This may be of some help in estimating what fittings you need to get a well lit workshop.
The degree of illumination is called illuminance, and it's measured in lux (that's lumens per sq M). Fortunately the eye can accomodate to a wide range of illuminance, as daylight provides about 100,000 lux in sun, and moonlight 0.2 lux. Of more practical use, minimum illuminance needed for critical tasks like sewing or reading or woodwork is about 300 lux at the task. People over 50 may need up to twice this level.
Light fittings vary in practical effectiveness according to room size, mounting height and overall wall and floor colour. For simplicity, in a workshop with lighting at height 2.5 to 3M and using a good reflector, with white walls and light floor, the Coefficient of Utilisation (C of U) is about 0.5. For a very dingy workshop, could be as low as 0.3.
LIght fittings get dirty, and light is lost as a result. If you spring clean once a year, allow a Maintenance Factor (MF) of about 0.6 (0.8 if you do it monthly!)
You calculate total lumens required (lamp output is given in lumens) thus:
Installed Flux= desired illuminance x floor area/C of U x MF
For workshops, desired illuminace is 300 lux.
My workshop is 5.5M x 5.5M, very light in colur, and cleaned once a year, so the
total flux needed = 300 x 5.5 x 5.5 / 0.5 x 0.6 which comes out to 30,250 lumens
The lumens could come from:
Lumens
1300 - 100W filament bult
3150 - 200W filament bulb
1100 - 20W energy saver fluorescent
2100 - 900mm fluorescent tube
3000 - 1200mm fluorescent tube
4800 - 1500mm fluorescent tube
5200 - 1800mm fluorescent tube
light outputs for tubes allows for fading during life, and is less than the 'new tube' figure
I chose 4 x 1.8M double fittings giving 8 x 5200 = 41,600 lumens, a bit more than was required (I was 45 yrs old then and getting a bit short sighted) 20 years on I find I need additional task lighting for critical jobs (see paragraph one; 6 doubles would have been better)
Data simplified from Electricity Council Publications
The degree of illumination is called illuminance, and it's measured in lux (that's lumens per sq M). Fortunately the eye can accomodate to a wide range of illuminance, as daylight provides about 100,000 lux in sun, and moonlight 0.2 lux. Of more practical use, minimum illuminance needed for critical tasks like sewing or reading or woodwork is about 300 lux at the task. People over 50 may need up to twice this level.
Light fittings vary in practical effectiveness according to room size, mounting height and overall wall and floor colour. For simplicity, in a workshop with lighting at height 2.5 to 3M and using a good reflector, with white walls and light floor, the Coefficient of Utilisation (C of U) is about 0.5. For a very dingy workshop, could be as low as 0.3.
LIght fittings get dirty, and light is lost as a result. If you spring clean once a year, allow a Maintenance Factor (MF) of about 0.6 (0.8 if you do it monthly!)
You calculate total lumens required (lamp output is given in lumens) thus:
Installed Flux= desired illuminance x floor area/C of U x MF
For workshops, desired illuminace is 300 lux.
My workshop is 5.5M x 5.5M, very light in colur, and cleaned once a year, so the
total flux needed = 300 x 5.5 x 5.5 / 0.5 x 0.6 which comes out to 30,250 lumens
The lumens could come from:
Lumens
1300 - 100W filament bult
3150 - 200W filament bulb
1100 - 20W energy saver fluorescent
2100 - 900mm fluorescent tube
3000 - 1200mm fluorescent tube
4800 - 1500mm fluorescent tube
5200 - 1800mm fluorescent tube
light outputs for tubes allows for fading during life, and is less than the 'new tube' figure
I chose 4 x 1.8M double fittings giving 8 x 5200 = 41,600 lumens, a bit more than was required (I was 45 yrs old then and getting a bit short sighted) 20 years on I find I need additional task lighting for critical jobs (see paragraph one; 6 doubles would have been better)
Data simplified from Electricity Council Publications
