No guidance that I'm aware of, but I've been involved with 'sensitive' facilities before & having similar arrangements for fire brigade access has been successfully implemented, in consultation with the relevant fire authority. There have been occasions where they have preferred a mechanical key override to the latch, rather than swipe cards/ Cotags - but this is only straightforwardly possible if solenoid-operated keeps are chosen (not mag-locks or shear-locks). There has to be a very robust 24/7 arrangement whereby the Brigade are met and the keys / pass handed over, though.
The only time that I wouldn't be at all happy with this arrangement is for a door separating the fire-fighting lobby from the fire-fighting stairs - as BS 9999 says this should be completely free from any fastenings.