Level 3 help please

[L.cunn]

Hi all 

I've been given my a question at college to answer and I've hit a wall.

The question is :

A college classroom measures 15m x 12m is to be illuminated.the type of light fitting chosen for the lighting scheme is a 230v high frequency fluorescent luminaire which supports 2 x 5' (1500mm)58w fluorescent lamps each having an efficacy of 67 lm/w

How do I establish the 'standard service illumination ' for this location 

Thanks liam

 

[Ardet R]

A classroom might be expected to need a lux level of about 400 lux on the working plane.

The lux level of an area can be roughly calculated from E = F x UF x MF / A, where Lux at the working plane is E, F is lumens from a light fitting,  UF utilisation factor, MF maintenance factor or light loss factor and A is area of room.

You might have a UF of 0.7 for a standard decorated classroom and for a fluorescent tube fitting an MF of about 0.8 maybe higher.  You have 77720 lm from one light fitting and an area of 180m², so about 240 lux, not too bright.

If you have other values available for the calculation then use those and also see if you have a recommended light level for the room.

 

[Sharpend]

I think we need to establish where the wall was hit? So how far did you get Liam? 

 

[L.cunn]

I know how to work out how many fittings are needed by using the formula with the uf factor and mf factor .

It's the last part that says  

establish the 'standard service illumination ' for this

Is that mean work out the lux for the room if so how do I do that 

Thanks 

Liam 

 

[Ardet R]

I am not sure what the standard service illumination is, however the service illumination is the light intensity after the light fitting has been used for a while and this is what I showed above, the use of the maintenance factor provides this value.

This is calculating the Lux for the room based on the fittings installed.

If this is not what you need then I am afraid I would be unable to provide more information.