First, Mike referenced an excellent article. In the first paragraph there is this statement,
"Several times now, I have considered deleting this article from my website because it is not significantly applicable to a home workshop dust collection system."
makes perfect and logical sense. Yes, think about it for a home shop but just think about it.
Dust explosions are a bit different than a normal fire or explosion. We all know the fire triangle, heat, air or oxygen and combustible material or fuel. In dust explosions there is a fourth side to the triangle, combustible in sufficient concentration to support combustion. This alludes to the LEL and UEL that was discussed in the article referenced by Mike.
There are other articles that express in scientific terms (that are over my head) that the LEL has a concentration of dust that makes breathing impossible. Also the static charge that is necessary for ignition is almost always beyond the capacity of a home dust collector.
With all of that said, and how we all want the "perfect" shop, it may be wise to take a step back and think about reality.
A home shop is basically a one man, one machine in simultaneous operation. It is possible to spend a lot of money on dust collection plumbing. The reality is that there is no dust collection that is perfect. I have worked in a shop where the dust collector was driven by a 125 HP motor and we still had to sweep up every day. (Yes one hundred twenty five horse power.)
The advice given to me by the salesman where dust collection plumbing and machines were sold was simple and direct. "You're only one man and one machine, MOVE THE DC HOSE." (Well, not exactly but this is a family forum.) I have one of these 21 foot flexible and expandable hose from Rockler and it is moved to the machine in operation. The move of the hose takes less than a minute.
If you really want to spend your money, get something similar to a "Long Ranger" (Penn State Industries) for your DC at less than $100. You'll be able to start and stop the DC while at the machine rather than running back to the DC switch.