Expanded perlite at 500 °C — heat-loss table

λ = 0.086 W/m·K at mean temperature ((500+20)/2 = 260 °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	215	172	141	129	504	61 °C	€162	0.59
DN50	312	240	190	170	909	68 °C	€326	1.19
DN80	412	308	237	210	1,341	72 °C	€504	1.84
DN100	500	367	278	244	1,724	75 °C	€662	2.42
DN150	685	491	362	314	2,538	78 °C	€999	3.65
DN200	857	606	439	378	3,304	80 °C	€1,316	4.82
DN300	1,212	841	596	507	4,884	83 °C	€1,972	7.22

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 4,800 W/m² → 707 W/m² at 50 mm (≈€1,996/m²·yr saved). Method: ASTM C680 simplified — methodology. Your exact case: free calculator.

Context

All materials at 500 °C

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.079	339	70 °C	€675	2.5
Ceramic fibre (RCF / AES blanket)	0.069	300	65 °C	€694	2.5
Aerogel blanket	0.038	173	46 °C	€757	2.8
Calcium silicate	0.083	356	73 °C	€667	2.4
Expanded perlite	0.086	367	75 °C	€662	2.4
Microporous (fumed-silica) panels	0.025	117	37 °C	€784	2.9
E-glass needle mat	0.068	297	64 °C	€696	2.5
Silica needle mat / fabric	0.062	274	61 °C	€707	2.6

DN100 pipe at 500 °C, 50 mm insulation, per metre of pipe; bare loss 1,724 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 500 °C lose with expanded perlite?

With 50 mm at 500 °C (λ=0.086 at mean): DN50 loses 240 W/m, DN100 367 W/m, DN200 606 W/m — vs 1,724 W/m bare for DN100. Full table on this page.

What surface temperature does expanded perlite give at 500 °C?

≈75 °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.