Executive Summary
The case of the warehouse fire allowed learning about structures and elements required for ensuring safety in commercial and industrial buildings. It has demonstrated what type of weaknesses fire detection, protection, and suppression systems may have if the design and maintenance procedures fail to correspond with regulations. Studying topics like fire dynamics, properties of different substances, as well as ways of handling and organizing them, allowed developing recommendations for improving safety in the re-built warehouse.
Water supply appears to be one of the core elements in the entire system. Characteristics such as flow from several directions, grid-type piping, and a network of valves allow ensuring pressure, quality, and quantity required for internal elements. Having a properly functioning fire pump is also very significant, as it determines whether the necessary amount of water would be supplied to the system. In-rack and ceiling sprinklers should be utilized in warehouses of this type to ensure a dense coverage of fire control and suppression activities. Water-based systems should be supported with those using foam, CO, and other substances, as there are flammable liquids and aerosols stored on racks. Smoke control strategies are also recommended to protect occupants from toxic gases.
Much needs to be improved to protect and educate workers regarding fire hazards. Audible alarms should provide clear voice directions on how to act in case of an emergency. Some employees should be trained as fire brigade members that would be able to mitigate fire before it fully develops. The paper provides references to codes and standards that may be utilized in the future when designing a fire detection, protection, and suppression system for creating a safe working environment.
Fire Pump Choice
Choosing a proper fire pump requires an understanding of the facility’s building components and stored materials. In the reviewed case, large amounts of cardboard, cooking oil, plastic bags, and other combustible items allowed the flame to spread quickly, and the existing sprinkler system failed to control it from the start. Partially, it happened due to the low water pressure, which is a direct result of a foreign-made fire pump not functioning correctly. The issue may have been caused by the air trapped in the system due to using elbows on the suction side, which was prohibited by the NFPA 20 (National Fire Safety Association, 2019c). Also, the case study claims that there was no power supply due to flooding in the area. If the pump was driven by an electrical engine, this could have been the cause of the malfunction.
The new system would require appliances that would not rely as much on external factors. Regarding the mentioned issues, the best choice for the warehouse reconstruction would be to install a horizontal split-case fire pump (Brakhage, Abrams, & Fortney, 2016).
The water supply comes from the public system, providing initial pressure so that there is no need for a self-priming model. Moreover, the pump should be driven by an electric motor having a direct feed from a transformer (Brakhage et al., 2016). The warehouse should consider using a private generator to ensure power cuts will not interrupt its functioning. The single-stage pump should be enough for creating pressure for the facility like a warehouse, which is not too high. Finally, the new appliance must meet all NFPA 20 requirements for its kind to prevent similar malfunctions in the future.
Ethical Dilemmas
It may seem at first glance that the foreign-made fire pump was a right versus the right ethical decision. The international regulations allowed using it, which could mean that it had been tested and considered safe in many countries. In such a case, a fire protector engineer would face a dilemma of short-term versus long-term, as explained by Kidder (2005). If the former was chosen, people could go to work as the warehouse would re-open on time. After all, since the foreign-made fire pump was internationally approved, it provides a substantial degree of safety. Yet, in the long run, there might be issues associated with it, so it would be right to wait and install the mechanism manufactured locally.
However, the foreign-made fire pump must meet all the national requirements like those mentioned by the NFPA 20. If there is something in the mechanism that contradicts the local regulations, then the choice transforms to the issue of following the rules. It is possible that there are fire pumps made internationally, which do not require installing elbows on suction sides, as it was in the case, and such an option may be chosen for having the warehouse re-opened faster.
If there is a possibility of issues in fire pump operations, in the long run, a fire protection engineer must share this information with the facility’s owners. Honesty in communicating data and estimates is one of the core principles of ethics for this profession under the SFPE guidelines (Code of ethics for fire protection engineers, 2018). If there are potential issues of using a foreign-made fire pump, they should be fixed so that the safety of warehouse employees is not compromised.
Fire Detection, Protection, and Suppression Systems
Engineers working on the site’s reconstruction must take into consideration the problems that led to the incident. It is assumed that alarms and early detection of fire contribute most to the safety of people and to major loss prevention (Brakhage et al., 2016). High-rack storage might have created obstacles for smoke and heat detectors situated on a ceiling level, resulting in a signal not being sent to a FACU. Since the fire protection system was designed for a warehouse with non-combustible materials, it appeared to be ineffective for a place with piled flammable items covering its elements.
The high-rack storage of combustible materials made it more complicated for the automated fire protection system to work properly. However, the new technologies may become an answer to the issue. For example, an autonomous system is designed that uses UV sensors to send an alarm about an existing fire (McNeil & Lattimer, 2016). After the signal is sent, infrared imagery is utilized to locate it and to determine its size and dynamics. Another technology is based on the SMART sprinkler system, which allows detecting fire based on smoke and ceiling temperatures (Xin et al., 2017). After the calculations being made based on the heat data, sprinklers closest to the actual source are activated, which helps saving time and water resources.
Finally, a new fire detection system must incorporate effective tools for letting employees and visitors know about the hazardous situation. An audible alarm must be functioning, and the emergency paths and exists must be supplemented with lights that can be seen through the smoke. This would help people unfamiliar with the warehouse’s construction plan to easily find the way out.
Fire Dynamics
The dynamics of fire are based on its elements and the character of each stage. The traditional fire behavior included four phases, being ignition, growth, fully development, and decay (Madrzykowski, 2016). At first, heat, fuel, and oxygen are required to start the reaction. Afterward, the fire grows in temperature until it reaches its maximum point and eventually turns into a fully developed stage. As one of the elements, fuel, for instance, is taken away from the reaction, the decay begins, and the heat decreases.
The fire triangle and the fire tetrahedron are helpful for understanding the components of every fire. The former includes fuel, oxygen, and heat as its elements, while the latter also incorporates an uninhibited chemical chain reaction (Reporter’s guide: All about fire, n. d.). The first three elements combine to produce fire, which later grows. Oxygen and fuel in a gaseous state engage in a reaction, which runs with a visible body seen as flames. The chain reaction helps to maintain the process, as it provides self-sustaining heat. Taking away one part of the tetrahedron allows extinguishing the fire by turning it to its decay stage.
Depending on the type of structure, there are different strategies for fire mitigation. For example, in a closed setting where the air source is limited, the reaction is likely to stop shortly after all available oxygen is used. In other cases, decreasing the heat level may be the best way of fire suppression. This principle is seen when applying water, as it cools the site by using the heat for evaporation. Sprinklers are very widespread in different types of structures as a part of this fire protection strategy.
Alarm Systems
The previous fire detection and alarm system did not function properly and failed to initiate an early evacuation. Firstly, devices that had to detect smoke and combustion products did not send any signals to the FACU. Apparently, there was an issue with their functioning, which had not been noticed previously. Ideally, a trouble signal should have been sent to the FACU to notify them about the problem. Another issue appeared to include a human factor, as one of the officers assumed the alarm was false. The utilized system was a pre-signal service with an integral delay, which allowed clearing the notification before it went public. As a result, there was no audible alarm translated to all the warehouse’s occupants.
The recommendations for rebuilding the place would include the changes in the fire detection system. A FACU is the center of alarm signal processing, functioning as a place for supervising and monitoring all the installed components (Brakhage et al., 2016). Apart from notifying an off-site monitoring station, the system informs the building’s occupants about the situation. When a device detects signs of a fire, it sends a signal to a FACU, which processes it and initiates audible and visual alarms.
The former can be of different types, including chimes, bells, horns, and sirens (Moore, 2018). Nowadays, speakers have become the most common choice for installing. It would be recommended for the re-built warehouse to incorporate this type, and having a human voice give directions on how to act, as it is more specific. Specialty signals, including alarm, supervisory, and trouble ones, should work correctly to provide accurate information. For example, if one or more components do not work properly, the trouble signal should indicate it on a FACU.
Emergency Action Plan
An EAP helps to prevent injuries and major property loss if prepared correctly. The government defines it as a written document required by OSHA standards, which aims to organize the actions of both employers and employees when an emergency takes place (Emergency action plan, n. d.). The minimum requirements include such elements as reporting, evacuation procedures, and escape routes, action plans for remaining employees, rescue and medical duties for designated personnel, accounting for everyone after an event, and contact lists (Minimum requirements, n. d.). For instance, the document lists actions that building occupants must take to minimize damage before and while they leave the site. This may include shutting all air sources like windows and doors during a fire. Work practices for employees who remain working on-site are also modified to prevent additional damage from sources like electricity or gas.
The re-built warehouse should develop an emergency action plan that would ensure employee safety. For example, the document would contain the evacuation map for visitors and employees based on their location on site. Office workers would have to switch off all electric appliances, shut doors and windows as they leave the building in case of fire. One of them should pull the manual alarm box to send a signal to a FACU. Several workers would have to examine the area to ensure nobody is left inside the building and check the lists of everyone who has escaped. Since the warehouse contains combustible materials, it would be beneficial to have designated employees as members of fire brigades. They would use fire extinguishers, hose racks, and other appliances to mitigate fire before it develops into its full stage.
Water Distribution System
The existing water distribution system did not provide the required quality and pressure for increased warehouse needs in case of a fire. Firstly, the facility was connected to the source by a dead-end main. It is not the best option, as the water supply in such a case is limited and does not have the necessary pressure (Brakhage et al., 2016). The primary recommendation for re-building the warehouse would be to design a grid system, as it has several flow directions. Moreover, this type of distribution system helps to prevent water deterioration, which was an issue in the case. As there is a constant flow in a grid-type system, there are fewer opportunities for sediment accumulation.
Secondly, there should be an issue solved with the quantity of water during emergencies, when the need for it increases. The solution could be in re-designing the system and making it private, making the warehouse independent from problems like municipal repair works on pipelines. At the same time, efforts of keeping all the system’s elements in working condition may be rather costly. Another way to solve the problem would be to re-build the storage tank of the industrial area to hold more water, which will increase its quantity and pressure.
Also, when both in-rack and ceiling sprinklers are activated, which usually happens, it creates an increased need in supply (Gulla, 2016). However, the updated FM Global Property Loss Prevention Data Sheet 8-9 offers to pay more attention to the system, which requires a larger quantity (Baker, 2016). For example, in-rack sprinklers may be chosen as the primary appliance for fire mitigation, and the amount of water will be calculated based on their number.
Fire Brigades
Fire brigades may often be found in an industrial and commercial setting. The scope of their responsibilities, as well as structure, required knowledge, and skills, is ruled by the official documents such as the NFPA 1081 standard (National Fire Protection Association, 2018c). To become a member of a fire brigade, a worker must meet educational, age, medical, and physical performance requirements issued by the authority having jurisdiction.
Depending on the type of fire, there are different characteristics of fire brigades. They also vary according to the hierarchy, as duties and responsibilities for leaders, training coordinators, and support provides are not the same. For example, according to the standard, an incipient facility fire brigade member should provide information on the emergency, respond to alarms, use designated equipment, and write incident reports (National Fire Protection Association, 2018c). He or she should be able to use communication system appliances to let occupants know about the situation. Equipment cleaning, inspection, and maintenance are also a part of the duties. Knowledge of different types of fire extinguish methods and how to apply them is also a requirement.
The characteristics of such units differ depending on the type of incident. The document distinguishes between incipient, advanced exterior, and interior structural facility fire brigade members. Depending on the severity of the emergency, different skill requirements apply. Maintaining a fire brigade may be beneficial regarding property loss prevention, but it increases risks for employee health. Nevertheless, industrial facilities such as the studied warehouse should have such a unit as a part of a protection strategy. Having brigades manage incipient fire may prevent its further development, as well as save facility occupants by informing them in a timely manner about the ways of escaping.
Water-Based Fire Sprinklers
The scenario demonstrates that the fire protection of the warehouse was not effective after it had become a place for combustible materials storage. High-challenge commodities, including those of Class III, allowed flames to spread rapidly on a horizontal level. Re-building the warehouse would include incorporating a system of special sprinklers, like CMSAs or in-rack ones with greater orifices and K-factors (Brakhage et al., 2016). The control mode-specific application type does not suppress a fire, as well as the rest except ESFR (O’Connor, 2018). NFPA 13 standard, which regulates sprinkler systems, offers to use in-rack ones combined with ceiling CMSAs (National Fire Protection Association, 2019b). The two types would be used one after another to prevent excessive water use, so different activation temperatures should apply.
Apart from controlling fire in several directions, foam-based systems should also be considered. As there are flammable liquids stored at the warehouse, there should be a possibility to stop the burning process by interacting with fuel (Brakhage et al., 2016). Smothering, separating, and suppressing methods will be effective for substances like cooking oil and aerosol liquids. A fixed foam system should be used so that an automatic process can be initiated when required.
Regardless of what substance is used by sprinklers, the pressure is highly significant for its work. The lack of it may result in poor water flow and failed fire control. To measure the pressure required for seven sprinklers, Q must be divided by the K-factor, each of the numbers squared. Having a total flow of 157.5 GPM, which would be 22.5 GPM per device, and the average K of 5.6, calculating these figures by a formula of P=Q²/K² results in 16.14 psi.
Hot Works
Hot works should usually be performed only in designated areas, which are specifically approved for this purpose. All manipulations that may cause sparks or heat will not lead to fire, as there are no combustible materials nearby. Other areas require permits for hot works to be performed there. In such a case, it is necessary to remove or cover any combustibles from sources of ignition (Wilmot, 2017). The NFPA 51B standard, for example, mentions that materials such as paper, wood, and fiber should be relocated to at least 35 ft from the work spot (National Fire Protection Association, 2019a). This is what should have been done with cardboard in the warehouse, which was set on fire.
Hot work permits must be required every time such type of works is performed in an undesignated area. For example, if stored combustible materials were relocated or covered as directed by NFPA 51B, the fire could have been prevented. A permit authorizing individual (PAI) can properly evaluate risks and give suitable directions on how to prevent personal injury and property loss by making the working area safe from igniting.
The role of a fire watch adds to the responsibilities of a PAI. AHJ usually determines if such a specialist is required under local jurisdiction (Wilmot, 2017). He or she should monitor hot works and prevent conditions from becoming unsafe (National Fire Protection Association, 2019a). A fire watch may also stop the process if it starts to present a threat to employees or property. The benefit of having such a specialist in a team is that workers can be concentrated on doing construction manipulations while he or she will monitor a fire situation.
Standpipe and Hose Systems
The new standpipe and hose system for the warehouse should be designed considering the issues with the previous one. The primary issue was poor maintenance, which resulted in low pressure. Thus, performing quality checks would be the first and most important recommendation. The activities should include an initial installation inspection of pressure and flow (Brakhage et al., 2016). For example, the NFPA 14 standard determines that there should be at least 65 psi on the most remote hose connection of 1.5 inches (National Fire Protection Association, 2019d). The flow must be kept at this pressure for at least 30 minutes.
The previous system was designed as Class II, which allowed using it by trained occupants and firefighters. It would be recommended to keep the same type with the components, including valves, pipe and fitting, hose stations, water supply, and FDCs (Brakhage et al., 2016). Class III system is more demanding in pressure and flow, as it has both 1.5- and 2.5-inch hose connections. NFPA 14 recommends having at least 100 psi for the latter, which would be excessive for a warehouse that is primarily protected by sprinklers.
Most importantly, regular in-service inspections must be performed on the system. It is planned to have an automatic wet system, as it used to be previously. However, as the water stays in pipes all the time, the components become subject to corrosion. Valves, reducers, and other elements must not be rusted to ensure a proper flow. Another checkpoint would be to ensure that the hose is dry, well maintained, and properly positioned (Brakhage et al., 2016). There should not be any leaks resulting in water loss during operations.
Managing Cooking Oil Fire
The cooking oil fire in the warehouse happened partially due to the type of packaging. Intermediate bulk container totes are made of polyethylene, which belongs to Group A of the fastest burning plastics (Brakhage et al., 2016).
As the flames got close to the packaging, PE melted, releasing oil onto the surroundings. Fire chemical reactions, including this substance, are known for their rapid development. Research suggests that burning cooking oil reaches its heat release maximum point just a few minutes after ignition (Hamins, Kim, & Madrzykowski, 2018). Moreover, it may soak into surrounding items like cardboard or textile, making it harder to extinguish the fire. The difficulty with burning oil is associated with its physical characteristics. The substance is hydrophobic and has a lower density than water. As a result, most sprinklers and standpipe hose systems may be ineffective against this type of fire. The oil will continue burning on the surface of water applied to it and may easily cover other parts of a facility.
The methods of mitigating fire caused by combustible liquids are regulated by the NFPA 30 standard. For example, it offers to have automatic sprinklers and foam-water protection systems (National Fire Protection Association, 2018a). A wet pipe mechanism would be beneficial as it has the solution readily available for fire extinguishing. Foam-based systems may be one of the solutions in dealing with burning oil. For example, the method of separation can prevent oxygen from combining with fuel, taking out one of the fire tetrahedron elements from the reaction. Cooling is another way of managing the incident, as it allows lowering the oil temperature. Foam-water sprinklers and automatic nozzles can be used effectively for this purpose.
Fire Pump Components and Accessories
The type of components arrangement for the previous pump has led to numerous issues leading to the device starting to malfunction. As the warehouse is being rebuilt, the new fire protection system should incorporate the new design that would prevent pressure failures, cavitation, reduced water flow, and other issues. Pipes of proper size should be installed to allow the required GPM amount rate to flow. An eccentric reducer will be useful to protect the system from cavitation (Brakhage et al., 2016). The suction side should be free of any devices restricting water flow.
As it is recommended to install a horizontal split-case centrifugal pump, it should be supported with a set of valves controlling pressure and circulation. The NFPA 20 standard prevents installing such components closer than 50 ft from the suction side (National Fire Protection Association, 2019c). There should also be a jokey pump connected to the system to prevent the main device from false activation (Brakhage et al., 2016). A metering device for inspection purposes must be added to the system, with discharge organized back to a supply source.
Finally, both the main and jockey pumps should be supported by OS&Y and check valves. Relief and check valves, as well as gauges, help to increase the level of control over the entire system (Brakhage et al., 2016). Maintenance should be performed regularly to discover any potential malfunctions. It is enough for an electric-driven fire pump to be checked for 10 minutes on a monthly basis (Brakhage et al., 2016). The offered construction of the system allows inspecting and repairing components independently, as there are numerous valves that help to isolate a part of the installation.
Electric Surge
Fire pumps are subject to voltage surges, as many of them are driven by electric motors. Loss of power due to storms or supply line damage can put at risk the system when it is needed (Brakhage et al., 2016). Recognizing hazards from voltage surges, NFPA changed the National Electrical Code regarding fire pumps, including a rule to Article 695 of installing a protector (National Fire Protection Association, 2017). Thus, a surge protection device (SPD) is currently a required element in this type of system.
If a surge protector is not utilized, an electric motor may be damaged as far as setting on fire. Even small voltage fluctuations can accumulate, leading to eventual appliance failure. While fire protection systems are used only in case of emergencies, the damage may become visible and critique only when an incident occurs. Thus, the most obvious benefit of using an SPD for a pump system is to keep it running during lightning storms and power cuts. Besides, components like valves and gauges running on electricity also stay protected. For instance, if there are numerous small voltage surges, it may affect those elements, resulting in inadequate performance.
Metering devices measuring flow or pressure can start to show wrong data, which would prevent maintenance workers from properly evaluating the state of a fire pump system. Installing an SPD may be rather expensive, as they range in prices. However, since the device can effectively protect the fire protection equipment, it eventually reduces maintenance costs for commercial building administration, as well as insurance expenditures. Moreover, in case of ignition caused by a lightning strike, the functioning system would prevent a company from a major property loss.
Smoke Management and Control Systems
One of the greatest issues regarding the warehouse fire was the absence of a system that would control or manage smoke. Large industrial buildings of this type have to utilize both passive and active means of dealing with it. The chimney effect makes smoke rise to the roof and collect there (Brakhage, Abrams, & Fortney, 2016). Despite the warehouse area is large, it is capable of filling the space in several minutes (Janssens, 2018). The scenario featured smoke moving further to enter offices, causing workers to inhale toxic gases. The new building should incorporate a system that would eliminate the covered issues.
Firstly, there should be a passive protection design, including smoke barriers like doors or dampers. The NFPA 101 code describes the criteria for these types of appliances (National Fire Protection Association, 2018b). The purpose of such components would be to prevent smoke from entering fire-free zones as offices, for instance, if a fire source is at the loading docks. Secondly, smoke management should be organized with a series of ventilation fans and smoke curtains. Large single-floor buildings should be using several roof openings and doorways to let in fresh air (Janssens, 2018). The flow would push smoke up, supporting its chimney effect, and force it to leave the building.
Pulling curtains would allow localizing smoke in one area, keeping fresh air and significant visibility level in others. At the same time, places not affected by fire may be pressurized (Brakhage et al., 2016). At the same time, it should be ensured that smoke does not enter those areas through a ventilation system. Finally, smoke detectors should be in place and working to warn occupants about the hazard.
Conclusion
The recommended way of re-building the warehouse includes improvements in its fire detection, protection, and suppression systems. A new electrically driven fire pump is to be installed, which corresponds with all NFPA requirements. The detection system would be designed to respond to hazards in high-rack storage conditions with the consideration of fire dynamics. Both audible and visual alarms should be installed and functional. Water supply will be coming from a combination of public and private sources, ensuring required pressure and flow for sprinklers and standpipe hose systems. Smoke control and management appliances will also be introduced to increase safety.
References
Baker, W. C. (2016). Rack rate. NFPA Journal, 110(2), 56-61. Web.
Brakhage, C., Abrams, A., & Fortney, J. (Eds.). (2016). Fire protection, detection, and suppression systems (5th ed.). Stillwater, OK: Fire Protection Publications.
Code of ethics for fire protection engineers. (2018). Web.
Emergency action plan. (n. d.). Web.
Gulla, B. (2016). Big innovations for in-rack sprinklers. FM Global. Web.
Hamins, A., Kim, S. C., & Madrzykowski, D. (2018). Characterization of stovetop cooking oil fires. Journal of Fire Sciences, 36(3). Web.
Janssens, P. (2018). General principles of smoke control. Web.
Kidder, R. M. (2005). Overview: The ethics of right versus right. In How good people make tough choices: Resolving the dilemmas of ethics (pp. 12–29). Web.
Madrzykowski, D. (2016). Fire dynamics: The science of fire fighting. International Fire Service Journal of Leadership & Management, 10, 27–35. Web.
McNeil, J. G., & Lattimer, B. Y. (2016). Autonomous fire suppression system for use in high and low visibility environments by visual servoing. Fire Technology, 52, 1343-1368. Web.
Minimum requirements (n. d.) Web.
Moore, W. D. (2018). Can you hear me now? Audibility, intelligibility, and visibility of notification appliances. Electrical Contractor. Web.
National Fire Protection Association. (2017). National electrical code (NEC Standard No. 70). Web.
National Fire Protection Association. (2018a). Flammable and combustible liquids code (NFPA Code No. 30). Web.
National Fire Protection Association. (2018b). Life safety code (NFPA Code No. 101). Web.
National Fire Protection Association. (2018c). Standard for facility fire brigade member professional qualifications (NFPA Standard No. 1081). Web.
National Fire Protection Association. (2019a). Standard for fire prevention during welding, cutting, and other hot work (NFPA Standard No. 51B). Web.
National Fire Protection Association. (2019b). Standard for the installation of sprinkler systems (NFPA Standard No. 13). Web.
National Fire Protection Association. (2019c). Standard for the installation of stationary pumps for fire protection (NFPA Standard No. 20). Web.
National Fire Protection Association. (2019d). Standards for the installation of standpipe and hose systems (NFPA Standard No. 14). Web.
O’Connor, B. (2018). Back to basics: Sprinkler types and systems. NFPA Journal, 112(6), 41-41. Web.
Reporter’s guide: All about fire. (n. d.). Web.
Wilmot, J. (2017). Hot work has many lessons that should be learned again: NFPA 51B covers the issues at stake for soldering, brazing and more. PM Engineer, 23(8), 16-17. Web.
Xin, Y., Burchesky, K., de Vries, J., Magistrale, H., Zhou, X., & Norwood, T. (2017). SMART sprinkler protection for highly challenging fires – part 2: Full-scale fire tests in rack storage. Fire Technology, 53, 1885-1906. Web.