Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox WM
- Max. temp.
- 650–750 °C
- Density
- 80–128 kg/m³
- Thermal conductivity (λ)
- 0.037–0.038 W/m·K (50 °C)
What is service temperature?
In short
Service temperature is the temperature range in which insulation can be installed continuously against a hot or cold surface while keeping its shape and without losing its properties beyond the limits the manufacturer sets. It is used to match insulation to a pipe or piece of equipment. It is not the same as the melting point, a fire-test result or a fire-resistance rating, and it must always be taken from the documents of the specific product.
- 1The service-temperature range stated by the manufacturer — check the conditions in the document
- 2The real pipe or equipment surface temperature, including its hottest or coldest moments, must stay within the range
- 3Service temperature is not a fire rating or non-combustibility — they are different tests
Why does it matter?
If insulation is used on a surface hotter than it was designed for, it can shrink, sag, crack or its binder can break down until heat escapes. Likewise, insulation for cold pipes has a lowest usable temperature; below it the material may become stiff, brittle or distorted.
Maximum and minimum service temperature
- Maximum service temperature — the highest hot-surface temperature at which the insulation still performs within the set criteria. Several test standards exist, such as ASTM C411 (hot-surface performance) or EN 14706 / EN 14707 (flat products and pre-formed pipe sections), looking at dimensional stability, thermal properties and other changes under heat
- Minimum service temperature — important for chilled-water and refrigerant pipework
Examples from manufacturers' documents:
| Product | What the maker states |
|---|---|
| --- | --- |
| ROCKWOOL ProRox WM | Maximum service temperature per grade (tested to ASTM C411 / C447) |
| SCG PCI | Service temperature range of the pipes it covers |
| MINEWOOL Ceramic Fiber Blanket | Classification temperature and working temperature, given separately |
See the product pages and manufacturers' documents for the actual figures — a value for one product cannot be used for another.
Classification temperature vs working temperature (ceramic fibre)
High-temperature insulation wools such as ceramic fibre are often labelled with a classification temperature, a value used to grade the material from a laboratory shrinkage test. It is generally higher than the temperature recommended for continuous use, so design should use the working temperature the manufacturer gives.
Common confusions
| Term | Meaning | Can it replace service temperature? |
|---|---|---|
| --- | --- | --- |
| Melting point | Temperature at which the fibres start to melt | No — far above what can be used continuously |
| Fire-test result, e.g. A1, non-combustible | How the material behaves in a standard fire test | No — a different question |
| Fire-resistance rating, e.g. 2 hours | Result of a complete tested system | No — not a property of the insulation alone |
| Mean temperature for λ | Temperature at which thermal conductivity is reported | No — a measurement condition |
For the fire terms, see reaction to fire, non-combustible and fire resistance.
Further points
- Leave a margin. Do not design for a surface temperature exactly at the insulation's limit. An engineer or specialist should consider the highest temperature that can really occur, including start-up and upset conditions
- λ changes with temperature. The same insulation conducts more heat when hotter, so thickness for hot work must be calculated at the real temperature
- First heat-up smoke. ROCKWOOL states that when mineral wool with an organic binder is first heated above about 150–200 °C, a one-time release of fumes from binder decomposition can occur; ventilate well during first start-up
High-temperature work
Selecting insulation and calculating thickness for steam pipes, boilers or furnaces should be done by an engineer or industrial-insulation specialist. See how to choose high-temperature insulation.
Sources
- ASTM C411 — Standard Test Method for Hot-Surface Performance of High-Temperature Thermal Insulation
- EN 14706 / EN 14707 — Determination of maximum service temperature (flat products / preformed pipe insulation)
- ROCKWOOL Technical Insulation — ProRox WM 950SA / 960SA / 970SA Product Data Sheets
- ROCKWOOL Technical Insulation — Safe Use Instruction Sheet, ProRox & SeaRox products
- 3T Insulation — MINEWOOL Ceramic Fiber Blanket catalogue
- SCG — SCG Insulation for Industrial : Pipe (PCI) catalogue
Related products
Categories and example products for this topic
- ROCKWOOL ProRox WM — Maximum service temperature 650 / 650 / 750 °C for WM 950 / 960 / 970
- SCG PCI / PCIF — Glass wool pipe section with a service range of 10–540 °C per the maker's document
- MINEWOOL Ceramic Fiber Blanket — Ceramic fibre: working temperature 1,050 °C (Standard) and 1,350 °C (Zirconium)
- ASK CS 220 — Calcium silicate: Type I up to 650 °C and Type II up to 1,000 °C
Pipe insulation · Glass wool
SCG PCI / PCIF
- Pipe size
- ½–18 in
- Thickness
- 25–50 mm
- Service temp.
- 10 – 540 °C
Industrial and high-temperature insulation · Ceramic fibre
3T MINEWOOL Ceramic Fiber Blanket
- Service temp.
- 1,050–1,350 °C
- Density
- 128 kg/m³
Industrial and high-temperature insulation · Calcium silicate
ASK CS 220
- Max. temp.
- 650 / 1,000 °C
- Thermal conductivity (λ)
- ≤ 0.060 W/m·K (93 °C)
- Density
- ≤ 220 kg/m³