How many Flourescent Fittings ?

[Rick Hughes]

I have recently built a double 'outbuilding' ... I now want to fit fluorescent lights in each 'bay'

As the ceiling is not boarded - open trusses, there will be no reflection downwards of light off ceiling. I intend using IP65 weatherproof versions, ... anybody know of a guide or even of freeware to calculate, how many & what size I will need. Floor area is : In one bay - 2.54 x 8m And in the other .... 3.75 x 8m

Floor to truss joist is 2.32m

I could fit lights up 100mm or so higher than the joist, so that angle of dispersion is slightly improved, but if I fit them higher than that the trusses will cause too many shadows. Guestimate is to go and fit 2 x 6' double fittings at 1/3rd in from each end ... but no details to support this.

[Tabby]

Preferences re light level vary a lot. Honestly I'd get a few lights and play & see, otherwise you're liable to end up not very happy with it.

6' tubes are long obsolete, go for 5', or for better energy efficiency 8'

Also I'd use a switchbank, you're likely to find that most of the time you dont want them all on.

I'm also wondering why you're going for weatherproofs, does the rain pour in?

Lot of tips here:

[Andrew Gabriel]

It would help to know what OP is going to do in there.

6' aren't obsolete. 8' aren't a good idea in unheated areas unless you're using electronic control gear. (IMO, 8' are more likely to go obsolete than 6'.)

Enclosed fittings are a good idea in unheated areas, as they'll make the tubes warm up fully and reach max efficiency, although it will take some time. Exposed tubes will never warm up in winter, but you can get tube jackets (or could, once upon a time) for use outdoors or inside fridges and freezers, to allow the tubes to warm up. (Since T5 fluorescents are designed to run even hotter, I would imagine these would be even worse than T8 outside.)

[Rick Hughes]

There is no front .. open to wind blown rain, plus one side open.

No direct rain as full pitch roof, with soffits & gutters etc.

Open deliberately ... one half is used as car port ... so front open. Other side is boat store, and front and side open to have loads of airflow.

If I used standard, fittings they would be likely to rust - unless you know of better ones than standard Thorne I use.

They will be individually switched.

Not sure where you get "6' tubes are long obsolete" ... I bought 4 new Thorne 6' twins last week, complete with tubes - they are standard items. ?

sealed ones would also mean no upwards light (good in this case)

[Rick Hughes]

Have give some more details in other response.

One side is car port, and back 1/3rd is a a 'shed' Other side is boat shed.

Both only require occasional light, for access etc. No fine detailed work - as that is done in separate garage/wkshop.

[Tabby]

i didnt realise it was open, sealed seems sensible then

If all you need's basic see your way around and unload the car lighting, some 2' lights dotted about would be plenty.

NT

[John]

In article , Tabby writes

Why not a couple of metal halide floods?

[Rick Hughes]

would these work at only 2.3m to truss ? might be too hot too close ?

[John]

In article , Rick Hughes writes

My experience is that they do not get too hot - there are some designed for ceiling mounting and others which are weatherproof fittings. Whilst they take a few moments to light up they give a good quality light - we have replaced all the halogen floods at church with them and the electricity meter no longer looks like a spinning top! I got them from Screwfix

[Tabby]

Sounds good, if you dont mind being overly dazzled.

NT