Hydrogen and First Responders

1. Virginia Clean Cities Webinar June 30, 2011 Hydrogen and First Responders Peter B. Sunderland Associate Professor Dept. of Fire Protection Engineering University of Maryland pbs@umd.edu

2. Acknowledgments • V. Molkov and the Hydrogen Safety and Research Centre at the University of Ulster. • NIST, under the technical management of J. Yang. • Fire Protection Research Foundation, under the technical management of K.H. Almand. • R.L. Axelbaum (Washington Univ.) and B.H. Chao (Univ. of Hawaii). • Students: M.S. Butler, C.W. Moran, N.R. Morton, V.R. Lecoustre.

3. DOE first responder training resources U.S. hydrogen vehicles Unique fire hazards Pressure relief devices Codes and standards Hydrogen firefighting Outline

4. DOE First Responder Training http://www.hydrogen.energy.gov/firstresponders.html

5. DOE First Responder Training http://www.hydrogen.energy.gov/pdfs/review11/scs015_elmore_2011_o.pdf

6. In 2003, President Bush announced an initiative to develop hydrogen vehicles and infrastructure. In 2003, Calif. Gov. Schwarzenegger announced plans for a “hydrogen highway” with 150 – 250 fueling stations by 2010. Government Initiatives

7. Annual U.S. production of hydrogen is 11 million metric tons, valued at $30 billion. The safety record is good. There are about 400 – 500 hydrogen vehicles in U.S. Most are in California. Average cost of a hydrogen fueling station is $1.5 million. There are 1100 km of hydrogen pipeline in U.S. U.S. DOE is researching the conversion of CNG pipelines for hydrogen service. U.S. Status

8. Hydrogen Fuel Cell Toyota FCHV Emergency Response Guide, 2006

9. Current Hydrogen Filling Stations77 total, 15 public (versus 170,000 gasoline stations) hydrogenassociation.org

10. Hydrogen vehicles can dramatically reduce U.S. consumption of oil. Challenges include high vehicle costs and lacking infrastructure. The predicted maximum numbers of vehicles are: - 2 million by 2020 - 60 million in 2035 - 200 million in 2050 By 2023, fuel cell vehicles will be cost competitive. Required funding by 2023 is US$ 55 billion by U.S. government and US$ 145 billion by industry. U.S. NRC Report (2008)

11. Vehicle Fire Statistics • USFA’s National Fire Incident Reporting System (NFIRS) • Fire cause and origin • Voluntary, but 42 states participate • DOT’s Fatal Accident Reporting System (FARS) • Fatal accidents only • Fire cause and origin not reported • Fuel type not reported • NFPA annual fire department survey • NFPA overviews (Ahrens, 2005)

12. Steel embrittlement. Lightest fuel, thus requiring the highest storage pressure. Highest volumetric leak propensity of any fuel. Permeation leaks. Smallest ignition energy of any fuel in air (28 J). Lowest autoignition temperature of any fuel ignited by a heated air jet (640 °C). Wide flammability limits in air (4 – 75% by volume). Highest laminar burning velocity of any fuel in air (2.91 m/s). Smallest quenching distance of any fuel premixed with air (0.51 mm). Highest heat of combustion (120 kJ/g). Dimmest flames of any fuel in air. Unique Fire Hazards of Hydrogen

13. Fuel Properties • In U.S. there are 30,000 fire departments and 1M firefighters, 75% of whom are volunteers.

14. A small leak develops in a H2 system, e.g., a H2 vehicle. The leak could arise from H2 embrittlement, H2 permeation, impact, equipment failure, or improper repair. The leak ignites from static discharge or heat. The leak burns undetected for a long period, damaging the containment system and providing an ignition source for a subsequent large release. Microflame Fire Scenario

15. 3.2 mm tube 6.4 mm tube 12.7 mm tube

16. SAE J2579 Leak Limits • Localized leaks must not be capable of supporting a flame. • The maximum localized leak rate is 5 μg/s (i.e., 3.6 sccm). • This equates to about 33 bubbles/s under water. • Total system leakage is limited to 150 sccm. SAE J2579, Technical Information Report for Fuel systems in Fuel Cell and Other Hydrogen Vehicles (2009)

17. CNG and Hydrogen vehicle containers require PRDs, primarily to protect against impinging fires. Modern composite tanks are good thermal insulators that weaken at high temperatures. Fuel pressure may not increase significantly during an impinging fire. A container may not be filled with fuel at the time of the fire. PRDs can be activated by pressure, temperature, or a combination. Most hydrogen, CNG, and propane containers are protected by temperature activated PRDs. Pressure Relief Devices

18. Mirada Bayonet PRD Rolander et al. (2003)

19. SAE J2579 Bonfire Test • Performed at initially NWP. • Involves hydrogen system, not entire vehicle. • Fire source must be 1.65 m long, with flames that impinge entire diameter. • Container is to be centered 100 mm above fire and in normal orientation. • Metal shields should prevent flame impingement onto the TPRD. • Thermocouple on container exterior must reach 590 C within 5 min of ignition. • TPRD must activate and prevent rupture. • Container cannot rupture before venting below 10 bar. SAE J2579 (2009)

20. Two CNG bus fires resulted in safe venting by the PRDs. A CNG Ford Crown Victoria in a fire experienced a container rupture in 2003. A CNG Honda Civic ruptured in 2007 (below). CNG Vehicle PRD Case Studies Seattle FD (2007).

21. Swain (2001) tests comparing hydrogen and gasoline vehicle fires (above). Hydrogen Vehicle PRD Test

22. SAE2578 Limits on Normal Hydrogen Discharges Scheffler (2008)

23. Hydrogen Vehicle Labeling SAE J2578 (2009)

24. Other Codes • There are at least 30 codes and standards applicable to hydrogen vehicles. • NFPA 2, “Hydrogen Technologies Code” (2011). • NFPA 2 extracted and updated material from about 10 other NFPA hydrogen codes. • NFPA 2 includes hydrogen generation devices. • NFPA 2 covers dispensing systems for gaseous and liquid hydrogen from NFPA 52. • Also under preparation is SAE J2919, Technical Information Report for Compressed Hydrogen Fuel Systems in Fuel Cell Powered Industrial Trucks.

25. Hydrogen Detectors • The traditional way to detect H2 flames is with a straw broom. • H2 gas detectors can detect down to 15 ppm (molecular sieve). • These require gas sampling and will not alert if flames consume the H2. • H2 flame detectors can detect a H2 flame of 50 mm from 30 m (UV/IR). • Thermal imaging firefighting cameras are effective. H2Scan Corp. Hy-Alerta Model 500 $3750 Det-Tronics (UTC) Model X3302

26. Hydrogen Firefighting • Listen for leaking gas. • Look for white clouds near liquid hydrogen spills. • Watch for heat shimmering. • Use outstretched brooms, hydrogen detectors, and thermal imaging cameras. • Prevent ignition sources (sparks, heat).

27. Hydrogen Firefighting • Stop the flow of hydrogen if possible. • Otherwise, allow flame to consume the entire gas supply when this can be done safely. • Protect nearby objects and fuels. • Extinguishing flames without stopping leaks can result in explosive mixtures. • Use a dry powder extinguisher or water.

28. Summary • The U.S. continues to invest in hydrogen vehicles and infrastructure. • Codes and standards are being revised to ensure hydrogen vehicle safety. • Hydrogen is not inherently hazardous, but requires specialized knowledge. • Extensive training materials are available for hydrogen first responders.