8.6.4 Insulation performance
Insulation performance shall comply with national standards. Issues to be taken into account include:
- thermal conductivity and pipe insulation size
- maximum daily hot water loss for hot water storage systems.
8.6.4.1 Thermal conductivity and pipe insulation size
Minimum thickness of pipework insulation for hot water services and space heating applications using high performance insulation see Table 2:
- all insulation should be designed so that the permissible heat losses in BS 5422 for hot water services at 60°C are not exceeded for the different pipe sizes
- this table relates to both plastic and metal pipes.
Table 2: Pipe insulation thickness for high emissivity (ε) outer surface = 0.90
Note(s)
For low emissivity, see BS 5422. Thermal insulating materials for pipes, tanks, vessels, ductwork and equipment operating within the temperature range –40°C to +700°C.
8.6.4.2 Maximum daily hot water loss for hot water storage systems
Maximum daily heat loss for hot water storage cylinder should comply with Table 3 below.
Table 3: Hot water storage heat loss
| Nominal volume (litres) | Heat loss kWh/24h |
|---|---|
| 50 | 1.03 |
| 100 | 1.49 |
| 150 | 1.88 |
| 200 | 2.06 |
| 250 | 2.22 |
| 300 | 2.36 |
| 350 | 2.48 |
| 400 | 2.59 |
| 500 | 2.80 |
Last updated: 2nd January 2025