btw: would this Stack be the correct place to ask building code questions that are beyond the scope of DIY? (i.e. not about house-shaped buildings, basically)

got a burning question about how the IMC's prohibition on referigerant lines in egress stairshafts interacts with the use of DX gear (vs water) to provide HVAC to said stairshafts

(NFPA 101 has a similar restriction as well)

errrrr - probably ? I recogniser HVAC in that alphabet soup.

You'd be best asking the question and see how it does. Do quote your location/jurisdiction too.

What is DX gear ?

What is IMC ? What is NFPA 101 in this context ?

Don't let my lack of comprehension put you off, I'm just a pleb here.

sorry, USA -- DX is "direct expansion" where you have refrigerant pipes between an inside unit and an outside unit (think of a typical N. American split system or minisplit)

IMC is our International Mechanical Code, NFPA 101 is the Life Safety Code

@Shalvenay Obvsiously I'm not American :) I think you should totally ask it as a question.