Can I use a civilian brand smoke bomb for training on the base for say Sergeants time CBRN training ?

So you want to use civilian fireworks, on a non-range, in the cantonment area without any approval process? I can't see that going wrong at all. Did you say this out loud to yourself before you posted this? What does smoke, have to do with the CBRNE tasks you are going to train? While obscurant is technically a CBrNE thing, ok...but it's a reach and I suspect it doesn't apply to what you are doing...if you are simply trying to replicate a chemical hazard, your mask doesn't do anything about smoke. Especially in a confined space.

Let me save you some grief. Each installation Has their own policy on where and when you can train, what ranges are allowed which munitions, and other constraints, like CBRNE training with a live or simulated agent.

Further, you have to have a land/range request in through S3. On it, you usually have to list the munitions, including CS, simulators, and pyro you want to use. That range has to be cleared for that. Use of obscurant is carefully controlled so it doesn't drift into a restricted area, Garrison, or an active public roadway. I can not see RC signing off on the use of a non-military munition or item.

I admire the initiative to make STT interesting. But this is going to end bad for you from what you posted. Especially if your non standard item causes a fire, injury, or accident. They will crawl up your 4th point of contact and bring friends. This is a bad idea.

Since the smoke bomb (even a civilian made brand) could be seen as pyro, I would recommend you seek approval from your unit, the MPs and Range Control before using. And if any one of them say no....don't use it.

Are you talking about the same one where Helicopters land? Yeah... good luck with that. You should always just ask Range control to see what they're guidance is. Maybe they say yes, that's for FS to answer.