I have a couple of questions regarding circuit venting. 1. Can circuit venting be used on a commercial kitchen grease-laden line? The IPC does not say that you cannot do this, but most figures I've seen only applies circuit venting to restroom applications. 2. If you are utilizing circuit venting, can you omit fixtures that are independently vented, from your 8 fixtures in a circuit vent? For example, if I had (from upstream to downstream) 4 water closets, 1 floor drain (with it's own vent), 1 lavatory (with it's own vent) and then 4 more water closets - would the last two water closets have to be on the another circuit vent? Thanks in advance for your help!