Cold storage applications use insulated panels to maintain a controlled environment. There are several types of insulated panels and to complicate things, the foam used can also vary. In this article, we will discuss the differences between PUR, PIR, XPS and EPS foam types used as the insulative core.
Commonly Used Insulative Foam Types
Polyurethane (PUR), Polyisocyanurate (PIR), Extruded Polystyrene (XPS) and Expanded Polystyrene (EPS) are the most common foam core types used in Insulated Panels.
Polyurethane (PUR) is a high performance, poured in place dense foam that expands when mixed and bonds tightly to metal skins as it sets. PUR foam provides a high R-Value and adds structural benefits because the foam amalgamates the individual components together as a monolithic composite panel.
Polyisocyanurate (PIR) is chemically similar to PUR, but PIR is more rigid with greater fire resistance. PIR is often categorized with PUR due to having several common physical properties as both are rigid urethane foams with excellent thermal values.
Extruded Polystyrene (XPS) is a smooth, dense, closed-cell foam that comes in pre-formed boards. XPS has several notable physical properties, such as moisture resistance and solid thermal performance. Additionally, the foam is lightweight.
Expanded Polystyrene (EPS) is commonly referred to as Styrofoam and consists of small beads molded into a shape. While the R-Value per inch is lower, panel thickness is usually doubled to obtain R-Values comparable to urethane. It’s cost effective and can be used for large scale warehouses and project applications. EPS is manufactured differently than XPS and has different structural and insulating properties.
PUR | PIR | EPS | XPS | |
R-Value per Inch | High | High | Low | Medium |
Structural Strength | High | High | Medium | Medium |
Fire Resistance | High | High | Low | Low |
Moisture Resistance | Medium | Medium | Low | High |
Cost | High | High | Low | Medium |
Insulation Performance
Polyurethane and polyisocyanurate provide the best R-Value per inch. Due to their insulative properties, PUR and PIR achieve results that would require thicker XPS or EPS panels to meet energy codes. Both PUR and PIR are ideal when every inch is crucial to space utilization.
EPS panels offer the lowest R-Value per inch. XPS provides a better R-Value than EPS.
Structural Strength
One of the biggest advantages of PUR and PIR is their bonding ability. When foamed-in-placed, the insulation acts as a “glue” between the individual components. As the foam cures it amalgamates the components (frame, metal skins and foam core) to act as one resulting in a structured panel. PUR and PIR panels are often referred to in the industry as structural insulated panels (SIP).
EPS and XPS cores provide less structural strength as they are lighter, and the foam sheets are attached to the metal skins with adhesive, which doesn’t create that same effect as a fully cohesive panel. Continuous Line Panels from KPS Global®, with an EPS core, can span up to 30’ (if using 10” foam) or when paired with structural steel for added structural strength can span up to 45’.
Moisture Resistance
All foam insulations should be protected from any moisture exposure!
Urethane panels protect against moisture in standard conditions. Moisture infiltration into the foam reduces the panel’s insulative capability by lowering its R-Value. In a study done for a freezer application, R-Values dropped an average of only 1.5% of its insulating ability.
KPS Global uses a large industrial foam press to precision seal our urethane panels together. With the core foam inside, the metal skins act as a vapor barrier that shields the foam core from harm and insulative degradation.
XPS and EPS tend to handle moisture differently than urethane panels. XPS is moisture resistant and provides a barrier to humidity. EPS is less resistant than XPS but still performs well against moisture.
XPS provides high moisture resistance when compared to urethane. However, over its lifetime the R-Value drops 21% on average for insulation in freezer uses according to DOW. This is a large difference when comparing to standard, properly sealed urethane panels.
Cost Differences by Foam Type
The various foam types leads to difference applications and uses.
For large-scale projects, EPS panels are an option to keep costs down. XPS panels are a mid-range cost. Polyurethane and Polyisocyanurate panels are a higher cost but are considered the industry standard for insulated panels when maintaining temperature or humidity control is critical.
Making the Right Choice
There’s no one-size-fits-all solution when it comes to foam insulation. Each project has unique needs based on budget, structural load and facility layout.
At KPS Global, we offer both Polyurethane (PUR) and Expanded Polystyrene (EPS) panels, providing a wide range of options to match your goals. With over 75 years of experience, KPSG has worked alongside countless customers across various industries solving complex cold storage challenges.
No matter what your project demands, KPS Global is here to help you make an informed decision. Contact us so we can begin working up plans for your project with the right foam type for each application.
