Fire and Emergency Preparedness PDF

DOMAIN - 5 Emergency Preparedness, Fire Prevention, and Security MAIN TOPICS FLASH POINT The flash point is the lowest temperature at which a flammable liquid gives off vapor in sufficient concentration to form an ignitable mixture that when exposed to a flame will momentarily ignite and quickl...

DOMAIN - 5 Emergency Preparedness, Fire Prevention, and Security MAIN TOPICS FLASH POINT The flash point is the lowest temperature at which a flammable liquid gives off vapor in sufficient concentration to form an ignitable mixture that when exposed to a flame will momentarily ignite and quickly self-extinguish. FIRE POINT Fire point is the lowest temperature at which a flammable liquid will generate vapors sufficiently dense enough to ignite and becomes self-sustained so as to continue burning the liquid. AUTOIGNITION TEMPERATURE The auto-ignition temperature is the lowest temperature at which the fuel will spontaneously ignite in a normal atmosphere without an external source of ignition such as a flame or spark Note: The autoignition temperature will be always higher than flash point and fire point. Lower Explosive Limit (LEL) Lower Explosive Limit the minimum concentration of vapor in air below which propagation of a flame does not occur in the presence of an ignition source. Work Permit for entry into a confined space should be issued when the concentration of flammable vapors is less than a) 0.5% of LEL b) 1% of LEL c) 10% of LEL d) 100% of LEL At what percentage of the LEL is a gas explosive? a) 5% b) 10% c) 50% d) 100% Upper Explosive Limit (UEL) Upper Explosive Limit the maximum concentration of vapor in air above which propagation of flame does not occur on contact with source of ignition.  Conversions %Vol to PPM % Vol x 10,000 =PPM LEL to PPM % LEL x LEL(%Vol) x 100 = PPM PPM to mg/m3 Mg/m3 x 24.45 = PPM MW 1. Convert 1PPM of benzene into a mass per volume concentration if the molar mass of benzene is 78.11g/mol? Mg/m3 x 24.45 = PPM MW 2. What is the LEL of a mixture containing 50% methane (LEL 5%), and 50% propane (LEL 2%)? 1 f1 + f2 LEL 1 LEL 2 GAS LAWS The gas laws are a group of laws that govern the behaviour of gases by providing relationships between the following: The volume occupied by the gas. The pressure exerted by a gas on the walls of its container. The absolute temperature of the gas. The amount of gaseous substance (or) the number of moles of gas. GAS LAWS 1. Boyle's law 2. Charles' law 3. Gay-Lussac's law 4. Avogadro's law 5. Combined gas laws 6. Ideal gas laws Boyle's law At constant temperature, the volume of a given mass of a gas is inversely proportional to its pressure. Charles' law At constant pressure, the volume of a given fixed mass of a dry gas is directly proportional to its absolute temperature. Gay-Lussac's law At constant volume, the pressure excreted by a given mass of an ideal gas on the sides of its container is directly proportional to its absolute temperature. Avogadro's law At constant temperature and pressure, the volume occupied by an ideal gas is directly proportional to the number of molecules of the gas present in the container. where n is equal to the number of molecules of gas (or the number of moles of gas) 6.024 x 1023 / Gram-mole Combined gas law Combined gas law combines Boyle's Law, Charles's law, and Gay-Lussac's Law. It shows the relationship between the pressure, volume, and temperature for a fixed mass of gas: Ideal gas law Ideal gas law combines Avogadro's law and the combined gas law. It shows the relationship between the pressure, volume, and temperature for a fixed mass of gas: 3. A cylinder of hydrogen having a volume of 5ft3 is under 1,000 psig pressure. The valve of the cylinder breaks releasing hydrogen to atmosphere. The volume of hydrogen released is approximately: a) 5 ft3 b) 5,000 ft3 c) 345 ft3 d) 456ft3 MODES OF HEAT TRANSFER There are three modes of heat transfer. 1. Conduction 2. Convection 3. Radiation Conduction of Heat Heat conduction is a process in which heat is transferred from the hotter part to the colder part in a body without involving any actual movement of the molecules of the body. Conduction: Q= K(A/L) (T1-T2) K= Thermal Conductivity A= Area L= Thickness of the wall Convection of Heat In this process, heat is transferred in the liquid and gases from a region of higher temperature to a region of lower temperature. Convection heat transfer occurs partly due to the actual movement of molecules or due to the mass transfer Convection  Q=HA(T1-T2) Q= Rate of heat transfer H= Heat transfer coefficient A= Area T1 and T2 are the temperature difference. Radiation of Heat It is the process in which heat is transferred from one body to another body without involving the molecules of the medium. Radiation heat transfer does not depend on the medium. Sprinkler System 1. Dry pipe 2. Wet Pipe 3. Deluge 4. Pre-action Hazardous Location Classification Class 1  Flammable vapours and gases Class 2 combustible dust Class 3 Ignitable fibres NFPA Fire Diamond In the development of emergency response plans, which of the following in the most critical factor than needs to be addressed? A. Emergency equipment needed B. Emergency Personnel C. Response to multiple emergencies D. How to protect people, property, and the environment The standards developed by the National Fire Protection Association (NFPA) for fire prevention and protection are called: A. NFPA Code of Fire standards B. Uniform Building Fire Code C. Fire Safety Standards D. National Fire Code Autoignition temperature is the minimum temperature at which a material would burn in the absence of an ignition source. This temperature is: A. Lower than ignition temperature B. Higher than ignition temperature C. The same as ignition temperature D. Depending on the material, it could be higher or lower than ignition temperature. In order for combustion reactions to start and proceed, which of the followings are needed simultaneously?: A. Fuel, heat, source of ignition, and air B. Fuel, spark, oxygen, heat C. Fuel, chemical chain reaction, oxygen, source of ignition D. Fuel, autoignition temperature, air, source of ignition. Which of the following is the most important consideration to prevent fire loss in a flammable liquid storage area? A. Compatible storage B. Use of explosive proof devices C. Availability of fire fighting equipment D. Use of pre-action automatic springler system In most fire situations there is not enough oxygen available for conversion of carbon in the fuels to carbon dioxide, and as a result, large amounts of carbon monoxide are produced. CO has been the primary killer in most fires. This gas can cause fatalities because: A. It is the most toxic of all gases produced in fire. B. It is more reactive with blood than oxygen C. It reacts with oxygen in the lungs and causes asphyxiation D. Only (b) and (c) above. The gaseous products of combustion have a vapor density of less than 1. This means that air in a fire situation is at: A. Low spot B. High spots C. Mixed with other gases D. Halfway between floor ceiling Fire point is defined as the lowest temperature at which enough vapor is generated to support continuous combustion in presence of an ignition source. Fire point is: A. Lower than flash point B. Higher than flash point C. Same as flash point D. Depending on the material can be higher, lower, or the same as flash point A lower Flammability Limit (LFL) of 10% for a gas or vapor means that the gas would support combustion at: A. Concentration with air below 10% B. Concentration above 10% but below the UFL C. Concentration 10% above UFL D. Only (b) and (c) above Materials that are classified as oxidizers must be separated from flammable because: A. They can produce heat and act as a source of ignition B. If mixed with flammable may cause a fire in the absence of a source of ignition C. They can release oxygen or catalyze the combustion reactions D. Only (b) and (c) above For more details contact: Safety Catch, Edappally, Kochi, India Ph: +91-484 – 6056051, 6056053 GSM: +91-9747567477, +91-8089169549 www.safetycatch.in