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 c. any combination of systems of the kinds High-usage entrance door A door to an entrance referred to in paragraph (a) or (b). primarily for people, through which many people are expected to move. Robustness and/ Fixed external lighting Lighting fixed to an external or powered operation are the main performance surface of the building and supplied from the requirements. A high-usage entrance door will have occupier’s electrical system. It excludes lighting automatic closers and, except where operational in common areas of blocks of flats and in other requirements preclude it, be protected by a lobby. communal accessways. Indirect-fired circulator A domestic hot water system g-value A total solar energy transmittance. in which the water is supplied to the draw-off points Hard water Water which has a high mineral from a device in which water is heated by an element content. For the purposes of this approved through which the heating medium is circulated so as document, hard water is water that has a total not to mix with the hot water supply. In practice, the water hardness of greater than 200ppm of CaCO . heat source is likely to be a boiler dedicated to the 3 supply of domestic hot water. Heat generator seasonal efficiency The estimated seasonal heat output from the heat generator Installed capacity of a fixed building service per divided by the energy input. unit area The design output of the distribution system output devices (the terminal units) serving Heating appliance or heat generator The part of a heating system that generates useful heat using the space in question, divided by the total useful one or more of the following processes. floor area of that space. • The combustion of fuels in, for example, a Instantaneous electrically heated A domestic hot water system in which the water is supplied to the boiler. draw-off points from a device in which cold water • The Joule effect, taking place in the heating is heated by an electric element or elements as it elements of an electric resistance heating flows through the water heater. The water heater system. is close to the draw-off points. The unit has no • Capturing heat from ambient air, ventilation storage volume, as water is instantaneously heated exhaust air, or a water or ground heat source as it flows through the device. using a heat pump. Light source lumens The sum of the average initial Heating zone A conditioned area of a building (100 hour) lumen output of all the light sources which is on a single floor and has the same in a luminaire. Does not include any losses or thermal characteristics and temperature control inefficiencies of the luminaire. requirements throughout. Lighting Energy Numeric Indicator (LENI) A High excitation purity light sources Colour- measure of the performance of lighting in terms tuneable light sources that can be set to at least of energy per square metre per year (kWh/m2 per the colours listed in Table A1 and which have for year). See Appendix B. each of these colours, measured at the dominant Local electrically heated A domestic hot water wavelength, the minimum excitation purity shown. system in which the water is supplied to the draw- Intended for use in applications requiring high- off points from a device in which water is heated quality coloured light. by an electric element or elements immersed in the stored water. The water heater is near the Table A1 H igh excitation purity light sources draw-off points and has a storage capacity of between 100 and 300 litres. Colour Dominant Minimum excitation wavelength (nm) of purity (%) Blue 440–490 90 Green 520–570 65 Red 610–670 95 8877 BBuuiillddiinngg RReegguullaattiioonnss 22001100 AApppprroovveedd DDooccuummeenntt LL VVoolluummee 22,, 22002211 eeddiittiioonn O N L I N E V E R S I O N