Bus Fire Report FINAL 08

PTSB SPECIAL STUDY

BUS FIRE ANALYSIS - PTSBINVESTIGATIONS 2002 thru 2006

Public Transportation Safety Board StaffPassenger Carrier Safety Bureau

December 8, 2008

Executive Summary

In 2007, the New York State Public Transportation Safety Board (PTSB) conducted a review of thecauses of previously investigated bus fires over a five year period (2002-2006). The reviewincluded 120 fire investigations conducted by PTSB staff. This report addresses significant trendsand, through the cooperation of an industry based committee1, provides recommendations to preventfuture, similar bus fires.

Although rider ship numbers are similar in 2002 and 2006, a 3.5% decrease in rider ship wasexperienced in 2004. PTSB bus fires experienced a spike in the number of occurrences in 2004,representing 41% of the total yearly investigations (34 fires out of 83 investigations).

---------------------------------1. An industry based review committee was formed to provide proper context to the report and recommendations. The

committee consisted of staff from MTA-NYCT (Steve Vidal, Charles Dagis, Scott Weinstein), CDTA (Tom M ckie),

MTA- IG and PTSB Board Member (Barry Kluger), NYSDOT (Ron Epstein), and PTSB (John Fabian). Special thanks

are given to these individuals, and to Steve Trudell and Matt Sokol, for their time and effort for provid ing statistical

information for this project.

In summary, the review identified trends indicating 59% of bus fires are caused by either non-maintenance random failures or non-maintenance manufacture design. An additional 28% were theresult of transit systems employees, followed by 13% unknown causes.

Known sources of fires were tied to two specific areas: electrical failures and high pressure lines orconnection failures. Electrical, including maintained and non-maintained equipment, accounts for60 of the 120 fires, or 50% of all fires in the study period.

The most frequently involved manufacturer was Orion, represented in 59 of 120 bus fires (50%),who also represents approximately 40% of the statewide fleet of buses in service.

The most common age of the bus involved in a fire is approximately 6 years old.

Report Recommendation Highlights

The review of bus fires from 2002-2006 has revealed that although most fires have been attributedto causes deemed either non-maintenance or random component failures, there is a great deal transitsystems can continue to do to prevent bus fire events.

Human failures still occur in areas such as : - improper repairs - neglect - lack of training - lack of supervisory oversight - failure to detect - lack of skill - bus operator, maintainer, or supervisor - improper policies and procedures

In order to reduce bus fires, transit systems must determine when pre-ignition conditions exist thatcan be corrected during the life expectancy of the bus. These conditions can exist from the very firstday the vehicle is on the property to the last month of its’ life span.

Specific Action by Responsibility:

Statewide Industry (in cooperation with NYSDOT)

PTSBFR08-1 - develop and task an industry based committee to provide feedback, support,information, and direction towards minimum procurement standards andrecommendations for future bus purchases aimed at reducing bus fires

PTSBFR08-2 -develop a statewide database of information on fires that includes causes offires, tracking related parts (by model, serial number and manufacture),evaluation of suppression system effectiveness, and statewiderecommendations to bus systems for improved performance

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PTSBFR08-3 - develop interface with industry partners such as NYSDOT, PTSB, APTA,NFPA, bus manufacturers, suppression system manufacturers, componentmanufacturers, and others involved in the prevention of bus fires

All Bus Transportation Systems (under PTSB jurisdiction):

Management

PTSBFR08-5 - provide direction and oversight thru policies, procedures, andtraining to reduce the occurrence of bus fires throughout the system,incorporating at minimum, the following recommendations:

Maintenance

PTSBFR08-9 - keep ignition points protected, covered, clean, and otherdebris away; engines clean of grease, oil, and other fuelsources for fires

PTSBFR08-12 -train technicians to properly diagnose a dangerous conditionand effect a proper repair; properly identifying and repairingleaking high pressure lines and chafing electrical wiring, thetwo most common sources of fires

PTSBFR08-13 - eliminate all areas of water intrusion

PTSBFR08-14 -understand new technology, such as particulate trapregeneration systems that operate at very high temperaturesand require special training to properly perform work on thesecomponents as well as updating PMI forms and procedures asneeded

PTSBFR08-17 - ensure buses that are overhauled or rehabilitated due to highmileage or hard service life are given quality controlinspections in areas where electrical cables, high pressurelines and connections, junction boxes, and other retrofitcomponents are installed

PTSBFR08-18 - use of quality OEM or equal replacement parts is highly recommended

PTSBFR08-19 - use quality control inspectors or supervisors to ensure workperformed on parts frequently related to fires are inspectedduring and at the completion of the task especially such areasas starters, generators/alternators, air conditioning units,wheel bearings, brakes, exhaust heat shields, turbo chargerheat shields, battery cables, and other related components

iii

Procurement/Rebuilds

PTSBFR08-20 - establish procurement standards requiring quality parts andvehicle components, along with fire resistant materials, andfire suppression systems

Operations

PTSBFR08-23 -ensure training of bus operators includes fire safetyprocedures and emphasizes the importance of passengersafety and immediate evacuation of the bus in a safe location,securement the bus along with dispatch notification

PTSBFR08-24 -ensure bus operator training and annual refresher includeearly detection and symptoms of potential fires such asleaking fluids (engine and wheels), low air in tires (especiallyduals), changes in gauge readings on instrument panel, loss ofdrive power, smell of overheating conditions, poor brakeperformance, lack of turbo power, etc

Safety

PTSBFR08-26 - conduct safety oversight thru competent investigations forcauses of fire incidents, disseminating the information, andimproving the policies and procedures based on what waslearned

PTSBFR08-27 - conduct ongoing quality control inspections to ensure the safety of buses in service

PTSBFR08-28 - ensure bus operators are conducting proper pre/post tripinspections as a critical aid for the mechanics in order toallow them to perform their jobs properly

Further study should be conducted beyond the availability of information found within the 120investigative reports of the PTSB throughout this five year period of history. As additional hightech, integrated technology is adopted into the day to day operation of transit systems, efficiency tooperate and ability to detect the inefficiency of safe operation of vehicles must grow continuously. In closing, the potential for catastrophic events that include human loss as a result of a bus fire makesit essential for government, industry and manufacturing to work cooperatively to ensure the safetyof all passengers, employees and the traveling public. The PTSB has remained vigilant, conductinginvestigations into causes and sources of bus fires for the past 24 years. Although the incidence ofinjury has been extremely low in New York, other locations in the US and the world haveexperienced horrific losses due to bus fires, demanding our continual oversight of our systems herein New York State. The review of bus fires from 2002-2006 has revealed that although most fireshave been attributed to causes deemed non-maintenance, random component failures, there is a greatdeal transit systems can continue to do in support of reducing bus fire events.

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Bus Fire Analysis: PTSB Investigations 2002 thru 2006

INDEX

Executive Summary .........................................................................................................................i

Introduction .....................................................................................................................................3

PTSB Fire Criteria ..........................................................................................................................4

PTSB Criteria Notifications of Bus Fires 2002-2006 .....................................................................4

Table 2 - PTSB 2002-2006 Criteria Bus Fires ................................................................................4

Data of Fires Investigated between 2002- 2006 ..............................................................................5

Table 3 - 2002-2006 Comparison of Fires by Company .................................................................5

Table 4 - 2002-2006 Comparison of Fire Rate per Property............................................................6

Table 5- 2002-2006 Comparison of Fires by Month ......................................................................7

Table 6 - 2002-2006 Comparison of Fires by Week .......................................................................7

Table 7 - 2002-2006 Comparison of Fires by Day ..........................................................................7

Table 8 - 2002-2006 Bus Fires by Origin ......................................................................................8

Table 9 - 2002-2006 Bus Fires by Cause ........................................................................................9

Table 10 - 2002-2006 Bus Fires by Source ...................................................................................11

Table 11 - 2002-2006 Bus Fires by Condensed Source ................................................................11

Table 12 - 2002-2006 Bus Fires by Age of Bus... .........................................................................12

Table 13 - 2002-2006 Bus Fires by Manufacturer.........................................................................13

Table 14 - 2002-2006 Orion Bus Fires by Source ........................................................................14

Table 15- 2006 NYS Percentage of Manufacturer by National Fleet............................................14

Table 16- 2006 Composition of Fleet for CDTA, LIB, NFTA and NYCT ..................................15

Page 1

Table 17 - 2006 NYS Percentage of Revenue Miles by Manufacture ..........................................15

Table 18 - 2006 NYS Revenue Miles by Manufacturer for CDTA, LIB, NFTA and NYCT .......16

Findings..........................................................................................................................................17

Recommendations .........................................................................................................................19

Appendices ....................................................................................................................................23

Page 2

Introduction

The Public Transportation Safety Board, under legislative authority, has been investigating bus firessince 1984. Three hundred and forty four fires were reported and investigated by PTSB bus staffduring this 23 year period (1984-2007). Although there have been significant property damage losses,there have been very few injuries associated with these events, mostly from smoke inhalation andthose injuries have been minor.

The potential for catastrophic human loss is present at most if not all bus fire events that occur,whether they are happening in a congested city environment such as New York City or in a ruralatmosphere like Essex County.

In the Summer of 2007, the PTSB Board requested staff to review previous PTSB fire investigationsconducted during a 5 year period (2002-2006), a total of 120 events. A scope of study was presentedto the Board in July, 2007 outlining the areas to be analyzed for trends. Those topics included theentity responsible for the operation and maintenance of the bus, bus manufacture and age, geographiclocation of the event, cause of the fire, location of the fire on the bus, type of fire involved, autoextinguishing features, related injuries, and a review of other bus fire data sources. The conclusionof the report was to address significant trends and provide recommendations to prevent future bus firere-occurrences.

PTSB Fire Criteria

The PTSB Rules and Regulations, Section 990.10(a)(3), classify a bus fire as a mechanical failureaccident and requires notification to the PTSB staff of any fire that occurs in revenue service thatrequires passenger evacuation and response by a fire department regardless of whether or not injurieswere incurred. The required reporting system under Section 990.10(b) establishes 90 minutes toreport the incident to PTSB staff. Written notice is required within 48 hours unless otherwisespecified by staff. PTSB staff are dispatched to investigate the incident and report the findings tothe Board.

PTSB Criteria Notifications of Bus Fires 2002-2006

Within the 5 year period selected for the database for this review (2002-2006), the PTSB staff hasinvestigated 120 PTSB criteria bus fires. These events have all occurred involving recipients ofStatewide Mass Transportation Operating Assistance (STOA) money. Receipt of STOA places thesystem under the jurisdiction of the PTSB. Each event is assigned an investigator and tracked by acase number. The investigation generally includes an inspection of the scene and the bus, aninterview with the driver and any witnesses, and a full review of all records including preventive andcorrective maintenance, pre and post trip inspections, recalls or retrofits, and any relative manufactureinformation. The goal of the investigation is to determine the cause of the fire and related fuelingsources, and to ensure that the company has taken the appropriate measures to prevent other busesfrom the same fate.

Table 2

Data of Fires Investigated between 2002- 2006 Fire incidents are reported under the definition of mechanical failure accidents. Reviewing acomparison of criteria accidents over this period of time, fire investigations have occurred at a lowof 17% in 2002, to a high of 40% in 2004. Looking at a five year average, fires represent 28% of theyearly number of PTSB investigations.

Distribution of fires reported by PTSB bus systems from 2002 through 2006

The distribution of bus fires by property during the study period, 2002 through 2006, includes 25 bussystems located throughout NYS; 61% upstate and 39% downstate (12 county metro region). Itincludes authority 30% (7 of 25), municipality 26% (6 of 25) and private 44% (10 of 25) operatedsystems. The most number of fires investigated associated with an individual bus system involvedthe MTA-NYCT with 51 occurrences, and the least (not including those with no fires) was oneincident involving seven different systems; TCAT, City of Oneonta, Intercounty Motor Coach,Greater Glens Falls Transit, Centro, Jamiaca Buses (now MTA Bus Co), Dutchess County LOOP,Chemung Tranist, and Adirondack Transit Lines. The remaining 95 systems did not report any fires.

Table 3During the past five years, 85% or 102 of the 120 fires occurred with a bus operated by a public

authority. Although there are only 6 public authority systems operating within the State; MTA(MTA NYCT, MTA Bus Company, MTA Long Island Bus), CDTA, Centro, RGRTA, and NFTA,data includes NJT (New Jersey Transit) who also operates buses in NY. These authorities operatea total of approximately 8,840 buses. This represents about 81% of the 11,000 buses operated underthe jurisdiction of the PTSB statewide. The remaining 7% and 13% are operated by municipal andprivate carriers respectively. The correlation of public verses private system type does not appearto reveal any unusual trends.

Large systems operate bus fleets in excess of 200 buses. Medium systems operate from 25 to 199buses in their fleet and small systems operate less than 25 vehicles. On average the large systemsgroup experience 21.1 fires yearly (106 total fires), the medium group 1.6 fires per year (8 total fires)and the small groups average 1.2 fires per year (6 total fires).

Due to the vast differences in fleet sizes and revenue miles performed by each system statewide, thefollowing table compares the number of buses in the fleet, the number of revenue miles traveledduring the study period and the number of bus fires experienced during the 5 year study period. Table provides a normalized bus fire rate of occurrence for the period 2002-2006.

Table 4

Table 5.

The review of fire incidences by month over the past5 year period, shows a random distribution ofoccurrences with a high of 15 in September and alow of 7 in December. The average number of firesin a month on a yearly bases is 2.

Table 6

The distribution of fires throughout the week on a 5year average reveals the lowest 5 year average isSunday at 5.8%, followed by Saturday at 9.1%(weekend rates). This compares logically with therest of the weekday averages at 85%, given themajority of peak service is provided during theweekday.

Table 7

Following the same trend as the fires occurring by dayof the week, a logical trend exists comparing fireoccurrences with the highest and heaviest passengerservice times of the day (peak service); 7 - 10 am and3 - 5pm. During the hours of 2 - 4 am, there were nofires reported.

A review of bus fires by origin of the fire shows 70% of the 120 fires occurred in the area of theengine compartment. The area includes the engine and all components, transmission, exhaust,wiring, hoses, fluids, turbo charger, etc, but does not include the AC unit (listed separately). Theother 30% of fires originated in six other areas as described below.

AC Unit: includes the air conditioning unit, fan, motor, electrical and fluid lines, and belts.

Undercarriage: includes the area underneath the bus, fuel tank, hoses, air lines, wheel bearings, airbags, suspension components, steering components, booster heaters, and air dryers.

Tires: includes tires, wheels, seals, lugs, etc.

Roof: includes top extension of exhaust (including exhaust after treatment devices), lights, roofhatches, destination sign exterior, etc.

Brakes: includes all air and hydraulic brake components.

Interior Bus - Passenger Compartment: includes seats, flooring, bus drivers compartment, doors,wheel chair lift and seating components, lighting, wiring, ballasts, cameras, video devices, destinationsign interior, and other interior devices.

Table 8. Breakdown of fire origin based on location of the fire on the bus.

An analysis by cause of the 120 fires within the study provides 9 specific areas of causes that providesa very clear trend. The two most frequently occurring categories are “non-maintenance randomfailures” and “non-maintenance manufacture design”. The combination of non-maintenance causesrepresents 59% of all fires over the period of the last 5 years. Random failures are parts orcomponents that internally fail or are not required to be maintained during preventive maintenanceactivities. Design issues are those fires that include improper routing of cables or hoses, orinaccessible components which require service or inspection activities. This is significant to offerthe opinion that the transit systems were responsible for only 28% of the fires occurring on theirbuses. In true numbers this represents 36 bus fires within the study period or an average of 7.2 firesper year associated with the failure of the transit system’s employee responsibilities overseeingapproximately 11,000 buses statewide. Where the transit system was held responsible, 17 times(14%) it was determined the lack of skill of the mechanic was the probable cause, 8 times (6.6%)failure to detect, 4 times (3.38%) lack of training, and 1 time (0.9%) lack of skill of the bus operator.Supervision was held responsible in 6 of the 36 bus fire events (5%).

Table 9.

Events by Source

Evaluation of fire events by source of the fire provides identification of the individual areas whichwill be suspect in future fires. Those areas typically either contain a source of fuel or a source ofignition. Fuel sources include diesel or gasoline, hydraulic oil, coolant, and contaminated air.Ignition sources typically include the engine, turbo-charger, exhaust, electrical wiring or connections,brakes and tires. Table 13 provides a breakdown of both ignition and fuel sources. The highestnumber of fires has been a result of compromised ignition sources, specifically electrical in nature,representing 50% of all bus fires. This number includes both maintenance related and non-maintenance components. The most common issue of an electrically ignited fire is a ground shortcondition. These mostly occur when coated, hot wires chafe against a metal surface and wear to thewire, creating a short to ground. The wire is supercharged and overheated, sometimes arcing like awelder. The heat and arcing can either start the wiring on fire or surrounding materials or cut throughhigh pressure lines, supplying an atomized fuel resulting in a substantial fire event. High pressurelines are the second leading source of fires. High pressure allows liquids to atomize into a vapor andflash ignite much more easily than the substance as a liquid. Any of the pressurized lines can be asubstantial source of fuel for a fire. Fuel lines and hydraulic oil lines are manufactured to withstandyears of service in the engine compartment, but when failures occur, through chafing, leaking fittings,or catastrophic failures, the results can be a fire that has a fuel supply sufficient to create a very hot,fast burning fire that can completely destroy the bus. Several PTSB investigated events involvedbuses burned from the engine to the driver’s compartment, with only a skeleton frame in between.These fires spread quickly throughout the passenger compartment due to the combustion ofconstruction materials and flow of super heated smoke through the ventilation system of the bus. Additional fire sources can be overheated brakes, defective wheel bearings, and under-inflated tires.Tires pose a serious threat to a fire when driven on in an under inflated condition. This can occur atany tire position, but mostly occurs at the dual wheels where one tire is properly inflated and the otherin a low air condition or flat and rubs the road surface or the other tire until heat is generated to thepoint of combustion. Once combustion occurs, the tire is able to supply sufficient fuel to the fireto support a significant fire event. Tire fires are marked by heavy, black, toxic smoke and aredifficult to extinguish. Smaller on-board fire extinguishers are not capable of snuffing out a tire firewhich sometimes allows the fire to spread to the passenger compartment of the bus prior to the arrivalof professional fire fighters. Some auto extinguishing systems offer the option to install heat and firedetection along with extinguishing equipment (nozzles, etc) to the wheel well areas. These are mostcommonly used on over the road coaches. Engine compartment fire extinguishing equipment iscommonly used on transit equipment starting back in the 1990's. The addition of alternative fueledbuses with hotter running engines and various other types of alternative fuels used as propellant(CNG, methanol, propane, etc), have required the additional use of suppression devices in the enginecompartment. The PTSB investigations conducted on buses that have suppression systems on-boardhave revealed substantially less fire damage to the bus and less passenger compartment intrusion byfire on those vehicles. This is notable, as the less heat, smoke and fire that enters the passengercompartment, the less chance of passenger injuries.

Table 10

Table 11 condenses the sources of fires within the study period reflected in Table 10, and shows thelargest percentage of fires (51%) are attributed to “non-maintenance” sources. Electrical sourcesrepresent 22%, and high pressure line sources represent 16 %.

Table 11

Table 12. Fires by age of bus.

Fires by Age

Buses distributed throughout NYS which are purchased through a mix of Federal, State and localfunds, are scheduled to be replaced on a 12 year life cycle. Some systems have continued to operatetheir buses for as many as 20 years. This table exhibits a trend for buses involved in fires occurringabout the age of 6-7 years old. Approximately 28% of the total number of fires occur around 6 yearsof age. This trend may be attributed to failures that occur after engine rehab takes place, usuallyaround 5-6 years, and both electrical and high pressure lines and connections have been disturbed,replaced and/or retrofitted.

Table 13

Manufacturer of the Buses Involved in Fires

Table 13 identifies the manufacturer of the buses involved in each fire from 2002 - 2006. Thehighest number of involvements are Orion buses accounting for 61 of the total 120 events. Thisrepresents 50% of the total number of fires. The second most represented is RTS and MCI, both with8 (6.6%) involvements. The lowest (1%) are tied with 11 different manufacturers; Nabi, Nova,Prevost, Neoplan, Navistar, AI, Ford, Flxible, Cheverolet, Gillig, and Dodge. The Orionmanufactured buses are the most represented number of buses in the statewide fleet (approximately40%), as such represent the highest number of involvements. Table 14 is a breakout of this table,selected to review the fire sources of Orion buses since it represents a significant total number of fireevents.

Table 14

A review of Table 14 exhibits most fires involving Orion buses involve an electrical source, eitherconsidered maintained by transit staff or a non-maintenance item in 53% (31 of 58 events) of the time.Approximately 27% of the time, the source was a non-maintenance electrical item. The totalnumber of non-maintenance or unknown sources was 55% (32 of 58 events) involving Orion buses. Table 15, Exhibits the 5 most common bus manufacturers in New York State as a percentage of thenational bus fleet for the year 2006. Orion (36%) and Nova (20%) make up 55% of the total NYSfleet.

Table 15

Table 16

Table 16, represents the breakdown of the four most common manufacturers by the NYS buscompanies (CDTA, NFTA, MTA LIB and MTA NYCT) experiencing 85% of the fires occurring inthe study period, 2002-2006. Orion, representing 38% of the group (most common) has beeninvolved in 50.8% of the fires. Nova, representing 28% of the fleet (second most common) has beeninvolved in 5.8% of the fires. Orion and Nova together represent 66% of the buses in service atthese four authorities.

Table 17, shows the NYS percentage of miles of revenue service for the 5 most commonmanufacturers in the State fleet. Again, Orion (34%) and Nova (21%) represent the most revenuemiles for services provided at these four selected authorities (CDTA, NFTA, LIB, and NYCT).

Table 18

Table18, represents the 5 most common manufacturers’ revenue fleet miles by bus companies withthe most number of bus fires (CDTA, NFTA, MTA LIB, and MTA NYCT)

Note: There were d ifferent data sets used to provide information for this report. Some of the charts reflect data that was

extrapolated from national data sets based on information that was available at the writing of the report. Every

reasonable effort was made to provide valid information. The recommendations are based on sound principles of safety

management and are supported by the industry peer committee notwithstanding the information gleaned from the data set

Summary Findings

The review of the 120 bus fires investigated by PTSB staff and which occurred between 2002 and2006, have identified several of the most commonly known causes of bus fires. Two causes inparticular that have also plague bus fleets across the country and have the highest rate of occurrencesin NYS are those fires related to electrical and high pressure fluid line failures. In NYS, during thestudy period, 74% of all reported fires (89 out of 120 total) involved these two areas. Someoccurrences have involved both, where an arcing electrical short has cut into a high pressure line,resulting in a continuous ignition source (until the breaker cuts the power supply) and a substantialatomized vapor fuel source. Modern day bus engine compartments running in service under normalconditions are also experiencing increasing engine temperatures. Over the past 10 years some enginecomponents have common operating temperatures 100 degrees hotter than in past years. This has,in some circumstances, increased operating temperatures greater than the flash points of commonfluids necessary to run the engine. Flash points of vaporized fluids are lower than auto ignitiontemperatures. Obviously, a spark is “hotter” than any operating temperature and can lead to ignitionof any volatile leaking fluid. A static spark is capable of igniting flammable atmosphere if the arccan transfer enough energy to heat a sufficient volume of the gas to sustain combustion after the arcis extinguished. A table of comparison temperatures is provided in Appendix D.

Once a fire ignites, the temperatures can reach in excess of 1500 degrees and can consume almost allof the vehicle, including melting the metal framing and other support components. This can resultin a total loss of the bus, which may have been over $500,000 when new.

NYS Transit Industry Response

An example of the NYS transit industry responding to an issue can be seen it the events followingseveral fan motor fires which resulted in significant property damage. The issue was an “O” ringinside a hydraulically driven fan motor, which was a common source of hydraulic oil leaks. This unitwas the power drive for the cooling fan and was located above the engine. It was powered by highpressure hydraulic fluid and was prone to leaking after being serviced. Oil would escape from the“O” ring seal and contact the hot surface of the engine’s turbo charger. Since the turbo ran hotterthan the flash point of the hydraulic fluid, a fire was a common result. A request to the manufactureto re-design the part was not successful. In response, the maintenance department of a New Yorkbased transit company re-engineered the part to eliminate the torque on the “O” ring, and was creditedwith eliminating the occurrence of these fires due to the faulty application. A PTSB Safety Advisorywas issued to inform all systems statewide. The photos below provide a before and after view.

Other types of fluid related fires have been tied to failures of hoses, fittings and couplings. This canbe a non-maintenance catastrophic failure of the line, fitting or coupling or it can be a failure basedon a human error such as a mechanic using the wrong replacement item, an improperly rebuiltconnection or miss-routing the line through an area that results in chafing and eventual failure.

Before and after views of the

redesigned hydraulic fan motor. The

new assembly eliminated the need for

maintainers to position the “O” ring

and ended the rash of fires.

Figures 1 and 2

Electrical FailuresElectrical failures are common with all bus types. This includes a rise in the number of electricallyrelated incidences with newer buses whose operational demands have increased the number of feetof wire snaked throughout the bus, the demand loads, and extra vigilance required by maintenancestaff performing their monthly PMI services. This includes checking for chafing wires, proper wireand hose routing, adequate stabilization of cables and hoses using plastic P-clamps (instead of metal)or other technology, searching out leaks, and ensuring proper connections (double nuts to studswithout cracking the ceramic insulator, positive terminal boots, secure firewall connections). Thissupports the use of commercially installed fire suppression systems directly from the originalequipment manufacture. Several types and manufactures are available. They are generally installedin the engine compartment and sometimes the wheel well area. They deploy an extinguishing agentthrough nozzles located in strategic locations with automatic temperature or flame sensors and/or amanual dump valve switch controlled by the bus operator. They are effective in reducing the spreadof engine fires and therefore repair costs, but more importantly gain vital time necessary for a fullevacuation of passengers from the bus in a safe and orderly fashion. Since the widespreadapplication of suppression systems began in the early 90's, systems are experiencing fires that resultin less damage. The systems can be re-charged and put back in service multiple times. Mechanicsperforming PMI’s must also be properly trained to recognize other issues such as turbo charger pre-mature failures, wheel seals and bearing quality, brake component effectiveness and proper airing ofthe tires. These efforts must be in compliment to a proper pre-trip and post-trip inspection programby bus operators.

Tire Fire Involvements

Tire fire involvements, created by excessive heat from the rubbing rubber on the road surface oragainst the other dual tire can usually only be contained by professional fire fighters. The on-boardextinguisher (usually a 5 lb CO2 type) can be used during the ignition stages only, and generally areineffective to extinguish tire fires. Although suppression systems are available for the tire wheelwell areas, they are not always effective for extinguishing a tire fire. A different concept used toreduce tire fires is the use of tire pressure monitoring systems. These systems are more commonlyfound in over the road coaches and allow a driver to monitor tire pressures from the driver’scompartment. The driver is given a warning when tire temperatures reach a certain thresholdindicating danger. This is still considered fairly new technology and is not in use in many transitfleets.

Particulate Trap Filters

The latest growing frequency of fires has been occurring in the area of the roof where the exhaust pipeexits the top of the bus. Modern design particulate trap filters (new technology) that burn excesscarbon particulate, are located near the tail end section of the pipe. The temperatures are hot enoughthat the manufacture has installed heat shields or blankets to the pipes to avoid potential fires. If workis performed in the area, requiring a mechanic to remove and replace the shields but does soimproperly, a fire can result. This has occurred enough times that one transit system has relocatedthe left roof marker light and its wiring harness out of the way of the excessive heat in an attempt toeliminate this fire potential.

Report Recommendations

The review of a five year history of bus fires from 2002-2006 has revealed that although most fireshave been attributed to causes deemed either non-maintenance or random component failures, thereis a great deal transit systems can continue to do to reduce bus fire events. Human failures still occur in areas such as :

- improper repairs - neglect - lack of training - lack of supervisory oversight - failure to detect - lack of skill - bus operator, maintainer, or supervisor - improper policies and procedures

In order to reduce bus fires, transit systems must be vigilant, using foresight, in determining when pre-ignition conditions exist that can be corrected during the life expectancy of the bus. These conditionscan exist from the very first day the vehicle is on the property to the last month of its’ life span, whendeferred maintenance is very common.

Specific Action by Responsibility:

Statewide Industry (in cooperation with NYSDOT)

PTSBFR08-1 - develop and task an industry based committee to provide feedback, support,information, and direction towards minimum procurement standards andrecommendations for future bus purchases aimed at reducing bus fires

PTSBFR08-2 - develop a database of information on fires statewide that includes causes offires, tracking related parts (by model, serial number and manufacture),evaluation of suppression system effectiveness, and statewiderecommendations to bus systems for improved performance

PTSBFR08-3 - develop interface with industry partners such as NYSDOT, PTSB, APTA,NFPA, bus manufacturers, suppression system manufacturers, componentmanufacturers, and others involved in the prevention of bus fires

All Bus Transportation Systems (under PTSB jurisdiction):

Management

PTSBFR08-5 - provide direction and oversight thru policies, procedures, and training toreduce the occurrence of bus fires throughout your system, incorporating atminimum, the following recommendations:

Maintenance

PTSBFR08-6 - gain understanding which parts fail and why particular parts fail at anunexpectedly high rate

PTSBFR08-7 - track part model and serial numbers, and manufacturer name of failed partsresulting in fires

PTSBFR08-8 - eliminate as many fluid leaks as possible (fuel, hydraulic, coolant, oil, etc)

PTSBFR08-9 - keep ignition points protected, covered, clean, and other debris away; enginesclean of grease, oil, and other fuel sources for fires

PTSBFR08-10 - constantly inspect for chafing wires and hoses, track previously failed areas,and increase vigilance in those areas

PTSBFR08-11 - ensure proper training of mechanics and technicians to perform dutiesproperly and keep staff informed of findings of fire causes

PTSBFR08-12 -train technicians to properly diagnose a dangerous condition and effect aproper repair; properly identifying and repairing leaking high pressure linesand chafing electrical wiring, the two most common sources of fires

PTSBFR08-13 - eliminate all areas of water intrusion

PTSBFR08-14 - understand new technology, such as particulate trap regeneration systems thatoperate at very high temperatures and require special training to properlyperform work on these components as well as updating PMI forms andprocedures as needed

PTSBFR08-15 - keep all fire and heat sensors clean and in proper operating condition

PTSBFR08-16 - be vigilant to incorporate retrofit and recalls with proper corrective andpreventive maintenance practices.

PTSBFR08-17 - ensure buses that are overhauled or rehabilitated due to high mileage or hardservice life are given quality control inspections in areas where electricalcables, high pressure lines and connections, junction boxes, and other retrofitcomponents are installed

PTSBFR08-18 - use of quality OEM or equal replacement parts is highly beneficial

PTSBFR08-19 - use quality control inspectors or supervisors to ensure work performed onparts frequently related to fires are inspected during and at the completion ofthe task especially such areas as starters, generators/alternators, airconditioning units, wheel bearings, brakes, exhaust heat shields, turbo chargerheat shields, battery cables, and other related components

Procurement/Rebuilds

PTSBFR08-20 - establish procurement standards for requiring quality parts and vehiclecomponents, along with fire resistant materials, and fire suppression systems

PTSBFR08-21 - use non-metallic P-clamps and electrical wire retention and support devices

PTSBFR08-22 - consider upgrades of capacity of fire extinguishers for onboard use by bus operators

Operations

PTSBFR08-23 - ensure training of bus operators includes fire safety procedures andemphasizes the importance of passenger safety and immediate evacuation ofthe bus in a safe location, securement of the bus along with dispatchnotification

PTSBFR08-24 - ensure bus operator training and annual refresher include early detection andsymptoms of potential fires such as leaking fluids (engine and wheels), low airin tires (especially duals), changes in gauge readings on instrument panel, lossof drive power, smell of overheating conditions, poor brake performance, lackof turbo power, etc

PTSBFR08-25 - ensure dispatchers and road supervisors are competently trained to providebus operators proper direction in the event of a smoke condition - commonlyin the areas of the engine, tires, brakes, and dashboard; also how to accesspower cut off switches

Safety

PTSBFR08-26 - conduct safety oversight thru competent investigations for causes of fireincidents, disseminating the information, and improving the policies andprocedures based on what was learned

PTSBFR08-27 - conduct ongoing quality control inspections to ensure the safety of buses in service

PTSBFR08-28 - ensure bus operators are conducting proper pre/post trip inspections as theyprovide critical aid for the mechanics in order to allow them to perform theirjobs correctly

PTSBFR08-29 - provide fire safety information to system employees thru safety meetings,bulletins, refreshers, and ongoing outreach efforts

Further study should be conducted beyond the availability of information found within the 120investigative reports of the PTSB throughout this 5 year period of history. As more high tech,integrated technology is adopted into the day to day operation of a transit system, efficiency to operateand ability to detect inefficiency of safe operation of the vehicle must grow continuously.

Some new technologies have been beneficial to reducing fires. LED lights burn significantly coolerthan incandescent bulbs which can hold a temperature of over 700 degrees at the glass bulb. Also,best practices exist, for example, where one transit system replaces all hoses throughout the enginecompartment whenever an engine overhaul is completed. At a cost of $1300 to $1800 depending onmodel, the system has effectively eliminated hose failures relating to bus fires. Another system wasexperiencing brake caliper failures due to rusting and seizures, which eventually lead to overheatingand fires. The system determined it was necessary to use only one brake pad supplier which provideda superior part that resisted the effects of expansion due to overheating. Brake fires were eliminated.The application of tire pressure monitors could also be used, although this most probably would bemost effective for over-the-road coach systems. The transit industry has also begun to examine theuse of hydraulic fluids with higher flash points. The Federal government has been experimentingwith low and non-flammable fluids for many years in military and aeronautical applications. Usingthe knowledge others have developed in similar applications could save years of research. Onesystem in NYS switched from standard hydraulic fluid to motor oil, which has a higher flash pointand the company saw a reduction in fluid related bus fires.

In closing, the potential for catastrophic events that include human loss as a result of a bus fire makesit essential for government, industry and manufacturing to work cooperatively to ensure the safety ofall passengers, employees and the traveling public. The PTSB has remained vigilant, conductinginvestigations into causes and sources of bus fires for the past 24 years. Although the incidence ofinjury has been extremely low in New York, other locations in the US and throughout the world haveexperienced horrific losses due to bus fires, demanding our continual oversight of our systems herein New York State. The review of bus fires from 2002-2006 has revealed that although most fireshave been attributed to causes deemed non-maintenance, random component failures, there is a greatdeal transit systems can continue to do in support of reducing bus fire events.

Appendices

PTSB Bus Fire Scope of Study ........................................................................................................A

Previous Activities Regarding Bus Fires in NY ...............................................................................B

Common Temperatures Associated with Buses ...............................................................................C

PTSB Safety Advisory :MCI Bus Fires, Nov 9, 2005 .....................................................................D

PTSB Safety Advisory: TMC/RTS Fires, July 2003.........................................................................E

PTSB Safety Advisory: Blue Bird Bus Fires ....................................................................................F

Coach USA: Fire Bulletin ................................................................................................................G

MTA-NYCT Maintenance Directive; Artic.Buses, Starter Cable Chafing Concern, 2007 ...................................................................................................................................H

National Transit Database, Safety and Security Newsletter, Vol.3, Spring 2005 ..................................I

FTA National Transit Statistics - Injuries from Fires, 1998-2007 ....................................................J

USA Today, Article; “Most Bus Fires Unrecorded”, 2006................................................................K

PTSB 31 Form, Bus Fire Investigation Data Forms, 2002 thru 2006...........(available upon request)

PTSB Bus Fire Scope of Study Appendix A

Appendix B

Previous Activities Regarding Fires in NYPTSB Safety Advisories

The PTSB will issue a “Safety Advisory” to affected parties whenever an accident cause isidentified. Sharing the information may assist in preventing the occurrence of a similar event atanother location. PTSB staff on several occasions have worked with the federal and other stategovernments, or specific bus manufactures to disseminate information on fire causes.

Electrical Shorting

On July 15, 2003 (Appendix C), the PTSB staff issued a safety advisory alerting all transit busoperators under PTSB jurisdiction of an electrical shorting condition found on TMC/RTS busesthat lead to two different fires involving 1993 and 1994 buses. The specific issue involved a “P”clamp connected to wiring bracket which became fatigued over time and allowed a starter cableto chafe and ground to short. The issue of future fires was resolved by the addition of anintermediate bracket which voided the chafing of the starter cable to the engine cradle. No othersimilar fires were reported.

Motor Coach Fires

On July 8, 2005 (Appendix D), the PTSB staff issued an advisory after investigating two MCI,Model DL-3, 45 foot, motor coach fires. Each fire was similar in nature and involved theshorting of the light ballast in the overhead lighting in the passenger section of the bus. Thiswas particularly dangerous in that the bus had only one door at the front of the bus for quick exit(buses also had emergency windows, wheelchair door and roof hatches). However, the ballast islocated in the front of the bus just behind the drivers compartment and the area where the fireextinguisher was stored. Buses were found to be experiencing water intrusion thru variousareas and this resulted in electrical corrosion of the ballast components. As a precaution, allballast controlled lights in all effected MCI DL-3 buses were disconnected and through anagreement with the MCI, all buses were rewired and water intrusion issues were eliminated. The National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigationswas also notified and informed of the issue.

Chafing Wires

In the past, the PTSB staff has worked with a jurisdictional bus company where a bus fire hasoccurred to oversee that policy directives be issued internally to aid in the dissemination ofinformation and proper modification of maintenance techniques that may have been related to ahuman causal or failure event. An example of a maintenance directive, filed on March 9, 2007,by the MTA-NYCT states the specific concern of chaffing wires which ground to a short andcaused a fire. The directive, sent to all appropriate parties within the system, provides thenecessary corrective action, along with documentation including photos of the improper wiringand new wiring configurations.

Improper Direction From a Dispatcher

The PTSB staff also ensures that operation’s personnel are properly trained and providing soundadvice to bus operators when a situation occurs. Such as the situation with a Coach USA busoperator (Appendix D) who was given improper direction from a dispatcher to continue on hisroute after he called into the dispatcher complaining about a smoke condition. This resulted in asignificant fire event with no injuries. The company responded appropriately by issuing adirective to all affiliated systems in NYS and countrywide, retraining the dispatcher, andstressing the importance of stopping the bus immediately (in a safe location) anytime there is afire threat.

Bus Accident Investigation Training For Identifying Safety Hazards (BAITFISH)

The PTSB Bus Accident Investigation Training For Identifying Safety Hazards (BAITFISH)program includes a one day facility maintenance training program (BAITFISH 4). This is taught program experts to identify the specific areas of concern when NYSDOT inspects a bus forcertification purposes. The class also includes open discussion of industry standards and bestpractices to avoid maintenance situations that can lead to fires and road side breakdowns.

BUS FIRE DEMONSTRATION CONFERENCE

In 2003, the staff coordinated a conference with the New York Statewide Traffic AccidentReconstruction Society, centering around bus and rail accident investigation technologies. Thelast day of practical testing ended with a staged enactment of a bus fire. The 1996 GMC RTSforty foot transit bus was filmed as it was consumed by fire in less than four minutes.

The amount of materials inside thebus, such as seats, flooring, etc thatgive off highly toxic fumes as theycombust create an un-survivableenvironment.

During the fire demonstration it wasclearly established that the interiorof the bus was unsurvivable afterone minute of interior exposure tothe fire. The first photo showsheavy smoke after two minutes, thesecond and third photos show thequick progression to totalinvolvement in less than 6 minutes.

Appendix C

Common Temperatures Associated With Buses

Auto Ignition Temperatures of Fluids Commonly Used on Buses

Diesel Fuel 445 degrees

Engine Oil 450 degrees

Power Steering Fluid 420 degrees

Transmission Fluid 420 degrees

Hub/Gear Lubrication Oil 430 degrees

Coolant (50/50 mix) 900 degrees

Tires (smoldering) 450-500 degrees

Common Surface Temperatures of Engine Components on Buses in Service

Turbo Charger 610 degrees

Engine Exhaust 585 degrees

Exhaust Manifold 390 degrees

Disc Brake Rotor 420 degrees

Diesel Particulate Trap Filter 600 degrees (min.) Regen up to 1500 degrees

Bus Fire Report FINAL 08

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