¿Son ignífugos los paneles PIR? Lo que los constructores deben saber

When specifying insulation for commercial or residential projects, fire safety isn’t negotiable. PIR (polyisocyanurate) boards are a top contender in thermal efficiency, but their fire performance often drives final decisions. Let’s cut through the noise: PIR isn’t fireproof, but its engineered fire resistance outperforms most foam-based alternatives. Here’s what professionals need to understand.

Fire Classification: Where PIR Stands

PIR boards typically achieve a Euroclass B-s1, d0 rating under EN 13501-1. This means:

• Class B: Combustible but resistant to ignition. Unlike EPS (Class E) or XPS (Class F), PIR won’t fuel rapid flame spread.
• s1: Minimal smoke emission during combustion. Critical for safe evacuation and reducing toxic exposure.
• d0: Zero flaming droplets. Eliminates secondary fire risks from molten debris.

For context, mineral wool holds a non-combustible Class A1 rating. However, PIR’s balance of insulation value (lambda as low as 0.022 W/mK) and fire performance makes it a pragmatic choice in many scenarios.

How PIR Reacts Under Fire

While no foam is entirely fireproof, PIR’s chemistry gives it an edge:

1. Char Formation: When exposed to flame, PIR’s surface chars, creating a protective layer that slows heat penetration.
2. Self-Extinguishing: Once the ignition source is removed, flames typically die out within seconds.
3. Low Smoke Toxicity: Unlike burning polystyrene, PIR emits fewer corrosive gases like hydrogen cyanide.

Field-Tested Applications

PIR’s fire behavior has been validated in real-world assemblies:

• Rainscreen Cladding: Paired with firebreaks and mineral wool barriers, PIR meets stringent façade safety standards (e.g., UK’s BR135).
• Flat Roofing: Systems using PIR with fibreglass facers achieve BROOF(t4) ratings, suitable for high-risk buildings.
• Compartmentation: When detailed with fire-rated boards (e.g., Gyproc FireLine), PIR maintains compartment integrity up to 60 minutes.

Upgrading Fire Performance

Smart detailing amplifies PIR’s inherent resistance:

• Barrier Boards: 12.5mm fire-resistant plasterboard adds 30+ minutes of protection.
• Intumescent Sealants: Expand under heat to seal gaps around PIR installations.
• Hybrid Systems: Layering PIR with mineral wool in staggered configurations balances U-values and fire safety.

Certifications Matter

Always verify third-party testing. Reputable PIR manufacturers provide:

• CE Marking with EXAP reports confirming reaction-to-fire class.
• ISO 1716 compliance for non-combustibility of facing materials.
• Large-Scale Test Data (e.g., BS 8414 for façades).

The Bottom Line

PIR boards aren’t fireproof, but their engineered fire resistance meets most regulatory demands when properly specified. For projects requiring non-combustible solutions, mineral wool remains king. Yet where thermal efficiency and space-saving are priorities – especially in retrofit or thin-wall constructions – PIR delivers a compliant, practical balance.

Always cross-reference system warranties and local codes. Leading manufacturers like Kingspan, Celotex, and Recticel offer technical support to tailor PIR solutions to your fire safety requirements.

Focus Keywords: PIR boards fireproof, PIR fire resistance, Euroclass B-s1 d0, insulation fire safety
Meta Description: PIR boards aren’t fireproof but achieve Euroclass B-s1,d0 ratings. Learn how their char-forming, self-extinguishing properties meet building codes when correctly specified.