[phentron]

A smoke test is the best way to test the efficiency of your exhaust system. Ducting specialists use ‘canned smoke’, but cigarette smoke or even smouldering paper can be used. Sit at your bench, with torch lit (these will influence air flow), there should be smoke movement towards the exhaust, particularly near your face & around the edges of the bench (you don’t want any of the heavy metal fumes ‘falling’ off the bench into your room). Also, you must have an air intake into your room or you will run out of suitable ‘breathing air’ (this will also affect the air flow test).

Less effective than the smoke test is to use a lit candle to detect air flow. The candle flame should have a slight have a slight leaning towards the exhaust intake. If the candle flame stays vertical, the exhaust is not enough. If the candle flame is sucked horizontal or blown out, you exhaust is far too strong (& probably too noisy!).

One area that is often ignored by lampworkers is what happens to the exhaust gasses after if leaves your room. In Australia, commercial glass blowing & lampworking premises should be registered with the EPA (Environment Protection Authority) & the exhaust gasses tested for heavy metals (& temperature) – these may need a filtering system.

For hobby lampworkers, do not have the exhaust gasses going near children’s play areas or near air conditioning units or open widows (or over the neighbours’ fence!). My exhaust goes through the wall, not through the roof – collecting rain water is my only water supply!!!! Also, your air intake to the room must not suck in any of the exhaust fumes (ideally it should come from the other side of the building).

Peter