Conservation of fuel and power: Approved Document L, Volume 1 — Dwellings

O N L I N E V E R S I O N AA Envelope area (the measured part of the building) • Capturing heat from ambient air, ventilation The total area of all floors, walls and ceilings exhaust air, or a water or ground heat source bordering the internal volume that is the subject of using a heat pump. a pressure test. This includes walls and floors below Heating plant emission rate The annual CO external ground level. Overall internal dimensions 2 emissions from the fuel and power consumed by are used to calculate this envelope area, and no the heating plant to deliver space heating and hot subtractions are made for the area of the junctions water, offset by the emissions saved as a result of internal walls, floors and ceilings with exterior of any electricity generated by the heating plant, walls, floors and ceilings. divided by the heat output over a year. Measured in Existing district heat network A district heat kilograms of CO . 2 network that is either in operation or is under Heating zone A conditioned area of a building construction on 15 June 2022. For these purposes, which is on a single floor and has the same under construction means any of the following. thermal characteristics and temperature control • The building to house the energy centre has requirements throughout. been constructed. Intermediate floor A floor in a building above the • There is a heat offtake agreement signed ground floor. between the heat network and a third party. Light fitting A fixed light or a lighting unit, and can • Excavation for pipework has been completed. comprise one or more lamps and lamp holders, control gear and an appropriate housing. The *Fixed building services Defined in regulation 2(1) as control gear may be integrated in the lamp or any part of, or any controls associated with: located elsewhere, in or near the fixed light. a. fixed internal or external lighting systems (but Light source lumens The sum of the average initial not including emergency escape lighting or (100 hour) lumen output of all light sources in a specialist process lighting); luminaire. b. fixed systems for heating, hot water, air Load compensation A control function that conditioning or mechanical ventilation; or maintains internal temperature by varying the flow c. any combination of systems of the kinds temperature from the heat generator relative to the referred to in paragraph (a) or (b). measured response of the heating system. Fixed external lighting Lighting fixed to an external *Major renovation Defined in regulation 35 as the surface of the building and supplied from the renovation of a building where more than 25% of occupier’s electrical system. It excludes lighting the surface area of the building envelope undergoes in common areas of blocks of flats and in other renovation. communal accessways. *Material change of use Defined in regulation 5 as: Hard water Water which has a high mineral content. Where there is a change in the purposes for which For the purposes of this approved document, hard or the circumstances in which a building is used, so water is water that has a total water hardness of that after that change: greater than 200ppm of CaCO . 3 a. the building is used as a dwelling, where Heating appliance or heat generator The part of a previously it was not; heating system that generates useful heat using one b. the building contains a flat, where previously it or more of the following processes. did not; • The combustion of fuels in, for example, a boiler. c. the building is used as an hotel or a boarding • The Joule effect, taking place in the heating house, where previously it was not; elements of an electric resistance heating system. d. the building is used as an institution, where previously it was not; 7744 AApppprroovveedd DDooccuummeenntt LL VVoolluummee 11,, 22002211 eeddiittiioonn BBuuiillddiinngg RReegguullaattiioonnss 22001100 O N L I N E V E R S I O N