in adapting a forest fire suppression unit and developing a fast, mobile, homemade suppression unit for rangeland .... volume of water in custom built tanks.
RANGELANDS 15(5), October 1993
200
Mobile Suppression Units for Prescribed Burning of
Rangelands
Barry D. Irving and Arthur W. Bailey Prescribed burning is becoming increasinglypopular as a vegetation management tool for rangelands. Ignition and suppression equipmentare required for successful operations. Ignition equipment is well developed and readily available. However, suppression equipment specifically forprescribedburningofrangelands is noteasily obtainedfrom commercial sources. Rangeland suppression equipmentis usually made up of modified wildfire fighting equipment, herbicide sprayers, or home manufacturedunits. In this paper, we discussour experiences in adaptinga forest firesuppression unit and developing a fast, mobile, homemade suppression unit for rangeland prescribed burning in the Albertaaspen parkland. A prescribedburning operationhas3 distinct phases, each with varying suppression requirements. The first phase of the operation consists of the development of firebreaks. One popular method is the burning out of firebreaksaroundtheperimeterof thearea.Suppression in thisphase mayrequire layingof wet lines and controlling and extinguishinghead fires and backfires that are usuallyburningin light, fine fuels.Inorderto beeffective, suppression equipment has to deliver a small volume of waterover a long period oftime.The second phase is the burningoperationitself. Ideally,if firebreaksarewell preparedand the prescriptionis followed, no suppression is required. The third phase of the burning operationis the post burn mop up and extinguishingof hotspotsclose to theperimeter of the burn. A low volume of waterover a long time period is usually required during this phase. The ability to deliver a large volume of waterto areas of intense heat such as smoulderingbrush piles or subsurace smoulderingroots may also be desirable. During anyof the 3 phases,thefire canbecomeuncontrolled. In theinstanceof a runaway fire, the key requirementof suppression equipmentis mobility, with asecondary requirement being largewatervolumes. Mobilityand watervolume may be incompatibleas larger water volumes inhibit mobility. The optimum balance between mobility and water volume will be determined by the topographyof theareas to be burned. Different kinds of suppression equipmenton each fire may be required to meet these needs. Personal preference of the fire boss and suppression crewswill probablybe a major factor in thedesignof suppression equipment. During the 1970's, Wajax 5 gallon back pack units carried by personnel and a modified herbicide sprayer pulled by a tractor were our principal fire suppression tools. The equipment was labour intensive, tiring, slow
f
Authors are with the Departmentof Plant Science, University of Alberta, Edmonton,Alberta, Canada, T6G 2P5.
A 6-wheel all terrain veh,cie l,twu wun ure suppression, equip-
ment. Photo by Barry Irving.
and cumbersome. Later, a 100-gallon homemade unit mounted on the 3 point hitch of a tractor providedmore mobility butwas limited by the slow tractor speed. In 1981, 2 WajaxTM (Model TFG-201) Slip-on Tank fire fighting units were purchased. The factory-equipped units consisted of a 160-Imperial gallon holding tank, a WajaxTM Mark 3 pressure-volume pump, and a hose reel with 100 feet of 1.5-inch high pressure rubber hose. The factory equipmentfulfilled most of the requirements for prescribed burning, but required 2 modifications. We installed asmall hose reel (100 feetof3/8 inch hose) and a return line from the pump to the tank. This enabled the deliveryof muchsmallervolumesof waterunder continuous pumping. The 1.5-inchhoseand reel was left intact for useon fires burningin heavy fuels. In 1990 a Polaris Big BossTM 6-wheel all terrain vehicle was also purchased. A homemade suppression unit was constructed and placed on the rear deck. A 40-gallon holding tank with a 1.5-inchwater pump was fitted and piped. Twenty feet of 1/2-inch water hosewas used for discharge. A hose reel was not installed becauseof space limitations, but maybe added later. Theunit wasequipped so that water filling could be accomplishedby backing into asurfacewatersourceand droppinga suctionhose. This adaptationenabled filling of the unit from intermittent wetlands that are common in centralAlberta. A high volume, light weightpump unit was purchased to provide rapid refill capabilityfrom nearby wet lands that dot the Alberta parklands during spring prescribed burningoperations. Thevolume pump permits refill of the 160-gallon truck unit in about 4 minutesandthe40-gallon quad unit in about 1 minute.
RANGELANDS15(5), October 1993
201
Field Use The combinationoftheWajaxTM Slip-on tanks (placed into 4X4 trucks) and thePolarisTM unit provideseffective suppression capabilitiesforrangeland fires. TheWajaxTM units have thenecessary watervolumesand nozzle pressureforcontrollingfires in eitherlightor heavyfuelswhile
maintaininggood mobility. The PolarisTM unit wasexcellent for rapidlypatrolling the fire perimeter, extinguishing spot fires, or for establishing firebreaksin light fuels.The PolarisTM unit also allowed us to access areas of rough topographyand wet soils that could not be crossed by a 4X4 pickup. Our modificationsto theWajaxTM unit werequite simpleand could be done to almost anycommercialslip-on or trailer type forest fire fighting unit. Our choice of a Polaris' all terrain vehicle was dictated by availablity. Thereare not many quadson the marketwith a payload sufficientto carrya40-gallonwatertank.Tandem wheels on the back add stability and reduce therisk of rollover (especially backwards). An alternative (for 4-wheeled quads) would be to build a small trailer unit (but this would reduce mobility) or to simply carry a smaller volume of waterin custom builttanks.
Summary The development and use of suitable rangeland fire suppression equipment has enabled us to more effec-
Slip-On rire Suppression
Photos byBarry Irving.
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unit mocifiedfor rangoland burning.
ovi n19 cj?York
coming. SAM,
tively and safely conduct prescribed burning research programs, often in cooperationwith ranchers, throughout the Alberta aspen parkland. The equipment has resulted in a sharp reduction in crew size. It has also reducedthe level of fatigueof our personnel following a long day of prescribed burning.
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