Flame Effects are cool, legal goodness!
You still have to be a little careful because they can become illegal. Over 30 foot flames can be considered a misdemeanor or felony. There are exceptions for entertainment but licenses and/or permits are usually required. I know in California you need to get insurance as well. It's hard to find exact rules on flame effects. From what I can tell a lot of companies that create these at large commercial events get a pyrotechnics license (about $1500), a permit from local fire enforcement, and a million dollar insurance policy. The pyrotechnics license does not seem to be legally required for large flame effects, but there does not seem to be much to cover that area. It seems like people get that figuring the license is for more dangerous effects, so by holding a license for those the lesser effects should be covered as well.
If anyone knows of specific laws or case law in this area, I'd be interested. Some in our camp would like to get legit so we can have these effects at small gatherings without the fire department showing up asking about the "explosions".