Fire Extinguishing Systems

For your safety and the safety of others at the University of Michigan (U-M), it is a good practice to know when to fight a fire, which fire extinguisher to use, and how to put out a fire.  The first decision you must make when a fire occurs is to only fight a fire if:

  • The fire is small and contained
  • You are safe from toxic smoke
  • You have a means of escape
  • Your instincts tell you it is OK

If at any time one of these criteria changes, SOUND THE ALARM and evacuate the area immediately.


Class A

  • Wood
  • Paper
  • The amount of water the fire extinguisher holds
  • The amount of fire it will extinguish

Class B

Flammable liquids, such as:
  • Grease
  • Gasoline
  • Oil
The approximate number of square feet of a flammable liquid fire that a non-expert person can expect to extinguishNA

Class C

  • Electrical equipment
  • Electrically energized fires
NAThe presence of the letter C indicates that the extinguishing agent is non-conductive
Class DFlammable metals (are often specific for the type of metal in question)NAThey are not given a multi-purpose rating for use on other types of fires
Multi-ClassMany extinguishers available today can be used on different types of fires and will be labeled with more than one designator (A-B, B-C, or A-B-C).

Using a Fire Extinguisher

Even though extinguishers come in a number of shapes and sizes, they all operate in a similar manner.  An easy acronym for fire extinguisher use is PASS: Pull, Aim, Squeeze, Sweep.

  1. PULL the pin at the top of the extinguisher that keeps the handle from being accidentally pressed.
  2. AIM the nozzle toward the base of the fire.
  3. Stand approximately 8 feet away from the fire and SQUEEZE the handle to discharge the extinguisher.  If you release the handle, the discharge will stop.
  4. SWEEP the nozzle back and forth at the base of the fire.  After the fire appears to be out, watch carefully because it may re-ignite.

Note: Fire extinguisher inspection and testing programs are managed by Facilities Maintenance.  All extinguishers are checked and pressure tested under regulatory requirements.  In the event a fire extinguisher is discharged, you must contact the EHS Fire Safety Service at (734) 647-1143.  EHS must be notified because depending on the type of building involved, notification must be made to the State of Michigan Bureau of Fire Safety.  To replace the discharged extinguishers, contact the Facilities Service Center at (734) 647-2059.

NOTE:  All fires must be immediately reported to U-M Police Department by dialing 911.  The Police Department will perform an investigation and complete an after action report necessary for U-M Risk Management to deal with insurance recovery for damages.

“Special Hazards” fire extinguishing systems are used in U-M buildings that include:

  • Certain fire hazards that standard automatic sprinklers systems cannot effectively control or extinguish
  • Equipment or operations that upon the application of water may cause excessive collateral damage or an interruption of critical operations

For some of these locations, a special hazards fire extinguishing system may be employed using one of the following fire suppression agents:

  • A non-water, “clean agent” (e.g., a halocarbon (halon) agent or an inert gas agent (a blend of one or more gases of helium, neon, argon, or nitrogen)
  • Carbon dioxide (CO2)
  • Dry chemical
  • Foam

U-M departments that have a special hazard fire extinguishing system installed must ensure:

  • The special hazard fire extinguishing system is in proper operating condition
  • That affected building occupants have been provided pertinent health and safety information

For information about special hazards fire extinguishing systems, contact Fire Safety Services at (734) 647-1143.

For more information about the health and safety of the fire suppression agent used in special hazard fire extinguishing system, call EH&S at (734) 647-1142.

Standard Operating Procedures, Guidelines, and Manuals

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