In my venue we are able to bypass individual units through our fire alarm panel, which we are able to do during performances. Another thing is that we're able to put the whole system into test mode if necessary. The caveat to putting the whole system into test is that, if that were needed during a show, we would need a "fire watch" - one or more fire-fighters or fire marshalls who are on hand backstage during the performance.
Other than that, dry ice is a substitute though it does have a different look/effect. Dry ice can be obtained at dry ice companies - look it up in your phone book. I order tons of the stuff for shows every year, pellet and block.
Another option is CO2 - a lot of tours use that for effects onstage. Again, its a different look than a hazer - but I believe its less sensitive for particle detectors.
Or, one last idea - seeing if you can get permission to change out the problematic detectors for heat detectors. They did that at my venue after the renovation, when they realized that the particle detectors were causing issues. Now I'm just down to my three main level dressing rooms having particle detectors, which as long as I keep the door to the stage closed I don't typically have issues with.
-Centaura