How long is my helmet good for?

NHRARacer.com - NHRA RULES

NHRA rule book
General Regulations
Section 21 Page 46

It says:

SNELL 2015 expires 1/1/2027

SNELL 2020 expires 1/1/2032


I won't be the best source for some rules. I retired from racing a few years ago and haven't been keeping up with the rules like I use to.
That's great news! I'm sure IHRA would accept the NHRA standard. Thanks!!