Fire-resistant glass products are considered to have better performance against fire. They are developed to replace conventional glass products. However, the smoke emitted from these products can be potentially harmful during fires and cause injuries or even deaths. Six samples of insulating glass available in the local market were selected. A variety of techniques, including X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermogravimetric FTIR, pyrolysis–gas chromatography–mass spectrometry and tubular furnace coupled FTIR spectroscopy, were employed. According to the test results, there are two types of protective layers of the fire-resistant glass. One consists of water, water-soluble salt and polyamide with possible presence of alcohols, and the other consists of water metal silicates with possible presence of carboxylate and alcohols. Gases emitted from the protective layers heated in air, in argon and in vacuum are similar. Water vapor, carbon dioxide and hydrogen chloride are the main components of the gases emitted. Copyright © 2014 John Wiley & Sons, Ltd.