Conservation of fuel and power: Approved Document L, Volume 2 — Buildings other than dwellings

O N L I N E V E R S I O N AA Principal works The work necessary to achieve the • The marginal additional cost is the additional client’s purposes in extending the building and/ cost (materials and labour) of incorporating, for or increasing the installed capacity of any fixed example, additional insulation – not the whole building services. The value of the principal works cost of the work. is the basis for determining a reasonable provision • The cost of implementing the measure should for some consequential improvements. be based on prices current at the date when Renewable technology Technology that uses the application is made to the building control renewable resources, which are naturally body and be confirmed in a report signed by a replenished on a human timescale, to produce suitably qualified person. electricity. Resources include wind, wave, marine, • The annual energy savings should be estimated hydro, biomass and solar. using the National Calculation Methodology Rooflight A glazed unit installed out of plane with Modelling Guide. the surface of the roof on a kerb or upstand. Also • The energy prices that are current when the sometimes referred to as a skylight. application is made to the building control body Roof window A window installed in the same should be used when evaluating energy savings. orientation as, and in plane with, the surrounding Current prices are given on the BEIS website, at: roof. https://www.gov.uk/government/collections/ quarterly-energy-prices. *Room for residential purposes Defined in regulation 2(1) as a room, or a suite of rooms, Simplified building energy model One of the which is not a dwelling-house or a flat and which current approved procedures for assessing the is used by one or more persons to live and sleep performance of a building, in line with this and includes a room in a hostel, an hotel, a document. boarding house, a hall of residence or a residential Specialist process lighting Lighting to illuminate home, but does not include a room in a hospital, specialist tasks within a space rather than the or other similar establishment, used for patient space itself. Specialist process lighting includes accommodation. theatre spotlights, projection equipment, Seasonal coefficient of performance (SCOP) A lighting in TV and photographic studios, medical measure of the efficiency of a heat pump over the lighting in operating theatres and doctors’ and designated heating season, measured using the dentists’ surgeries, illuminated signs, coloured or procedures in BS EN 14825. stroboscopic lighting, and art objects with integral lighting, such as sculptures, decorative fountains Seasonal energy efficiency ratio (SEER) The total and chandeliers. amount of cooling energy provided by a single cooling unit over a year, divided by the total Standard Assessment Procedure The current energy input to that single cooling unit over the approved procedure for assessing the performance same year. of dwellings in line with Approved Document L, Volume 1: Dwellings. The Standard Assessment Sequence control Enables two or more heating Procedure is detailed in The Government’s boilers to be switched on or off in sequence when Standard Assessment Procedure for Energy Rating the heating load changes. of Dwellings version 10. Simple payback The amount of time it will take Target emission rate The maximum CO emission to recover the initial investment through energy 2 rate for the building, expressed as kgCO /(m2.year). savings, calculated by dividing the marginal 2 additional cost of implementing an energy Target primary energy rate The maximum primary efficiency measure by the value of the annual energy use for the building in a year, expressed as energy savings achieved by that measure, taking no kWh /(m2.year). PE account of VAT. The following guidance should be used. 8899 BBuuiillddiinngg RReegguullaattiioonnss 22001100 AApppprroovveedd DDooccuummeenntt LL VVoolluummee 22,, 22002211 eeddiittiioonn O N L I N E V E R S I O N