Have a certified contractor inspect your chimney annually for blockage or deterioration – moisture stains, cracks, white chalky deposits or loose mortar. Also please remember that the glass of a gas fireplace heats up to 200° Celsius (400° F) in just 6 minutes and takes 45 minutes to cool down to a safe temperature. Anyone who touches a surface this hot will suffer a serious burn instantly. It is also important to be aware that the pilot light of a gas fireplace may also heat the glass enough to cause a burn.