Developing a flammability test system for sunglasses: results

摘要

Sunglasses popularity has increased tremendously. This fact has further led to the need of certificating sunglasses accordingly to the standard NBR 15111 to protect consumers from damages and secondary hazards caused by sunglasses use. The ongoing need comes at the expense that none certification institution in Brazil performs all tests procedures required by the NBR 15111. This manuscript presents the development of a flammability test system for sunglasses and the assessments results. The equipment for testing flammability developed is made of an electrical furnace with a thermocouple and electronic system that maintains the temperature in 650 °C. This furnace heats a steel rod used for testing flammability. A steel cable connected to a linear actuator drives the rod. The main control system is based on an ARM Cortex M0 microcontroller and we developed a PC interface in LabView to acquire data and store it. The equipment built also has a control panel with a push button, status LEDs and temperature indicator. We performed flammability tests in 45 sunglasses: 45 lenses and 45 frames using the equipment described. None of the samples ignited or continued to glow when the test has finished, however, all polycarbonate samples were melted in the contact region with the steel rod. All samples complied with the NBR 15111. The proof argues that the polycarbonate is extremely resistant to ignition.