$26.$ You are sampling a person for dust. They are filling $10$ KG bags of dusty product during their shift. They put a bag over the fill nozzle, a clam$-$shell closes which encloses the filling process. When done, the chamber is evacuated for a set duration, then opens. The operator removes the full bag, closes the fill flaps, and put the bag on a conveyor. After review of the operation, what documentation should be collected pertaining to potential level of exposure or the task information that can make the result different each day? List them

$27.$ You are sampling a welder for manganese and iron fume while they fabricate a pipeline in a trench by welding together $16-$inch carbon steel pipe. What documentation should be collected pertaining to potential level of exposure or the task information that can make the result different each day? List them

$28.$ I am about to use a $4-$gas meter with $\%$LEL, $\%$O$2,$ H$2$S$,$ and CO sensors$.$ The meter has a $12$ ft hose line attached. What is a quick field test you can do to bump the instrument AND determine the time it takes for the sampled air to travel to hose to the sensors$?$ You do not have any cal$/$bump gas. It is just you.