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but specialist advice should be sought before installation.


Home help reductions


Five key changes in the revised Part L1A n CO2


Part L1A 2010 aims to reduce CO2 emissions by 25 per cent over Part L1A 2006.


This is a 40 per cent improvement over a dwelling built to the 2002 regulations. This corresponds roughly with the trigger point for Code for Sustainable Homes Level 3.


n The flat TER The Target Emission Rate (TER) is calculated in much the same way as it was in Part L1A 2006. The main differences are that an improvement factor of 0.4 is used, rather than 0.2, to give the 40 per cent improvement referred to above. The Standard Assessment Procedure (SAP) 2009 methodology is also used to estimate the carbon emissions from heating, hot water, lighting, pumps and fans.


n Low energy lighting


A minimum of 75 per cent of light fittings must be low energy. If further light fittings are also low energy, the full 100 per cent will contribute towards meeting the Target Emission Rate.


n Electric secondary heating In Part L 2006, a penalty was applied in dwellings not fitted with a secondary heating appliance. In such cases, it was assumed that 10 per cent of the heat in the property came from direct acting electric heaters, thereby significantly increasing the Dwelling Emissions Rate (DER). In Part L 2010, there is no such penalty, unless the dwelling has a chimney or flue and no appliance is installed.


n The performance gap Many completed dwellings do not in practice achieve the intended energy performance – this is referred to as the performance gap. If a near zero carbon is to be achieved it is vital that this gap be closed. Part L1A 2010 contains various things that aim to contribute to this, including clarity between what is regulation and what is guidance.


locations in the dwelling, to a number not less than three out of every four.


n Fixed external lighting Fixed external lighting means lighting fixed to an external surface of the dwelling supplied from the dwelling occupier’s electrical system. It excludes the lighting in common areas in blocks of flats and other access-way lighting provided communally. Reasonable provision would be to enable effective lighting control and/or the use of energy efficient lamps, such that the lamp rating does not exceed 100W per light fitting, and the lighting automatically switches off when there is enough daylight and when the area illuminated is unoccupied at night.


n Electric heating systems Guidance given in this section covers the various types of electrical heating installations for dwellings to meet the new energy efficiency requirements and includes electrical boilers, panel heaters, warm air heaters, storage heaters, convector and radiant heaters, and electric underfloor heating systems.


n Micro-combined heat and power (Micro-CHP) A new classification is included in the 2010 regulations for micro-combined heat and power packages. These are gaining in popularity and produce both heat and power for dwellings. They are classed as low carbon producing systems


56 ECA Today Winter 2010


n Commissioning of heating and hot water systems A heating and hot water system should be commissioned so that, on completion, the system and its controls are left in the intended working order and can operate efficiently for the purposes of the conservation of fuel and power.


Part L1B – Work Within Existing Dwellings This Approved Document gives guidance relating to: extensions; the creation of a new dwelling or part of a dwelling through a material change of use; material alterations; the provision of a controlled service or fitting; and the provision or renovation of a thermal element. It does not cover buildings containing rooms for residential purposes, halls of residence, nursing homes, etc. Although much of the guidance outlined in Part L1A is the same for Part L1B, there are some notable exceptions. For fixed internal lighting within these buildings, Part L1B


comes into effect when a dwelling is extended, a new dwelling is created from a material change of use, or an existing lighting system is being replaced as part of refurbishment or rewiring works. There are exemptions from the energy efficiency


requirements of the regulations for those buildings that are listed under Section 1 of the Planning and Conservation Act 1990, and are in a conservation area or are included in the schedule of monuments maintained under Section 1 of the Ancient Monuments and Archaeological Areas Act 1979.


Part L2A – New Buildings Other Than Dwellings This section deals with the construction of: new buildings other than dwellings; the first fit-out works in buildings that were built to comply with Part L as amended in 2010 (if the fit-out was deferred); and the construction of extensions to existing buildings where the gross floor area of the extension is greater than 100m2


, and greater than 25 per cent of the


total useful floor area of the existing building. When a building contains dwellings, account should also be taken of Approved Documents L1A and L1B.


Electrical contractors can provide building owners with the products, services and information needed to ensure energy efficient operation


n General lighting efficacy Office areas include those spaces that involve predominantly desk-based tasks, including classrooms, seminar rooms and conference rooms, including those in schools. Lighting in new and existing buildings should meet the


average recommended minimum standards for efficacy, averaged over the whole area of the applicable space in the building. For general lighting in offices, industrial and storage areas, this is not less than 55 lamp lumens per circuit watt. The previous 2006 edition of the Regulations only called for 45 lumens per circuit watt, but now lighting for display purposes has to meet an average of 22 lumens per circuit watt, up from 15 lumens per circuit watt. Lighting controls should be provided so as to avoid


unnecessary use of lighting during the times when daylight levels are adequate or when spaces are unoccupied. For safety reasons, automatically switched lighting systems should be subject to a risk assessment. Display lighting should be connected to dedicated circuits that can be switched off at times when people will not be


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