UMass Boston

Portable Fire Extinguishers

Availability of Portable Fire Extinguishers at UMass Boston


On the UMass Boston campus over 1,000 portable fire extinguishers have been installed at strategic locations throughout every building. Most of these extinguishers are multi-purpose, ABC dry chemical extinguishers. Upon special request, extinguishers designed for combustible metal fire fighting have been installed in laboratories. These assorted types of portable fire extinguishers are available for occupant use under the limited conditions discussed below.

When to Fight a Fire With a Portable Fire Extinguisher

It is critical to understand the circumstances under which it is appropriate to attempt to extinguish a fire with an extinguisher. This important "fight-or-flight" decision must include consideration for all of the following factors.

  • You know that the fire department is being called. This is accomplished by either activating one of the alarm pull stations (located in corridors) or by calling 911 on a campus phone or cell phone.
  • You know the building is being evacuated. This is accomplished when you alert everyone within your immediate area to immediately evacuate the building. The Campus Police will continue the evacuation when they arrive on the scene.
  • You are trained in the extinguisher's use and feel confident about using it. This is accomplished by being familiar with the different types of fires, fire extinguishers and extinguishing agents. In addition, you must be familiar with the general principles of fire extinguisher use and with incipient-stage firefighting.
  • The fire is small and contained. Do not consider fighting a fire unless it is confined to a small area, such as a wastebasket, and it is not spreading. A portable fire extinguisher should only be used for incipient-stage firefighting. An extinguisher is no match for a large or rapidly-advancing fire.
  • The exit for your escape is clear and you can fight the fire with your back to the exit. You must always assume that you may not be able to extinguish the fire you are fighting. If the fire does not diminish with your first attack or if anything goes wrong, immediately leave the building and do not return.
  • The proper type of extinguisher is available. Fire extinguishers are designed to fight specific classes of fires. Your selection of an extinguisher to use depends on what is burning.
  • You can stay low and avoid breathing smoke. Do not delay your personal evacuation by fighting a fire in an area filled with smoke. Without protective breathing equipment, you could quickly find yourself unable to breathe or see. Smoke can also obscure your exit path.

Fire Extinguisher Maintenance and Inspection

Annual maintenance of the extinguishers is done by a state-certified and DOT-registered service contractor, and coordinated and monitored by the EHS Office staff. Monthly, routine inspections of fire extinguishers are done in house by EH&S and laboratory personnel.  This is done to insure that all extinguishers on the University property are available for use at any time.

Fire Classifications

The A, B, C, and D classifications describe a fire's fuel, that is, what is burning. When the classifications are used for rating fire extinguishers, they tell you what classes of fire the various extinguishers should or should not be used on.

  • Class A fires involve "ordinary combustibles" - wood, paper, household rubbish, cloth, rubber and many plastics.
  • Class B fires involve flammable liquids - oils, greases, tars, oil-based paints, lacquers, flammable gases and some plastics.
  • Class C fires involve energized electrical equipment. Note: if the electrical equipment involved in a fire is not energized (e.g., unplugged), the fire becomes either a Class A or a Class B fire.
  • Class D fires involve combustible metals such as magnesium, titanium, zirconium, sodium, lithium and potassium.
  • Class K fires involve burning and smoldering kitchen greases and fat.  The extinguishing agent is designed to extinguish high temperature fats and oils used in the commercial cooking industry.

How to Operate a Portable Fire Extinguisher

There are four basic steps to operating a portable fire extinguisher. An easy way to remember the procedure is to think of the word "PASS." This general procedure pertains to extinguishers used for Class A, B and C fires. A different procedure is used for Class D fires.

  • Pull the pin: Holding the extinguisher with the nozzle pointing away from you, release the locking mechanism. Usually, this means pulling out the pin located below the trigger.
  • Aim low: Standing 6 to 8 feet (2-3 meters) away from the fire, point the extinguisher nozzle at the base of the fire--the lowest point of the fire nearest you. Extinguishers are designed to be operated in an upright position. Always hold the extinguisher vertically. Never cradle it horizontally or at an angle in your arms.
  • Squeeze the trigger: Squeeze the trigger slowly and evenly. This will release the extinguishing agent and expel it through the nozzle.
  • Sweep side to side: As the extinguishing agent is expelled, sweep the nozzle from side to side--"driving the fire back." As the fire closest to you goes out, you may move closer to the fire and continue the sweeping motion until the fire is extinguished. Remember, hold the extinguisher upright. If the fire does not diminish immediately, get out of the building!

Extinguisher Concerns

  • If you discover any problems with a portable extinguishers such as an extinguisher losing its pressure, a missing extinguisher, or the need to have an additional extinguisher on site, please do not hesitate to contact OEHS at 617.287.5445 for assistance.

Fire Extinguisher Classes Defined

Class ABC

Class ABC Fire Extinguisher


The ABC fire extinguisher is considered the “universal” fire extinguisher because it can combat A, B and C type fires. ABC fire extinguishers contains dry chemical, usually a mixture of monoammonium phosphate and ammonium sulfate. This is the most common fire extinguisher found across the UMass Boston campus. All ABC units will have ABC labeled on the unit.



Class A


Class A Fire Extinguisher


The small number of Class A fire extinguishers available on campus are the 2-1/2 gallon pressurized water extinguishers. The picture symbol on fire extinguishers suitable for Class A firefighting is a flaming rubbish barrel beside a burning pile of wood. The letter symbol is a triangle containing the letter "A." If colored, the triangle is green. The campus used to have a few multi-purpose dry chemical extinguishers, also effective for Class A fires, but they have now been replaced with ABC units.

Class C

Class C Fire Extinquisher


The Class C fire extinguishers available on campus are the carbon dioxide (CO2) fire extinguishers. The picture symbol on fire extinguishers suitable for Class C firefighting is an electrical plug and outlet. The letter symbol is a circle containing the letter "C." If colored, the circle is blue.




Class D

Class D Fire Extinguisher


A few Class D fire extinguishers containing a sodium chloride dry powder extinguishing agent are located in laboratories where combustible metals are used (Note: Lithium fires require a copper extinguishing agent, sodium chloride should not be used). These extinguishers are provided on request. There is no picture symbol for Class D extinguishers. The letter symbol to identify extinguishers suitable for fires involving metals is a five-pointed star containing the letter "D." If colored, the star is yellow.

Class K

Class K Fire Extinguisher


A few of the Class K extinguishers are found in the Campus Center in the commercial cooking area behind the food court and the U-Hall kitchen area.  These are available for the University’s food service vendor to use in the event of a kitchen fire. Class K extinguishers contain a special extinguishing agent that is designed to extinguish kitchen fires involving high temperature oils and fats that are commonly found in deep fat frying and other high temperature, cooking applications.

All fire extinguisher nameplates have either the letter or picture symbols described above. The newer picture symbols use the International sign system diagonal red slash to indicate a potential hazard if the extinguisher is used on that particular type of fire. Absence of a picture symbol means only that the unit is not recommended as particularly effective for that class, but not dangerous if used in error.