truck company officer study notes 1st edition june 2009

7/23/2019 Truck Company Officer Study Notes 1st Edition June 2009

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1STEDITION JUNE 2009

Truck CompanyOfficer Study Notes

The City of HendersonFire Department


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PurposeThe diverse tasks of a truck company include ladders, overhaul, utilities, ventilation,forcible entry, rescue and salvage. Truck Company supervision requires unique

perspective and additional training. This document provides specific material to thecompany officer who may be assigned to the truck.


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Delivery Plan

The program is a self study program that will be administered by the Shift BattalionChief.

Documentation Plan

Completion of this training manual, and verification by the Battalion Chief will bedocumented in Sunpro under Truck Operations>Officer>TCOCO


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Table of Contents

Purpose.........................................................................................................1

Delivery.........................................................................................................2

Documentation Plan ....................................................................................2

Chapter 1. Apparatus Considerations Pierce 100ft. Aerial ....4

Chapter 2. Positive Pressure Ventilation............................17

Chapter 3. Roof Types Ventilation Tips andConstruction Considerations ............................22

Concrete Roofs

Wooden I beams Combustible Metal deck roofs Panelized roofs

Built up roofs

Chapter 4. Solar Panels .......................................................... 44


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Chapter 1. Apparatus Considerations

Pierce 100 ft. Aerial

The purpose of this class is to give general information regarding the Pierce 100 ft.aerial platform. This class is merely an overview and is not meant to thoroughlyexplain all aspects of aerial operation and maintenance. More detailed informationcan be obtained by reading the Pierce Aerial Platform operation and inspectionmanual.

Objectives

Familiarization Command Zone Information Center (CZIC) Pre-Driving and Truck Positioning

Stabilizer Set-up Procedures

Aerial Operation

Post Operation Stowing Procedures Override Controls

Optional Equipment

Trouble Shooting Specifications

Familiarization

The following figures list and identify the instruments and controls that are installedon our trucks:

In-cab switches

These switches are located to the right of the steeringwheel on the bottom of the instrument panel.

Before activating these switches, the front wheel parking brakemust be set. If the brake is not set prior to the activation of the

aerial master switch, the stabilizer controls will not functioneven though all indicator lights are illuminated. The operatormust reset the switches and start from the beginning.

In Cab SwitcheFront Wheel Loc


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Sequence includes:

Setting front parking brake Activation of aerial master switch (Activates all electrical circuits) Activation of aerial PTO switch (Activates the transmission mounted

PTO)

PTO engagement light illuminates (Verifies when PTO has engagedsuccessfully)

Platform Leveling Switch (Levels the basket relative to the angle of thetruck)

Lower Control Station

These controls are located at the rear of the truck behind a control panel

door.

Diagnostic interface is used by the mechanics to diagnose and retrievecodes.

Stabilizer remote control unit is tethered to the truck and enables theoperator to visualize both sides of the truck during stabilizerdeployment.

The Override switch overrides interlocked circuits for emergencyoperation. This switch allows full override of all safety controls for thetruck.

The Emergency Stop switch stops all aerial functions and sends an

alarm signal to the CZIC.

Stabilizer Remote Control

Stabilizer Power indicator indicates controls are energized.

Stabilizer Not Stored indicator indicates when one or more stabilizers arenot stowed fully.


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RF/RR/LF/LR controls control the operation of the stabilizers.

Stabilizer Beam Fully Extended indicator- indicates when beam is fullyextended.

Stabilizer Firm on Ground indicator indicates when stabilizer is firm onthe ground.

EPUswitch activates the secondary hydraulic system

EPU- 2 systems for hydraulic function; PTO(diesel motor), EPU electricpump

Level Assist control switch hold the switch down once stabilizers on firmground to assist with vehicle leveling.

Manual Stabilizer Controls

These controls are located on the Captains side under the rear stepsbehind a control panel door. When this door is opened an audible alarmand visual indicator is transmitted to the CZIC.

Emergency Power Unit (EPU) Engages the secondary hydraulicssystem. It does not rely on microprocessor circuits or bypass theelectronics.

Manual control levers Used in the event of an electrical systemmalfunction. These controls are not subject to interlock safety lockouts.

Stabilizer Remote Stabilizer Remote

Manual Stabilizer Controls


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Turn Table Control Console

These controls are located at the turn table control console under thepanel lid. It is very similar to the basket control console.

Emergency Stop button Stops all aerial functions

Emergency Hydraulic Power switch Activates the secondary hydraulicsystem

Command Zone Information Center (CZIC) Displays all systeminformation and hazardous conditions.

Elevation Control Raises and lowers the aerial (All aerial controls are pullup to activate)

Rotation Control Rotates the aerial

Extension Control Extends and retracts the aerial

Monitor Raise/Lower moves the electric monitor up and down Monitor Left/Right moves the monitor left and right

Monitor Pattern changes the monitor pattern from fog to straight stream Speed switch controls the relative speed of aerial functions

Tip/tracking Light switch controls power to tip and tracking lights Intercom On and off switch and volume control located at turntable not in

basket.

Aerial Basket Controls

Left

Monitor Pattern switch same as turn table Monitor Left/Right switch - same as turn table

Speed Switch - same as turn table

Monitor Raise/Lower switch - same as turn table

120 VAC Electrical outlet

Center

Extension control Extends and retracts the aerial

Rotation control Rotates the aerial

Intercom Voice activated no volume controls

Elevation control Raises and lowers the aerial

Right

CZIC Enables user to switch between screens to verify informationon ladder status (breathing air, leveling, rung alignment, gpm flowing,tip temp., reach, PTO and aerial hrs.) More info later.


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Emergency Stop button Stops all aerial functions

Software navigation button (Yellow) changes screen displays Screen navigation buttons (red) labeled: MENU, HELP, ENTER

and BACK

Breathing air coupling (there are 4 of these coupling located in thebasket with 4 air supply lines).

Emergency (manual) Aerial Controls and Oil Sample Port

Located under the first step on the turn table. Release fasteners andopen. These controls are not subject to safety interlocks and will allowthe operator to override all safety controls built into the truck.

Oil sample port Used to obtain hydraulic oil samples (Not for our use)

Extension control Extends and retracts the aerial Rotation control Rotates the aerial Elevation control Raises and lowers the aerial (All aerial controls are pull

up to activate)

Emergency Stop PTO Bypass switch If in the event an emergency stopswitch is activated and cannot be reset, the operator can use the switchand operate the manual aerial controls.

Emergency Controls Stabilizers

These controls are not subject to safety interlocks and will allow theoperator to override all safety controls built into the truck. Opening thedoor to this compartment will send an alarm to the CZIC.

The EPU should only be used when the main hydraulic pump is not running(diesel engine failure.)

Emergency Manual AerialControls Stabilizer

Controls


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The EPU should not be run for longer than 30 minutes without allowing 30minutes cool down time.

In the event of multiple system failure the Emergency Power Unit switchlocated in this compartment will be the only switch active, the two otherswitches located on the pedestal and the basket will not be operational. This

requires a two-person operation, one to activate the switch and levers andone to observe for obstructions.

Breathing Air System

Located on the turn table, on the captains side.

Air bottles high pressure breathing air 4500 psi Shut-off value used to open/close value (when hooked up to truck air,

SCBA bottles should remain closed, otherwise bottle air will be consumedbefore using truck air supply, leaving no air for possible escape.)

Valve guard guards valve assembly High pressure hose assembly transfers high pressure air to regulator Low pressure hose assembly supplies breathing air to coupling located

in basket

Pressure transducer monitors air pressure in storage tanks.

Fill adapter Used to fill bottles (The Fire Equipment Technician fills allhigh pressure tanks)

Turn Table Power Distribution

These controls are located on the Engineers side of the controlpedestal on the turn table.

Calibration N/A

Basket Leveling Mode Switch Used to switch between AUTO andMANUAL basket leveling. Switch must be in manual position beforemanual switches are functional.

Manual Basket Leveling Switch Used to move basket up and down. Fuses N/A

Turn Table PowerDistribution


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Command Zone Information Center

Three centers; one located on the turn table pedestal, one in the basket, one inthe cab. Unit in the cab does not relate to aerial operation, only concernedwith chassis operation. Does not have the screens or additional buttons.

Main aerial data screen Displays ladder load in %breathing air, in % gpm, rung aligned for climbing andladder aligned for stowing.

Aerial reach screen Displays tip temp, basketheight, degree of angle, extension of ladder.

Aerial level screen Displays degree of grade andslope, visual on stabilizer deployment.

Hydraulic System Screen Displays hydraulic psi,

hydraulic oil temp, aerial hrs, PTO hrs.

Pre-Driving and Truck Positioning

Leveling the basket

This does not have to be done on a regular basis. With the truck running andthe aerial master switch OFF, press the leveling switch to activate the levelingsystem. This will level the basket based on the current slope of the truck. If

this must be done, find a level area to provide good base line.

Make sure the aerial and the stabilizers are stowed properly. If they are notstowed fully, the CZIC in the cab will signal with an audible and visual alarm.

Positioning the Truck

The truck can be positioned uphill or downhill and each has its advantagesand disadvantages. The truck must be leveled within acceptable limits basedon the manufacturers specifications.

Clear the area around apparatus for stabilizer deployment. If there is notsufficient space to fully extend the stabilizers, the operator can short jack theapparatus. When the vehicle is short jacked there are limitations to operationon the short jacked side. When short jacking is needed, position the truck sothat the fully extended stabilizers are on the needed for aerial operation.

Command Zone


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Full extension of the stabilizers is required for 360 ooperation or 180oover therear for full basket and ladder load.

Verify stabilizer pad placement is not over manholes, storm drains, or anyother questionable ground.

Positioning UphillAdvantages

Extending the rear jacks will raise the rear of the truck, reducing thegrade

The front tires will remain in contact with the ground

The rear tires can remain in contact with the ground to preventsliding

Raising the rear axle off the ground adds to the truck ballast weightoffering greater stability.

Disadvantages With the rear wheels off the ground, less sliding resistance

Access to compartment is difficult

Reaching the ground with the tip of the aerial is difficult

Positioning Downhill

Advantages

Compartments are closer to the ground Easier to reach the ground with the tip

Disadvantages Jacks cannot be extended to reduce grade without raising front

tires off the ground

When front tires are off the ground, improper bedding may occur

Stabilizer Set-Up Procedures

Cab Controls

Set front parking brake

Activate Aerial Master Switch Activate Aerial PTO Switch Visualize PTO engagement light


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Stabilizer Set Up

Set front wheel chocks Open rear access door and verify green power light is illuminated Place ground pads with handles towards truck with handle in up position

Extend beams and lower stabilizer jacks

Level truck using manual methods or auto leveling assist Verify all four firm on ground indicator lights are lit.

Place safety pin into highest slot available

Safe operating limits as described in Pierce Aerial platform manual:

Anytime the truck tips more than 8 degrees from level, a warning will bedisplayed on the CZIC and all control functions will be disabled. Use theoverride switch to safely correct the condition.

Short Jacking

Enables jack set up in tight situations

Short jack must be extended far enough to remove safety pin Operate only over the side with fully extended jacks

Interlocks will prevent operation over short side


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100 ft. Load Chart

Operation from the Turn Table

Select Main Aerial Screen

Select Aerial Level Screen Turn on intercom

Turn on air

Activate controls in appropriate order (Elevate, rotate, extend, lower) Check for overhead and side-to-side obstructions


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Stowing the Aerial

Retract aerial sections

Rotate aerial to align with boom support (as close as possible; truck willmake final adjustments)

Lower aerial into boom support (hold lower control lever for severalseconds until RPM change is noticed)

Turn off intercom, lights, breathing air etc.

Close cover

Stowing the Stabilizers

Remove safety pins

Fully raise jacks

Retract stabilizer beams Confirm all jacks and beams are properly stowed

Turn off stabilizer power Close and secure all doors

Replace ground pads and wheel chocks Turn off aerial master and PTO switch

Override Controls

Stabilizer Override Controls- Used to override interlock safety controls or tooperate stabilizers due to equipment malfunction.

Label on inside of the door indicates level control operations and positions.

Aerial Override Manual Controls Located in step of turn table, used to overrideinterlock safety and to operate aerial during equipment malfunctions.


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Optional Equipment

LyfeEye

Used as a rappelling attachment point.

Rated capacity of 300 pounds All additional weight must be subtracted from platform capacity

Eyes underneath basket are rated at 500 pounds

LyfeLadder

Used to accommodate egress over parapet walls

LyfeSupport Rescue Basket Option

Used to secure a stokes basket to the platform

Uses straps that are provided to secure stokes to basketarms

Trouble Shooting

Many commonly encountered problems are addressed in detail: Malfunction,possible problems and corrective actions.

Specifications

Apparatus Length 429

Apparatus Length with basket 469 Apparatus Height with Ladder 126

Apparatus Weight 76,800 #

Ladder Length 93 + 7 (truck height) = 100 Horizontal Reach 0 Degrees = 93 ft

45 Degrees = 66 ft 6 inches 75 Degrees = 25 ft 6 inches

LyfeEye

Lyfe Support & Lyf


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Additional Information:

Apparatus length from turntable to front bumper 38

Usable ladder length over front of apparatus 55 at 0 degree horizontal

Typical single family dwelling setback 25 curb to garage Residential roof may be an additional 20 further back

Aerial operators and company officers should realize the significant distanceto a single family dwelling when setting up, nose in, in a cul-de-sac. Otheroptions would be to back the apparatus into position or use ground ladders.

The roof/LyfeLadder should be positioned prior to elevation of the aerialwhenever a parapet or commercial type occupancy might be accessed.Placing the ladder in position early will allow extra room in the basket forpersonnel to prepare for roof operations.

No more than 3 personnel with tools and PPE should occupy the basket whenthe waterway is dry, based on 1000 pound capacity (1).

No more than 2 personnel with tools and PPE should occupy the basket whenthe waterway is charged, based on 500 pound capacity (2).

A tip overload alarm may be encountered when operating the 100-foot aerial.When this condition is encountered, it is routinely caused by severalsituations. Failure to make firm stabilizer contact with the ground is one cause.Another cause may be failure of the rear tires to break contact with the groundduring setup. The Pierce Aerial Platform Manual states, Rear tires mustbreak contact with the ground (3).

When a tip overload alarm is encountered, the operator should first ensurethat the aerial is properly set up and within operational specification. A false tipoverload alarm can sometimes be reset by retracting the aerial, clearing thealarm, and resuming normal operation. If an alarm is repeated then the aerialis probably operating at its maximum limits.

Driving Considerations:

The Pierce 100-foot Aerial weighs 76,800 pounds. The truck should not be driven

onto any structure which will not support its weight. The south parking lot of Green Valley Ranch is a two-story structure. The main

parking area is a rooftop for the valet parking area below.

The main/south entrance to the M Resort also covers a valet parking area.

Low overhangs should also be considered, especially when operating in andaround apartment complexes and businesses with covered parking. The aerialbasket extends 4 feet in front of the cab and the overall height is 126.


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Chapter 2. Positive Pressure Ventilation

Developed by LAFD in the 1970s, a door was opened and a fan positioned outsidethe doorway creating a cone of pressurized air that just covers the entrance opening.This method will force clean, fresh pressurized air inside the room. The positivepressure will be equal at the top, bottom and corners of the room. Where the exhaustport is created, all products of combustion will be exhausted

Todays fires produce 20,000 BTUs per pound compared to 8,000 BTUs 20-plusyears ago. This is due to the increased use of plastics, synthetics and adhesives inbuilding materials and household items. Products of combustion have also becomemore toxic.

Entrance OpeningA cone of pressurized air issued from a blower should completely cover an entranceopening and can be accomplished using a single blower or multiple blowers.

Single Blower

A single blower should be positioned so the cone of pressurized air just covers theentrance opening. Blowers are manufactured so that they can tilt back 20 30degrees to enhance the sealing of the entrance opening. Normally a fan should beplaced 6 -7 feet back from the entrance opening. Although it is important to seal the

entrance opening for smoke removal, it is not absolutely necessary. Entrances thatare not sealed will recirculate the contaminants from the unsealed portions of theopening to the blower and back into the contaminated area lengthening the time forventilation.

It should be noted that if a blower is being used for fire attack and the fire is near anentrance opening, fire can recirculate from the unsealed portions of the entranceopening to the blower and back into the fire area. Interestingly, the efficiency ofPositive Pressure in these cases is not compromised only the time it takes to removethe contaminants.

Multiple Blowers

For standard entrance openings (i.e., door openings of 3 feet by 6 feet), maximumeffectiveness can be achieved by placing two blowers in line (series) with each other.The blower nearest the doorway should be positioned about 2 feet from the entranceopening. This ensures that all of the pressurized air from the blower enters thebuilding, yet allows sufficient room for ingress-egress of personnel. The blowerfurthest from the doorway is positioned behind the aforementioned blower and is


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used to cover the entrance opening with pressurized air, and force additionalpressurized air into the building. If two blowers of unequal size are used in the seriesposition, place the larger blower about 2 feet back from the entrance opening andutilize the smaller blower behind the larger blower.

For large entrance openings, multiple blowers in a parallel configuration should be

used due to their combined ability to cover the larger opening with pressurized air.The size of the opening will dictate the number of blowers that will be necessary tocover the opening with combined cones of pressurized air. Remember that someopenings (i.e., vertically moving loading-dock doors) can be reduced in size bypartially closing the door which will reduce the size of the entrance opening that mustbe covered by pressurized air

Flow of Pressurized Air

It is imperative that the flow and path of pressurized air between an entrance andexhaust opening be controlled to achieve maximum ventilation. Simultaneouslyopening unwanted windows and/or doors will not facilitate a successful positivepressure ventilation operation.

Exhaust Opening

Exhaust openings can be selected to provide horizontal or vertical ventilation ofcontaminants. Always create the exhaust opening first (If there ever was analways in the fire service, this is it!), and then pressurize the structure or area to beventilated. If the order is reversed, there will be nowhere for the pressurized airflow togo until an exhaust opening is created. The size of an exhaust opening can vary andis dependent upon:

The number of blowers used.

The cubic feet per minute (CFM) rating of the blowers that are used.

The size of the area to be ventilated.

As an example, let's apply this general guideline to a single-story, single-familydwelling of about 1,800 square feet:

A single 18-inch blower powered by a 2- to 3-horsepower engine would be mostefficient when used with exhaust openings that are three-fourths to about thesame size as the entrance opening.

A single 18- to 24-inch blower powered by a 5-or-more-horsepower engine wouldrequire an exhaust opening between one and one and one-half the size of theentrance opening.

Multiple 18- or 24-inch blowers powered by approximately 5-horsepower enginesand in series or stacked configurations would require exhaust openings up toone-and-three-fourths the size of the entrance opening.


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Carbon Monoxide

If a gasoline powered blower is being used and an exhaust odor is noticeable insidethe area to be ventilated, this is an indicator that the exhaust opening is not largeenough. An insufficient exhaust opening will allow pressurized air and the blowerexhaust contaminants to accumulate inside the area to be ventilated. The exhaust

odor should disappear by increasing the size of the exhaust opening (openinganother window, door, etc.) and will also reduce the amount of carbon monoxide inthe area to be ventilated.

Carbon monoxide in the exhaust from gasoline-powered blowers can be a majorconsideration. To alleviate this problem, some manufacturers produce flexible tubeextensions that attach to the muffler of gas powered blowers and allow exhaustingthe carbon monoxide (and other exhaust by-products) away from the inlet to theblower and area to be ventilated.

Weather

Temperature, humidity, snow, and rain do not have any appreciable effect on positivepressure ventilation. Although cold, damp weather conditions may limit the ability ofsmoke to rise, it will not limit the ability of blowers to move contaminants horizontally,and in most cases, vertically. Wind can have an adverse effect on positive pressureventilation, but its effect is dependent on direction and velocity. If it is not possible toutilize the prevailing wind as an advantage, positive pressure has proven effectiveagainst winds (leeward to windward) of up to about 25 mph. As winds exceed 25mph, efficiency will be reduced accordingly.

To achieve the maximum efficiency with positive pressure in ventilating a structure,do not "open the structure up," or ventilate all rooms simultaneously, as is the

common practice in structure fires. Multiple openings can diminish the flow of airthrough each room and increase the time necessary for ventilation. Normally, themost effective method for most structures is sequential ventilation of contaminatedareas. Sequential ventilation, or targeting specific areas and ventilating them in astrategic sequence, maximizes the flow of pressurized air from a blower into andthrough a contaminated area. This also minimizes the time required for ventilation.Remember that closing a door or window will isolate the area from the ventilationoperation by eliminating the flow of pressurized air to an exhaust opening.Additionally, an area that has open walls or ceilings (from a fire) or other largeopenings can be isolated from a ventilation operation by closing an appropriate door,if applicable.

Basements

If a basement has multiple openings that can be used for entrance and exhaustopenings (e.g., interior door, exterior cellar door, windows, etc), position a blower tocover an appropriate opening to the basement (such as the interior doorway to thebasement) with pressurized air and use the appropriate basement opening(s) as an


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exhaust opening. If a basement does not have suitable exhaust openings, severalmethods can be used to provide them.

If a frame-wood structure has shiplap siding, the two bottom shiplap boards (next tothe plate on the foundation) can be easily removed, exposing the opening betweenthe ends of the floor joists and between the floor and plate, creating an exhaustopening (it will be necessary to remove the basement ceiling to complete theopening).

If the preceding method is not practical, position a blower to pressurize the structureabove the basement (e.g., front door to the first floor) creating a flow of air throughthe structure to an appropriate exhaust opening (e.g., rear door). Next, place anadditional blower in the interior doorway to the basement. This will pressurize thebasement and force contaminants out of the upper portion of the doorway, which willthen be carried out of the structure by the flow of pressurized air through the firstfloor.

Search and Rescue

Currently, there is an interesting debate concerning the viability of using PPV withsearch-and-rescue operations. It is a fact that PPV has the potential to enhance asearch-and-rescue operation and increase firefighter safety. These facts weregraphically demonstrated by recent tests conducted by the North Carolina Bureau ofInsurance and the United States Coast Guard. However, there is also concern fortrapped occupants that may be located between a fire and an exhaust opening,which when combined with PPV, may result in increasing the potential of death to atrapped victim. Although both of these viewpoints have merit, most structure firevictims die from smoke inhalation, not burns. Therefore, victims who may be locatedbetween a fire and an exhaust opening (when PPV is initiated) will most likely have

died before the implementation of PPV or will be saved by the implementation ofPPV as follows:

Victims who are near the seat of a fire will probably have died from heat or contactwith the fire. Therefore, although PPV can change the direction of fire and heattowards an exhaust opening, it does not normally contribute to the death of victimsnear the seat of a fire who are most likely the victim of high heat, contact with flame,or smoke inhalation.

The rescue of victims who are still alive can normally be enhanced by PPV due tothe introduction of fresh air (and oxygen). The introduction of air (oxygen) willreduce contaminants (carbon monoxide) and increase the percentage of

available oxygen; therefore, improving a victims chance of survival. Additionally,PPV also has the potential to enhance a search-and-rescue operation due to itsability to increase visibility (enhanced speed of a search) and reduce the potentialfor flashover (safety for firefighters and victims).


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Attic Fires

The implementation of PPV in structures with attic fires should be evaluated incombination with the presence and size of attic vents. If fire has extended into anattic with attic vents that are of sufficient size to allow a significant flow of pressurizedair that can spread fire, PPV should not be used unless attack lines are in place.

However, the absence of attic vents will normally allow PPV to pressurize a structure(and attic) without spreading an existing attic fire.


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Chapter 3. Roof Types Ventilation Tips and

Construction Considerations

The extent to which firefighters are able to safely and efficiently ventilate a buildingthrough its roof will depend to some degree on the firefighters' knowledge of roofconstruction. Construction practices and materials vary throughout the city ofHenderson, so Captains are encouraged to visit buildings under construction in theirresponse districts to become familiar with the varying construction techniques.Obviously, we deal extensively with lightweight construction when dealing with anyhome built in the last 20-30 years, but the potential is there for many differentconstruction techniques. The more likely possibilities are discussed here.

Pitched Roofs

The most common examples of pitched roofs seen in the city of Henderson are thegable and hip roofs, especially when dealing with residential construction. Withcommercial occupancies (i.e. strip malls and big box) it is more likely that themodern mansard which is really more of a flat-style roof will be used. Though notprominent, a crew may also face shed, bridge truss or mansard styles as well. Thedegree of slope or pitch of the roof varies with different builders throughout the valley.The most common roof pitch in a track home is the 5:12 pitch (22.5 degrees), withmany custom homes using 6:12 (26.6 degrees) or greater pitches. The company

officer must make a decision whether or not the roof pitch/slope is safe to work on,and if not, whether it should be attacked from the bucket or with the use of a roofladder. Anything over an 7/12 pitch (30.3 degrees) is considered steep, and analternative to walking on the roof without aids should be required. See ODS materialfor further information regarding operating on roofs.


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In the average home, the space between the roof members and the ceiling forms anattic space, which may be vented by louvers at each gable end. Other types ofbuildings may have different roof vents. Access to attic spaces can usually be gainedthrough a small attic scuttle in the ceiling of a hallway or closet, or there may be a

stairway or ladder leading into the space. Insulation material, which may or may notbe combustible, is sometimes found between the framing under the roof (the Pultesystem unvented attic) or on top of the ceiling.

Types of Pitched Roofs

Gable Roof

The gable roof is perhaps the most common style of roof constructionand can be found on most residential dwellings and many commercialstructures. This type of roof is constructed in a semi-flat to a very steep

pitch. The points where the rafters meet the outside walls and theridge beam provide the most support. Its A-frame configurationconsists of rafters that run perpendicular to the ridge beam and downto and usually beyond the outside walls. The ridge and rafters are often2 x 6 inches or larger, and the rafters are commonly spaced at 16 to 24inches on center. The size and spacing of the rafters will vary with thehorizontal distance being spanned. Additional support may be providedby collar beams and ceiling joists. Valley rafters are used where tworoof lines intersect. The trussed pitched roof is designed to cover aconsiderable span, and its rafters can be made of timber or metal.


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Hip Roof

The hip roof is similar to the gabled roof in every respect except thatthe ends of the roof terminate in a "hip" configuration rather than gable.In other words, the roof slopes down to meet every outside wall.

Hip roof construction consists of a ridge beam with conventional raftersrunning perpendicular to the ridge and hip rafters running from the endof the ridge beam, at a 45-degree angle, down to and beyond theoutside walls at the corners. The rafters in the hip sections run in thesame direction as the ridge beam. The dimensions and spacing of hip

roof structural members follow the same engineering rules as those forgabled roof construction. The strongest parts of this roof system arethe ridge beam, valley rafters, hip rafters, and the points where therafters cross the outside walls.


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Shed Roof

The shed roof can be seen as a flat roof sloped from only one side usually from the front of the building down to the back or as half of agabled roof. This type of roof may utilize the mono-pitch truss, whichemploys only a single web member and therefore may be more proneto early collapse than other lightweight wooden trusses. These aremost likely seen in Henderson as either detached buildings or asadditions to existing homes.


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Bridge Truss Roof

Bridge trusses known as Howe or Pratt trusses, are heavy-dutytrusses with sloping ends. When constructed of wood, the trusses areusually made from 2- x 12 lumber, and vertical metal tie rods may beused for additional support. Joists are usually 2 x 6 inches or 2 x 8

inches covered with 1- x 6 inch sheathing. Composition roofing may beused throughout this type of roof, or the sloping sections may beshingled. Due to the shape of bridge trusses, they form a roof that isvery similar to the modern mansard roof discussed later in this section.

The strongest areas of bridge trussed roofs are at the perimeter of thebuilding where the trusses and roof meet the outside bearing walls.The trusses are in constant tension and compression and will fail undersevere fire conditions. The likelihood of roof collapse is dependent onthe dimensions of the materials used and the span of the trusses. Ifmetal tie rods are used, early failure of the rods will also affect thestability of the trusses.

Mansard Roof

The mansard roof has a doubleslope on each of its four sides.Instead of the roof running at aconstant angle, there are twoangles. One angle forms a steeppitch running from the eaves to acertain height, and the otherproduces a flatter pitch to the ridgeof the roof.


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This style is similar to the gambrel roof in that the lower slope issteeper than the upper slope. The difference between the mansardand the modern mansard is the way in which the four sides meet in themiddle. The mansard forms a hipped peak or ridge, while the modernmansard forms a flat central portion.

Hazards of Pitched Roofs

Pitched roofs are designed to shed moisture. A major hazard is the steepnessof the roof and the lack of secure footing for firefighters working on them. Thishazard is increased when the roof is covered with water; but it may even behazardous when dry due of the loose granular texture of some roof coverings.Loose roof tiles, slate, or broken pieces can also be hazardous to firefightersworking on the roof and on the ground. Loose tiles and broken shards maycause firefighters on the roof to slip, and this debris can fall on firefighters

working on the ground.

In addition to the hazards presented by the angle of the roof and by fallingdebris, the growing use of 2- x 4 inch trusses with metal gusset plates and1/2-inch or 3/8-inch plywood decking can present an even greater hazard tofirefighters. These assemblies offer little fire resistance and can fail rapidlyduring a fire, resulting in sudden roof collapse with little or no warning.

Venting Pitched Roofs

Pitched roofs should be vented at the highest point on the leeward sidedirectly over the fire or as close to it as safely possible. The opening should becut parallel to the rafters, perpendicular to the ridge, and to the size deemednecessary with a 4x8 hole being the standard in most situations. In somecases, as with tile roof coverings, it is necessary to strip the roof coveringbefore cutting and louvering the decking. In other cases, especially whendealing with asphalt shingles or built up roofing, leaving the roof coveringattached works well and saves time. On metal covered roofs, it may bepossible to remove an entire section at one time by cutting or prying along theedges, pulling screws or nails as necessary, and removing the panel. Ofcourse, a circular saw may be necessary and perhaps more timely in thissituation.

Because of the steep slope of many pitched roofs, the job of cutting a roofventilation opening can be difficult and dangerous. Company officers mayneed to order the use of roof ladders to prevent firefighters from sliding downthe roof. When working from a roof ladder, the firefighter will often need toreach as far as safely possible laterally from the ladder in order to cut thelargest possible ventilation opening. Long pike poles or rubbish hooks will be


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needed when ventilating this type of roof because the ceiling can be severalfeet below the roof level, and sections of the ceiling may have to be removedfor complete ventilation.

Flat Roofs

There are many types of flat roofs found around the country. For the sake of thistraining, we will focus on the three most common types of flat roofs that areencountered in the city of Henderson. These include the following: modern mansard(as discussed above), wooden and metal deck roofs, and concrete roofs. Flat roofsare more common on commercial buildings, multiple dwellings, and in apartmentcomplexes than on single-family dwellings. This type of roof ordinarily has a slightslope (two-in-twelve pitch or less) toward the rear or side of the building to permitdrainage and is frequently penetrated by vent pipes, shafts, scuttles, bulkheads, andskylights. The roof may be surrounded and divided by parapets. It may also supportwater tanks, HVAC equipment, antennas, solar panels, billboards, and other deadloads that may interfere with ventilation operations and increase the likelihood of roof

collapse.

Flat roofs are commonly supported by horizontal joists or rafters similar to the joistsused in floor systems. The structural elements of flat roofs consist of a wooden,concrete, or metal substructure covered with sheathing. The sheathing is, in somecases, covered with a layer of dense foam insulation under the weatherproof finishlayer. There is usually a concealed, and possibly unvented, space between the flatroof and the ceiling of the top floor below. This space is referred to as an attic,cockloft, crawl space, or interstitial space. The often unprotected underside of theroof assembly will be exposed to the effects of any fire in this concealed void, whichmay contribute to early roof failure.

Components of a Flat Roof


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Types of Flat Roofs

Wooden Deck Flat Roof

This is the most common type of flat roof found in Hendersoncommercial structures. Most small- to mid-sized commercialoccupancies as well as most non-anchor store occupancies in a strip

mall will be of this construction. Wooden deck roofs present a hazard iflightweight plywood decking is used; and this is used frequently.Plywood of 3/8- to 5/8-inch thickness offers little fire resistance, and itmay be difficult to remove for ventilation purposes due to roofcoverings.

The structural stability of the joists will vary depending on the span, thesize and spacing of the joists, and whether the joists are suspended bymetal hangers.

Wooden I BeamsComponents

Wood I-joists are composed of twohorizontal components called flangesand a vertical component called a web.Wood I-joists are used as a framingmaterial, primarily in floors, but mayalso be used as roof rafters where longlength and high load capacity arerequired. Wood I-joists offer the

advantages of exceptional stiffness, light weight, and long spancapability. Holes may be cut in the web according to manufacturersrecommendations, allowing ducts and utilities to be run. I-joists aredimensionally stable, and thus are unlikely to warp, twist or shrink; theyare uniform in size; and are consistent in their manufacturing.

The I shape allows the most efficientuse of wood necessary to carrydesign loads. This is achieved byplacing the material with high strengthand stiffness in the flanges. Similarly,

the web material is high quality, butwith different structural properties. I-

joists utilize the geometry of thecross-section and high strengthcomponents to maximize strengthand stiffness of the available woodfiber. Flanges are manufactured fromend-joined, solid sawn lumber or


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structural composite lumber (SCL), while webs typically consist of highstrength plywood or oriented strand board (OSB).

Manufacture of I-joists

All web and flange materials are carefully graded to ensure theywill perform properly in I-joists. The flanges range from 1-5/16to 1-1/2 thick and from 1-1/2 to 3-1/2 wide.

Today, the web material used almost exclusively is OSB. I-joistsmanufactured prior to the early 1990s also had webs made ofplywood. Web material in typical residential I-joists is either 3/8or 7/16 thick.

Performance Requirements for Code Acceptance

Although I-joists differ among manufacturers, they are all

manufactured to an industry consensus standard. I-joistperformance is closely monitored by the manufacturer and anindependent third-party quality control agency. The qualitycontrol program assures the product continually meets code-recognized test standards. The two most importantperformance characteristics are strength and serviceability.

Fire Incidents with I-Joists

Specific fire incident reports indicate that when directly exposedto fire (unprotected), the loss of strength of I-joists often occurs

in conjunction with burn-through of floor sheathing. Within the I-joist itself, the web is consumed first (because of reducedmass). Once the web is consumed, the bottom flange is nolonger attached to the joist and falls from the system. Numerousfire incidents have been reported where the only remainingstructural components in the floor system were the top flangeand floor sheathing. The resulting floor systems, whileremaining intact, had over 12" of deflection. Similarly, manyreports indicate that firefighters either felt a floor become softor spongy or visually observed deflection and exited thestructure.

Fire Resistance of Structural Composite Lumber(SCL)

SCL is a modern alternative to large-section solid-sawn andglulam timbers. In general, SCL and solid-sawn wood productsburn similarly in a fire. As with solid-sawn wood, the size and


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mass of SCL has an effect on fire resistance. A studyconducted at the USDA Forest Products Laboratory involvingseveral types of SCL (laminated veneer lumber, parallel strandlumber, and laminated strand lumber), showed that charring ofSCL products was comparable to solid-sawn wood and glulam.These results support the use of fire resistance calculation

design procedures developed for solid-sawn wood and glulamfor SCL as well. (White, 2000) The adhesives used in the SCLproducts tested in this study were polymeric MDI and phenolics.

General Thermal Degradation Information

Phenolic adhesives are temperature-resistant polymers andyield high amounts of char during pyrolysis (Knop). The thermaldegradation of phenolic adhesives can be divided into threestages (Knop):

In the first stage, up to 300C (572F), the pol ymer remainsvirtually intact. The quantity of gaseous componentsreleased during this stage is relatively small (1-2%) andconsists mainly of water and unreacted monomers (phenoland formaldehyde) that were entrapped during curing.

During the second stage, from 300C to 600 C (572F to1112F), decomposition commences and gaseouscomponents (mainly water, carbon monoxide, carbondioxide, methane, phenol, cresols, and xylenols) areemitted. Random chain breakage begins to occur in boththe adhesive and wood.

In the third stage, above 600C (1112F), carbon dioxide,methane, water, benzene, toluene, phenol, cresols, andxylenols are liberated.

Metal Deck Roof

Metal deck roofs most commonly consist of metal bar joists, which usually runacross the narrow dimension of the building, and metal decking that is laidperpendicular to the joists. In most cases, the

metal decking is spot welded to the joists.Large-area metal deck roofs consist of largesupporting beams that run across the narrowdimension of the building and bar joists thatrun perpendicular to the beams and parallel tothe long dimension of the building.


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Combustible Metal Deck Roofs (CMDR)

Built-Up Roofs (BURs)

Twenty firefighters were evacuated from a hot, dense smoke situationin a strip mall 60 seconds before the roof collapsed. The roof was a

Combustible Metal Deck Roof (COMR) generally known as a "built-uproof" (BUR), because of its layers of tar, insulation and roofinggenerally topped by gravel and supported by steel-bar joist trusses.

Built-up roofs (BURs) consist of multiple plies of roof felts laminatedtogether with bitumen. BUR material can consist of bitumen-saturatedfelt, coated felt, polyester felt or other fabrics. A surfacing is generallyapplied and can be asphalt, aggregate (gravel or slag), emulsion or agranule-surfaced cap sheet.

BUR is one of the oldest and most reliable ways of installing a newroof. It was first known as composition roofing and started in the1840's. BURs come in two basic types asphalt and coal tar andthree basic components which are layered on a lightweight roof coverof either Q-decking or OSB.

Waterproofing component

Reinforcing component

Surfacing component which is used to protect the othercomponents from the elements.

Many different types of materials are used in built-up roofingsome examples are:

Base Sheets

Asphalt-Coated OrganicBase Sheet Perforatedand Non-Perforated

Asphalt-Coated Glass FiberBase Sheet

Asphalt-Coated Glass FiberVenting Base Sheet

Felts and Fabrics Asphalt-Saturated Organic

Felt Coal Tar-Saturated Organic

Felt

Smooth-Surfaced AsphaltRoll Roofing


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Asphalt- or Coal Tar-Saturated Cotton Fabrics

Asphalt- or Coal Tar-Saturated Woven BUR Lap Fabrics Asphalt-Impregnated Glass Felt

Coal Tar-Impregnated Glass Felt

Thermoplastic Fabrics for built-up roofing

Bitumens

Asphalt

Coal Tar

Lap Cement aka Cold-Applied Liquid Adhesive,aka Solvent Based(Cutback) Asphalt

Surfacings

Gravel or Slag

Asphalt Roof Coatings Asbestos and Non-Asbestos

Aluminum-Pigmented Asphalt Roof Coatings Non-Fibered,Asbestos Fibered, and Fibered without Asbestos

Emulsified Asphalt Fibered and Non-Fibered

Mineral-Surfaced Asphalt Roll Roofing (Organic)

Mineral-Surfaced Asphalt Roll Roofing (Glass Felt)

The service life of a flat roof is dependent on many factors:geographical location and weather conditions, foot traffic, materials

used, conditions under which the roof was installed, slope of roof, typeof surfacing material, etc. Under ideal conditions, a 3-ply built-up roofshould last at least 15 years, a 4-ply should last at least 20 years, anda 5-ply should last at least 25 years. We have seen ten-year old 4-plyroofs that needed to be replaced and 20-year old 3-ply roofs that werestill functioning.

In the event of vertical ventilation the depth of the built up roof relatesto the climate and location of the building in question. In the west it ismore common to find 3-ply roofing due to the lower incidence of snow,rain, and inclement weather.

Once a size-up has been completed, removal of the built-up roof maybe accomplished by either the K-12 rescue saw or the Stihl chainsaw.Ideally, the entire built-up roof should be removed prior to performingvertical ventilation on the roof structure itself.


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Firefighting Related Information

When looking up in the interior, steel-bar joists and steel decking maybe present and appear to be a non-combustible void. It may beclassified as non-combustible when the potential of propagation of aroof fire may exist and pose a hazard to fire companies operating

above the fire.

If there is a built-up roof above, it is a very dangerous situation in theevent of a fire.

The burning contents of the building heats the steel deck.

The tar above begins to boil.

The gases form a bubble and cannot vent upward.

The gas vents downward through the joints in the steel.

The gas ignites.

The gas fire heats more steel deck.

The fire is now a self-sustaining roof fire, independent of the building'scontents, spreading in all directions. This situation requires only 800Fahrenheit for five minutes on the steel.

Some fires may show above the roof, but throwing water on the roof isnot productive. The tactic is to hit the underside of the roof with aheavy smoothbore stream to cool the steel from a safe location, andthus cut off the gas.

Do not attempt roof ventilation. A huge vent would be required. In afactory mutual test building, 100 ft x 20 ft, no contents, just the roof

burning, a 54 sq. ft. vent was needed. And there is serious danger ofcollapse. A six-firefighter roof team of the Dallas Fire Department fellinto the fire when the heated elongated bar joists pushed down the walland the roof collapsed. Fortunately, they were near the edge and wereretrieved.

Factory Mutual Type-I roofs and UL Classified roofs have much lesstar adhesive and are intended to not self propagate. These roofs arecommonly found in new construction.

Sprinklers that are installed to cool the steel overhead can stop the fire.Sprinklers below the ceiling will not cool the steel.

Built-up roofs should be a signal to the company officer to thoroughlysize up both the roof construction from below and above the fire.While commonly encountered in Type-II construction the built-up roofposes many hazards to the company officer operation above the fire.


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Concrete Roof

Concrete roofs are constructed in a variety of ways. The two most commonare made of lightweight concrete poured over metal decking or of precast"Double-T" panels. This type of roof provides a smooth, hard surface that isstructurally strong and highly resistant to fire, but it may be extremely difficult

to breach for ventilation purposes. These roofs exist in Henderson, with onerecent example being the M Resort.

Lightweight concrete roofs may be cut using a rotary saw with a masonryblade. Because it is difficult and time consuming to cut concrete roofs that areover 4 inches in thickness, they are often designed with built-in access panelsthat can be lifted out in an emergency. Using existing openings, such asbulkheads, ventilators, skylights, or scuttles, is the fastest way to create anopening in these roofs and may be the only practical way. Once again,thorough pre-incident familiarization will greatly speed the process ofventilating these roofs.

Modern Mansard Roof

This type of roof has characteristics of bothpitched and flat roofs. The perimeter of the roofconsists of steeply pitched sections thatsurround a flat roof area in the middle. Theseroofs are most commonly supported by bridgetrusses, and the same operational and safetyconsiderations apply to these roofs as to anyother pitched or flat roof, with a couple ofexceptions.

First, some modern mansard roofs are actuallyonly false roofs, each consisting of a wall (witha triangular cross section) that has beenadded to the perimeter of a flat roof foraesthetic reasons. This construction creates adepressed area behind the false roof that canrange from a few feet to several feet deep.


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Unsuspecting firefighters can fall from the top of this false roof onto the actualflat roof if visibility is obscured by smoke and/or darkness. Second, whenbuilding these false roof structures, an uninterrupted concealed space thatmay run the entire perimeter of the roof is often created. This arrangementcan allow fire to travel around the entire roof undetected. These false roofsusually extend beyond the exterior wall, creating an overhang that can

collapse if fire weakens the bracing on the original roof.

Hazards of Flat Roofs

Firefighters preparing to ventilate a flat roof should look for hot spots orsagging of the roof area prior to walking on the roof surface and should lookcontinuallyfor these signs during ventilation operations. The roof shouldalways be sounded before stepping onto it and repeatedly sounded whenfirefighters are moving about on the roof. Hot spots may be recognized bymelting, soft, or bubbling tar and by waves of heat rising from one area.Sagging indicates damage to the substructure of the roof assembly. Each of

these signs indicates severe heat and fire conditions directly below the roofand suggests that the roof may be ready to collapse, either partially or totally.Inspection holes can be cut to help firefighters monitor fire conditions. Crewsworking on flat roofs must exercise extreme caution if these signs exist ordevelop while work is in progress.

Overhangs are often added to flat roofed buildings to give the appearance ofa mansard roof. These overhangs form concealed spaces through which fireand smoke can quickly spread undetected.

Due to rising energy costs, solar panels on the roof are seen frequently than

in the past. These panels must ALWAYS be treated as charged, and underno circumstances should they be manipulated by firefighters.

Many buildings with flat roofs also have parapet walls that can be both ahazard and a help to firefighters during ventilation operations. These wallsmay extend from a few inches to several feet above the roofs surface. Highparapet walls create a potential fall hazard, and walls that are too low maycause firefighters to trip and fall over them. These will often need to beaccessed with the aid of the roof ladder located on the stick of the trucks. Itshould come within approximately one foot of the roof for ease of getting onand off safely. Before stepping off a parapet wall or the roof ladder on thebucket especially if the roof is obscured by smoke or darkness firefighters

should always sound the roof by striking it with the blunt end of an axe orother tool. This process will reveal the condition of the roof as well as thevertical distance from the top of the wall to the roof. Properly constructedparapet walls can help prevent the spread of fire from building to building andcan help prevent firefighters from accidentally falling or walking off the roof.Because the heights of parapet walls vary so much from building to building,firefighters must become familiar with those in their response districts throughpre-incident inspections.


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Venting Flat Roofs

As with pitched roofs, flat roofs should be vented as close to directly over theseat of the fire as is safely possible. Flat roofs may be vented by removingroof vents, cutting a large square or rectangular ventilation hole, cutting a stripor trench ventilation opening, or using some combination of these methods.

When smoke under pressure is issuing from a roof ventilator, the ventilatorshould be removed to facilitate the movement of the smoke and fire gases. In

some cases, it will also be advantageous to enlarge the opening by cutting themetal shroud down to the flashing and folding the shroud back. At least twosides of roof monitors should be removed.

If bubble skylights need to be opened for ventilation, they should be removedfrom their frames, and the panes in wired glass skylights should be removedor broken. Before breaking glass in skylights, interior crews should be warned.Firefighters should break a single pane first and then pause before breakingout the remaining panes. The pause will give firefighters who did not hear thewarning an opportunity to move out of the way or to alert the vent crew of theneed to delay breaking the remainder of the panes.

To create sufficiently large exit openings for efficient ventilation of buildingswith flat roofs, cutting ventilation holes may also be necessary. Many flat roofshave a thick covering of tar and gravel or other material that will need to be re-moved or cut before cutting the sheathing. An axe can be used to cut the roofcovering or to scrape away some of the gravel to facilitate cutting with a powersaw. Thick tar coverings tend to gum up chain saws, so a rotary saw may bea better choice.

Ventilation holes in flat roofs should be cut parallel to the rafters andperpendicular to the side walls of the building. After marking the perimeter ofthe opening to be cut, and working with the wind at their backs, firefighters

should start by making a cut across the leeward end. This should be followedby making parallel side cuts approximately 4 feet apart between the rafters.These cuts should start at the ends of the first cut and be made as long asnecessary to create an exit opening of the required size. The roof coveringand the sheathing may then be pulled back, as a unit or separately, with twopick-head axes, pike poles, or rubbish hooks. If it is necessary to break out asection of ceiling below the exit opening, a rubbish hook or the butt of a pikepole works well.


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Center rafter or louver vents may be cut in flat roofs in the same manner asdescribed previously, but with the addition of a fourth cut connecting the otherends of the side cuts. If it is necessary to cut a strip or trench vent, the louvervents may simply be extended from one outer wall to the other across the fullwidth of the building.

Arched Roofs

Arched roofs are found in Henderson, but modern construction is making this type ofconstruction more and more uncommon. One of the greatest concerns to firefightersis the infamous bowstring truss roof, which the Railroad Pass in District 81 currentlyhas. There are several other types of arched roofs which may be encountered, butwill not be discussed in this training. These include the ribbed arch roof and thelamella roof (geodesic domes).

Bowstring Arch Roof

The bowstring arch roof, commonly found in older bowling centers andsupermarkets, uses tie rods for lateral support and turnbuckles to maintainproper tension. The main supporting members are easy to locate from theoutside if the tie rods pass through the exterior wall to a plate orreinforcement. The chords of these arch members are usually laminated 2- x12-inch or larger lumber. The rafters (usually 2 x 10 inches) are covered by 1-x 6-inch sheathing and composition roofing material. The perimeter of thebuilding and the arch members are the strongest points.

This roof is normally quite strong because of the size of the lumber used in its

construction; however, bowstring arches have a history of early and suddencollapse when the tie rods are exposed to fire. The tie rods act to hold theouter walls together, so the walls can be pushed outward when the tie rodsfail, causing the entire building to collapse.


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Firefighters can estimate the hazards of bowstring truss roofs by the sizeof the lumber and the span of the arches. In trussed arch roofs, the lowerchord of the truss may be covered with a ceiling that forms an enclosedcockloft or attic space. These concealed spaces are a definite impedimentto effective ventilation and contribute to the spread of fire.

The single biggest hazard of all arched roofs; however, is the danger ofsudden and total collapse, often without warning. Due to this potential andbecause the rounded surface makes the use of roof ladders difficult, it isrecommended that personnel work only from aerial devices whenventilating arched roofs.

Venting Arched Roofs

Arched roofs should be ventilated at the top of the arch directly overthe fire or by a long, narrow strip vent along the centerline of the roof. Aconventional square opening can be cut perpendicular and adjacent toa main arch support, or a louver vent (which will probably be faster)

can be made. If a strip vent is to be cut along the centerline of the roof,a series of louver vents may be the best choice.

Sources:http://www.houstontx.gov/fire/firefighterinfo/ce/2001/August/vertical_ventilation.htm

Concrete Roofs

Concrete is not often used as a roof system but can be commonly found incommercial structures between floors especially in high rise buildings. The concreteis usually placed over corrugated metal but may also be a cast in place or a pre-cast

system. The concrete will be reinforced with either a wire mesh or rebar grid pattern.The concrete itself is usually a lightweight concrete allowing for larger spans betweensupport columns without sacrificing strength.

Here is an illustration of a typical concrete floor poured over corrugated metal. Thisparticular picture shows an insulation layer laid into the concrete.


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Concrete absorbs and disperses heat very well making it difficult to assess conditionsbelow you. A thermal imager may show hot spots depending on the thickness of thefloor. Sounding the floor is not a reliable tool in this setting. A more accurateassessment will come from the overall fire conditions.

How long has the fire been burning?

Has there been direct impingement on support columns? Are there any signs of degrading such as large amounts of cracking, spawling or

sag?

How thick is the roof?

The strength from this type of roof comes from a few things that must work in unisonwith each other. Unfortunately, failure from any one of these will cause catastrophicfailure of the whole system.

1. First, you have the very strong chemical bonds from the cement. Concrete

under high heat will cause this molecule to dehydrate and those bonds willbreak and essentially become a powder again.

2. Depending on thickness and span, concrete roofs will have some variation ofsteel reinforcement. Rebar, the most common concrete reinforcement, is verystrong under normal conditions. When exposed to high heat the rebarbecomes very pliable which may cause the floor to sag, break or even shearat the point of attachment to walls or support columns.

3. One of the most common construction methods for concrete roofs is a Q-decksystem. This has the corrugated metal underlayment supported by a truss

system, usually an open web steel truss. Again, this is a very strong systembut has a great potential for catastrophic collapse due to the steel failingduring the fire.

Cutting a hole for the purpose of ventilation should be a last resort. Depending on thethickness, reinforcing, and other support structures, this process could take up to anhour or more. Utilize existing structural openings such as skylights, ductwork orstairwells. If cutting is necessary, remember that the more holes that are made, theweaker the roof becomes. Try to incorporate existing openings into your cut.


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A general guide for the fire rating of a concrete roof or floor based on the thickness ofthe concrete.

ConcreteType

1

HOUR

1.5

HOURS

2

HOURS

3

HOURS

4

HOURS

Lightweight(SlabThickness)

2.5 3.1 3.6 4.4 5.1

Panelized Roofs

Panelized roofs or prefab roof panels are a fairly new construction method. It hasbecome popular for so-called green construction and is very energy efficient. Thebasic Structural Insulated Panels (SIP) are assembled with 5/8 OSB on two sideswith Styrofoam sandwiched in between (see Figures below). The foam is styreneand has varying thicknesses to provide R values.


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Are Structural Insulated Panels a fire Hazard?

"Modified SIP" contains flame retardant additives that improve itsburning characteristics compared to the SIP variety that can be

found in disposable cups and packaging materials. SIP products willprogressively distort, soften and melt when exposed to

temperatures in excess of 175F. As exposure temperaturescontinue to increase, combustible gases given off by molten residue

will ignite in the presence of an ignition source. This temperature

level, referred to as the flash ignition point, is approximately 700Ffor Modified SIP. This value may be directly compared to flash

ignition temperatures for white pine and Douglas fir of 500 F.

Unlike wood, however, MSIP makes a very small fuel contributionbecause it contains only about 3% combustion material by volume.

In addition, most building codes require interior wall and ceiling

surfaces covering foam insulations to provide a 15-minute rated firebarrier.

Firefighting Related Information

The attic is so well sealed it can mask any fire conditions that normallywould be seen from the outside.

Airtight buildings will increase the dangers of flashover and backdraft.

The roof systems do not need to have a truss system. They are not stableto work on.

The floor systems also do not have to have joists.

Videos:http://www.youtube.com/watch?v=bSUDBII-no0http://www.youtube.com/watch?v=_kvm2oOv3CA

Diagram of Typical Roof Panel


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Considerations for Ventilation of SIP roofs

If possible, use Horizontal Ventilation instead.

If you have to vertically ventilate on a SIP Roof, always work from thebucket to cut.


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Chapter 4. Solar Panels

Basic Design

A basic solar system consists of: The solar panels themselves, a combination box, adisconnect box, and an inverter. The panels all feed into a combination box. Thecombination box (which is almost always located on the roof) takes in all the energyand sends it to a disconnect box. The disconnect box takes the energy and thensends it into the inverter which converts the DC current into AC current. From there,the AC energy "pushes" into the structure's normal electrical system.

The combination box has fuses in it that come from the solar panels themselves. Ifthat box is accessed, all the fuses inside can be pulled and will "kill" anything after the

combination box. Remember, the panels are still live and have up to 600 volts inthem. If the energy is cut at the disconnect box, anything up to that box is stillenergized the solar panels, the combination box, the line going from thecombination box into the structure and into the disconnect box. The power companypulling the meter for normal service has no affect whatsoever on the solar panelsystem. It is all still live and has up to 600 volts of DC current. The only "good" thingwhen it comes to the disconnect box and the inverter is that they need to be co-located with the normal service panel for the structure and each should be marked asappropriate.

Even if it is nighttime and the solar panels have not been exposed to direct sunlight

for several hours, they still are energized and can kill a person. It is estimated that thepanels would need to be covered with an opaque tarp for 7-10 days before thepanels will "de-energize" down to minuscule levels.

Firefighter Concerns

Solar panels cannot be shut down - they are ALWAYS ENERGIZED. They areenergized with up to 600 volts of DC current. For example, a firefighter cannot put anax through them to open up a roof to vent that would mean putting the ax through600 volts. If fire is infringing upon solar panels on the roof, it will compromise theintegrity of the panels. This means 600 volts of live electrical energy. What should

everyone know not to do when there is live electrical energy present? Dont putwater on it! The roof may burn through and the panels may fall into the structure; but,unless the panels are destroyed (de-energized) by the fire and/or falling into thestructure, they still have the potential to be live. They must ALWAYS be treated aslive because they still have the potential of carrying 600 volts of DC current.

truck company officer study notes 1st edition june 2009

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