PRODUCTS OF FIRE & EFFECTS ON LIFE SAFETY

 

PRODUCTS OF FIRE & EFFECTS ON LIFE SAFETY

Generally there are two types of products liberated in the process of combustion

v    Thermal products (Heat  &  Flame)

v    Non –thermal products ( Smoke & Toxic gases   

Toxic Gases  

v           CO₂, CO,SO₂,H₂S,HCN ,NH₃ ,HCL, NO₂

SMOKE        

           Visible smoke is composed of unburned particles, dust and liquid droplets.

Effects

¨     Suffocation

¨    Visibility is affected.

¨    Creates irritation in the respiratory tract.

EFFECTS OF TOXIC GASES

Carbon-Di-Oxide (CO₂).

The main effect of CO2 is    suffocation but at different concentration it has       different effects as shown in the table:-

Amount of CO2 in air	Effects
0.5%	No symptoms and no permanent danger.
2.0%	Increase the breathing rate by 50%
3.0%	Increase the breathing rate by 100%
5.0	Vomiting, dizziness, breathing difficulties after 30 minutes.
8.10%	Vomiting, headache, dizziness, unconsciousness and death after some time.

                    

CARBON-MONO-OXIDE (CO)

When (co) is inhaled, it combines with hemoglobin; and car boxy hemoglobin is formed. Car boxy hemoglobin has different effects as shown in the table:-

Amount of Car boxy

Hemoglobin in blood	Effects
10	Possible shortness of breathe
20-30	Shortness of breath, headache.
30-50	Severe headache, mental confusion, dizziness, fatigue
50-70	Unconsciousness, death and respiratory failure if exposure is continued.
70 & above	Rapidly fatal.

SULPHER-DI-OXIDE (SO₂)

          Its source materials are rubber ,wood , sulfuric acid and pesticides etc. Its toxicological effects are eyes and lungs irritation.

HYDROGEN SUPHIDE (H₂S)

          Its source materials are leather, wood and other materials containing Sulpher. Its lethal concentration is 20 PPM. It is a nerve agent and creates paralysis.

AMMONIA (NH₃)

                   When wool, silk and melamine are involved in fires then (NH₃) is produced. It is soluble in water and      its main effect is irritation in eyes. It is fatal if exposure is longer.

HYDROGEN CHLORIDE (HCl)

          Its source materials are plastics i.e. PVC and ploy urethane. At low concentration causing coughing, choking and irritation in eyes.

          At high concentration can damage the upper respiratory tract, causing asphyxiation or death.

NITROGEN DIOXIDE (NO₂ )

                   Source materials are fabrics, cellulose acetate and all plastics containing Nitrogen. Its main effect is Asphyxiation and longer exposure can prove fatal.

HEAT

   Effects of heat

Ø           It declines blood pressure.

Ø           By inhalation of hot air fluid may build up in lungs.

Ø           It can cause burns & scalds

Ø           It can cause hypothermia