Steel Designers Manual - TheBestFriend.org

This material is copyright - all rights reserved. Reproduced under licence from The Steel Construction Institute on 12/2/2007
To buy a hardcopy version of this document call 01344 872775 or go to http://shop.steelbiz.org/
Steel Designers' Manual - 6th Edition (2003)
Modern portal frame design has played a significant role in reducing the embodied
energy burden of single storey industrial and commercial buildings. Portal
frames are capable of spanning considerable distances using relatively light sections.
Roof beam depths are generally of the order of span divided by 60, as opposed to
span divided by 25 for a conventional beam and column roof. The combination of
steel frames with light gauge purlins and rails supporting insulated cladding systems
provides a very efficient form of construction resulting in the very high (95%) major
share. Systems are available to meet the requirements of the new Part L to the UK
Building Regulations 5 in terms of both insulation and air tightness.
A key element in achieving low embodied energy is the pursuit of structural
efficiency. By reducing the amount of structural steel required per unit area
of commercial building, designers can not only achieve elegant and economic
structural solutions, but also reduce embodied energy burdens.
8.6 Operational energy
Buildings require energy for heating and lighting, powering equipment and machines,
and possibly mechanical ventilation and cooling services.This type of energy,
known as operational energy, is greatly influenced by the design of the building, and
the servicing strategy.
The threat of global climate change resulting from ‘greenhouse gases’, of which
the most prevalent is carbon dioxide, is driving a concerted effort to reduce energy
use in buildings. In the UK, buildings account for 40–50% of carbon dioxide emissions.
Significant reductions in operational energy (and hence CO2 emissions) are
necessary to combat climate change. Through careful design, it is possible to reduce
operational energy by at least one third, by reducing the need for air conditioning
or even eliminating it altogether. 2
8.6.1 Housing and operational energy
Operational energy 281
Residential buildings account for about 30% of the total energy used in the UK.
This relatively high percentage of energy use, together with increasing demand for
new housing, indicates the importance of achieving improved energy efficiency in
this sector.
Light steel frame residential buildings have proved to have good standards of
environmental performance, particularly in terms of energy conservation. Many
have significantly exceeded the requirements of UK Building Regulations in terms
of thermal performance, as shown in Table 8.1.
The following measures are recommended to reduce operational energy
requirements: