Which buildings require firefighter access windows?

Under building regulations, a window through which firefighters can enter must be installed on floors from the 2nd to the 11th. There are exceptions, such as apartments with evacuation spaces or emergency elevators. Practically important is that current standards may apply not only to new construction but also during remodeling and change of use.

What are the size and position standards?

Width of at least 90cm and height of at least 1.2m, with the bottom of the window within 80cm of the interior floor. It must face a road or a clearing where a fire truck can approach, arranged at intervals within 40m on each floor. The glass must be an easily breakable type (float glass 6mm or less, tempered glass 5mm or less, etc.), marked with a red inverted triangle of at least 20cm diameter, visible even at night.

Must access windows be added when remodeling an existing building?

It depends on the scope of work and the type of permit. Where major repairs or a change of use trigger application of current evacuation and fire-protection rules, new firefighter access windows may be required. In fact, there are cases where adding access windows became a permit condition when converting a neighborhood facility into an educational facility (academy).

Regulation Guide · 2026. 06

Firefighter Access Windows —
The Meaning of the Red Triangle

LEA Architects · Junsu Kim, Architect

Have You Seen the Red Triangle on Glass?

That red inverted-triangle sticker on commercial building glass. It is not decoration but a statutory marking. It indicates the position of a firefighter access window — the window firefighters break and enter through in a fire — and no obstruction may be placed in front of it.

The background is clear. As commercial glass shifted to ever-thicker tempered and double-pane glazing, the very window firefighters could break through in a fire disappeared. So building regulations mandated a breakable access window on floors from the 2nd to the 11th. The reason it stops at the 11th floor is that the typical working height of fire-brigade aerial ladder trucks is around there.

Firefighter access window installation standards (Building Act Article 49 and subordinate rules)

Remodeling Is Scarier Than New Construction

In new-build design, you simply reflect it from the start. What causes problems in practice is remodeling and change of use of existing buildings. The moment major repairs or a change of use trigger application of current evacuation and fire-protection rules, a situation arises where you must add a firefighter access window that did not originally exist. From a tenant's perspective, it is like "coming to do interiors and ending up replacing the exterior windows" — easy to be caught off guard.

Our completed Jungdong remodeling in Giheung-gu, Yongin was such a case. It involved converting a neighborhood facility into an educational facility (a math academy), and under current-code application it required fire-resistant gypsum board reinforcement along with new firefighter access windows, plus accessibility facilities as an educational-facility requirement. A single change of use brought fire, evacuation, and accessibility rules in a chain. View this project →

If you plan to change use to academy, clinic, or multi-use establishment categories, checking these retroactive items before signing the lease is the way to keep budget and schedule. The full change-of-use procedure is covered in the change of use guide.

Frequently Asked Questions

Q. Which buildings require them?

Floors from the 2nd to the 11th. Exceptions exist, such as apartments with evacuation spaces.

Q. Size and position standards?

Width 90cm and height 1.2m or more, window bottom within 80cm of the floor, intervals within 40m, and a red triangle of 20cm+ diameter on easily breakable glass.

Q. Required when remodeling too?

Where major repairs or change of use trigger current rules, new installation may apply. Review before signing a lease is advised. LEA Architects reviews this in Yongin. Contact us →

Firefighter Access Window · Fire Entry Window Standard · Red Triangle · Access Window Size · Building Act Article 49 · Change of Use Fire · Yongin Architect · LEA Architects

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