occupancy sensors on fluorescent fittings

[dingodeano]

Occupancy sensors on fluorescent fittings a customer asked me if they were worth fitting to a warehouse where there is stock held and occasional traffic. I replied they were and went through the costs.
Few days later I got call from same customer who had been told that the current of the lamps being struck up each time the outweighed the cost saving of lights being off.
Is this true ?

 

[ricicle]

There are issues to consider here.

Safety: Will there be enough strategically placed sensors to ensure that the lights never switch off when someone has entered the working zone ?

What is the frequency of usage of the warehouse ie will there actually be any cost savings from the lights being off as fluorescents should really be on for at least 20 mins to enable the lamps to warm up otherwise lamp life can be reduced ?

Some PIRs enable fluorescent switching - just get the rating right. If not use relays.

 

[dingodeano]

Would a fluorescent light cost more or less to run if it was
(a) turned on and left on for 2 hours
or
(b) if it was turned on for 20 mins turned off 20mins turned on 20min turned off 20mins turned on for 20 mins turned off 20mins

 

[ricicle]

Obviously less with the cycling but is there long periods when the warehouse will not be occupied ?

 

[dingodeano]

Yes. To call it a warehouse is misleading. It's an industrial unit but the actual space that I am referring to is regained office space due to lower rates for warehouse useage. The suspended ceilling had to be ripped out and the plasterboard off the walls for it to bre reclassified The space is approx 10 x 20m. There are only 4 members of staff 2 of which are part time. The space will be used to as a goods in out area and will not see much traffic.

 

[ricicle]

Your original post said warehouse where stock was held

Anyway with that fewer staff lights being left on may not be an issue. If energy saving really is the order of the day then T5 fittings with occupancy/absence sensing with daylight-linked dimming (if there are windows or rooflights) may be worthwhile.