Insulation for 400–600 °C — superheated steam, turbine casings, engine exhausts

Stone wool approaches its 640 °C limit (use high-density wired mat); silica mat cores take over in removable covers; microporous buys space on turbine casings. Every uninsulated m2 here is a four-figure annual bill.

Valid materials

What survives 400–600 °C

Material (serves this class)	Max service	λ at 500 °C duty
Stone wool (mineral wool)	640 °C	0.079
Ceramic fibre (RCF / AES blanket)	1200 °C	0.069
Aerogel blanket	650 °C	0.038
Calcium silicate	650 °C	0.083
Expanded perlite	650 °C	0.086
Microporous (fumed-silica) panels	1000 °C	0.025
E-glass needle mat	550 °C	0.068
Silica needle mat / fabric	1000 °C	0.062

Computed · DN100 at 500 °C, 50 mm

The numbers at this temperature

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).

FAQ

Questions on this topic

What insulation is best for 400–600 °c?

Shortlist for superheated steam, turbine casings, engine exhausts: Stone wool (mineral wool), Silica needle mat / fabric, Calcium silicate, Microporous (fumed-silica) panels. Stone wool approaches its 640 °C limit (use high-density wired mat); silica mat cores take over in removable covers; microporous buys space on turbine casings.

How much heat does a pipe at 500 °C lose?

A bare DN100 pipe at 500 °C loses ≈1,724 W per metre in still air (ASTM C680 simplified). 50 mm of stone wool (mineral wool) cuts that to ≈339 W/m — ≈€675 and 2.47 t CO2 saved per metre·year at €0.05/kWh.