam can expand, causing the cell walls to weaken or rupture, which in turn increases thermal conductivity and reduces insulation performance (Makaveckas et al., 2021). These results suggest that PIR insulation might not be the best choice for climates prone to large temperature shifts or for roofs that are in risk of high temperatures, highlighting the need for cooling mechanisms within the structures to maintain insulation performance.
Moisture. Even though the closed cells of PIR insulation make it resistant to water absorption, moisture still poses a problem for this insulation type (Cai, Cremaschi and Ghajar, 2014; Walker and Pavía, 2018). If PIR insulation is installed incorrectly or without an appropriate vapor barrier, moisture can accumulate behind the insulation, causing condensation which in turn can lead to mold growth and structural damage. Also, exposure to constant water and humidity will eventually fill the cells with moisture, especially if not a proper vapor barrier is used. Moisture, combined with high temperatures, tend to accelerate the aging process of PIR insulation (Tariku, Shang and Molleti, 2023).
Installation. PIR insulations should be installed to avoid excessive moisture exposure and minimize temperature fluctuations. It is recommended to use a vapor barrier and protect the insulation from UV radiation and chemical exposure. There are some disagreements regarding the installation of EPDM membranes and how loosely it should be installed (Atchley, Hubbard and Desjarlais, 2019; Habibi, Obonyo and Memari, 2020; Machfudiyanto and Riantini, 2023). PIR insulations installed under a loosely fitted EPDM membrane appear to age more slowly whereas others argue the opposite. Loosely installed membranes allow for better ventilation, which can slow down the aging process of the insulation and moisture accumulation. A fully adhered EPDM membrane more effectively prevents moisture from entering the insulation, but it can also cause greater temperature fluctuations within the insulation, accelerating the aging process.
How VILPE Sense secures PIR insulation properties
PIR insulation is known for its excellent thermal performance and fire resistance, but it can be sensitive to moisture and requires proper ventilation to maintain its effectiveness. The VILPE Sense system can proactively mitigate moisture and temperature issues associated with PIR insulation. The VILPE Sense product family consists of two products.
- The VILPE Sense leak detectors monitor moisture levels in the structures, alerts to excessive moisture, and locates leak areas also on larger roofs, allowing for quicker and cheaper repairs.
- The VILPE Sense humidity control system is designed to prevent moisture damage that arise due to structural causes, such as leaking vapor barriers, and solves the problem by enhancing ventilation as needed. The VILPE Sense humidity control can be used with PIR insulation if air circulation can be secured within the structures. This can be done, for instance, by installing insulation material with ventilation grooves on top of the PIR insulation or if the EPDM membrane is installed loosely to allow for ventilation.
Humidity control. VILPE Sense humidity control uses sensors to continuously monitor the humidity levels within roof structures. This is crucial for PIR insulation, which can lose effectiveness if it absorbs moisture. The system detects increased humidity levels, which could indicate potential leaks or condensation issues, and automatically adjusts the system’s roof fan to ventilate the roof to remove excess humidity. When sensors detect elevated humidity, the fan speeds up to enhance ventilation, removing moisture from the insulation and preventing damage. This automated adjustment helps maintain optimal humidity levels within the roof structure, protecting the PIR insulation from moisture-related degradation.
Heat removal. During hot weather, the VILPE Sense humidity control ventilates the roof and helps to remove excess heat from the roof structures, which can otherwise lead to overheating and reduce the effectiveness of PIR insulation. This dual functionality—managing both moisture and heat—helps maintain the integrity and performance of PIR insulation over time.
Early leak detection and alerts. The VILPE Sense leak detector identifies leaks and excess moisture in the roof structure that might otherwise go unnoticed. Early detection allows for timely repairs, preventing extensive and costly damage to both the roof and the PIR insulation.
In summary, the VILPE Sense system enhances the performance and longevity of PIR insulation by effectively managing moisture and heat through advanced monitoring and demand-based ventilation. This proactive approach ensures that the insulation remains dry and effective, thereby maintaining its properties.
References
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