Timeserved:

I would have one above the door and maybe halfway down between the first and ground floor you to ensure that the spiral staircase is sufficiently lit. 


Is there any borrowed light?

There will be no borrowed light at all. Pitch darkness.


Z.

kfh:

Having just read lots of guidance on emergency lighting and forgotten most of it. I would go for more lower brightness lights that will provide the required levels of illumination on each step rather than fewer bright ones. A bright one high up may cast a lot of shadows and may cause some people to be temporarily blinded if they have to look at a bright light which may occur if they are on steps.


One expert advised me not to bother about design just make sure everywhere is well lit with the emergency lights, quite how you do that without some design I was not sure. Another expert designed the lighting for me using Relux, I felt the levels in some areas were a bit low at just the legal minimum so  I put in a couple of extra lights as it added little to the overall cost and ensured legal minimums were exceeded. 

A  big problem that I encounter is the customer who advises the position  of emergency lights but that position is not the best one for effective illumination in the dark. Perhaps his wife has said, "Oh John it does not look good there." They fail to see the reason for the light and its position. Sometimes they see my point of view, sometimes not.


Z.

ebee:

Well it depends upon the particular situation.

Sometimes A sometimes B and sometimes C situations arise but sometimes two or more is really what is needed. So it`s not always OR sometimes it`s AND. Only you can decide.


I know I`ve mentioned this before but quite a few years back a couple had an old cottage three floors two staircase home they wanted rewiring. They wanted "steplights" like they`d seen at airports (Glass and steel stairways) built into their stairways (Traditional wooden stairways and plaster walls). The effects were not immediately comparable but they liked the idea.


LED lighting was pretty much in its infancy but they wanted say blue LED lighting sunk into the string of the stairs every two steps.

So I had a word with the joiner to cut some squrare holes in the strings prior to installing the stairways.

The finished result was actually very nice.

At each stairway they could switch two options 1/ Bog standard lightng above their heads or steplights lighting.

Either were adequate to enable them to safely navigate the stairwas and off course they could have both lights on and this was quite nice too.


They were not emergency lights of course but I did take the opportunity to put the different lighting for each stairway on two different lighting circuits because there were three lighting circuits - one each floor. This gave the added bonus that if any one lighting circuit was isolated then at least one method of lighting each staircase was still available if required.

You are experienced ebee and pre-planned. The family company directors that I am working for presently, despite being very nice people,  all advise me with different requests at different times for the same work. It can be confusing. Pre-planning can be scuppered sometimes.


Z.