|SBEM Calculations are a method of showing compliance with Part L2: Conservation of Fuel & Power, of Building Regulations for non-dwellings otherwise known as commercial property. SBEM calculations seek to evaluate that the 'actual' building concerned performs much better, in terms of efficiency, than a 'notional' building which conforms to the current standards set by Building Regulations. The notional building is the same form and orientation as the actual building and the activities performed within each individual zone are also the same, the only things that do differ are the percentage windows used within the calculations and the M&E installations such as heating, cooling, ventilation, hot water generation and lighting.|
Within the SBEM the notional building will generate a Target Emission Rate (TER) in KgCO2/m² per annum and as this suggests this is a target that the actual building must not exceed in order to show compliance with Part L2 of UK Building Regulations. The actual building will generate a Building Emission Rate (BER), if BER x04; TER then the building concerned complies with the regulations and the SBEM Calculation is passed.
There are a couple of other hoops that must be jumped through in order to gratify Building Regulations such as limiting u-value standards W/m².K for all external elements, efficiency of heat sources, power consumed through mechanical ventilation, lighting and air tightness of the building. The SBEM Calculation report will demonstrate whether these factors have been adhered to.
Producing a building which merely complies to standards will almost certainly not be enough to give a successful result of any SBEM Calculation, Building Regulations 2013 have sought to vastly improve energy performance of new buildings in the UK and minimum standards must be largely improved upon in order to achieve a sure outcome. Whether it is improved u-values, air tightness or lighting efficiencies which are implemented, a situation of robbing Peter to pay Paul is a regular occurrence when performing SBEM Calculations.
On many occasions properties will not pass an SBEM Calculation without the introduction of renewable energy such as Photo-voltaics, Air or Ground Source Heat Pumps, Solar Thermal or Combined Heat and Power (CHP) Plant, all of these can be modelled into the SBEM calculation tool to identify the most ideal solution for a given site and client.
To achieve success in working an SBEM Calculation it is advisable to make the building as thermally efficient as economically possible in the first instance, this will provide a great starting point. Ensure that the building has very good air tightness of around 5 m³/hr.m² at 50pa or less. Following this, efficiency of m&e installations is key. The most thermally efficient building is only as good as the efficiency of the systems within so ensure that the lighting loads are to a minimum with technologically advanced switching applied and heating and cooling efficiencies are maximised within financial constraints.
Having significant experience in producing SBEM Calculations is the key to success, there are a whole manner of differing building types out there from schools, hospitals and leisure to multi-storey office blocks, flagship industrial facilities and large hotel developments, each will present different challenges. Whatever the scheme, a solution can be found.