Lenses are simply divided into plastic lenses and glass lenses. Generally, plastic lenses will not break without explosion problems.
The explosion occurs when exposed to the sun or grilled on fire. But don't worry, lenses are very safe!
Because the manufacturers use a Lens Flame Retardant Testing Machine to test the safety of the lenses when they are manufactured.
The Lens Flame Retardant Testing Machine is used to determine whether the material has the required flame retardant properties to ensure the safety of users.
This machine with an adjustable maximum temperature of 800 ℃, equipped with a pneumatic device.
Automatically raise and lower the heating rod to prevent the tester from touching the heating rod.
It meets the standards with EN168:2001 Clause 7, ISO12870 2004 clause 8.6, ANSI Z87.1-2010 clause 9.7, and ISO 12311:2013 clause 9.9
For more information please to refer:
http://www.lab-testequipment.com/Lens-Flame-Retardant-Testing-Machine.html
Video:https://youtu.be/SOYQvpeET4c