Mike,

I don't know much about building codes, but I know that there are
pretty strict rules about opening a 'chase' between floors.

Not in residential building.

My brother-in-law built a new house a few years back and they required him
to install fire doors at the top and bottom of his laundry chute. They also
made him install a fire sprinkler system in his house, and improve the road
coming in so firetrucks could get in. They took fire safety very seriously
there (Cowlitz County, Washington).

Unfortunately, just as they completed their house we had extremely heavy
rains and their new house (and dozens of others) was destroyed in a
landslide...

We built our own house last year (Clark County, Washington) and my
inspector was also quite serious about fire safety. We didn't have a
laundry chute (single story home) or have to install a sprinkler system,
but they were very attentive to fire blocking and sealing off all passages
where fire could travel.

Anthony