Hi Dave, just looking throw some of your older episodes and noted a question about your smoke detector.
This unit looks like a Notifier FSP851AUS analogue addressable smoke detector most likely hooked up to a Notifier IFS2800 FIP.
By default these detectors are factory set at 8% obscuration but can be varied up or down.
These are most sensity to opaque types of smoke such as failed caps, burning wires or dust. No so sensitive to clea burning fires such as solvents or alcohol.
You can get various detection chambers which can plug into the system sensor base such as CO detectors, multi criteria detectors and high sensitivity laser smome detectors.
If false alarms are becoming a prob delays can be programmed to give you time to clear out the smoke.