Extinguishing Chimney Fires With Positive Pressure Ventilation

Extinguishing a working chimney fire with PPV and a dry chemical extinguisher is a relatively easy task to perform. It eliminates the need for placing personnel in harms way with extended roof operations, especially during periods of inclement weather...

EO 1-2 Apply the steps required to successfully extinguish a working chimney fire using PPV and a dry chemical extinguisher.

EO 1-3 Check for and prevent possible fire extension into an uninvolved structure during PPV operations.

Instructional Guide

Opener: Call to order; start with a motivator (need to know) related to objectives; state objectives and main points.

I. Chimney Construction Features (1-1)


• Solid/waterproof modular concrete block, lined with a fire clay flue or fire clay brick

• Uses refractory cement mixture to join brick and flue lining

• Two-three inches is the rule of thumb air space clearance between the interior masonry chimneys and combustible material


• Single-wall metal chimney or unlisted metal shall not be used inside or outside one and two story single family dwellings

• May be used on a residential type or low heat appliance such as a pellet stove

• Must be properly riveted, welded, or bolted, and properly secured to the structure

• Must also have the proper clearance from structure to prevent pyrolysis

Factory built (zero clearance)

• Pre-engineered and designed to function as a unit

• Manufacturer provides a special starter section that locks into the collar at the top of the fireplace

• When passing through combustible material, a fire stop spacer must be used as specified by the manufacturer

Replacement (re-lining)

• Consists of rigid and flexible stainless steel

• Is placed inside of an existing flue, and surrounded by noncombustible insulations

Fireplaces consist of:

• Cap

• Flue

• Mantel

• Smoke Dome

• Smoke shelf

• Damper

• Facing

• Throat

• Lintel

• Firebox

• Hearth

• Ash pit

• Foundation


II. Extinguishment (1-2)

• Conduct a size-up in accordance with established SOPs (AHJ)

• Conduct interior size-up of fireplace and upper/lower floor space in structure

• Advance attack lines into first floor and upper floor(s) as directed and standby

• If interior environment is smoke filled, monitor air samples for CO levels and don SCBA

• Remove contents from firebox and extinguish outside of structure with water

• Place PPV blower at appropriate door nearest fireplace and close off the rest of the house or door isolating fireplace room from rest of structure

• Start up blower and run at 1/2 to full rpm as required to facilitate chimney drafting

• Place dry chemical extinguisher hose in fireplace

• Aiming it up the flue opening

• Discharge the product in 1-2 second bursts

• Be careful not to prolong this process as the product will be heavy and fall back down into the firebox area

• Monitor the drafting process while discharging the extinguisher

• Place a spotter outside the structure to monitor product egress from the top of the chimney cap area


III. Check for Extension (1-1-2)

Send attack crews to upper floors and attic areas with charged hoselines, to ensure that extension has not occurred (Use 11/2 - 13/4" hoselines)

• No booster lines

• No PW cans

• Use a mirror device to check for flue extinguishment

• Advise homeowner to have a professional chimney company come out to perform an inspection before it is used again

• Do not forget to clean up the mess before leaving a structure


Basic Firefighting: Extinguishing Chimney Fires With Positive Pressure Ventilation

• Chimney Construction Features

• Extinguishment

• Check for Extension

Oral Review: Under each review point, recall and list three features from the discussion. Make a note of these points or highlight points in your notes so you may use them for exam review.

Other Evaluation: Instructor may use course quizzes, if any, or create and use lesson quizzes and other learning reinforcements. Quizzes are diagnostic and may be given as in-class group assignments to generate discussion or as home assignments and used as review prior to starting the next session.