Construction Fire Safety: Material Classification & Ratings

Classification of Construction Materials by Flame Behavior

Classification of materials used in construction: M0: non-flammable; M1: non-fuel flame; M2: moderately combustible; M3: medium combustible; M4: highly combustible.

Fire Resistance of Structural and Separating Elements

Fire resistance of elements of the construction (wall, door, fan, etc.) is expressed as the time during which that element maintains its load-bearing capacity or fire stability, integrity and insulation. The three basic criteria are:

• R (Stability / Bearing capacity): The time during which a structural element supports its load without loss of structural stability under fire exposure.
• E (Integrity): The time during which a separating element prevents fire transmission to the unexposed face due to passage of flame or hot gases, and prevents ignition of materials adjacent to the unexposed surface.
• I (Thermal insulation): The time during which a separating element resists fire exposure on one side without significant heat transfer to the unexposed side.

Risk Classification by Intrinsic Combustible Load

Spaces/areas are classified according to their intrinsic risk (Qp, Qs):

• Qp < 200 - low
• 200 ≤ Qp < 800 - medium
• Qp ≥ 800 - high

[Qp: Mcal/m²]

Definitions of Variables and Coefficients

Gi: weight in kg of each combustible material.
Qi: calorific value of each combustible item (see Table 1.4).
Ci: dimensionless coefficient that weights the degree of hazard of each fuel in the sector (see Table 1.1).
A: surface area of the burned area (m²).
Ra: dimensionless coefficient that corrects the level of risk (see Table 1.2).

Active Fire Protection: Equipment and Extinguishers

Active protection: extinguishers, BIE (hose reels), detection systems, sprinklers, etc.

Dry-column extinguisher: a device containing an extinguishing agent that can be projected and directed over a fire. Projection is achieved by internal pressure obtained either by permanent compression, by a chemical reaction, or by the release of a propellant gas.

Auxiliary (extinguishing) agent: one or a set of products contained in the extinguisher whose action causes extinguishment.

Load: the mass or volume of medium contained in the extinguisher, quantified in liters for water-based agents or in kilograms for other types.

Types of Extinguishers

• Portable (Notebook / Portátiles): directly transportable extinguishers whose total mass is < 20 kg.
• Wheeled (Sobre ruedas): extinguishers directly transportable but equipped with wheels for transportation.