My builder/electrician is saying that Part P of building regs says that
one halogen (he didn;t mention wattage) is required per square metre of
room. This means in our 7.5m by 3.5m living room we would need 26
halogen spotlights which is crazy.
Anyone have experience of the building regs and.or recommended number
of lights for a particular size room?
Judging by my old house where i had 6 x 50watt low voltage halogen
spots in a 4.5 x 3.5 m room and that was more than sufficient, i think
1 spot per 2.5 to 3sq metres is more sensible.
Which is bullshit. Part P doesn't mention anything about this at
Part L requires that a certain proportion of the mains rooms are
are lit using lights of 40 lumens/watt efficiency or better, and
halogens are only half this.
It's news to me that Part P says anything of the sort. You can read Part
P of the Building Regulations online.
Area x candle-feet required = total nett lumens
25' x 11' x say 6 candle-ft (brightness) = 1650 nett lumens
guesstimate 66% efficiency (losses becauuse of depreciation (bulbs
getting dirty) and utilisation (distribution of light from fitting and
reflextivity of walls) = 2500 gross lumens. Using ordinary GLS lamps
about 2.5 100-watt lamps = 250 watts
or about 8 40-watt lamps = 320 watts
Note the relative efficiency of the two schemes.
Very roughly you need 1 x floor area in sq ft in Watts of GLS lighting
for living rooms using the largest available lamps; smaller lamps are
less efficient in terms of lumens per watt.
Halogen spots are rather an inefficient way of lighting a room anyway,
especially if they're downlighters, unless you've got a very reflective
floor. Although they have quite a high output per watt, the utilisation
factor is usually poor.
Sorry, but your sentance construction left whatever meaning you were
trying to convey inaccessable to me. What were you trying to say? I
presume it was an insult, but I can't tell if it was directed at the
electrician, the OP, or me...
Oh, on second thoughts, don't bother.
wow! thanks very much for the replies. its not the electircian who is
saying this but this guy who sort of project manages the build for the
main builder. he has apparently read Part P and is claiming this is the
case. he came back to me today with the following SMS:
"called bream (sic) the regs for spots. 1 per sqm not including linear
around the wall"
don;t make sense to me, but this guy has been pretty annoying so far,
he basically comes up with lots of problems but no solutions. gonna
talk to the electrician to make sure, and i'll give building regs at
the council a call when i have time as they have been pretty helpful on
On 29 Aug 2006 15:44:13 -0700, a particular chimpanzee named
email@example.com randomly hit the keyboard and produced:
Not true. The requirements that have any bearing on lighting are Part
L (Conservation of Fuel and Power), Part M (Access To and Use Of
Buildings), and Part P (Electrical Safety). Part B (Fire Safety) has
a bearing, but not in dwelling houses.
Part L requires a number of the lighting locations in new dwellings,
extensions and material alterations to be energy efficient. It
doesn't require a minimum number of lighting locations; indeed, it
would defeat the object if the Requirements laid down more lights than
was needed. Halogens don't count as energy efficient.
Part M governs the height of switches, and Part P governs the wiring
to the lighting circuits. Neither govern the number of fittings.
"If no-one on the internet wants a piece of this,
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