"Stuart" wrote
| I'm fitting a cooker hood in the kitchen. The wall it's going
| on has the garage on the other side. The obvious solution is
| to drill a hole for the pipe into the garage, and then vent it
| out from there. Are there any fire regulations concerning
| holes into the garage?

Yes. You will probably need an intumescent pipe collar around the extraction
duct, to seal the opening in the event of fire. Worth considering that fires
are actually much more likely to start in the kitchen and spread to the
garage through the duct than vice versa.

(I presume you mean run a duct through the garage to the outside, rather
than venting into the garage, which is Not A Good Idea unless you like your
car covered in moist grease-laden kitchen fumes.)

Owain