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

L1(a) O N L I N E V E R S I O N Table 4.4 M inimum thickness of pipework insulation for low temperature hot water space heating applications in non-domestic buildings Nominal internal pipe Minimum insulation thickness (mm) for low temperature diameter (mm) hot water systems(1)(2)(3) Thermal conductivity (λ) = Thermal conductivity (λ) = 0.025W/m·K 0.04W/m·K Less than or equal to 10 15 30 Less than or equal to 15 15 35 Less than or equal to 25 20 40 Less than or equal to 32 20 45 Less than or equal to 40 25 45 Less than or equal to 80 25 50 Less than or equal to 100 30 55 NOTES: 1. Thicknesses apply for low-emissivity faced insulation. 2. Insulation thicknesses designed to achieve permissible heat losses from BS 5422 for heating systems ≤95°C. 3. For other circumstances refer to BS 5422. Table 4.5 M inimum thickness of pipework insulation for domestic hot water services in non-domestic buildings Nominal internal pipe Minimum insulation thickness (mm) for domestic diameter (mm) hot water services(1)(2)(3) Thermal conductivity (λ) = Thermal conductivity (λ) = 0.025W/m·K 0.04W/m·K Less than or equal to 10 15 35 Less than or equal to 20 20 35 Less than or equal to 40 25 40 Less than or equal to 80 25 45 Less than or equal to 100 30 45 NOTES: 1. Insulation thicknesses designed to achieve permissible heat losses from BS 5422 for hot water services at 60°C. 2. Thicknesses for low-emissivity faced insulation. 3. For other circumstances refer to BS 5422. 30 Approved Document L Volume 2, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N