Fire Safety and Detection Quiz

Combustion

• The rapid exothermic or heat-producing chemical reaction of oxygen with a fuel.

Heat of combustion

• The amount of heat released as a result of complete combustion of a fuel. Expressed in units of energy per mass of combustible material.

Heat transfer by radiation

• Electromagnetic mechanism of heat transfer. The amount of heat transfer is proportional to the fourth power of temperature.

Convection

• Heat transfer by convection takes place as a result of fluid motion. Hot fluid rising, cold fluid sinking.

Conduction

• Heat energy is transferred between molecules through molecular collisions or direct contact.

Thermal conductivity

• The ability of a material to transfer heat. Different materials have different thermal conductivities. Metals are generally good conductors, while plastics are generally good insulators.

Four elements of combustion (fire tetrahedron)

• Oxygen
• Fuel
• Heat
• Chemical Reaction

Flammable liquid

• A liquid with a closed-cup flash point below 100°F and a vapor pressure not exceeding 40 psia (pounds per square inch absolute) at 100°F.

Combustible liquid

• A liquid with a closed-cup flash point at or above 100°F.

Flash point

• The lowest temperature at which a liquid can generate enough vapor to support combustion in the presence of an ignition source.

Vapor Pressure

• The pressure exerted by a vapor on its liquid at equilibrium. Increases with temperature.

Fire point

• The lowest temperature at which a flammable liquid in an open container gives off enough vapors to continue to burn once it has been ignited. Higher than flash point.

Lower Flammability Limit (LFL)

• The minimum concentration of vapor in air below which a flame will not propagate through the mixture.

Upper Flammability Limit (UFL)

• The maximum concentration of flammable vapor in air above which a flame will not propagate.

Auto-ignition temperature

• The temperature at which a material will spontaneously combust in the absence of an external ignition. Higher than the ignition temperature.

Specific gravity

• The density of a liquid relative to the density of water. Liquids with specific gravity less than 1 are lighter than water.

Vapor density

• A measure of the relative densities of vapors and gases compared to air under the same conditions of temperature and pressure. Most flammable liquids have vapor densities lighter than air.

Evaporation rate

• The rate at which a liquid is converted to vapor at a given temperature and pressure.

Water solubility

• Flammable liquids with water solubility can be mixed. The mixing with water can reduce flammability.

Carbon monoxide (CO)

• A colorless, odorless, toxic flammable gas. For -med by incomplete combustion of carbon.

Carbon dioxide (CO2)

• A colorless, odorless gas produced in large quantities during fires. Acts as a simple asphyxiant.

Hydrogen Cyanide (HCN)

• A deadly gas that can be produced during fires from the combustion of certain materials.

Sulphur dioxide (SO2)

• A strong irritant gas produced from combusting sulfur-containing materials.

Ammonia (NH3)

• Can by produced during fires from combusting materials like wool, silk, fertilizers, explosives, acrylic nitrile and nylon.

Hydrogen sulfide (H2S)

• A gas generated from incomplete combustion of sulfur-containing compounds like wool and rubber.

Nitrogen Dioxide (NO2)

• A gas generated from combusting materials like fabrics, cellulose nitrate, celluloid, catalysts, and polymerization inhibitors.

Fire Hazard Identification (NFPA 704) System

• System to classify the hazards of a material into four major categories.

Boiling Point

• Temperature at which a liquid transforms into vapor at a given pressure.

Fire Gases

• Gases that may be produced during a fire. Includes Carbon Monoxide, Hydrogen Cyanide, Sulfur Dioxide, Ammonia, Hydrogen Chloride, Hydrogen Sulfide, and Nitrogen Dioxide.

Class A fire extinguisher

• Used on fires involving ordinary combustible materials such as wood, cloth, and paper.

Class B fire extinguisher

• Used on fires involving flammable liquids and gases such as gasoline, oil, and cooking fats.

Class C fire extinguisher

• Used on fires involving energized electrical equipment.

Class D fire extinguisher

• Used on fires involving combustible metals such as magnesium, titanium, zirconium, sodium, and potassium.

Class K fire extinguisher

• Used on fires involving cooking oils and fats.

Travel distance from fire extinguishers to possible fire/ignition source

• OSHA regulations for various classes of extinguishers regarding maximum distance to possible fire or ignition source.

Hydrostatic testing

• Testing procedure required to detect corrosion, physical damage, improper assembly, and damage to mechanical properties of metal parts of fire extinguishers.

Types fo sprinkler systems

• Dry pipe, wet pipe, pre-action, deluge, residential sprinkler systems. Different systems are suited for different conditions.

Types of Fire Detectors

• Fixed temperature, rate-of-rise, sealed pneumatic line-type, smoke, flame detectors, and combustible gas indicators.

Combustible Gas Indicator

• Indicates the concentration of gas in the air that might be dangerous/flammable.

Fire alarms

• Type A (manual), Type B (automatic). Type A - requires an operator to transmit alarm. Type B - automatically transmits the alarm.

Fire proofing

• Insulating steel in structures from excessive heat to prevent collapse.

Fire doors

• Most often rated by hourly rating, and may be combined in combination with an alphabetical rating.

Hot work permit

• Required before any equipment capable of igniting combustible materials is used outside designated/approved areas.

Planning for workplace emergencies

• OSHA requires written procedures/policies for larger companies (10+ employees). Smaller companies may use oral communication.

Duties of emergency response coordinator

• Determining what emergencies may occur.
• Developing emergency procedures.
• Directing emergency activities (including evacuation of personnel).
• Notifying outside emergency services when necessary.
• Directing the shutdown of plant operations when necessary.

BLEVE (Boiling Liquid Expanding Vapor Explosion)

• A rapid, violent explosion resulting from heating liquids in closed containers, thus leading to rapid pressure increase and container failure.

Pyrophoric material

• A substance that spontaneously ignites when exposed to atmospheric oxygen, without an external ignition source.

National Fire Code

• A set of standards developed by the National Fire Protection Association (NFPA). Covers fire safety prevention and protection.