(l) Fiberglass and other materials that melt at 750 °C. ±10 °C. If the material submitted for approval is fiberglass or other material that melts at 750° ±10 °C., it is tested as described in paragraphs (b) through (k) of this section, except the average weight loss of the sample is determined as follows:
- (1) Five cylindrical specimens in addition to the five cylindrical specimens required in paragraph (b) of this section are prepared as described in paragraph (b) of this section.
- (2) Each of the additional specimens is placed on a weighing dish and both the specimen and the weighing dish are conditioned as described in paragraph (c) of this section.
- (3) The weight of each specimen and its weighing dish is determined as described in paragraph (d) of this section.
- (4) After a specimen and weighing dish are conditioned and weighed, they are placed in the specimen holder with the specimen supported by weighing dish. No specimen thermocouple or surface thermocouple is attached to the specimen.
- (5) The apparatus is prepared as described in paragraph (g) of this section, and after the furnace temperature has stabilized for at least 10 minutes, the specimen and weighing dish are inserted into the furnace. The specimen and weighing dish are then heated for 20 minutes or until peak temperatures have passed. At the end of the heating period, the specimen and weighing dish are removed from the furnace and weighed while still hot.
- (6) The average weight loss of the specimens after heating may not be more than 50 percent of their average weight before heating.