The use of vermiculite fire doors for fireproofing, prevention, and retention in Australia is common and well-known.  Vermiculite makes up the fireproof core used inside Spartan fire doors as a form of passive fire protection. It has a low density and excellent insulation properties.

What does vermiculite do?

Because of its fireproof and prevention properties, it has many purposes in construction. It can be used as a loose-fill insulation, sprayed on building boards and drywall, fireproofing structural steel and piping, and constructing fireplaces. As a product it is also very absorbent, making it an excellent packing material. Vermiculite even has agricultural uses, like peat, compost or soil to germinate seeds. The automotive industry also uses it in its brake pads because of its thermal resistance.

But what makes vermiculite an excellent door core material is its light, inert, and inorganic nature. Besides offering fire protection, it also offers soundproofing qualities and it is used in acoustic panels for Spartan acoustic doors as well.  

Yet its fire retention properties outweigh all of its other possible uses. Here’s how it works. Exfoliated vermiculite retains moisture very well. In the event of a fire, the moisture turns to steam. The steam has a cooling effect on the steel substrate used in the door and the door frame. This delays the rise in temperature needed for combustion and therefore delays or stops the spread of fire.  It also expands when heated, giving it a dual fire prevention and retention effect.

Vermiculite is also very durable. It cannot decay or rot while being strong and resilient. But yet it is not brittle or apt to crack, tear or peel. It can be frozen, thawed out and still retain all of its most necessary qualities. As a mineral used in major construction projects since 1946, its benefits are well-documented.

The benefits of vermiculite include:

• Lightweight
• Fire retardant
• Insulates
• Fire retention
• Noise reduction
• Fireproofing
• Adaptable properties
• Durable

Where does vermiculite come from?

Vermiculite has many uses besides fire doors. It is a hydrous, silicate mineral normally found where felsic and ultramafic rocks come into contact. South Africa, Brazil, the United States and China are top producers. The four countries produce about 90% of the product available worldwide. It is mined using open mining techniques where ore is detached from the other minerals and then screened and separated. As society has become more environmentally conscious, mining operations take significant care in minimising impact and restoring mined land to its natural state.