Civil Engineering Reference
In-Depth Information
Negative
Sustainability Spectrum
Positive
Responsibility
Destroys silence
Creates silence
No participatory design
Participatory design
Needs frequent repair
Maintains itself
Addictive and enslaving
Enlightening and liberating
No response to nature
Responsive to nature
No response to change
Responsive to change
No response to culture
Responsive to culture
Table 4.3
(cont.)
and therefore have increased heat losses from the building fab-
ric due to wind behaviour. In such circumstances it would be
beneficial to reduce the impact of the heat losses by protect-
ing the building from wind. Building earth bunds or vegetation
barriers could contribute to the overall design solution.
Carbon emissions in commercial and domestic buildings
are calculated using different methodologies but each includes
an assessment of fundamental building - physics principles.
In commercial buildings the calculation method used is the
Simplified Building Energy Model (SBEM), which measures
carbon emissions by calculating the percentage improvement
of the Building Emission Rate (BER) over the Target Emissions
Rate (TER). In domestic properties the calculation method is
known as the Standard Assessment Procedure (SAP) where the
Dwelling Emissions Rate (DER) substitutes the BER and the
percentage of improvement is the DER over the TER.
There are alternative, more rigorous methods, which involve
further building physics; for example, the use of Dynamic
Simulation Software can lead to a better assessment of the
overall energy performance and carbon emissions.
The construction solutions of tomorrow will be heavily
influenced by building science and bioclimatic design and will
need the structural engineers to provide input on materials, not
only their structural properties but also their thermal behav-
iour. How the individual elements fit together will need to be
in accordance with certified robust methods detailing how to
reduce sound transfer and heat losses.
There are many research projects in the UK and Europe
such as the Passivhaus project that explore passive design tech-
niques. The project originated in Germany and was established
in the UK in 2001 with the project Cost Efficient Passive Houses
as European Standards (CEPHEUS). To achieve the reduction
in carbon emissions to Levels 5 and 6 of CSH standards, Part
L (2010) and 2013 Building Regulations, the construction type
will need to move away from the traditional masonry cavity
wall to modern methods of construction such as Structural
Insulating Panels (SIPs), Insulated Concrete Form (ICF), insu-
lated solid wall construction, Phase Change Materials (PCMs),
or thermal mass techniques such as Trombe walls.
During the conceptual design stage the operational energy of
the building needs to be considered and actions taken to reduce
it. This requires a significant amount of modelling using quick
tools such as SBEM, SAP and the LT Method. A number of
examples showing how this can be done to increase the credits
gained in this category are provided below:
Designing the building to ensure that there is sufficient natural
■
ventilation using stack effects. If, right from the conceptual design
stage, the appropriate ventilation is 'designed in' then less of an
active energy requirement will be needed to ventilate the final
design. A good example is the natural ventilation approach applied
to the Inland Revenue Building, Nottingham.
Considering the modern methods of construction combined with
■
producing a façade that is adaptable by taking into account its
response to orientation, the local climate and seasonal variation.
In order to make these decisions, the early conceptual designs will
need to be modelled to assess their thermal performance. It may
be that some insulation will need to be removable, and innova-
tive materials might be used to ensure sufficient natural sources of
heating and cooling.
Ensuring the rooms are sized correctly with sufficient glazing to
■
ensure natural daylighting. Once again the design will need to be
modelled at the conceptual design stage in order to ensure this.
Early decisions made in consultation with a sustainable build-
ing structural engineer will produce a building with a low oper-
ational energy. If a building is designed passively so that it
requires less operational energy then local renewable sources of
energy become much more cost-effective and the building may
then have the potential to become effectively carbon-neutral.
4.4.2.3
Focus 2: Water and surface water run-off
All construction projects have an ecological impact, the effects
of which can more often than not be detrimental to the water and
nitrogen cycles through land-use depletion. Sustainably focused
projects will look at how this impact can be reduced. It is also
important to minimise surface water run-off at source as this can
help reduce flood risk downstream; such measures reduce the
amount of water discharged into surface water drainage systems,
thus helping to minimise infrastructure costs. For sites in the UK
