Fire safety and VFR compartmentalization: cavity engineering in VM Group ventilated facades

In modern civil and industrial architecture, the building envelope must not only ensure energy efficiency and durability, but must also meet the most stringent passive fire safety requirements. Fire safety design of façades is a crucial issue, governed in Italy by stringent regulations (such as the technical guides of the National Fire Brigade and the VFR provisions).

If not properly engineered, the ventilated façade's technical cavity, essential for thermo-hygrometric insulation in summer and winter, risks becoming a conduit for rapid flame and smoke propagation due to the natural chimney effect.

In over 30 years of experience, VM Group has developed an active and passive protection strategy that eliminates this risk through the selection of materials and the geometric control of internal flows.

Fire dynamics on facades and control of the stack effect

In the event of a fire starting inside an apartment (which breaks windows and spreads outside) or triggered by external causes at the base of the building, the flames seek a vertical outlet. The air cavity of a ventilated façade, if free of obstacles, acts like a true chimney: the thermal gradient generated by the fire accelerates the upward convective motion of the air, feeding the fire with new oxygen and carrying flames, hot gases, and smoke to the upper floors at extremely high speeds.

To combat this physical phenomenon, VM Group's engineering approach does not aim to eliminate ventilation (which is vital to the building's health), but to dynamically and locally interrupt it only in the event of an abnormal rise in temperature.

Selection of materials: choosing non-combustible materials (Class A1)

The first line of defense against fire spread is eliminating the fire load within the insulation package. Unlike traditional thermal insulation composite systems (ETICS), which often use plastic or synthetic polymer materials (which, if not properly added, can liquefy or drip, fueling the fire), VM Group uses exclusively non-combustible mineral insulation materials:

Rock Wool or High Density Glass Wool: Certified in fire reaction class A1 (or A2-s1, d0 depending on the system configuration). These materials do not contribute in any way to the fire, do not produce toxic fumes (s1), and do not generate dripping of burning particles (d0), protecting the lives of occupants and facilitating rescue operations.
Aluminum Alloy Substructure and Stainless Steel Fixings: Inherently non-combustible metal materials that maintain the mechanical stability of the system even at high temperatures, preventing premature collapse of the external cladding panels.

Compartmental Fire Barriers: The VM Group Solution

The heart of fire safety in VM Group's building envelope is the horizontal and vertical cavity compartmentalization systems. These elements divide the façade into "watertight sectors" in the event of an emergency.

"Open" Horizontal Barriers with Dynamic Construction
To avoid compromising the thermal performance of the façade throughout the building's service life, VM Group installs special perforated metal profiles with highly expanding intumescent gaskets at the interfloor level.

Under normal conditions: The barrier allows the free passage of the laminar airflow necessary for the chimney effect and moisture removal.
In the event of a fire: When the temperature in the cavity reaches approximately 150°C - 180°C, the intumescent material reacts chemically, expanding to 20-30 times its original thickness. In just a few seconds, the carbon foam completely seals every millimeter of the air gap, creating a firestop that blocks the passage of flames, radiant heat, and toxic fumes to the upper floors.

Regulatory Compliance and Safety of Tall Buildings

The design of VM Group façade systems strictly follows the ministerial guidelines for fire safety of facades in residential buildings (RTO Facades and subsequent regulatory updates). The system is configured to ensure:

Propagation limitation: Fire cannot travel inside the building envelope.
Joint protection: The joints between the exterior panels are sized to prevent heat from directly penetrating behind the cladding into areas not affected by the fire.
Escape route integrity: By preventing the detachment or violent shattering of exterior panels (such as stoneware or stone installed with our calculated fastening systems), we ensure that the area beneath the building remains safe for the evacuation of residents and access by firefighters.

Technical Portal for Sustainable Architecture