So apparently lighting you N95 on fire (or not lighting on fire to be more precise) is a way of validating its authenticity. There is some truth in this, but also a lot of false assurance.
To understand why this is, you have to know a little bit about how the filtering aspect of a N95 is created. You may have heard the terms melt-blown or non-woven to describe it. The filter is not created by a woven fiber. It is created by melting polypropylene and blowing it on a roller, where it forms a non-woven or melt blown sheet. So essentially, your mask should be made out of polypropylene and much like when your nylons get too close to a flame, they melt, not burn.
So if you put a flame to your mask, it should melt. Now it can still burn if you get it hot enough, as evidence by an Exxon-Mobil plant burn in Baytown recently.
When you perform the burn test, you are simply confirming that the mask is not made of paper or cotton. However, this does not confirm the filtration capabilities of you mask. Even the poorly functioning KN95s with 50% 0.3 micron filtration, still pass the flame test.