Engine compartment questions

[Figment]

Should the intake for the bilge blower feed from the top of the engine compartment, or the bottom?

My instinct says to locate at the bottom, as lighter-than-air gasses should theoretically find their own way out, but instincts have been wrong before....

I also splurged on an automatic fire suppression (halon-alternative) unit. Of course the immediate conflict is that the most sensible mounting location is about 8" from the exhaust manifold. One side of my brain says "if the manifold is radiating enough heat to set off the extinguisher, I've got other problems to contend with as well". The other side says "follow the directions, dummy".

Thoughts?

[JetStream]

ABYC says that the blower intake should be:
Self draining, Permanently fixed, Located in the lower 1/3 of the compartment, Above the normal level of accumulated bilge water, As nearly as practicable below the engine that it serves.

There are other caveats about wiring and so forth.