# Fire Safety Risk Analysis of Conventional Submarines
## 4 Fire Safety Risk Considerations--Technology Review
### Fire Risk--Hydrogen Fuel Cell
#### 4.4.4. Technology Maturity  
Hydrogen fuel cells have seen extensive development and application in a variety of industries including the energy and automotive sectors [64]. Over the last decade, PEMFCs have been used on submarines in service with German, Italian, Israeli and Russian  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Component** & **Failure** & **Effect** & **Consequence** \\ \hline Hydrogen distribution & Failed valve, gasket, seal or flange & Reduced or loss of hydrogen supply to fuel cell, release of hydrogen gas & Loss of fuel cell power, build-up of hydrogen gas and ignition leading to explosion/fire, or jet flame stemming from leak leading to fire & Loss of fuel cell power, embrittlement and possible failure of components exposed to cryogenic liquid, oxygen enriched atmosphere leading to ignition of surrounding materials and explosion/fire \\ \hline Feedstock distribution & Failed valve, gasket, seal or flange & Reduced or loss of feedstock supply to reformer, release of hydrocarbon fuel in the form of a drip or spray & Loss of fuel cell power, spray of flammable liquid onto hot surface or accumulation of flammable liquid leading to ignition and fire \\ \hline Reformer reactor & Failed pipe/channel & Reduced or loss of hydrogen supply to fuel cell, high or low pressure release of heated feedstock, steam and hydrogen & Loss of fuel cell power, spray of flammable liquid onto hot surface or accumulation of flammable liquid leading to ignition and fire \\ \hline \hline \end{tabular}
\end{table}
Table 4: Hydrogen Fuel Cell System Failures Leading to Fire.  
Navies [65], and could be considered to be a relatively proven submarine technology. A Siemens PEMFC is shown in Figure 11.  
Steam reformers have been used in large scale hydrogen production or fuel processing for fuel cells for many years now with methane the most popular choice of feedstock. This technology has been successfully developed and integrated with fuel cells using gaseous and liquid feedstocks for smaller applications including stationary power sources, road vehicles and military applications [64].  
In terms of application to conventional submarines, steam reformers have not yet seen integration into a submarine, and hydrogen fuel cells have not yet been integrated into large conventional submarines of 3000 tonnes displacement or greater. In a drive to develop fuel cell based AIP for larger submarines, a number of companies have been developing PEMFC-reformer systems for submarines. TKMS have successfully integrated a methanol reformer with the Siemens FCM120 hydrogen fuel cell in a land-based test facility. The complete solution reportedly completed more than 1500 h of successful operation. As of mid-2015, the system is in the process of being submarinised before further land-based testing [55]. The proposed submarine module is shown in Figure 11.  
Naval Group Australia or French Directorate for Naval Construction also reported their development and successful land-based testing of a similar AIP configuration [59] and Navantia completed designs for a bio-ethanol fed fuel cell AIP solution, to be integrated into the S-80 submarines and in service from 2016 onward [63].  
In summary, steam reformer and fuel cell technology has seen extensive use and integration in a variety of industries, however whilst there has been extensive development and testing for submarine-based systems, the PEMFC-reformer AIP configuration currently has no proven service history on a submarine.