|Fossil Fuel Facilities - A Fire Protection Analysis Challenge|
Fossil Fuel Facilities - A Fire Protection Analysis Challenge
The demand for energy (and specifically, electricity) is at an all-time high as populations around the world grow. More communities are planned in remote locations where power generation is critical for infrastructure and business. Based on this need, multi-national companies are developing fossil fuel electricity generating power plants (natural gas, petroleum fuel, or coal) at a record pace.
While fossil fuel power plants are not new, modern facilities can be large and complex. Thus, it is up to the fire protection engineer to understand the risks and develop a fire protection basis of design according to an in-depth fire protection analysis (or performance-based design approach).
Fossil fuel power generating facilities pose a unique set of challenges for today's fire protection engineer. An engineer must take into account life safety and asset protection, as well as business continuity when developing a fire protection design strategy for a facility.
A power plant may include a diverse set of risks and areas such as (but not limited to):
There are a variety of codes and standards that might be applicable to a fossil fuel power generating plant. Depending on location, these can range from National Fire Protection Association (NFPA) codes and standards, local building codes, funding organization requirements, and insurance requirements such as Factory Mutual, Chubb, etc. It is critical that a fire protection engineer fully understand all risks associated with the power plant in question and the minimum code requirements before beginning an analysis. Based on the minimum requirements of applicable codes and standards, the fire protection engineer must determine any areas where it is appropriate to exceed the minimum requirements of the codes and then communicate that to the owner/client for approval.
Many prescriptive codes and standards exist that will provide fire protection engineers guidance as to the minimum level of protection required for some hazards. A Fossil fuel power generating facility can benefit from a proactive performance-based design approach due to its complexity, unique risks, and the economics of the installation of specific fire protection systems.
The first step in this performance-based design approach is executing a fire hazard analysis. The fire hazard analysis will determine areas where fire protection is required, what type of protection is needed, and how much protection should be provided. Fire protection requirements will focus on building construction, separation of hazards, ignition protection, process safety (e.g., control of releases) , and detection and suppression. Additionally, other information should be sought by the fire protection engineer such as emergency response support from an internal fire brigade or local fire department. The fire protection engineer should interview fire brigade members and local fire department personnel to determine their ability to address the hazards present. This will play a critical role in the fire protection system's design phase of the project (manual response vs. fixed protection).
Many facilities do not make use of a public water distribution system for firewater supply (many facilities outside the U. S. lack this infrastructure). Therefore, the fire protection engineer must determine the worst case fire water demand scenario as a result of a fire hazard analysis. This information will be utilized to properly size the water supply (i.e., body of water, tank, reservoir, etc.), fire pumps, and distribution system.
Based on results of the performance-based fire protection analysis, systems should be sized according to the facility's hazards. This can be a challenge if a fire protection engineer is designing based on the prescriptive codes and not a performance-based approach to fire protection engineering. That is, a fire protection engineer must take into account the type of hazard and determine the overall amount of water (or other suppression agent) required for fire fighting during and after an event.
Specific fire hazards, such as coal, require that water not only be budgeted for firefighting during a fire, but also for a post-fire event if the area re-ignites. If the water source and pumping capacities were not adequately designed, this could pose a problem for emergency responders.
Fire pumps should be designed with a vision for future expansion and redundancy. Many power generation facilities expand as demand requires; therefore, the fire protection engineer should consider future projects when sizing fire pumps and distribution systems. Moreover, a facility's utilities should be studied carefully to determine whether diesel- or electric-driven fire pumps should be used. NFPA 20 and NFPA 70 handbooks1,2 should be examined to fully understand what makes up a "reliable" electric grid for use of electric-driven fire pumps. Most power generation facilities should have at least one 100% redundant pump with alternate power generation, such as a diesel-driven fire pump.
Once the fire hazard analysis has been
completed, and thorough performance-based design criteria set, the fire
protection engineer should determine the best fixed or manual fire
protection system to complement the firewater distribution system. In
the case of power generating facilities, many choices exist, each with
its own pros and cons. These systems include, but are not limited to,
The systems listed above should be installed as part of fixed equipment, but some can be designed for manual operation if emergency response personnel are trained to combat the hazards involved. One example is water spray systems that are connected to both flame-detection and manual pull stations for activation by process personnel and emergency responders. Another example is the use of foam via manual monitors by emergency response personnel responding to a fire where foam has been used in emergency response plans.
As part of the overall fire protection strategy of a power generating facility, one of the key features should be the fire- and gas-detection system. Although NFPA provides prescriptive guidance3 on where to install such detection devices, it does not approach the subject at a deeper level, such as recommending the execution of gas dispersion models to locate gas detectors, or fire and explosion models to locate flame detectors. That is, it is up to the fire protection engineer, through the performance-based analysis, to determine what detection device should be utilized and where. The key component of a fire and gas detection system is rapid detection and its logic.
A cause and effect matrix should be developed that sets forth the chain of events based on the activation of certain detection devices. For example, if two out of three flame detectors initiate near a boiler, the logic in the system may start the fire pumps and subsequently a water spray or other equivalent system.
Fossil fuel power generating facilities create a unique challenge for fire protection engineers. Life safety is always the number one priority, but fire protection engineers must take into account business continuity and asset protection when developing a fire protection strategy. Merely relying on prescriptive codes and the minimum required by the Authority Having Jurisdiction may not be sufficient depending on client needs and location of the facility. Thus, the fire protection engineer must execute a fire hazard analysis and performance-based design before specifying any solutions. The final goal is to keep people safe and the lights on.
Marcelo D'Amico is with Orcus Fire Protection LLC.