Table 2. Comparison of charring properties by test specimen according to fire resistance time

Specimen name	Fire-exposure time (min)	Average char depth (mm)	Average char rate (mm/min)
CLTWP-NL-1.0h	60	52.6	0.87
CLTWP-NL-1.5h	90	84.6	0.94
CLTWP-NL-2.0h	120	112.3	0.94
CLTWR-NL-2.0h	120	70.8	0.59
CLTWP-NL-2.5h	150	150.7	1.00
CLTWP-NL-3.0h	180	183.9	1.02

CLTWP: CLT wall panel bonded with PUR, CLTWR: CLT wall panel bonded with PRF, CLT: cross-laminated timber, PUR: polyurethane resin adhesive, PRF: phenol-resorcinol-formaldehyde resin adhesive.