Effective Fire Protection for HVAC

Person holding match

Smoke, heat and flames represent major fire risks to building users. How materials behave in a fire - from ignition to flashover and fully developed fire - therefore needs to be optimised from the design stage with the correct choice of HVAC insulation materials.

Whether you are looking to protect a school, hospital, shopping mall, office or residentials building, ISOVER has developed a range of HVAC insulation solutions that provide efficient insulation for HVAC pipes and ductwork. Using ISOVER HVAC insulation materials ensures your building is thermally protected and noise disruption is kept to a minimum. These ISOVER HVAC insulation solutions also provide a reliable, affordable and long-lasting guarantee for fire safety.

Passive fire protection for your HVAC pipes and ducts  

Different protection methods can be used to avoid or minimize fire propagation: passive methods - where fire propagation is minimised by the correct choice of building materials - and active methods - using mechanisms to reduce fire risks to a pre-designed level. Insulation can play an important role in passive fire protection in buildings.

For more than 30 years, we’ve been working closely with the construction industry and fire safety experts to develop high-performance passive fire insulation for metal ducts and pipes across your building. This means ensuring that, in a fire, the HVAC components remain stable, prevent the passage of flames and smoke and keep the temperature down for as long as possible. All ISOVER HVAC products are rated as non-combustible and do not contribute to fire or create any toxic smoke or burning droplets. 


ULTIMATE™ HVAC fire insulation

To take fire protection to a new level, our R&D teams have developed ULTIMATE™, a new-generation mineral wool insulation that uses breakthrough technology to combine the performance and handling benefits of glass wool with the outstanding fire resistance of stone wool.

ULTIMATE™U PROTECT HVAC insulation materials are non-combustible, do not contribute to the ignition of fire and do not emit any smoke and burning droplets. 


Up to 2 hours of fire protection

The ULTIMATE™ U PROTECT range provides all the advantages of conventional thermal and acoustic insulation with increased fire protection. Guaranteeing superior material stability and thermal resistance at high temperatures, our HVAC insulation materials are non-combustible and offer up to 2 hours of fire protection for pipes as well as rectangular and circular ductwork systems.


  • Rectangular ducts - up to 2 hours fire resistance for fires located inside or outside the duct, both horizontally and vertically. U Protect Slabs are used for rectangular ducts.

  • Circular ducts - up to 2 hours fire resistance for fires located inside or outside the duct, both horizontally and vertically. U Protect Wired Mats are used for circular ducts.



What exactly is ULTIMATE™ mineral wool?

ULTIMATE™ mineral wool has excellent thermal, acoustic and fire-resistance properties thanks to a unique internal micro-structure.  The long, light, elastic fibres can be compressed and, once installed, retain their properties and thickness over time, even when exposed to vibrations and thermal shocks. 

The benefits of ULTIMATE™ U PROTECT for your HVAC insulation

  • Fire protection certified as fulfilling EN 1366-1, -3 and -8, BS 476: Part 24 for ventilation ductwork
  • Totally non-combustible for Euroclass A1 or A2,s1-d0 fire rating, Class 0 Compliance
  • Up to 70% lighter than traditional systems
  • Compressed packaging saving up to 60% of total freight mileage
  • Easy to install - light and adaptable for faster cutting, bending and filling

Find the right ULTIMATE™ U PROTECT HVAC insulation materials - whether slabs, wired mats or pipe sections - for your project. Covering different types of pipes, rectangular and circular ventilation and smoke extraction ducts, the U Protect range offers a complete solution with excellent, lightweight thermal and acoustic properties, as well as low maintenance costs.

Fire resistance & reaction to fire


Two criteria reflect the different performances of construction products, and more specifically of mineral wools, in a fire situation:


  • Fire resistance

  • Reaction to fire

Reaction to fire

The reaction to fire of a material reflects how the material reacts when exposed to fire: how easily it can ignite; its contribution to calorific value; how much smoke is emitted and whether it generates flaming droplets that might represent a risk. All ISOVER materials are designed to exhibit the lowest possible levels of smoke emission and flaming droplets, and represent low or zero fire load.

The main risks in a building fire are smoke propagation and flaming droplets.


Smoke propagation:

When building users are exposed to smoke generated by a fire, two main problems occur: opacity (dense smoke prevents people from finding exits by visual darkening of evacuation areas) and toxicity (levels will depend on the chemical composition of the material that is burning).

Flaming droplets:

Another parameter to consider in reaction to fire is the production of flaming droplets and/or particles that will contribute to fire propagation, especially in ducts since they are typically installed over suspended ceilings.​

Fire resistance

The fire resistance of a building component is a measure of the time during which it is able to prevent the spread of flames and flammable gases, whilst maintaining structural integrity and minimising the temperature of the unexposed face. Ducts can be designed to meet fire resistance requirements, as required by regulations. For example, where ducts pass through separating walls designed to function as fire-breaks, they must also be designed with a minimum level of fire resistance.

Fire resistant ducts can be created by insulating metal ducts with a mineral wool that provides fire resistance in addition to thermal and acoustic insulation. ISOVER has developed ULTIMATE Protect (U Protect), a unique solution for creating fire resistant ducts. Based on ULTIMATE  mineral wool, ULTIMATE Protect combines:


  • Optimum fire resistance values for duct work

  • Lower weight than traditional stone wool insulation solutions

  • Reduction of thickness for equivalent fire resistance, compared to traditional stonewool solutions

  • Ease of installation



Learn more about HVAC insulation

HVAC duct with ULTIMATE insulation