EPS vs PIR Insulated Panels — A Melbourne Specification Guide
How the two most common insulated panel cores compare on thermal performance, fire rating and cost for Australian commercial and industrial buildings.
Two cores, two very different profiles.
Insulated sandwich panels used across Melbourne cold storage, food production, warehousing and industrial fitouts almost always run one of two cores — EPS (expanded polystyrene) or PIR (polyisocyanurate). The steel skins and profiles look similar; the core is where the specification decision sits.
EPS is the more economical, general-purpose core. PIR delivers a higher R-value per millimetre and better fire performance, and is the default for cold storage and higher-risk commercial buildings. The right answer depends on the internal environment, the building's fire strategy and the budget.
EPS vs PIR at a glance.
Thermal (R-value)
EPS
Lower R per mm — thicker panels for the same R
PIR
Higher R per mm — thinner panels hit the target
Fire performance
EPS
Combustible; suited to low fire-load buildings
PIR
Improved fire performance; preferred for cold storage & food production
Cost
EPS
Cheaper per m² at same thickness
PIR
Higher panel cost; may still be cheaper overall on thinner spec
R-value per millimetre is where PIR pulls ahead.
Typical PIR panels deliver about R2.8 at 75mm through to R7.9 at 200mm. EPS sits roughly a third lower per millimetre, so an EPS panel needs to be noticeably thicker than a PIR panel to reach the same R-value.
For a chiller room targeting around R4, PIR at 100–125mm is usually enough. Matching that with EPS pushes panel thickness up, which drives door, framing and detailing costs — one reason PIR often wins on total cost even though the panel price is higher.
The core reason PIR dominates commercial cold storage.
EPS is combustible and drops its structural integrity quickly under fire load. PIR chars rather than melts and holds up longer, which is why fire engineers routinely specify PIR-cored panels for cold storage, food production, distribution and higher-risk industrial buildings under the National Construction Code.
EPS still has a legitimate place in lower fire-load buildings — general warehousing, back-of-house partitioning, non-food industrial — where the fire strategy allows it and the panel system's group number and spread-of-flame rating are acceptable.
EPS is cheaper on paper. Look at the full build.
At the same thickness, EPS is meaningfully cheaper per square metre than PIR. The catch is that thickness is rarely the same — matching a PIR spec with EPS usually means thicker panels, larger door leaves, heavier framing and more insulation on penetrations.
On cold storage and food buildings, PIR often lands close to or below EPS once the whole build is priced. On general warehousing where PIR isn't required, EPS is the more sensible choice.
How Square IPC specifies for Victorian sites.
- Cold rooms, freezer rooms & chillers — PIR
- Food production halls & cleanroom-adjacent — PIR
- Distribution & logistics with strict fire strategy — PIR
- General warehousing & non-food industrial — EPS acceptable
- Back-of-house partitions in low fire-load areas — EPS acceptable
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