Hi
I'm again struggling with a long overdue 2396 project but, as before, am at a standstill when it comes to the lighting design.
Please could someone point me in the right direction? I don't know how many luminaires there should be.
The scenario is a fire station appliance bay built for two fire engines.
I think I need to achieve 150 lux on the floor in normal operation (as it's a bit like a loading bay) and 1 lux on the floor for emergency operation (as it's an escape route), with due consideration of the obstacles (the fire engines are probably about 3.3m high). The bay is 15.8m x 13m x 4.8m high. It has plaster finish walls and epoxy-based paint finish to bare screed floor and of course those two big shiny metal fire engines!
I'd like to use this 1500mm maintained LED batten (Tamlite Lighting Cyclone G Linear IP66 weatherproof 63W 9800 lumens, 370lm emergency lumen operating; beam angle 128deg), admittedly because it's the only luminaire whose spec I could find online setting out beam angle, lumen and emergency lumen.
This is how I've tried to approach this.
At first I thought I should use the Lumen Method F = (E*A)/(U*M). Having realised I would not be able to come up with a sensible U factor taking into account all reflective surfaces, windows etc., I thought I could probably get away with providing sketchy values for U (say 0.6) and M (say 0.7) for the whole room area, then just divide that by the manufacturer's total lumen output for a given fitting to get the number of fittings required (doing this I got eight fittings), then locate the fittings around the obstacles. But then I realised the ceiling was higher than normal which must make a difference to the result, so I probably should be adding some other factor (which I couldn't find by googling). Also I realised with dismay that I probably shouldn't have even used the manufacturer's lumen output to begin with because it refers to the total output from a 1.5m long batten fitting, and not from a point source (and I couldn't find out how to deal with this either by googling).
So then I thought maybe I could get around the problem by applying instead the cosine law to either end of the batten fitting as if each end were a point source, which would at least take into account the high ceiling. Then maybe I could convert candela into lumen ... and really now I'm just plugging in values and hoping for the best, and the niggling doubt of applying a formula made for a point light source to a linear light source application is still there. I won't pretend I understand fully about converting candela into lumen over a steradian etc. but I can't imagine it can be used here.
No amount of effort I've made so far as got me out of this hideous loop of confusion and I think I'm making this too complicated. But I just can't see my way out of here. Please can someone help?
Thanks in advance
Suki
I'm again struggling with a long overdue 2396 project but, as before, am at a standstill when it comes to the lighting design.
Please could someone point me in the right direction? I don't know how many luminaires there should be.
The scenario is a fire station appliance bay built for two fire engines.
I think I need to achieve 150 lux on the floor in normal operation (as it's a bit like a loading bay) and 1 lux on the floor for emergency operation (as it's an escape route), with due consideration of the obstacles (the fire engines are probably about 3.3m high). The bay is 15.8m x 13m x 4.8m high. It has plaster finish walls and epoxy-based paint finish to bare screed floor and of course those two big shiny metal fire engines!
I'd like to use this 1500mm maintained LED batten (Tamlite Lighting Cyclone G Linear IP66 weatherproof 63W 9800 lumens, 370lm emergency lumen operating; beam angle 128deg), admittedly because it's the only luminaire whose spec I could find online setting out beam angle, lumen and emergency lumen.
This is how I've tried to approach this.
At first I thought I should use the Lumen Method F = (E*A)/(U*M). Having realised I would not be able to come up with a sensible U factor taking into account all reflective surfaces, windows etc., I thought I could probably get away with providing sketchy values for U (say 0.6) and M (say 0.7) for the whole room area, then just divide that by the manufacturer's total lumen output for a given fitting to get the number of fittings required (doing this I got eight fittings), then locate the fittings around the obstacles. But then I realised the ceiling was higher than normal which must make a difference to the result, so I probably should be adding some other factor (which I couldn't find by googling). Also I realised with dismay that I probably shouldn't have even used the manufacturer's lumen output to begin with because it refers to the total output from a 1.5m long batten fitting, and not from a point source (and I couldn't find out how to deal with this either by googling).
So then I thought maybe I could get around the problem by applying instead the cosine law to either end of the batten fitting as if each end were a point source, which would at least take into account the high ceiling. Then maybe I could convert candela into lumen ... and really now I'm just plugging in values and hoping for the best, and the niggling doubt of applying a formula made for a point light source to a linear light source application is still there. I won't pretend I understand fully about converting candela into lumen over a steradian etc. but I can't imagine it can be used here.
No amount of effort I've made so far as got me out of this hideous loop of confusion and I think I'm making this too complicated. But I just can't see my way out of here. Please can someone help?
Thanks in advance
Suki
