This document has been electronically signed and/or sealed in accordance with the applicable State Board of Professional Engineering requirements.

Fort Bend ISD Fire Origin and Cause

3130 Lake Olympia Parkway Missouri City, TX 77459

Client File: COMP2014083502 Haag File: 0214000076-247

Texas Association of School Boards 12007 Research Boulevard

Austin, TX 78759-2439

Attention: Ms. Wanda Johnson

May 16, 2014

May 16, 2014

Texas Association of School Boards 12007 Research Boulevard Austin, TX 78759-2439 Attention: Ms. Wanda Johnson

Re: Fort Bend ISD Fire Origin and Cause 3130 Lake Olympia Parkway Missouri City, TX 77459 Client File: COMP2014083502 Haag File: 0214000076-247

Complying with your request, we inspected a 2004 Thomas bus at the captioned location to determine the origin and cause of a May 6, 2014, fire that occurred in the vehicle. This report presents an overview of our May 10, 2014, inspection as well as our specific conclusions and pertinent supporting data. Should you require additional detailed information following review of this document, an expanded report with in-depth discussion and additional supporting documentation can be written. This engineering report has been written for your sole use and purpose, and only you have the authority to distribute this report to any other person, firm, or corporation. Haag Engineering Co. and its agents and employees do not have and do disclaim any contractual relationship with, or duty or obligation to, any party other than the addressee of this report and the principals for whom the addressee is acting. Only the engineer who signed this document has the authority to change its contents and then only in writing to you. This report addresses the results of work completed to date. Should additional information become available, we reserve the right to amend, as warranted, any of our conclusions. Description/Background The involved bus (#444) is identified by vehicle identification number (VIN) 1T88S4D2541138941 and carries Texas license 860-446. The vehicle is owned, operated and maintained by Fort Bend Independent School District and is parked at a fenced facility located at 3130 Lake Olympia Parkway in Missouri City, Texas.

Texas Association of School Boards Page 2 Fort Bend ISD May 16, 2014 Missouri City, TX Haag File: 0214000076-247

A fire occurred in the vehicle May 6, 2014, while parked at Quail Valley Elementary. Reportedly, a teacher on the passenger load side of the bus first saw smoke in the area of the front wheel well and underside of the vehicle. The Missouri City Fire Marshal's office (Mr. Matt Rios) investigated the fire and concluded the fire originated in the engine compartment; the cause was undetermined. We understand from Mr. Bob Bongio, shop foreman for Fort Bend Independent School District, the involved bus had not experienced any significant electrical problems and was most recently repaired (air intake hose) on May 5, 2014. The electrical system in the bus includes two lead acid storage batteries installed in a compartment behind the driver side front wheel well. Conductors from the batteries are routed along the vehicle frame and to the engine starter, then to other electrical panels at the front of the vehicle and the driver side of the vehicle. Electrical conductors energized when the key is in the OFF position include the main conductors connected to the engine starter. Most of the electrical wiring in the vehicle is not energized when the key is in the OFF position. Inspection Our May 10, 2014, inspection included discussions with maintenance personnel and examination of the involved and exemplar vehicles. Photographs were taken, and some are appended for review. Overall inspection revealed fire and heat damage to the upper front portions of the bus, including the engine compartment and interior front. Damage included melted and burned combustible materials such as plastics and wiring insulation. The driver side of the engine compartment was more damaged than the passenger side, and the damage was more severe at the bottom (underside) of the engine compartment compared to the top of the compartment. The batteries housed in the compartment behind the driver side front wheel well were not damaged. However, the main battery conductors (stranded copper) did display evidence (melted insulation) of high amperage draw. We traced the main conductors from the batteries to the engine starter and noted heat damage (melted insulation) to the conductors increased at the starter and engine compartment. The main battery (positive) conductor was separated from the starter and hanging. The conductor also displayed evidence of electrical arcing activity from contact with a support bracket; the bracket had melted from electrical arcing activity. We continued tracing conductors from the engine starter, and discovered one conductor had apparently become fused to the vehicle frame. The location on the frame had a visible heat pattern (different shades of circular marks) that resulted from the electrical short circuit between the conductor and vehicle frame. We traced and examined other portions of the electrical system on the vehicle and found no other remarkable evidence of electrical activity. Our inspection also included examination of other exemplar buses (2004 Thomas). On one of the exemplar buses (#440), we observed and noted deteriorated protective sheathing on the same conductor we found fused to the frame of the involved bus. We also found an abraded area on the protective sheathing of another conductor near the engine starter.

Texas Association of School Boards Page 3 Fort Bend ISD May 16, 2014 Missouri City, TX Haag File: 0214000076-247

Discussion Results of our inspection (burn patterns and extent of fire damage) indicate that the fire originated at the front of the bus, specifically on the driver side of the bottom part of the engine compartment. This is consistent with the area identified by an eyewitness. The cause of the fire was an electrical malfunction that created a short circuit and sufficient heat to ignite wiring insulation and nearby combustible materials. We found evidence of electrical arcing activity (melted metal) on the main battery (positive) conductor from the battery to the engine starter, and on another large conductor between the engine starter and the electrical panel at the front of the bus. Both of these conductors are energized at all times. The main battery (positive) power conductor had melted a steel support bracket and become separated from the terminal on the engine starter. The other conductor appeared to have fused to the vehicle frame and created a visible circular heat pattern on the frame. Inspection of exemplar buses (specifically #440) revealed areas of deteriorated protective sheathing and abrasion of the conductors connected to the engine starter. Continued abrasion from vibrations during operation of the bus could compromise the protective sheathing and insulation on the conductors and lead to a short circuit similar to our observations on the involved bus. Conclusions Based on our inspection and the information discussed above, we have reached the following conclusions:

1. The fire originated at the front of the bus, specifically on the driver side of the bottom part of the engine compartment.

2. The cause of the fire was an electrical malfunction.

3. The electrical malfunction created a short circuit and sufficient heat to ignite wiring insulation and nearby materials.

Respectfully submitted, HAAG ENGINEERING CO. Haag Engineering Co. CA F-311 Expires: 06/30/14

John Z. Wlascinski, P.E., CFEI Texas License 82127 JZW/IHN:lea

 

 

 

 

Photographs

Fort Bend ISD

Missouri City, TX

0214000076-247

1. Overall front view of the involved (#444) bus.

2. Overall rear view of the involved (#444) bus.

Fort Bend ISD

Missouri City, TX

0214000076-247

3. Overall view of the engine compartment.

4. A clear heat pattern is visible on the lower left side of the engine radiator.

Fort Bend ISD

Missouri City, TX

0214000076-247

5. The batteries and main conductors of the involved bus.

6. Close-up of a main battery (negative) conductor that has melted from high amperage draw.

Fort Bend ISD

Missouri City, TX

0214000076-247

7. The main battery conductors are routed along the vehicle frame.

8. Visible damage to electrical conductors routed along the vehicle frame and near the engine.

Fort Bend ISD

Missouri City, TX

0214000076-247

9. Insulation is gone from most of the wiring adjacent the engine.

10. The main battery (positive) conductor is separated and hanging.

Fort Bend ISD

Missouri City, TX

0214000076-247

11. This wiring support bracket for the main battery (positive) conductor has melted from electrical

activity.

12. The main battery (positive) conductor placed near the melted support bracket.

Fort Bend ISD

Missouri City, TX

0214000076-247

13. The main battery (positive) conductor placed near the melted support bracket.

14. Close-up of electrical arcing activity damage to the main battery (positive) conductor.

Fort Bend ISD

Missouri City, TX

0214000076-247

15. The main battery (positive) conductor had separated from a terminal on the engine starter.

16. The main battery (positive) conductor had separated from this terminal on the engine starter.

Fort Bend ISD

Missouri City, TX

0214000076-247

17. Other damaged conductors near the engine starter.

18. Another view of other damaged conductors near the engine starter.

Fort Bend ISD

Missouri City, TX

0214000076-247

19. A heat pattern is visible on the vehicle frame.

20. Close-up of the heat pattern on the vehicle frame. The conductor appears to be fused to the

vehicle frame.

Fort Bend ISD

Missouri City, TX

0214000076-247

21. Another view of the heat pattern on the vehicle frame.

22. Wiring near the engine starter on an exemplar (#440) bus.

Fort Bend ISD

Missouri City, TX

0214000076-247

23. Deteriorated protective sheathing on an exemplar (# 440) bus.

24. Deteriorated protective sheathing on an exemplar (#440) bus.

Fort Bend ISD

Missouri City, TX

0214000076-247

25. Abraded protective sheathing on an exemplar (#440) bus.

26. Another view of abraded protective sheathing on an exemplar (#440) bus.