Consequential improvements

One of the most controversial aspects of the current Building Regulations is the requirement for consequential improvements to be made in buildings larger than 1000 m2 when improvements are made.
Consequential improvements was a new line of thinking in the latest Building Regulations. Malcolm Jeary offers guidance on what it all means.New Building Regulations are almost guaranteed to send those involved into a spin, and this is proving the case with Part L2B that came into effect on 6 April 2006. Designed to conserve fuel and power in existing buildings other than dwellings, all fit-out work carried out on existing buildings may need a different approach. The most controversial part of L2B is proving to be the consequential improvements aspect to buildings larger than 1000 m2. A consequential improvement to one element of the building triggers a requirement for general improvements to another, subject to the technical and economic criteria. A new building fitted out to category A standard has to fulfil Part L2A. But the subsequent tenant fit-out has to comply with part L2B, which could trigger consequential improvements. Taken literally, adding a new fan coil to an office that has had the partitioning changed could trigger consequential improvements, although this is plainly nonsensical. This is why it is important that the fit-out company knows its way around L2B regulations. One of the key requirements of Part L2B is ‘to provide energy-efficient and properly commissioned fixed building services with effective controls’. When considering improvements, the general requirement is to consider all thermal elements, including heat gains and losses through thermal elements and other parts of the building fabric as well as pipes, ducts and vessels used for space heating, space cooling and hot water services. Insulation is at the top of the agenda when approaching the fit-out of offices in an existing building. It is important that all walls are insulated to improve insulation, including stud and track walls. It is also important to insulate dry-lined walls and ceilings. When considering where to site offices within an existing structure, it is important to reflect on whether or not the office will be located in an existing heated area. If the building is being enlarged, for example by the installation of a mezzanine floor or by building offices in a stores area that does not have heating, it is important that heating and cooling losses in the newly created offices meet Part L2B. Should the area have a concrete floor, the regulations state that insulated raised access floors should be used, where feasible, to improve thermal quality. Regardless of efficiency, all heating and cooling systems more than 15 years old should be upgraded. Lighting controls also play an important factor in L2B regulations. Any general lighting system with average lamp efficiency of less than 40 lamp lumens/circuit watt should be upgraded by either a new luminaire or with improved lighting controls. Controls should be provided to avoid unnecessary lighting when daylight levels are adequate. Automatically switched lighting systems should be subject to risk assessment for safety reasons. Energy-saving lamps are also available for most situations. The thermal performance of windows and doors also needs to be considered. The L2B regulations stated that where windows, roof windows, roof lights or doors are to be provided, reasonable provision should given to draught-proof units. To comply with the new regulations, it is normally necessary to replace existing windows and doors. Economic feasibility requires a simple payback not exceeding 15 years. Simple payback is the amount of time it will take to recover the initial investment through energy savings and is calculated by dividing the marginal additional cost of implementing an efficiency measure by the value of annual energy savings achieved by the measure. Part 2LB gives effective examples, which include upgrading most heating, cooling and air-handling systems that are over 15 years old. Introduction or increases to micro-generation systems (low- and zero-carbon technologies or LZC) are considered economically feasible if they have a pay back period of seven years or less. The list of challenges in the development of existing office and public buildings is extremely long, both in terms of project management and technical success. Balancing regulations and guidelines for factors such as energy performance, and indoor climate, as well as acoustic and lighting conditions whilst maintaining the flexible use of space and also better working conditions in buildings that are sustainable and attractive can prove to be problematical. For this reason it is important that companies moving to or developing an existing building refer to specialist fit-out companies to ensure that they meet Part L2B of the Building Regulations. Malcolm Jeary is managing director of the Spaceway Group.
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