Class C fire extinguisher

The extinguishing agent in a class C fire extinguisher must be electrically non-conductive. Both carbon dioxide and dry chemicals can be used in electrical fires. An advantage of carbon dioxide is that it leaves no residue after the fire is extinguished. When electrical equipment is not energized, extinguishers for class A or B fires may be used. 

Electrical fires First disconnect the apparatus or equipment by pulling the safety switch or switch off the mains to avoid possibility of being electrocuted. Then use Class C fire extinguisher. 

Eirst aid procedures should be developed and all personnel handling chlorine should be familiar with their application. These procedures should be posted in the chlorine area. Eire protection should be provided by class C fire extinguishers (for energized electrical equipment) and located in the area immediately adjacent to the chlorination room. Procedures should be developed to handle chlorine leaks from storage cylinders or application equipment. Periodically operating personnel should review these procedures in a hypothetical emergency situation. 

Are class C fire extinguishers patterned among class A and B extinguishers where... 

Dry powders are effeetive on flammable liquid or eleetrieal fires. Speeial powders are available for use on metals. Dry powder extinguishers may be used on Class C fires, ineluding gases and liquefied gases in the form of a liquid spillage or a liquid or gas leak. This must be aeeompanied by other aetions, e.g. stopping the leak this is neeessary to avoid aeeumulation of an unburned flammable gas-air mixture whieh eould subsequently result in an explosion. Aetivation may be automatie by a deteetion system, or manual. 

At least one CO2 extinguisher (10-B C) or equivalent other clean agent extinguisher should be located outside the entrance door to the unit electrical substation for Class C fires. 

Steam-generating plants, air compressor plants, and similar plants should be provided with potassium bicarbonate dry chemical extinguishers (120-B C) for Class B or Class C fires in the areas containing hydrocarbons or other flammable liquids. For fires in electrical equipment, at least one extinguisher (10-B C) should be provided. If Class Afire hazards exist, multipurpose dry chemical extinguishers (20-A 80-B C) or water extinguishers should be provided. 

Class C Fires. These are fires in electrical equipment, where the use of a nonconducting extinguishing agent is essential. Water spray, carbon dioxide, dry chemical, or vaporizing liquid is satisfactory... 

Class C Fires These are electrical fires in equipment and electrical gadgets where live electricity is present. The material that burns is the insulation and component parts. The use of only C02 or dry-chemical fire extinguishers is recommended. 

Class C fires occur in live electrical equipment. Clearly, water and wet-type fire extinguishers must be avoided. 

Class C fires involve energized electrical equipment, such as appliances, switches, panel boxes, power tools, hot plates and stirrers. Water is usually a dangerous extinguishing medium for class C fires because of the risk of electrical shock unless a specialized water mist extinguisher is used. 

Class C Fires involving energized electrical equipment where safety to the operator requires the use of electrically nonconductive extinguishing agents (after the electric equipment has been de-energized, the use of Class A or B extinguishers may be indicated). 

Class C fires are electrical fires, and may be extinguished with Halon 1301, Halon 1211, carbon dioxide, or dry chemical fire extinguishers. Class C extinguishers have no additional numerical rating. 

Figure 14.4. The new pictograms, representing Class A, B, and C fire extinguisher. There is no pictogram for Class D extinguishers. Online at http //www.hanford.gov/fire/safety/extingrs.htm. (Dec. 2005).

Since most lab fires are Class B and/or Class C fires, water is usually not a good first choice to extinguish a fire in a lab. The only exception to this would be, for example, a situation where some papers caught on fire in a lab. This is clearly a Class A fire and can be doused easily with water or by, if possible, moving the papers into a nearby sink and turning on the water. 

FIGURE 2.1.2.3 CO2 Fire Extinguisher. This extinguisher should be used only on Class B and Class C fires. 

Class C fires involve energized electrical equipment where safety requires the use of electrically nonconductive extinguishing media. 

Class C fires involve electrical equipment and are usually smothered by oxygen control but never by using water Typically, carbon dioxide or dry-chemical extinguishers, nonconductors of electricity, are used. 

Class C - fires which involve gases such as natural gas or liquefied gases such as butane or propane. They can be extinguished using foam or dry powder in conjunction with water to cool any containers involved or nearby. 

Class C is not reaUy a class of fuel but refers to fuels that may be part of an electrically charged itan or component. Class C fires present an electrocution hazard hence water-based agents are mostly inappropriate. If at all possible, these situations should be approached by disconnecting the electricity. Transformers, capacitors, and other electronic components store electricity after the source is disconnected and may still provide a shock. Class C-rated extinguishers are tested against 100,000 volts... 

Extinguishers suitable for Class C fires should be identi-fed by a circle containing the letter C. If colored, the circle shall be colored blue. ... 

---