Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox SL
- Max. temp.
- 450–850 °C
- Density
- 60–160 kg/m³
- Thickness
- 50–100 mm
Industrial and high temperature
Stone wool slabs, blankets, wired mats and pipe sections: how do they differ and how to choose?
In short
Choose the form from the shape of the surface first, then the grade from the temperature: slabs for flat equipment walls; blankets for large tanks and vessels that do not vibrate; wired mats for large pipes, curved or irregular surfaces and equipment that vibrates or runs very hot; and pre-formed pipe sections for standard pipe sizes. Grades within each form have different maximum service temperatures, which must be read from that grade's own document.
Why does one material come in several forms?
All four are made of the same stone wool. They differ in density, stiffness and how they are shaped, which decides how closely the insulation follows the surface and how it is fixed. Insulation that does not suit the shape leaves gaps and open joints, and heat leaks there however good the material is — see gaps and compression.
Four forms and the surfaces they suit
| Form | Nature | Suitable surfaces | Usual fixing |
|---|---|---|---|
| --- | --- | --- | --- |
| Slab | Semi-rigid to rigid board that holds its shape | Flat walls of boilers, tanks, columns; rectangular hot ducts | Impaled on insulation pins and locked with washers, or held by bands |
| Blanket | Long flexible roll, no mesh | Large tanks and vessels that do not vibrate; wide-radius curves | Wrapped and banded, or pinned |
| Wired mat | Stone wool stitched to wire mesh | Large pipes, bends, vessels, furnaces, flue ducts, irregular surfaces, vibrating equipment | Mesh edges stitched together with wire or hooks, plus pins or bands |
| Pipe section | Split cylinder sized to the pipe | Standard pipe sizes | Snapped over the pipe and tied with wire |
Slabs
Slabs hold their own shape on vertical and horizontal faces, so they suit wide flat areas. ROCKWOOL's documents describe slabs being fastened to equipment on insulation pins, which are welded or mechanically fixed to the surface, with slab edges butted tightly together.
- Example: ROCKWOOL ProRox SL, six grades from 60 to 160 kg/m³
- Denser slabs are stiffer and carry more load, but follow a curve less readily
Blankets
Long rolls cover area quickly with few joints and bend to a tank wall. The manufacturer specifies them for equipment that does not vibrate.
- Example: ROCKWOOL ProRox BL, three grades from 60 to 100 kg/m³
- For vibrating equipment the manufacturer points to wired mats instead
Wired mats
The stitched-on wire mesh acts as a carrier that holds the wool together, so the mat can be wrapped around large pipes, bends and complex shapes and stands up to vibration better than a plain blanket. ROCKWOOL describes wired mats as suited to large-diameter pipework, vessels and columns and to work where design flexibility is needed.
- Example: ROCKWOOL ProRox WM, three grades from 80 to 128 kg/m³, on galvanised wire mesh (stainless on request)
- Wired mats have little resistance to compression, so ROCKWOOL's installation guidance calls for spacers to carry the cladding and keep it from crushing the insulation
Pipe sections
Formed to the pipe size, split and hinged, they close snugly around the pipe. They go on faster and leave neater joints than wrapping.
- Example: ROCKWOOL ProRox PS 960 SA / PS 970 SA, 120 / 150 kg/m³, made with the water-repellent WR-Tech binder
- Pipes larger than the sizes made, or with many fittings and special shapes, usually switch to wired mats
Grade and maximum service temperature
These values come from ROCKWOOL Thailand data sheets (tested to ASTM C411 / C447).
| Form | Grade | Density (kg/m³) | Max. service temperature |
|---|---|---|---|
| --- | --- | --- | --- |
| Slab | ProRox SL 930 SA | 60 | 450 °C |
| Slab | ProRox SL 950 SA | 80 | 650 °C |
| Slab | ProRox SL 960 SA | 100 | 650 °C |
| Slab | ProRox SL 978 SA | 110 | 850 °C |
| Slab | ProRox SL 970 SA | 128 | 650 °C |
| Slab | ProRox SL 540 SA | 160 | 650 °C |
| Blanket | ProRox BL 938 SA | 60 | 350 °C |
| Blanket | ProRox BL 958 SA | 80 | 450 °C |
| Blanket | ProRox BL 960 SA | 100 | 650 °C |
| Wired mat | ProRox WM 950 SA | 80 | 650 °C |
| Wired mat | ProRox WM 960 SA | 100 | 650 °C |
| Wired mat | ProRox WM 970 SA | 128 | 750 °C |
| Pipe section | ProRox PS 960 SA | 120 | 650 °C |
| Pipe section | ProRox PS 970 SA | 150 | 650 °C |
Points to note:
- Higher density does not always mean higher temperature. SL 978 SA (110 kg/m³) is rated to 850 °C while SL 540 SA (160 kg/m³) is rated to 650 °C. Read the grade's value; do not infer it from density
- Maximum service temperature is the material's ceiling, not a temperature to design right up to. See what is service temperature?
- Some sizes and grades are made to order or need to be confirmed first; see the product pages
A short selection sequence
- What is the surface? Flat, wide-radius curve, tight or irregular curve, or a standard pipe
- Does it vibrate? If so, rule out plain blankets and consider wired mats
- What is the real maximum temperature? Include start-up and upset conditions, then choose a grade that covers it with margin
- Must the insulation carry load? Where it is stepped on or loaded, consider denser slabs, spacers, or rigid insulation such as calcium silicate
- Is the pipe or equipment stainless steel? All four ranges in the table are documented as low-chloride to ASTM C795, but water still has to be kept out. See corrosion under insulation
- Have a specialist calculate the thickness and detail the fixing
Fixing and joints
- Insulation pins — for slabs and blankets on flat or wide-radius surfaces. Number and spacing depend on the insulation's weight, the orientation of the surface and the temperature; the designer sets them
- Bands and wire — for blankets and pipe sections. Tight enough to seat the insulation, not so tight that it is crushed
- Support rings — on vertical pipes and vessels, to carry the weight of the insulation so it cannot slide down
- Several layers with staggered joints — thick or very hot work should go on in layers whose joints do not line up, so heat has no straight path out
- Cladding — stone wool in every form needs cladding against water and knocks
Read more: insulation fixing accessories · insulating tanks, boilers, ovens and hot ducts
Safety
Pin welding, work on equipment that is still hot, work at height and work in confined spaces must be done by qualified contractors under the plant's safety procedures. Thickness and fixing details must be designed for the real conditions; we do not give ready-made thicknesses.
Sources
- ROCKWOOL Thailand — ProRox SL 930 / 950 / 960 / 978 / 970 / 540 SA Product Data Sheets (08/25)
- ROCKWOOL Thailand — ProRox BL 938 / 958 / 960 SA Product Data Sheets (08/25)
- ROCKWOOL Thailand — ProRox WM 950 / 960 / 970 SA Product Data Sheets (08/25)
- ROCKWOOL Thailand — ProRox PS 960 SA / PS 970 SA Product Data Sheets (08/25)
- ROCKWOOL — RockTech Slab Series data sheet (Handling and Installation section)
- ROCKWOOL Technical Insulation — Insulation with SeaRox wired mats (wired-mat installation principles)
- ROCKWOOL Technical Insulation — ProRox WR-Tech factsheet; Installation guidance videos
- ASTM C612 (block and board), ASTM C592 (metal-mesh covered blanket), ASTM C547 (pipe insulation) — scopes of the standards
Related products
Categories and example products for this topic
- ROCKWOOL ProRox SL — Slabs for flat equipment walls: six grades, max. service 450–850 °C by grade
- ROCKWOOL ProRox BL — Blankets for non-vibrating tanks and equipment: three grades, 350 / 450 / 650 °C
- ROCKWOOL ProRox WM — Wired mats for large pipes, curves, furnaces, flues: 650 / 650 / 750 °C by grade
- ROCKWOOL ProRox PS — Split pre-formed sections for industrial pipes, snap-on, up to 650 °C
Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox BL
- Max. temp.
- 350–650 °C
- Density
- 60–100 kg/m³
- Thickness
- 50–100 mm
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)
Industrial and high-temperature insulation · Stone wool
ROCKWOOL ProRox PS
- Max. temp.
- 650 °C
- Density
- 120–150 kg/m³
- Thermal conductivity (λ)
- 0.037–0.038 W/m·K (50 °C)