Interesting that for existing buildings Churches tend to be considered a special case but for new buildings they are lumped into the same purpose group as assembly buildings.
On the one hand they can be considered Large volume open spaces with relatively little fire loading. On the other hand not many other assembly buildings conduct public tours of the roof spaces with enormous travel distances, often no separation and little communication.
Many have numerous inner rooms, different uses such as meetings, playgroups etc, sometimes concurrent sometimes not, so alarm and detection requirements are variable. Property protection is paramount as well as life safety.
Invariably all exit doors are inward opening- at times of peak use I always recommend the positioning of stewards on these doors.
Most do not have emergency lighting- this is a must. For those that are likely to attract large numbers of visitors- rather than worshippers- exit signs are important. Often but not invariably worshippers will be focussed and can be directed.
I thik the only way to deal with these buildings is to consider a fire in any scenario and the range of likely causes, then calculate the time lines that would arise- ASET / RSET, and this should be stressed as part of any new guidance..