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

O N L I N E V E R S I O N L1(b), L2 6.43 The installation of anti-vibration instruments and flexible hose connections should be in accordance with the manufacturer’s guidance in order to limit the effects of harmful vibrations on building structures. Solar water heating systems NOTE: The guidance for solar water heating in this document applies to indirect solar systems that supply domestic hot water and have both of the following. a. A solar collector area of less than 20m2. b. A solar heated water storage volume of less than 440 litres. 6.44 New solar hot water collectors should be independently certified as complying with all tests required by BS EN 12975-1 and BS EN ISO 9806 for both of the following. a. Thermal performance. b. Reporting and identification. 6.45 The electrical input power of the primary pump in the solar water heating system measured in watts should be less than the higher of the following. a. 50W. b. 2% of the peak thermal power of the collector. 6.46 For a heat exchanger between a solar primary and secondary system, a minimum of 0.1m2 or equivalent of heat exchanger area should be provided for every 1m2 of the net absorber area of the solar collector. 6.47 For work on new or existing solar water heating systems, controls should be fitted to or upgraded in solar domestic hot water systems to do all of the following. a. Maximise the useful energy gain from the solar collectors. b. Minimise the accidental loss of stored energy. c. Ensure that hot water produced by back-up sources is not used when adequate solar pre-heated water is available. d. Provide a means to control the adverse effects of excessive temperatures and pressures. e. Where a separate domestic hot water heating appliance is pre-heated by a solar system, the appliance should be controlled to add no extra heat if the target temperature is met from the solar pre-heated vessel. 6.48 The dedicated storage volume of solar heated water relative to the area of the collector should be either of the following. a. A minimum volume of 25 litres for every 1m2 of the net absorber area of the solar collector. b. A volume equivalent to at least 80% of the daily hot water demand (as defined by the Standard Assessment Procedure). 48 Approved Document L Volume 1, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N