Incheon factory fire causes 11.8 billion won in damage, sparking calls for non-combustible insulation

Following the factory fire in Wonchang-dong, Seo-gu, Incheon, and a subsequent large blaze at a Gimpo warehouse last week, industry voices are growing louder in calling for the insulation cores inside sandwich panels to be replaced with non-combustible materials. The type of insulation used, they say, is the single most critical factor determining how large a fire grows.

Fire authorities said Wednesday that the Wonchang-dong blaze spread rapidly across multiple factory buildings, burning 20 of them to the ground and causing 11.8 billion won ($7.62 million) in property damage. The sandwich-panel construction of the buildings, combined with large quantities of combustible materials such as timber inside, made the fire difficult to extinguish.

Industry experts, however, say the more important question is not whether sandwich panels were used, but what kind of insulation was inside them. Sandwich panels consist of insulation material sandwiched between steel sheets. They are widely used in industrial facilities such as factories, warehouses and logistics centers because they are easy to install and offer strong thermal performance. The problem is that the type of insulation dramatically changes how a fire behaves.

When organic insulation materials — such as polyurethane (PUR), polyisocyanurate (PIR) or expanded polystyrene (EPS) — are used, fire that reaches the interior panels can ignite the insulation itself, causing flames to spread far more rapidly. The outer steel sheets block firefighting water from penetrating to the interior, making suppression extremely difficult. Toxic gases including hydrogen cyanide (HCN) can also be released, compounding the damage through smoke as well as flames.

Inorganic insulation materials such as glass wool, by contrast, are classified as non-combustible. They do not burn when exposed to fire, slowing the spread of flames and generating almost no toxic gases — qualities that experts say significantly improve fire safety in factories and logistics facilities.

The government has made regulatory adjustments in response to repeated industrial fires. A 2021 amendment to the Building Act required insulation used in sandwich panels to meet at least quasi-non-combustible standards, and eased some full-scale model testing requirements for inorganic insulation materials that meet non-combustible performance criteria.

Domestic inorganic insulation manufacturers have responded by investing in expanded production capacity and quality upgrades. Major producers including KCC and Byuksan have committed roughly 200 billion won toward increasing glass wool output and improving product quality, aiming to stabilize market supply.

On the ground, however, industry observers say much work remains. About 60 percent of the domestic sandwich panel market still uses products with organic insulation, according to industry sources, as cost competitiveness and ease of installation continue to drive demand for conventional products. The Gimpo warehouse fire in Unyang-dong last week was also found to have involved quasi-non-combustible EPS panels.

Tightened standards have focused primarily on new construction, leaving many existing factories and logistics facilities still vulnerable to fire. Industry representatives argue that preventing a repeat of large-scale disasters like the Incheon fire will require not only stricter rules for new buildings but also phased support measures to improve fire safety in existing industrial facilities. If fires cannot be prevented entirely, they say, the least that must be achieved is stopping flames from engulfing an entire building in an instant.

Regulatory reform, however, has been slow. A Building Act amendment bill sponsored by Rep. Yeom Tae-young of the Democratic Party of Korea is pending in the National Assembly. The bill would require non-combustible materials for interior and exterior finishes and insulation in underground parking lots, as well as for pipe insulation on piloti-structure ceilings, and would mandate fire-resistant construction for roofs of factories and warehouses. The measure aims to address both the growing fire risk in underground parking lots as electric vehicle adoption expands and the recurring large-scale fires at industrial facilities.

Experts say the regularity of major industrial fires makes it urgent to expand the mandatory use of non-combustible insulation. Kim Hyo-beom, research director at the Korea Fire Investigation Society, said sandwich-panel structures allow flames to spread explosively due to the chimney effect. "The share of organic insulation remains high in Korea because of cost," he said. "To address this, institutional mechanisms that mandate the use of non-combustible materials must be put in place."