Expanded perlite at 100 °C — heat-loss table

λ = 0.061 W/m·K at mean temperature ((100+20)/2 = 60 °C, from the published curve). Pipe losses per metre, four thicknesses, savings vs bare.

Pipe	30 mm W/m	50 mm W/m	80 mm W/m	100 mm W/m	BARE W/m	Surface @50 mm	Saving €/m·yr @50 mm	t CO2/m·yr
DN25	26	21	17	15	84	25 °C	€31	0.11
DN50	39	29	23	20	152	26 °C	€60	0.22
DN80	51	37	28	25	223	26 °C	€91	0.33
DN100	62	45	33	29	287	27 °C	€118	0.43
DN150	86	60	43	38	423	27 °C	€177	0.65
DN200	107	74	53	45	551	27 °C	€233	0.85
DN300	152	103	72	61	814	28 °C	€347	1.27

Assumptions: 20 °C ambient, still air (h=10 W/m²·K combined), €0.05/kWh fuel, 8000 h/yr, 82% efficiency, 0.183 kg CO2e/kWh (DESNZ 2024). Flat surfaces at this duty: bare 800 W/m² → 87 W/m² at 50 mm (≈€348/m²·yr saved). Method: ASTM C680 simplified — methodology. Your exact case: free calculator.

Context

All materials at 100 °C

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.041	31	25 °C	€125	0.5
Glass wool	0.038	29	24 °C	€126	0.5
Ceramic fibre (RCF / AES blanket)	0.060	44	27 °C	€119	0.4
Aerogel blanket	0.023	18	23 °C	€131	0.5
Calcium silicate	0.056	42	26 °C	€120	0.4
Expanded perlite	0.061	45	27 °C	€118	0.4
Cellular glass	0.047	35	25 °C	€123	0.4
Microporous (fumed-silica) panels	0.022	17	23 °C	€132	0.5
Elastomeric foam (FEF)	0.040	30	24 °C	€125	0.5
PIR / PUR rigid foam	0.028	21	23 °C	€130	0.5
E-glass needle mat	0.045	34	25 °C	€124	0.5
Silica needle mat / fabric	0.055	41	26 °C	€120	0.4

DN100 pipe at 100 °C, 50 mm insulation, per metre of pipe; bare loss 287 W/m. λ at mean temperature; € and CO2 per metre·year at €0.05/kWh, 8000 h, 82% efficiency. Method: ASTM C680 simplified (h=10).

Material datasheet: Expanded perlite → · temperature class: by temperature →

FAQ

Questions on this topic

How much heat does a pipe at 100 °C lose with expanded perlite?

With 50 mm at 100 °C (λ=0.061 at mean): DN50 loses 29 W/m, DN100 45 W/m, DN200 74 W/m — vs 287 W/m bare for DN100. Full table on this page.

What surface temperature does expanded perlite give at 100 °C?

≈27 °C with 50 mm on DN100 (20 °C ambient, still air). Personnel-protection targets (≤45–60 °C) may need more thickness — see the 80/100 mm columns.