Passive Fire Protection

Those responsible for the design, specification, and construction of new and renovated buildings must take fire prevention into serious consideration. It is also a very important factor in the continuing maintenance of occupied premisies. As causes of fire are often unpredictable, design measures are taken to influence the formation and spread of fire, smoke and toxic gasses.

Building fire safety includes the protection of residents, firefighters, the structure and its contents, as well as the nearby structures. The possible risks to residents throughout the evacuation process must be minimised to allowable levels. It is crucial to keep the fire as contained as possible in the area where it started in order to minimise damage to the structure and its contents.

Active and passive fire protection systems should be planned and implemented in conjunction with one another to produce a balanced approach to fire protection. Effective firefighting in a building is often achieved through a combination of active and passive systems.

With many years of experience within the fire protection industry BTS are perfectly placed and commited to ensure that passive fire products are not just supplied but are backed up by technical support and a comprehensive locally held range of stock.This enables us to fully support your project ne matter how big or small. 

Fire resistance

The fire resistance of an element is determined by its ability to resist fire by maintaining its stability (load capacity), integrity and insulation which is normally expressed in hours of resistance. 

The three requirements can be defined as: 

Stability (load bearing capacity), the ability of the element to maintain the load without collapse. 

Integrity, the ability of the element to resist the development of cracks or voids allowing the passage of flames, smoke or toxic gasses to pass. 

Insulation, the ability of the element to prevent heat transfer from one element face to another. 

The fire triangle

Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, emitting heat, light, flame and the emission of sound. 

There are three elements, heat, fuel and oxygen which form a fire triangle and each element needs to be present to sustain the oxidation process. Therefore, the principle to extinguish or control a fire would be to remove one of these elements.

Fire Classification

According to the National Fire Protection Association (NFPA) a fire can be classified by the type of fuel they burn: 

Class A Combustible solid material such as wood, paper, fabric, plastic

Class B Combustible liquids and gasses such as oil, gasoline, paint, methane, hydrogen, acetylene

Class C Energized electrical fires such as wiring, circuit breakers or fuse boxes

Class D Combustible metals such as magnesium, sodium, potassium, titanium, zirconium

Fire cells/compartments are generally included in the building design as a requirement of the buildings functional or intended use. 

Over the life cycle of the building these cells/compartments may change in size, shape or requirement. 

However, the four application areas which should always be considered and could hinder the compartmentation principle are: 

Construction joints: A construction joint or movement joint is an assembly designed to safely absorb the heat-induced expansion and contraction of construction materials; it also absorbs vibration and allows movement due to ground settlement, thermal expansion or earthquakes.

Service penetrations: A service penetration is an opening designed and created to accommodate the passage of a mechanical, electrical service or structural element.

Cavity barriers: Cavity barriers are usually considered between two ’skins‘ separated by a hollow space (cavity). The skins can be either masonry brick / concrete block or drywall systems. They have been design to divide the area into separate spaces. 

Membrane barriers: Membrane barrier is an opening made through one side of the cavity wall, floor, ceiling of an assembly allowing exposure to the cavity. 

These products are designed to work in different ways to withstand the thermal and mechanical  pressures applied during a fire, whilst maintaining its functionality as a firestop. 

Intumescent insulating (Char Forming) - is a substance that swells as a result of heat or flame exposure, it increases in volume and decreases in density. Upon exposure to heat the material produces a light charring (Carbon) to its outer surface to form an insulating layer. The charred surface is a poor conductor of heat and protects the covered surface.

Fire Resistant – is a non-burning material which does not decompose and remains integral throughout the fire. 

Intumescent with pressure (Graphite) – a more substantial charring is generated in conjunction with a quantifiable expansion pressure. The material can be used around nonmetallic service penetrations. The expansion closes the void that would have developed once the service penetration had melted and burned away. 

Endothermic – is a chemical reaction which absorbs energy (heat) and releases water vapor to cool the surface.