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 L1(b), L2 Controls and zoning for new and replacement space heating systems 5.11 Heating systems should have all the following controls. a. The systems should be subdivided into separate control zones for areas of the building in which any of the following are significantly different. i. Solar exposure. ii. Pattern of use. iii. Type of use. b. For each control zone it should be possible to control both of the following independently of other control zones. i. Timing. ii. Temperature. c. The service should be appropriate to the requirements of the space. If both heating and cooling are provided, the controls should prevent them operating simultaneously. d. Central plant should operate only when the zone systems require it. The default condition should be off. e. Where appropriate and technically feasible, heating systems should have weather compensation. 5.12 System controls should be wired so that when there is no demand for space heating, the heating appliance and pump are switched off. System treatment for hot water systems for space and domestic hot water heating 5.13 Before a new heating appliance is installed, all central heating and primary hot water circuits should be thoroughly cleaned and flushed out. A suitable chemical inhibitor should be added to the primary heating circuit to protect against scale and corrosion. In hard water areas, suitable measures should be taken to treat the feed water to water heaters and the hot water circuit of combination boilers to reduce limescale accumulation. Thermostatic room controls 5.14 For heating and cooling systems in a new non-domestic building, or when a heat generator such as a boiler is replaced in an existing non-domestic building, each room should be provided with thermostatic room controls. These should be capable of being used to separately adapt the heating or cooling output in each room served by the heating or cooling appliance. Where justified in accordance with paragraph 5.15, heating and cooling may be controlled for each heating zone rather than individual rooms. NOTE: There is no need to install thermostatic room controls in rooms/zones without heating or cooling in new and existing non-domestic buildings. NOTE: Installing thermostatic room controls may not be technically feasible in some cases. These may include the following. a. Buildings with very low heat demand (e.g. less than 10W/m2). b. Buildings with buffer zones for heat absorption or dissipation with high thermal mass. 37 Building Regulations 2010 Approved Document L Volume 2, 2021 edition O N L I N E V E R S I O N