Specifications are always tricky, particularly when it comes to new buildings or major refurbishment projects. It may be that the client knows exactly what they want, but this seems to be quite rare. In speculative office buildings, for example, it can be difficult to predict exactly what the building will be used for and how each prospective occupant might use the space they take.
But generalisations can be made for example occupancy levels and time of occupation particularly in offices where it’s not difficult to work out what sort of work will be going on there.
When it comes to specifications, anyone who works in the construction industry knows that these can change as projects move forward. Financial constraints arise, and recommendations are given on the basis of reducing capital costs. The original specification can drift from its intention at the outset. For those of us in the controls sector, this can be frustrating.
Reducing and changing the specification for a controls system, or building energy management system (BEMS) almost always has an impact on the long-term effectiveness of that system. Removing even seemingly small items, for example CO2 or occupancy sensors, reduces the ability of the system to save energy in the operational lifetime of the building.
Clients and building managers increasingly view their BEMS as central to the energy-saving capabilities of their buildings, but if corners are cut at the start, the system is less able to offer the type of benefits they are looking for and that is not just lower energy use, but also better maintenance programmes, improved occupant comfort and extended life of building services equipment such as boilers and air conditioning systems.
The British and European Standard BS EN 15232 is due for updating this year, and offers both clients and specifiers a useful way to draw up specifications for control systems that both technical and non-technical staff can understand. Clients can decide to opt for a Level A, B or C BEMS, and the Standard will outline what each of these levels should incorporate including occupancy sensors, or CO2 sensors, blinds linked to daylight sensors or night-cooling features.
By using this document as a specification tool, it is easy to see the benefits of each feature chosen – and therefore easier to ensure that the specification remains unchanged throughout the construction process. It is only by ensuring that what is required for a building is the same as the system that is installed that clients can really gain the full energy saving benefits of building controls.