By Sai Enterprises Team • Aurangabad
Choosing between Rockwool and Nitrile Rubber is one of the most common questions we get from plant engineers and builders. The short answer: hot services use Rockwool, cold services use Nitrile Rubber. Here is why.
Rockwool — built for heat
Rockwool (mineral wool) is a fibrous insulation made from spun volcanic rock. It is non-combustible, handles temperatures up to 750°C, and is the standard material for steam lines, boilers, furnaces and hot ducts. It is supplied as slabs, boards, pipe sections and blankets, and is always protected with aluminium or SS cladding.
Nitrile Rubber — built for cold
Nitrile rubber (NBR) is a flexible closed-cell foam that resists moisture and prevents condensation. It is the standard choice for chilled water lines, refrigerant piping, HVAC ducts and anything below ambient temperature. Because it is closed-cell, it doubles as its own vapour barrier — critical for cold services.
Key differences
- Temperature: Rockwool up to 750°C; NBR from -50°C to +110°C
- Moisture: Rockwool needs cladding and vapour barrier; NBR is naturally moisture resistant
- Flexibility: NBR bends around elbows and valves easily; Rockwool is rigid and fabricated
- Fire: Both offer good fire performance in their standard grades
- Cost: NBR is more expensive per metre but simpler to install on complex pipework
Which one for your project?
Use this simple rule: if the surface temperature is above 100°C, choose Rockwool. If it is at or below ambient (chillers, chilled water, air conditioning), choose Nitrile Rubber. For clean rooms and cold storage walls, PUF panels are often the better option — read our comparison here.
Not sure? Share your line temperatures and pipe sizes with our team on WhatsApp or email and we will recommend the right material, thickness and cladding — free of cost.