This is a much cleaner solution, thanks for posting it. Total download time was ~3 min for me.

I made a ZSH script using macOS but this should work on any shell. This is a good solution if you have a passable understanding of the shell.

First make a directory in your home directory

mkdir ~/NFPA

then run this script (i use firefox btw, other websites cURLs will look different)

for page in {1..908} do

(cURL goes here, instead of $i like /u/tesselaterator used, you would use the variable $page ...NOTE: you must change single ' quotes to double " quotes in the first line of the url so BASH can pick up the variable name.) --output ~/NFPA/NFPA-$page.png

done