walls. In the handbook on insulating glass furnaces, it is recommended that there should be a high-temperature layer adjoining the refractory, which should be made of a material having a working temperature of about 1400~ To avoid the molten glass leaking through joints in the refractory, the points of contact between the rods are not insulated. It is recommended that the widths of the horizontal and vertical gaps in the insulation should be 50-70 mm. The gaps have a substantial effect on the temperature and thermal patterns if the insulation were continuous,* the contact zone between the refractory lining and the insulation would attain 1400~ Observations have been made on 18 glass furnaces and computer calculations have been performed on the three-dimensional temperature pattern, which have shown that the temperatures in the contact zones for discrete block insulation for all block sizes did not exceed 1000~ In field studies, an infrared radiometer may be used to measure the temperature patterns at all the surfaces, which enables one to identify anomalously hot parts and make more careful measurements there. One can use reference substances, in particular silver or sodium sulfate (melting points, correspondingly, 960 and 884~ in the contact zone between the liner and the insulation to determine whether local temperature rises exceed the melting points. At such points, we never found temperatures over 960~ and only occasionally did the temperature exceed the melting point of the sodium sulfate, 884~ At most points, the temperatures had been monitored with thermocouples, but values over 1000~ have never been found. Consequently, discrete block insulation around the liner can be based on insulating materials with working temperatures of about 1000~ such materials are usually more readily available, cheaper, and more effective. The design characteristics and thermophysical parameters influence the temperature patterns, which has been examined by computer via a program written at the Urals Building Materials Research Institute. Over 200 models were computed, which differed in wall blocks parameters: 400 x 600 x 250; 400 x 900 x 250; 400 x 400 x 250 mm; gaps between blocks, 30, 40, 60, 90 mm, and thicknesses of insulating blocks 80, 120, 180 mm. The thermal conductivities were taken as follows: lining i, 2, and 3.5 W/(m-K), and insulation 0.14, 0.21, and 0.315 W/(m.K). The heat-transfer coefficients ~were I0, 50, and gO W/(m='K). Temperature within the furnace was 1500~ outer air temperature - 20~ and air in the gaps between the insulating blocks - 60~ The mean heat flux per m 2 of wall surface was found as 2.45-10.5 kW/m 2. Most of the heat lost to the environment occurs at the gaps in the block insulation and constitutes 70-90% of the total heat loss through the refractory lining.