Ceramic fibre (RCF / AES blanket) — properties, λ(T) and computed performance

Service limit ≈1200 °C · density 96–128 kg/m³ · ASTM C892 · EN 1094-1 (AES low-biopersistence grades per Note Q). Supplied as: blanket, modules, paper, rope — furnace and exhaust territory.

Honest assessment

Strengths, limits, verdict

Strengths: survives 900–1200 °C; very low thermal mass (fast-cycling furnaces); flexible around complex shapes.

Limits: RCF is classified carcinogen cat. 1B in the EU — handling controls or AES substitution required; fragile; expensive per thermal R below 400 °C.

Verdict: Above ~650 °C it is the only flexible option; below that, stone wool or needle mat does the job cheaper and safer.

Thermal conductivity (typical published values)

Mean temperature	λ W/m·K
200 °C	0.060
400 °C	0.090
600 °C	0.150
800 °C	0.220

λ at mean temperature — rises with T because pore radiation grows with T³.

Computed performance · ASTM C680 simplified

Ceramic fibre (RCF / AES blanket) on real pipe sizes

At 100 °C (λ=0.060 at mean)

Pipe	Thickness	Bare W/m	Insulated W/m	Surface	Saving €/m·yr	t CO2/m·yr
DN50	30 mm	152	38	30 °C	€55	0.20
DN50	50 mm	152	29	26 °C	€60	0.22
DN50	100 mm	152	20	22 °C	€64	0.23
DN100	30 mm	287	61	31 °C	€110	0.40
DN100	50 mm	287	44	27 °C	€119	0.43
DN100	100 mm	287	29	23 °C	€126	0.46
DN200	30 mm	551	106	32 °C	€217	0.79
DN200	50 mm	551	73	27 °C	€233	0.85
DN200	100 mm	551	45	23 °C	€247	0.90

At 250 °C (λ=0.060 at mean)

Pipe	Thickness	Bare W/m	Insulated W/m	Surface	Saving €/m·yr	t CO2/m·yr
DN50	30 mm	436	110	49 °C	€159	0.58
DN50	50 mm	436	82	36 °C	€172	0.63
DN50	100 mm	436	57	27 °C	€185	0.68
DN100	30 mm	826	177	52 °C	€317	1.16
DN100	50 mm	826	127	39 °C	€341	1.25
DN100	100 mm	826	83	28 °C	€363	1.33
DN200	30 mm	1,583	304	55 °C	€624	2.28
DN200	50 mm	1,583	210	41 °C	€670	2.45
DN200	100 mm	1,583	128	30 °C	€710	2.60

At 400 °C (λ=0.061 at mean)

Pipe	Thickness	Bare W/m	Insulated W/m	Surface	Saving €/m·yr	t CO2/m·yr
DN50	30 mm	720	185	69 °C	€261	0.95
DN50	50 mm	720	139	48 °C	€283	1.04
DN50	100 mm	720	97	32 °C	€304	1.11
DN100	30 mm	1,365	298	74 °C	€520	1.90
DN100	50 mm	1,365	214	52 °C	€561	2.05
DN100	100 mm	1,365	140	34 °C	€597	2.19
DN200	30 mm	2,616	513	79 °C	€1,026	3.75
DN200	50 mm	2,616	354	55 °C	€1,103	4.04
DN200	100 mm	2,616	217	36 °C	€1,170	4.28

Assumptions: 20 °C ambient, still air (h=10 W/m²·K), €0.05/kWh fuel, 8000 h/yr, 82% boiler efficiency, 0.183 kg CO2e/kWh. Your numbers: free calculator.

Against the field

Same duty, all materials — DN100 at 250 °C

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.052	112	37 °C	€348	1.3
Glass wool	0.050	106	36 °C	€351	1.3
Ceramic fibre (RCF / AES blanket)	0.060	127	39 °C	€341	1.2
Aerogel blanket	0.027	61	29 °C	€373	1.4
Calcium silicate	0.067	139	41 °C	€335	1.2
Expanded perlite	0.070	145	42 °C	€332	1.2
Cellular glass	0.058	122	38 °C	€343	1.3
Microporous (fumed-silica) panels	0.023	50	27 °C	€378	1.4
E-glass needle mat	0.050	106	36 °C	€351	1.3
Silica needle mat / fabric	0.055	117	37 °C	€346	1.3

DN100 pipe at 250 °C, 50 mm insulation, per metre of pipe; bare loss 826 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).

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FAQ

Questions on this topic

What is the thermal conductivity of ceramic fibre (rcf / aes blanket)?

Typical published values: 0.060 W/m·K at 200 °C, 0.090 W/m·K at 400 °C, 0.150 W/m·K at 600 °C, 0.220 W/m·K at 800 °C (mean temperature). λ rises with temperature — design with the mean-temperature value, not the ambient one.

What is the maximum temperature for ceramic fibre (rcf / aes blanket)?

≈1200 °C continuous service for typical grades (ASTM C892 · EN 1094-1 (AES low-biopersistence grades per Note Q)). Product-specific limits vary — check the datasheet of the exact grade.

Where is ceramic fibre (rcf / aes blanket) the right choice?

Above ~650 °C it is the only flexible option; below that, stone wool or needle mat does the job cheaper and safer.