Smoke: Silent Killer In Fire
Assistant Manager, Technical Cell
Most of the indoor fire deaths are not caused by burns, but by inhalation of smoke. These killing fumes have more tricks up its sleeve.
Smoke inhalation’s symptoms aren’t as obvious as those of a major burn, so many people think they are fine as long as they get out of a house fire before suffering skin injury. However, people who breathe in smoke during a fire can have life-threatening consequences even if they have no other injuries. Smoke inhalation is even compared to the feeling of drowning. Exposure to hot gaseous products can cause serious respiratory complications. Smoke leads to disorientation and clouds your vision, making escape difficult.
Along with inhaling smoky air, the person trapped may breathe in harmful, toxic chemicals from items burned in the fire’s path adding to the suffocation. A major component adding fuel to this menace are wires and cables.
Majority of the wires and cables used in any residential or commercial building in India are offered with PVC (Polyvinyl Chloride) insulation.
PVC when subjected to heat and fumes burns rapidly emitting dark and toxic smoke. As a product of combustion, PVC emits deadly chlorine gases which have pungent irritating odours and are classified as pulmonary irritants. These emissions further increase when commercial grade PVC material is used in the cable.
Hence, the Indian standards for wires and cables have the inclusion of PVC variants based on the fire performance characteristics viz., Flame Retardant (FR) and FR-LSH (Flame Retardant Low Smoke & Halogen).
Flame Retardant (FR) is the property of insulation or sheath material of a wire or a cable to slowdown the ignition process and prevent the flame propagation.
This material has two characteristics viz., Limited Oxygen Index (LOI) and Limited Temperature Index (LTI) supporting the fundamental FR requirements.
Limited Oxygen Index (LOI): It is the measure of the minimum percentage of oxygen required to support the combustion. In FR PVC this level is 29% minimum.
Limited Temperature Index (LTI): It is the minimum temperature at which the material supports combustion in air containing 21% of oxygen under controlled conditions. In FR PVC this requirement is 250°C at 21% oxygen.
However, FR PVC material is not supported with any measure to control the emission of dark and toxic smoke which is equally lethal.
The wires and cables offered with FR-LSH PVC materials have reduced smoke and toxic gas emission levels along with the above two characteristics viz., LOI and LTI.
As per the Indian standard for wires and cables, the maximum smoke and halogen acid gas emission permitted for FR-LSH PVC material is 60% and 20% respectively.
Fire Smoke - A silent killer, has been identified as the primary cause of death for victims of indoor fires.
We are now a global village, which means we need to be better prepared to deal with any adversity to protect ourselves and at the same time, the nation. With this responsibility, we have to necessarily review our infrastructure safety. Fire safety should be our top most priority for all developments specially for all the public buildings, schools, colleges, hospitals, malls theatres, etc., which are generally cramped up with people. Considering the impact of thick dark smoke during a fire hazard, it is a high time that we switch to products that emit low smoke and are non-toxic in nature.
No one can prevent every fire from starting. But you can surely reduce the risk of the lives of your loved ones.