The Nine-Minute Test: How Korea Measures the Smoke of a Burning Finish

Staged visualization. The swatch panel reproduces our actual colour AS011M.

Read a Korean fire test report from top to bottom and you will find an item that surprises most international buyers: a gas-toxicity test with live laboratory mice. It sits alongside the cone calorimeter as a second, separate gate for the quasi-non-combustible grade. The cone calorimeter asks how much heat a material releases. This test asks how poisonous its smoke is.

What the test measures

The method is direct. The specimen is heated, the combustion gas is routed to a chamber with laboratory mice, and the lab records the average time until the animals stop moving. Less toxic gas, longer movement. The legal threshold, set by the Ministry of Land, Infrastructure and Transport's quality-recognition standard for building materials, is 9 minutes or longer.

A live-animal test can feel uncomfortable, and we won't pretend otherwise. The reason it persists is that fire smoke is a mixture of carbon monoxide, irritant gases and fine particles, and a single chemical assay does not capture the combined effect. The mouse does.

Why heat alone was never enough

Because heat is not what kills most people in building fires. An analysis by the Korea Fire Safety Institute (national fire data, 2014 to 2018) found that 77.9% of deaths in apartment-building fires involved smoke or toxic-gas inhalation; burns alone accounted for 4.4%. The figure covers Korean apartment fires specifically, but the pattern repeats across countries: smoke, not flames, is the main killer. A rating system that regulated heat release and ignored smoke toxicity would be doing half its job. Korea's system does both, which is part of why the certificate travels well in conversations with safety-minded specifiers.

One gate, three grades

The 9-minute requirement is not unique to the quasi-non-combustible grade. Korea's non-combustible, quasi-non-combustible and flame-retardant material grades all share the same gas-toxicity gate; what separates them is the severity of the heat-release side. Note that "flame-retardant" surface treatment under Korean fire-service law (bangyeom) is a different system entirely and does not include this test, which is one more reason not to treat the two as interchangeable when a supplier waves a certificate.

Our measured values

On the KFI test behind the SAVE film we distribute (certification number 내장26-5, issued June 2026), the recorded behaviour-stop times were 14 minutes 16 seconds and 14 minutes 24 seconds against the 9-minute floor. Material chemistry gives this a straightforward reading: PVC-based films contain chlorine, and chlorine produces corrosive hydrogen chloride gas when the material burns. Our film's PP and PET base contains no chlorine, so that pathway does not exist in the first place.

One honest caveat, because this is a safety topic: we have not found a published quantitative comparison of smoke toxicity between PP-based and PVC-based decorative films, so we don't make "X% less toxic" claims. What the composition removes is the chlorine-derived acid gas at its source. What the test shows is the measured result above.

What a pass means, and what it doesn't

• It means the material's combustion gas met the legal toxicity threshold, with margin you can read off the report.
• It does not mean the smoke is safe or the material is non-toxic. Any organic material produces carbon monoxide and smoke when it burns. Nine minutes is a regulatory gate, not a safety guarantee, and no serious supplier should present it as one.

When you review a report, ask for the measured minutes, not just the pass mark. Ours are in the certificates section on this site, and if you want the full document set for a project file, email us and we will send it as issued.