These proposals will radically change current methods for complying with the UK Building Regulations. For example the Elemental, Office CPR and Whole Building Methods will no longer be valid for compliance. Building compliance will now be driven by building performance as the EC attempts to meet its Kyoto Agreement commitments and these changes will become law on 4 January 2006. However, many engineers and architects do not appreciate just how much these changes will affect them.

The changes aim to reduce the energy consumption of new buildings, thereby reducing the level of carbon dioxide emissions that cause global warming. At the same time, designers will still need to ensure standards for ventilation, indoor air quality and health are maintained. These amendments will have far reaching effects on the way buildings are designed. The main changes within Part L are:

A requirement to determine an energy performance target for each new building and to demonstrate compliance with this target at completion. This target will be 23.5-28 percent lower than an equivalent or notional building designed to 2002 regulations.

A requirement to consider building performance holistically rather than elementally, hence the dropping of the current Part L2 calculation methods as compliance techniques and a new National Calculation Methodology introduced.

An Asset Rating Certificate issued on hand-over to the new building owner.

After two - three years an Operational Rating Certificate will be issued.

Although I welcome the proposed changes, one concern I have is that it appears easier to achieve compliance for an air conditioned building than for a naturally ventilated building. At IES, we have conducted a number of simulations considering different design options for mechanical, airconditioned and naturally ventilated buildings. From these studies it appears far easier to achieve compliance for air conditioned buildings because as there are far more energy processes you can easily achieve significant savings, for example by improving the COP of a chiller. As a consequence far fewer naturally ventilated building designs would be compliant. Having a situation where it is easier to pass Building Control if the building is mechanically ventilated or air conditioned would be contrary to the objective of the EC Energy Performance of Buildings Directive. This issue should be addressed.

However, I would propose making the compliance requirements for mechanically ventilated and air conditioned buildings more stringent rather than making it easier to comply with a naturally ventilated building.

One of the major changes is the proposal for a new National Calculation Methodology. Two methods of achieving compliance are being suggested. One being a simplified calculation tool based on the emerging CEN calculation methods. The other involves the use of a detailed building simulation tool, which will have to adhere to internationally recognised compliance tests. While the simplified approach will suit the majority of the market, by promoting the use of detailed simulation software the Government can enable more complex buildings to be easily assessed within a national methodology.

However, what will the impact be on engineers and those involved in the Building Services industry? The UK leads the world in having the highest proportion of buildings that are designed using building simulation products at some stage of the design process, and most of this experience sits with engineers. Therefore, arguably this is a unique opportunity for many engineers, who already offer consultancy services to architects, to expand their services to cover compliance of these new regulations. Many firms have already invested in such tools, and as long as the software complies with the selected tests, this investment will stand them in good stead.

IES has worked closely with companies such as White Young Green, Gifford & Partners and TBA, in integrating building simulation software completely into the company’s culture, a process that requires close collaboration and support on training over a period of time.

With compliance shifting from being based on elements within a building towards the building as a whole, this will give engineers an increased say in the overall design of a building, a fact that may make many architects uncomfortable.Today, engineers are frequently not engaged until the design has been ‘evolved’ by the architect and if this continues it could result in significant re-design when the engineer gets involved.

I expect two likely consequences: architects will have to start using the tools permitted via the National Calculation Methodology or engineers will have to get involved at earlier stages of the design process. The latter option would lead to a more holistic approach, where all parties work and communicate effectively together throughout the whole process, a working method that has proven to be extremely successful.

Building simulation software offers the tools necessary to shift the emphasis of the design process and allow design teams to make more effective design choices at earlier stages; this however means the process will no longer be centred only on CAD, which requires a huge change in perception by those in the industry.

I would suggest that companies start thinking about how they are going to cope with these new regulations now. Currently, energy used in buildings is responsible for roughly 50 percent of the UK’s carbon dioxide emissions. Therefore, improved standards of construction can have a positive impact.

So these proposed amendments do really make sense, and the commercially aware companies will see the opportunities and embrace these new regulations.

Don Mclean has over 25 years experience in the development of building analysis software for use in the building design process and is the founder and MD of IES Ltd.

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