The latter takes in offices, industrial buildings and those of multi-
residential use, such as hotels, hostels, old people’s homes, hospitals and
boarding schools. This is a very broad sweep of the majority of buildings,
and architects should be aware of the implications... it will not be
sufficient to say that your client has demanded illumination levels of 1000
lux in a hotel foyer when to provide this level the amount of energy used
is far in excess of the amount allowed for this type of space.
To give an example of the legislation the following is a quotation from
Part L2: This refers to general lighting efficiency in office, industrial and
storage buildings:
1.43 Electric lighting systems serving these buildings should be pro-
vided with ‘reasonably efficient lamp/luminaire combinations.’ A
way of meeting the requirements would be to provide lighting
with an initial efficacy averaged over the whole building of not
less than 40 luminaire-lumens/circuit watt. This allows considerable
design flexibility to vary the light output ratio of the luminaire, the
luminous efficacy of the lamp, or the efficiency of the control gear.A table of lamps which meet the criteria for general lighting follows:Light source Types and rating
High pressure sodium All types and ratings
Metal halide All types and ratings
Induction lighting All types and ratings
Tubular fluorescent 26 mm. diam. (T8) lamps
16 mm. diam. (T5) lamps rated above 11 watts,
provided with high efficiency control gear.
38 mm. diam. (T12) linear fluorescent lamps
2400 mm. in length.
Compact fluorescent (CFC) All ratings above 11 watts
Other Any type and rating with an efficiency greater
than 50 lumens/ circuit watt.
Whilst this clearly precludes the use of tungsten lamps for general use,
they can still be used in some areas which may demand their use; where
the average over the whole building does not exceed the predetermined
40 luminaire-lumens/circuit watts... there is flexibility.
A major difference in the new regulations is that they apply to display
lighting, defined as ‘lighting designed to highlight displays of exhibits or
merchandise.’ (Examples of display lighting are included in the Case
Studies shown later, a good example being the Sainsbury Store in
Greenwich (Case Study pp. 164–167) where high levels of environmental
lighting are available during the day by the use of natural light from roof
lights, but where in terms of Part L the overall energy use is below the
limits of the requirements.)
Part L of the building regulations encourages the use of daylight
linking, stressing the relationship between the available daylight, and
controlled artificial light sources. Daylighting can be at the heart of
energy savings in buildings, and whilst in the early twentieth century this
was largely forgotten, at the beginning of the twenty-first it has been
shown to be a key to the future.
Energy 43