Solar Photovoltaic (PV) systems-power systems that convert solar energy into direct current, which then supplies usable power-and their respective technologies are here to stay. The components of these systems are ever-changing and evolving as a result of continued research and development. Often, when creating safety mandates, building codes are sometimes slow to react or, conversely, too far in advance of these technological developments. As such, firefighter awareness on these issues and the knowledge of the basic operation of these systems are key in effectively mitigating a fire event involving solar PV systems. Departments must establish mitigation techniques, which include maintaining firefighter safety.
The foundation for firefighter solar PV system safety and awareness lies in having a basic understanding of the system’s principles as well as the configuration and operation of the system’s components. You cannot expect a firefighter to be an electrical engineer. However, you should expect that fire department line, safety, and training officers will provide firefighters with the proper solar PV system awareness training “toolbox” they need to deal with a solar PV system fire incident. The key is finding a curriculum that has accurate and reliable information to effectively deal with these systems. In addition to the explanation of the basic electrical design and operations of a solar PV system, fire service training should also include awareness related to the structural design philosophy of the system.
|(1) A parking canopy. (Photos by author.)|
I have attended a number of solar PV training courses and have found that they were taught by instructors who were not totally familiar with a solar PV system’s installation or operation. As a result, much misinformation has been presented or relevant information has been left out from these instructional sessions. To provide accurate and meaningful information, find instructors with solar PV knowledge and an electrical background. Just as valuable are fire service members who have had practical experience in dealing with a solar PV fire incident.
The foundation of solar PV firefighter safety and awareness is the basic understanding of the various systems’ configurations that firefighters may encounter on the fireground. Conduct training on a step-by-step basis and by describing the various types of systems, some of which follow:
- Residential rooftop.
- Residential rooftop with battery backup.
- Building integrated.
- Ground mount.
- Commercial rooftop.
- Parking canopy.
- Solar thermal (subtle differences to be explained).
In your training, describe these systems’ various components such as inverters, combiner boxes, required safety switches, modules, and so on, and explain their operation. Vital to this discussion is the safety switch operation, which is not one of the system’s disconnection but that of the system’s isolation. Demonstrating this isolation aspect will reinforce the idea to the fire service community that some parts of the system will always be energized.
Once the instructor satisfactorily conveys the foundation of a solar PV design and operation and the instructor feels confident that the students have grasped the fundamentals, then-and only then-can the discussion of firefighting tactics and strategy begin. As with all fireground operations, the health and safety of the responding firefighters are paramount.
|(2) A parking canopy. (Photos by author.)|
Numerous publications and organizational/National Testing Laboratory reports deal with these fire incidents. The safety instruction should include a list of the related safety publications that firefighters can use for future reference and refreshment of the subject matter. Much like building code requirements, as technology advances, the various test methods and analyses will forever change with it. To keep up, establish fire service refresher training, and schedule it every few years to keep pace with product development and the associated technological advancements.
Despite the best efforts of the solar PV industry, engineers/designers, fire/building code officials, and code-making authorities, solar PV fire incidents will continue to occur. The fire service can obtain valuable information from these professionals’ case studies, which are based on real-life experiences. The review of these incidents’ results, including cause and origin, will be made available as vital information in the advancement of firefighting tactics and strategy.
While developing firefighter solar PV safety and awareness training, consider incorporating the following three factors into your program:
- What to do before a fire incident (building identification, preplan, building code requirements, and so on).
- What to do during the fire incident (tactics and strategy).
- What to do after a fire incident (overhaul and fire investigation).
Before the Fire Incident
Your training should include preincident planning, a key of which is having the fire official develop a working relationship with the authority having jurisdiction responsible for the review of design plans and the subsequent issuing of permits. Through this coordination, you can compile an inventory of buildings featuring solar PV systems.
|(3) A ground array.|
From this inventory, you can develop the appropriate preplan and associated standard operating guidelines/procedures (SOGs/SOPs) as a preemptive measure in handling a solar PV fire incident.
In my state, New Jersey, a recent solar law was enacted that requires building owners to notify fire officials of the presence of roof-mounted solar panels. However, one- and two-family structures are exempt from this requirement. Additionally, the building must be identified as having rooftop solar panels by installing an exterior identification placard (similar to a roof/floor truss placard) at the building entry. The preplan should also include a list of special technical advisers (electrical engineers/contractors, and so on) ready for reference by the incident commander (IC).
During the Fire Incident
The training should include sufficient content, whereas the IC in charge of the solar PV fire incident has been provided with enough awareness training, giving him the required knowledge of whether to implement an offensive or a defensive firefighting strategy. The knowledge base should include providing a sufficient amount of information on how to safely operate around and extinguish a solar PV system during a fire incident.
|(4) A ground array.|
After the Fire Incident
Your training should include awareness of how to safely operate around a system during the overhaul and investigation phases. Once a solar PV fire has occurred, the involved structure and the solar PV systems’ components such as grounding, safety switches, overcurrent protection, stability, structural integrity, and so on are now compromised. The system will now be in a state that is subjected to abnormal conditions, which needs special consideration. Therefore, at the overhaul and investigation stages of the fire incident, the overhaul safety officer or fire investigation team may find it necessary to consult with on-call technical advisers and building officials to ensure that the involved systems are made as safe as possible.
When developing this course, you must consider the electrical as well as the structural systems. As previously mentioned, during the course of a fire, normal building and electrical systems are compromised; this is also true for the structural systems. Your course should explain that a structural engineer will determine the reserve capacity of a roof assembly (pounds per square foot), providing this information to the mounting system’s designer as required to design the rooftop racking system. Although the original design considers working within the parameters of the established reserve capacity, once compromised, the roof assembly may be subjected to an accelerated and premature roof collapse. Given the fact that a solar PV system is either mechanically attached or ballasted with block, collapse of the roof and racking/ballast must always be a concern.
|(5) A roof array.|
In many instances, solar PV fire safety instruction does not address the fire investigation phase. The same safety awareness required during the fire suppression stage must be continued at the salvage/overhaul and fire investigation stages. Fireground safety officers should remain on scene while these stages of the fire operations are conducted.
The course of instruction should also provide basic information the fire investigator can use to help determine the cause and origin of the solar PV fire. The basic fundamentals of fire investigation also apply to a solar PV fire incident. Was the fire started by the PV system? By an outside source? If it is determined that there are no outside sources of ignition, then it is an electrical fire. So, look for electrical causes. The same factors that apply to a standard electrical fire can also apply to a solar PV fire incident; they include wiring, grounding, ground or arc fault, and system maintenance. Consider all of these items when performing an investigation.
The block of instruction should be developed to include certain aspects of National Fire Protection Association 921, Guide for Fire and Explosion Investigation, particularly the aspect of a “systematic approach to fire investigation” and “arc mapping.”
|(6) A ballasted roof racking.|
Firefighter safety and health are the main concerns for any fireground or fire training activity. It is especially true for incidents involving solar PV. Solar PV is a type of electrical system that is unfamiliar to the fire service. Over time, with proper training, the fire service community will gain confidence and develop the strategy and tactics to mitigate these types of fire incidents. It is only through the establishment of quality training programs-with qualified instructors-that the fire service will gain confidence in its responses. The practical application of the knowledge gained will remove some of the apprehension that currently exists.
As with many aspects of firefighting, knowledge is a powerful weapon. In this case, it will help prevent and mitigate solar PV fires and, at the same time, maintain firefighter health and safety. As a result, the future looks much brighter for the fire service community when it comes to dealing with solar PV fire incidents. Quality training, which provides solar PV education and awareness, will replace fear of the unknown.
JOSEPH C. CAMAROTA, MIFireE, CFEI, IAAI, IABTI, is a 38-year fire service veteran. He is a certified fire and explosion investigator, a certified fire official, a building and electrical inspector, a firefighter, and an instructor in the state of New Jersey. He has a bachelor of science degree in electrical engineering and an associate degree in science in architectural design. Camarota is the electrical systems design director at Ray Angelini, Inc., an electrical and solar photovoltaic contractor.
Green Building Challenges for the Fire Service
UL Releases Report on Firefighter Safety and Photovoltaic Systems
Firefighter Training Drill: Photovolt-what?
Construction Concerns for Firefighters: Solar Collectors
Fire Engineering Archives