FIRE EXTINGUISHERS EXPLAINED

ROLE OF THE FIRE EXTINGUISHER

Fire extinguishers can represent an important segment of an overall fire protection program. However, their successful functioning depends upon the following conditions having been met:

  1. The fire extinguisher is located properly and in working order
  2. The fire extinguisher is of the correct type for a fire that can occur.
  3. The fire is discovered while still small enough for the fire extinguisher to be effective.
  4. The fire is discovered by a person ready, willing, and able to use the fire extinguisher.

UNDERSTANDING YOUR NEEDS

Every business needs to understand the three different Hazard Occupancy Ratings that dictate how big and how many fire extinguishers required: Light (low), Ordinary (moderate), Extra (high).

  • Light (low): Hazard occupancies can include, offices, classrooms, churches, assembly halls, guest room areas of hotels/motels and so forth. This classification anticipates that the majority of content items are either noncombustible or so arranged that a fire is not likely to spread rapidly. Small amounts of class B flammables used for copying machines, art departments, and so forth, are included, provided that they are kept in closed containers and safely stored. Require minimum rating of 2-A with a maximum floor area of 3000 square feet per unit of A and maximum travel distance to extinguisher 75 feet. Requirements for B Class are 5-B at 30 feet between extinguishers and 10-B for 50 feet between extinguishers.
  • Ordinary (moderate): Hazard occupancies could consist of dining areas, mercantile shops and allied storage, light manufacturing, research operations, auto showrooms, parking garages. Require minimum rating of 2-A with a maximum floor area of 1500 square feetper unit of "A" and maximum travel distance to extinguisher 75 feet. Requirements for "B" Class are 10-B at 30 feet between extinguishers and 20-B for 50 feet between extinguishers.
  • Extra (high): Hazard occupancy could consist of woodworking; vehicle repair; aircraft and boat servicing; cooking areas; individual product display showrooms; product convention center displays; and storage and manufacturing processes such as painting, dipping, and coating, including flammable liquid handling. Require minimum rating of 4-A with a maximum floor area of 1000 square feet per unit of A and maximum travel distance to extinguisher 75 feet. Requirements for B Class are 40-B at 30 feet between extinguishers and 80-B for 50 feet between extinguishers.

OVERVIEW

Most buildings have class “A” fire hazards. In any occupancy, there could be predominant hazards well as special hazard areas requiring supplemental protection. For example a hospital will generally have need for Class “A” fire extinguishers covering patients’ rooms, corridors, offices, and so forth, but will need Class “B” fire extinguishers in laboratories and where flammable items are stored or handled. Class “C” fire extinguishers in electrical switch gear or generator rooms, and Class “K” extinguishers in the kitchens.

**Footnote: Information herein has been obtained from the NFPA 10 Standard for Portable Fire Extinguishers 2007 Edition (National Fire Protection Association).

Lord Baltimore Fire Extinguisher is a member in good standing of both the National Association of Fire Equipment Distributors (NAFED) as well as the National Fire Protection Association (NFPA).

TYPES OF FIRE BY CLASSIFICATION

Letters designating the fire source classifies the Fire Extinguishers:

  • A-class fires are ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics. Maximum travel distance to extinguisher is 75 feet.
  • B-class fires are flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, lacquers, alcohols, and flammable gases. Maximum travel distance to extinguisher is 30 feet for lower rated units to 50 feet for larger extinguishers.
  • C-class fires involve energized electrical equipment. Maximum travel distance to extinguisher is 75 feet.
  • D-class fires involve combustible metals such as magnesium, titanium, zirconium, sodium, lithium, and potassium. Maximum travel distance to extinguisher is 75 feet.
  • K-class fires involve combustible cooking oils and fats. Maximum travel distance to extinguisher is 30 feet.

TYPES OF FIRE EXTINGUISHER BY CLASSIFICATION

  • A-type: stored water pressure holds 2 ½ gallons of water discharge time of approximately 50 to 60 seconds. Maximum range 30 to 40 feet.
     
    Positives: No chemical residue to clean up after use. Longest range and duration of use.
    Maintenance: Requires Hydrostatic testing every 5 years.
     
    Buyer Alert: Subject to freezing if not treated with anti-freeze solution. Not rated for flammable liquids or electrical fires
  • ABC-type: Multipurpose Dry Chemical (ammonium phosphate) - Discharge time 8 to 25 seconds depending on the size of extinguisher. Maximum range 5 to 20 feet.
     
    Positives: Lower cost and highly effective.
    Maintenance: Requires internal exam every 6 years and Hydrostatic testing every 12 years.
     
    Buyer Alert: The dry chemical power used is corrosive not to be used around chlorine and is messy.
  • BC-type: Carbon Dioxide - Discharge time approximately 8 to 30 seconds depending on the size of extinguisher. Maximum range 3 to 8 feet. Discharges as a white cloud of “snow” which smothers the fire by eliminating oxygen.
     
    Positives: No chemical residue to clean up after use.
    Maintenance: Requires Hydrostatic testing every 5 years.
     
    Buyer Alert: not to be used in an unventilated or small space.
  • BC-type: Dry Chemical (Sodium Bicarbonate) - Discharge time approximately 8 to 25 seconds depending on the size of extinguisher. Maximum range 5 to 20 feet.
     
    Maintenance: Requires internal exam every 6 years and Hydrostatic testing every 12 years.
     
    Buyer alert: the dry chemical power used is corrosive and is messy. Positives lower cost and highly effective.
  • BC-type: Purple K Dry Chemical (Potassium Bicarbonate) - Discharge time approximately 8 to 25 seconds depending on the size of extinguisher. Maximum range 5 to 20 feet.
     
    Positives: Particularly effective on class B flammable liquids and pressurized gases and it is electrically non-conductive.
    Maintenance: Requires internal exam every 6 years and Hydrostatic testing every 12 years.
  • BC-type: Halogenated Agent, ideal for use around computers or electronics - Discharge time 8 to 14 seconds depending on the size of extinguisher. Maximum range 3 to 18 feet. Discharges a gas/mist.
     
    Positives: No chemical residue to clean up after use.
    Maintenance: Requires internal exam every 6 years and Hydrostatic testing every 12 years.
     
    Buyer Alert: Not to be used in an unventilated or small space or around chlorine and is expensive.
  • D-type: Dry Powder (Sodium Chloride Particles) for fighting metal fires - Discharge time approximately 8 to 25 seconds, maximum range 3 to 6 feet.
     
    Maintenance: Requires internal exam every 6 years and Hydrostatic testing every 12 years.
  • K-type: Wet Chemical (Water and Potassium Carbonate) for fighting kitchen fires - Discharge time 30 to 85 seconds depending on the size of extinguisher. Maximum range 8 to 12 feet. Forms a foam blanket to prevent reigniting of the fire.
     
    Maintenance: Requires Hydrostatic testing every 5 years.

REQUIRED FIRE EXTINGUISHER SERVICE

Annual Maintenance: All fire extinguishers require an annual examination of the fire extinguisher. It is intended to give maximum assurance that a fire extinguisher will operate effectively and safely. It includes a thorough examination for physical damage or condition to prevent its operation and any necessary repair or replacement. It will normally reveal if hydrostatic testing or internal maintenance is required.

Six-Year Maintenance: Every 6 years, stored-pressure fire extinguishers that require a 12-year Hydrostatic test shall be emptied and subject to the applicable maintenance procedures as detailed in the manufacturer’s service manual.

Hydrostatic Testing: Pressure testing of the extinguisher to verify its strength against unwanted rupture.

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