Design Energy Efficiency rating
One of the major challenges the National Health Service faces in the future is
controlling their energy consumption to meet government set targets for carbon
emission.
In an effort to try and help reduce the energy consumed within the healthcare
sector the Chartered Institute of Building Service Engineers (CIBSE) in
collaboration
with the Department of Health (DoH) introduced into the 2007 LG2 a
Design Efficiency Rating system (DEER). The system is aimed at promoting greater
levels of design responsibility in an effort to increase installed efficacies. The DEER
rating system is loosely based on the governments Part L requirements for
conservation of fuel and power.
In line with the Part L requirements the DEER system uses the target values
published within these documents as a base level or "statutory minimum ". It then
simply extends the scheme by introducing two new higher levels of efficiency
called "Best Practice" and "Exemplary". The three levels and their energy target
values are as follows:
DEER level C)
Statutory Minimum = 45 to 59 inclusive Luminaire Lumens/Circuit Watt
DEER level B)
Best Practice = 60 to 69 inclusive Luminaire Lumens/Circuit Watt
DEER level A)
Exemplary = 70 and above Luminaire Lumens per Circuit Watt
Compliance to the DEER levels must be proved by a calculative process, it can
not be achieved by the exemption rule, i.e. using lamps with an efficacy
≥45 Lumens/Watt. The calculation should be carried out in much the same way as
detailed within the Part L approved document. The DEER level calculation does
however deviate from the approved document method in one area. Part L requires
a calculation to be carried out to all the individual areas of a building to find the
total circuit watts and luminaire lumens used within each area, these are then
added together and divided to find the average installed efficacy for the whole
building. To calculate a DEER level for the same building it is first necessary to
evaluate each area individually to find its own installed efficiency value. All the
areas efficiency values should then be added together and divided by the number
of areas considered; the value it provides represents its DEER level.
In order for the DEER method to be effective it must consider all of the areas of a
project, however in large projects lot of areas can be repeated so it makes sense
to base the DEER rating on a number of the fundamental areas that make up and
account for a large part of the building. The actual number of areas can be set by
specification but the minimum quantity
on anything other than very small projects
should be no less than 10. In addition the 10 selected areas should include the
following:
- Minimum 12 meter section of corridor < 2 meters wide
- Minimum 12 meter section of corridor > 2 meters wide
- Single bedded ward
- Multi-bedded ward (either 4 or 6 bedded)
- Public reception desk including waiting area
- Administration office greater than 40m2
- Doctors/Consultants examination room
- Recovery room or area greater than 25m2
- Minor operating theatre including any scrub-up and anaesthetics areas
(general lighting only)
- Major operating theatre including the scrub-up and anaesthetics areas
(general lighting only)
Not all projects will of course include all of the areas listed above so the list above
should be revised to include as many of the above or changed to reflect the
project areas under consideration.
