Wildland Firefighting (3rd Edition)
Chapter 1 - Wildland Fire Behavior: Fuel, Weather, & Topography
"By the Numbers"

  • The National Fire Danger Rating system (NFDRS) lists 20 standard fuel models.
  • The NFDRS models are aligned with 13 fire-behavior models to predict large area daily fire danger ratings.
  • NFPA 1574, Aids to Determining Fuel Models for Fire Behavior, provides a complete explanation of fire behavior models.
  • Fuels exposed to heat from the sun can reach 150oF.
  • Most wildland fuels must be heated between 400oF to 700oF to ignite.
  • Live fuels usually have a moisture content from 35% to 250% of their dehydrated rate.

Live Fuel Moisture Content
Moisture Content / Stage of Development
300% / Fresh foliage, annuals
200% / Maturing foliage (still developing)
100% / Mature foliage & older perinnials
50% / Entering dormancy, coloration starting, some leaves have dropped
< 30% / Completely cured (dead fuels)
  • Dead plants have a moisture content between 1.5% to 30%.
  • One fire behavior prediction system uses the following to determine the time it takes for moisture content to equalize with that of the surrounding air.

Classification / Diameter of Fuel
1 hour / <1/4"
10 hour / 1/4" to 1"
100 hour / 1" to 3"
1,000 hour / 3" to 8"
  • Fuels in full sun can contain up to 8% less moisture than those in the shade.
  • Surface fuels include brush up to 6 feet in height.
  • Aerial fuels include brush over 6 feet in height.
  • Fuel loads can range from 1 ton to more than 500 tons per acre (Grass: range from 1/4 ton to 1 ton per acre, Timber: can be up to 600 tons per acre).
  • 1,000 hour fuels, roughly 42 days, is of little value for fire behavior forecasts done in 12 hour increments.
  • Light fuels are short grass and light brush up to 2 feet in height.
  • Medium Fuels include brush up to 6 feet in height.
  • Heavy fuels include heavy continuous brush more than 6 feet in height.
  • 14 firefighters were killed in the 1994 SouthCanyon fire near Glenwood Springs, Colorado.

Atmospheric Layers
Layer / Distance above ground level
Troposphere / 0-10 miles
Stratosphere / 10-20 miles
Mesosphere / 20-50 miles
Thermosphere / 50-700 miles
  • An average lapse rate is 3.5oF per 1,000 feet of elevation.
  • Stable atmosphere lapse rates are 5.5oF or less per 1,000 feet of elevation. Above 5.5oF is unstable.
  • Within an inversion layer, temperature may increase as much as 25oF in 250 vertical feet.
  • Daytime sea breezes usually extend 5 to 6 miles inland but may extend up to 25 miles from the coast.
  • For each pound of water condensed from vapor, more than 1,000 Btu of heat energy is released.
  • A thunderstorm cell can be up to 10 miles in diameter. Multiple cells may converge to form a mass that extends more than 50 miles.
  • Downdraft winds produced by thunderstorms range from 25-35 mph (most common) up to 60 mph.
  • Winds may shift as much as 180 degrees between the time of a storm's approach and its departure.
  • Fuels in sun may be more than 50oF than those in shade.
  • Temperature change in dry air is approximately 5.5oF per 1,000 feet in altitude.
  • When relative humidity is low (< 30%), moisture is drawn out of fuels, dehydrates them, and makes them susceptible to ignition.
  • Fire with humidity of 30% or less burn freely. Less than 10% burns vigorously.
  • Gradient winds occur at approximately 1,500 feet above the earth's surface.
  • Upslope winds early in the day average 3 to 5 mph.
  • Up-canyon or valley winds (developed upslope winds) average 7 to 10 mph.
  • Downslope winds average 5 to 7 mph and are present after sunset.
  • Along the PacificCoast, sea breezes may reach speeds of 10 to 30 mph.
  • Firewhirls range in size from 1 to 2 foot up to small tornado in size and intensity.
  • Fire behavior timeline:

Time / Fire Behavior
10 am to 6 pm / Fire Behavior most erratic
6 pm to 4 am / Wind usually moderates, air cools, relative humidity rises, and fuels begin to absorb moisture
4 am to 6 am / Fire activity at its lowest
6 am to 10 am / Wind increases, temperature rises, controlling fire is more difficult
  • Elevation divided by Distance times 100 = % of slope.
  • Latitude is measured in degrees from 0 through 90, North and South of the equator.
  • Longitude is measured in degrees from 0 through 180, East and West of the Prime Meridan.
  • General survey map breakdown:

Ranges / North/South rows of Townships
Townships / 6 miles square
Section (36 per township) / 640 acres
Quarter-Section / 160 acres
One acre = 209 square feet or about 70 x 70 yards
  • Each side of a square acre is about 2/3 the length of a football field.
  • The agonic line is 0 degrees declination.
  • Spot fires from sparks and burning embers can occur more than 1 mile away.
  • Forward rate of spread doubles twice when moving from timber to brush and twice again when moving to from brush to grass. Spread slows conversely when moving from lighter to heavier fuels.
  • Rate of spread doubles for every 20% increase in slope.
  • Rate of spread doubles for every 10 mph of wind above 10 mph.
  • The burning index (BI) rates the expected fireline intensity from 0 to 110.

Suppression Limitations
Flame Length / Suppression
< 4 feet / Attacked at head or flanks
4 to 8 feet / Heavy equipment and/or aircraft needed
8 to11 feet / Serious control problem, attack on head may be ineffective
> 11 feet / Indirect attack, major fire runs probable

Wildland Firefighting (3rd Edition)
Chapter 2 - Fire Apparatus & Communication Equipment for Wildland Fires
"By the Numbers"

  • NFPA 1901, Standard for Automotive Fire Apparatus, contains requirements for structural fire engines.
  • Minimum pump volume capacity is 750 gpm, however,2,000 gpm pumps are not uncommon today.
  • Minimum water tank size is 500 gallons, however, 1,000 gallon tanks are not uncommon today.
  • Apparatus with tanks larger than 1,000 gallons are considered mobile water apparatus.
  • Initial attack fire apparatus must have a capacity of 250 gpm. Typically it carries 100 to 300 gallons of water and has 3 to 5 crew members.
  • In regards to resource typing, Type 1 engines have a crew of 4, a 1,000 gpm pump, and 1,200 feet of 2 1/2 inch hose, while Type 2 engines have a crew of 3, a 500 gpm pump, and 1,000 feet of 2 1/2 inch hose. All figures are minimums.
  • Type 1 and 2 engines are used as structural engines, while Type 3 and 4 are typically brush or wildland engines.Type 5, 6, and 7 engines are rarely used (also referred to as patrols).
  • Most auxiliary engine-driven (15 to 50 horsepower) pumps have capacities less than 500 gpm.
  • Mobile water supply apparatus have engine-driven pumps with capacities up to 1,250 gpm.
  • Midship transfer drive pumps commonly range from 1,000 to 2,000 gpm, however, capacities up to 6,000 gpm are available.
  • Most engines can only draft water from about 20 feet below the pump and only at about 60% of the rated capacity.
  • In flashy fuels with high heat output or long flame length, 1 1/2 inch hose should be used for safety.
  • Short lengths (5 to 20 feet) of booster hose attached to the front, rear, or sides of the apparatus allows personnel to walk along with the apparatus and apply water or foam.
  • Booster lines should not be extended with unlined 1 inch forestry hose, except during mop-up operations.
  • Remote control nozzles are capable of flows from 10 to 300 gpm.
  • Baffles inside water tanks must extend from wall to wall and cover at least 75% of the area spanned.
  • The fill opening/vent on the top of a water tank must be able to accommodate a 2 1/2 inch hose and coupling.
  • Covered tank openings must be designed so that they will blow off when tank pressure exceeds 2 psi.
  • The tank fill line from pump to tank must be at least 1 inch in diameter.
  • When figuring gross vehicle weight, tank weight (with water) estimation is 10 pounds per gallon, personnel is 190 lbs. per person, and weight of fire equipment is also estimated.
  • Gasoline engines are susceptible to stalling on slopes greater than 35%.
  • NFPA 1906, Standard for Wildland Fire Apparatus, requirements:

Covers requirements, construction, and design for wildland apparatus.
Requires wildland apparatus to carry a minimum of 150 gallons of water.
Requires that the difference in weight on each axle (side to side) does not exceed 7% difference when the vehicle is fully loaded.
Requires that vehicles have a center of gravity no higher than 75% of the rear track width, on flat ground.
Requires fuel tanks to be large enough for the apparatus to pump at full capacity for at least 2 hours.
Prevents firefighters from riding outside a cab while the vehicle is in motion.
Specifies the distance from the ground to the first step of a wildland apparatus not exceed 24 inches with subsequent steps no farther than 18 inches apart. Steps should have a depth of 8 inches and a maximum surface area of 35 square inches (skid-resistant). If a ladder is used to access the top of the apparatus, it must be at least 7 inches away from the body of the apparatus. All steps must be capable of supporting 500 pounds.
  • Any apparatus compartment greater than 2 1/2 cubic feet must be weather-resistant.
  • Most wildland apparatus carry 10 to 100 gallons of Class A foam concentrate.
  • Class A foam concentrate is typically proportioned at 0.1% to 1% of the total volume of the fire stream.
  • In the mid-1980's, the U.S. Bureau of Land Management (BLM) conducted research that led to the development of high-energy Class A foam.
  • Apparatus fighting structural or wildland fires using Compressed Air Foam Systems (CAFS) do so with an airflow rate of 0.5 cfm to 1 cfm per gallon of foam solution.
  • 2 cfm per gallon of foam concentrate will produce a dry foam with an expansion ratio of 10:1 for flows up to 100 gpm.
  • NFPA 1500, Standard on Fire Department Occupational Safety and Health Program, contains standards related to apparatus safety.
  • When backing an apparatus, the alarm must be at least 87 decibels. Technical requirements can be found in SAE J994, Alarm Backup Electric Performance, Test, and Application by the Society of Automotive Engineers.
  • Markings (unit letters/numbers) on tops of apparatus should be at least 2 feet in size.
  • Minimum equipment for wildland apparatus:

Quantity / Item
1 / Axe
1 / Round-pointed shovel
2 / Handlights
1 / Fire extinguisher (minimum rating 40 B:C)
2 / Spanners
200 feet / Hose
1 / Nozzle
1 / First-Aid kit
1 / Hand-pump water extinguisher
2 / Wheel chocks
  • Water tenders have pumps ranging from 50 to 300 gpm and tank capacities from 1,000 to 5,000 gallons. (page 73) **DISCREPANCY** Page 74 states water tenders have fire pumps ranging from 200 gpm auxiliary engine-driven pumps to 5,000 gpm midship-transfer drive pumps.
  • NFPA 1231, Standard on Water Supplies for Suburban and Rural Fire Fighting, covers water shuttle operations.
  • It may be possible for a water tender to refill as many as 20 wildland apparatus before needing to refill itself.
  • Quick-dump piping on water tenders is generally at least 8 inches in diameter.
  • NFPA 1231 states that converting tank vehicles designed for another purpose to mobile water supply apparatus is not recommended.
  • Some engines are equipped with a 50 to 75 foot aerial ladder or elevated master stream device.
  • Referring to bulldozers, Type 1 is known as heavy, Type 2 is medium, and Type 3 is a light dozer.
  • A dozer can construct a single-pass fireline approximately 1/2 mph over moderate terrain and in medium fuel.
  • A Type 2 tractor plow can cut a 6 foot wide fireline at a rate of 1 mph. A Type 1 is 2 mph.
  • In paracargo drops, the drop zone is a strip 200 feet wide on each side of the flight path, 300 feet short of the target in the direction of approach, and 1,300 feet after the target in the direction of the aircraft's exit.
  • Do not mark target areas for air drops within 600 feet of the incident base.
  • An air drop target should be marked with a "T" at least 7 feet long. For multiple drops, a number should be placed below and to the right of the "T". The top of the "T" should be toward the wind.
  • Fireground communications involves everything from face-to-face oral communication to 800 MHz radios.
  • Most modern radios can transmit and receive on at least 32 frequencies and up to 200 or more.
  • Most portable radios have 1 to 5 watts of transmitting/receiving power compared to the 100 to 150 watt mobile radio.
  • Portable radio communication with another portable may be less than 1 mile.
  • Newer portable radios are capable of handling up to 210 channels.
  • Most modern CB radios have 40 channels.
  • Global Positioning Systems (GPS) can generally determine the location of a vehicle within 100 feet.

Wildland Firefighting (3rd Edition)
Chapter 3 - Wildland Fire Fighting Tools & PPE
"By the Numbers"

  • Personnel should walk at least 10 feet apart when carrying or working with hand tools.
  • Cutting edges on axes should be sharpened back approximately 2 1/2 inches on each side with an even bevel on each side (page 98) **DISCREPANCY** Page 99, figure 3.5 states the blade should be sharpened back 1 1/2 inch.
  • Not over 1/2 inch of the axe handle shoulder should be exposed.
  • Pulaski tool cutting edges should be tapered 2 inches with an even bevel on each side. The grubbing edge should be beveled 3/8 inch wide on a 45 degree angle on one side of the head.
  • Round-point shovels should be sharpened starting 4 inches from the heel on each side of the blade (page 100). **DISCREPANCY**Page 100, figure 3.10 states the blade should be sharpened 1 1/2 inches from the heel.
  • McLeod tools consist of a head with 5 to 7 tines.
  • Fire swatter flaps are usually square in shape with each side being 16 to 24 inches.
  • Both solid and collapsible backpack pumps carry 5 gallons of water.
  • Vest-type backpack pumps can carry up to 8 gallons.
  • Occasionally, when a chain saw is running, the tip of the saw should be held 1 to 2 feet from an object and revved up to determine the amount of oil thrown off (indicates need for oiling).
  • NFPA 1921, Standard for Fire Department Pumping Units, covers design requirements for portable fire pumps.
  • Portable fire pumps intended for 1 person to carry should not exceed 80 pounds, 2 person=160 lbs. max.
  • Most portable pumps are capable of drafting from heights of 10 to 12 feet, though capacity is diminished.
  • To avoid excessive pressures, it is best to put portable pumps used in tandem more than 100 feet.
  • Booster hose (non-collapsible rubber) is most often used in 100 to 200 feet lengths wound on a reel. Some apparatus have a 5 to 20 feet section of hose to facilitate pump-and-roll operations.
  • Booster hose is most commonly found in 3/4 inch and 1 inch diameter and generally have flows less than 30 gpm.
  • Garden hose carried on some apparatus is usually 1/2 inch or 5/8 inch and flows generally less than 10 gpm.
  • The most common sizes of jacketed, lined fire hose for wildland applications is 1 1/2", 1 3/4", 2", and 2 1/2". Lightweight jacketed, lined wildland fire hose is available in 1" and 1 1/2" sizes.
  • 1 firefighter can carry 300 to 400 feet of unlined (forestry) firehose in a relatively small package.
  • Unlined fire hose comes in 1" and 1 1/2" and is most often found in 100 feet sections.
  • Hard suction hose used on portable fire pumps is usually 1 1/2", 2", or 2 1/2" in diameter.
  • A hoseline tee is designed to be placed between 2 sections of 1 1/2" hose and allows a 1" hose to be ran off the 1 1/2" line.
  • Hoseline pressure relief valves are used on 1 1/2" hoselines from positive displacements pumps and are designed to operate anywhere from 50 to 200 psi.
  • A check-and-bleeder valve is used on 1 1/2" hoselines being supplied by a portable pump and it also contains a 1 inch discharge similar to a hoseline tee.
  • Water ejectors can be used on lifts greater than 18 to 20 feet where drafting is difficult or beyond the capacity of the pump.
  • Drip torch tanks generally use on of the following 3 mixtures:2 parts diesel-1 part solvent, 2 parts crank case oil-1 part gasoline, or 3 parts diesel fuel-1 part gasoline (fill only 3/4 to allow for expansion).
  • Some fusees have 6 to 8 inch handle attached.
  • Fusees burn phosphorus at 1,400oF and burn for about 15 to 30 minutes.
  • NFPA 1977, Standard on Protective Clothing and Equipment for Wildland Fire Fighting, requirements:

Covers the requirements, design, testing, and performance of wildland gear and equipment.
Reflective trim on wildland gear is not required.
Wildland boots should measure at least 8 inches from the heel to the top of the boot and the height of the heel of not less than 1/2 inch.
Does not require wildland boots to have steel safety toes. If steel toes are issued, they should meet ANSI Z41 standards.
Requires at least 4 square inches of retroreflective material be on each side and rear of the helmet shell.
  • Eye goggles and safety glasses protect the wearer from about 85% of all eye hazards.
  • ANSI Z87.1, Practice for Occupational and Educational Eye and Face Protection, has a major requirement that eye protection afford the wearer a 105 degree field of view.
  • Fire shelter outer foil skin reflects approximately 95% of the flame's radiant heat. The remaining 5% is absorbed in part by the heat warming the fiberglass cloth liner with the reamainder heating the shelter space.
  • Fire shelter inside temperatures can reach 150oF, however, some dry saunas are often around 190oF. These temperatures can be survived for prolonged periods.
  • The heat adsorbed by fire shelter fiberglass cloth is not a problem until temperatures reach 500oF. Fire shelters will begin to melt at 1,200oF.
  • Typical forest fires can produce temperatures around 1,100oF, while peak temperatures can reach 1,800oF.
  • Tears of 1 inch in length in folded edges, punctures in foil over 1 inch, or 1/2 inch or more foil missing on fire shelters is reason for removing from service.
  • Scientific studies don in Australia in the late 1980's determined that wildland firefighters are unlikely to experience hazardous levels of CO, so filter masks are adequate.

Wildland Firefighting (3rd Edition)
Chapter 4 - Water Supply
"By the Numbers"

  • Most water systems now use at least 6 inch diameter pipe for mains.
  • Hydrant Colors:

Red caps and bonnets / < 500 gpm
Yellow caps and bonnets / 500-1,000 gpm
Green caps and bonnets / > 1,000 gpm
Blue caps and bonnets / High static pressure hydrants (in some communities)
  • Water tanks on fire engines usually have capacities less than 1,000 gallons.
  • Many water tenders have 6 to 10 inch quick-dump valves.
  • Hard suction hose should be at a depth of at least 2 feet.
  • When pumping a draft, a lift of not more than 10 to 12 feet is optimal.
  • When drafting, if a pump fails to prime within 30 to 45 seconds at a 10 foot lift, disengage priming device and check for leaks around caps and connections.
  • A dry hydrant is defined by NFPA 1231 as "a permanent piping system, normally a drafting source, that provides access to a water source other than a municipal-type water system."
  • A dry hydrant typically consists of a pipe of 6 inches in diameter with a strainer permanently submerged in a body of water.
  • The riser for a dry hydrant extends about 2 feet above grade into a 90 degree elbow.
  • Suppression capabilities of water can be increased 2 to 3 times by mixing it with certain chemical additives (foam).
  • Properties of additives used for wildland fires can be found in NFPA 298, Standard on Fire Fighting Chemicals for Class A Fuels in Rural, Suburban, and Vegetated Areas.
  • The combination of water and 0.1% to 1.0% foam concentrate produces a foam solution, while adding air to the foam solution (aeration) produces foam.
  • When using Class A foam to construct a wet line, mix ratios should be set at 0.3% for CAFS or at 0.3% to 0.5% for air-aspirating nozzles. This ratio may have to be adjusted for consistency when used for structure protection.
  • A wet line should be set at least 2 1/2 times the expected flame length.
  • A foam blanket of at least 1/2 inch thickness should be applied for structure protection.
  • Depending on environmental factors, CAFS foam should last about 1 hour.
  • When using gelling agents for fire extinguishment, it should be mixed with tank water at a ratio of 1:100 or 1% (1 gallon gelling agent for every 100 gallons of tank water).
  • When constructing a line, gelling agents are normally applied at 1.5% to 2%.
  • Gelling agents remain hydrated for several hours, up to 24 hours in some cases.

Wildland Firefighting (3rd Edition)
Chapter 5 - Initial Fireground Command
"By the Numbers"