The LONG TERMO loft ladder is designed for high rooms (up to 330 cm) and is the basic model of the ladder with a 26 mm thick sealed hatch. The heat transfer coefficient of the hatch is 1.22 W/m2*K. To increase safety, the LONG TERMO loft ladder is equipped with a handrail to facilitate entry and with non-slip feet. Ud - coefficient of the hatch centre.