Smoke from the chimney

This is the medical device I acquired. It is fairly large, and I will have to place it partly beneath the layout's surface. The connection to the "vapour distribution system" should, of course, be air-tight.
The original fan was a noisy centrifugal type, and I replaced it with a fan from an old PC power source.

As I wanted to build an interior in the building, the vapour generator was placed very low. A central "chimney" inside the building is therefore the starting point for the rest of the distribution system. Being flat but wide, it has a sufficient inside surface to let the air through smoothly.
The rest of the distributed airflow travels through smaller channels, their sizes calculated with the needed final airflow in mind.

I used hollow square styrene profiles to make these smaller channels. It took some "advanced plumbing" to calculate and connect the various tube sizes.
In any case, the connections should be glued both air-tight and allow the air to flow smoothly internally.

The chimneys are built with a hollow inside, of course. I used rectangular profiles, glued together. Some styrene brick-imitating sheets are glued on their outsides, taking care to have the masonry look just right.

On top of these chimneys, a prototypical plate is placed. It should have holes to fit small tubings, which form the actual chimney vents. They are, for now, not glued...

... as we glue this plate as a whole on top of and inside the brick chimney parts. Afterwards, it can be nescessary to adjust the bottom sides of the chimneys to fit the vapour distributing profiles.

As a pictures tells more than a thousand words: a photo of my smoke distribution system. It looks complicated, but with a little thought it isn't that hard to accomplish.

The factory's production hall holds four larger chimneys, which I made from 8mm round styrene tubing. The photo shows myown - a suggested construction method.

Because of a planned interior in the building, the smoke generator is mounted under the layout. This means I made a large hole in the layout surface and a supporting construction. Using M4 nuts and bolts, this suspension wasn't that difficult to make. The photo shows the device's replacement fan, too.

After connecting the device to a power source, its functionality can be tested. Not every chimney should exhaust fumes - that wouldn't be realistic.
We should get a balance. On one hand a sufficient air flow and, on the other hand, enough - but not to many - chimneys producing smoke. By obstructing some exhaust pipes, I experimented with the desired result. I wanted life-like rising fumes from some chimneys of the factory.