I'm not a fire safety expert by any means, which is why I added the "as far as I understand" qualifier. That said, don't you have the possibility of something blocking the path of the door regardless of which way it swings? I guess if it's on your side of the door, there is a greater chance that you can move it out of the way as long as it's not too hot or bulky. Then again, if something unexpected is blocking the way in a fire I'd expect there is a very good chance that it is hot or bulky.
So far I was under the impression that doors should generally open towards the exit (as the sibling already noted) in order to make it as easy as possible to exit the building. But maybe that is a misconception. I find this a very interesting topic, if you have more information to share I'd be very curious.
EDIT: Also, aren't hot door handles a big issue in case of a fire? I'd imagine that the ability to push the door open (assuming it doesn't lock when closed) rather than having to pull the handle is a plus. And I guess a door that swings both ways is ideal with regard to blockage.
I'm not in any way a safety expert, as well. But this argument caught my eye. So I asked my brother who is a fire fighter. Fire exits are, in general, supposed to open outwards. Regarding blocking, according to him, there is a reason why when you look at any properly made fire exit, there is nothing heavy hovering above it.
Now as for the door knobs, most fire exits don't have the normal door handles. Like in cinemas and theaters, there's this small slot where you can place your hand. For larger buildings though, there are bigger handles shaped like a hook.
The question is: what way do most people go in case of an emergency and how can we make that way the easiest?
If the door of a bathroom would open to the outside, the door would block the path (the hallway) people would take in case of an emergency. It would block more people than it would help escape the bathroom. The same with the doors of offices, etc. No one needs to enter a bathroom in case of an emergency (well, a different kind of emergency...), so it doesn't matter if it may blocked to the inside. So doors to closed rooms adjacent to a hallway open to the inside, while doors in the emergency path of the entire stream of people open to the outside.
Of course, there are situations where emergency paths cross and neither option is ideal. However, for most cases, the rule is pretty clear and obvious.
In England and Wales your door layout needs to comply with these regulations:
Part B Fire safety:
http://www.planningportal.gov.uk/uploads/br/AD_B_v1_wm.pdfhttp://www.planningportal.gov.uk/uploads/br/AD_B_v2_wm.pdf
The actual regulations are very simple; most of these documents are guidelines. Example, the regulation for alerting of fire and providing for escape is: "Means of warning and escape B1. The building shall be designed and constructed so that there are appropriate provisions for the early warning of fire, and appropriate means of escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all material times.
(a) 1952 C.52; Section 33 was amended by Section 100 of the Criminal Justice and Public Order Act 1994 (C.33) and by S.I. 1963/597."
You can do something different from the guidelines as long as you are willing to spend the money to get a fire engineering strategy which proves to the satisfaction of the Building Control department that your design will comply with these regulations.
In the US the regulations vary state by state and are generally more proscriptive. I remember when I was working on a building in New York the actual manufacturer of the drainage pipe required appeared to be specified by the regulations, which seemed a bit fishy to me. But, I'm not an expert in US building codes, so maybe I misunderstood.
So far I was under the impression that doors should generally open towards the exit (as the sibling already noted) in order to make it as easy as possible to exit the building. But maybe that is a misconception. I find this a very interesting topic, if you have more information to share I'd be very curious.
EDIT: Also, aren't hot door handles a big issue in case of a fire? I'd imagine that the ability to push the door open (assuming it doesn't lock when closed) rather than having to pull the handle is a plus. And I guess a door that swings both ways is ideal with regard to blockage.