The fire sprinkler system is a valuable resource in our fire arsenal. As building codes continue to evolve, these systems are becoming more and more common in all types of occupancy and building scale. This increasing presence in our community requires all firefighters (including firefighters, company officials, commanders, and regulatory officials) to increase awareness and understanding. Everyone involved needs to understand how these systems will affect their functions and how they affect other fire operations. Without an adequate and reliable water supply, sprinkler systems are of little value; however, one of the least-known components of water supply is the Fire Department Connection (FDC). Members of all identities need to be able to ensure that these systems operate in the best condition and are used correctly to minimize the risk of fire to property and life.
Let's first make it clear: The hose connector on the outside of the building is not a "conjoined piece"; it is no longer a sprinkler connection, but a riser connection. This equipment is the connection of the fire department. Before we laugh at it and treat it as a technical issue, let us first consider the importance of being "technically" accurate on the fire. Assume that the engine that the command arrives "hits Siam". I'm pretty sure we agree that the purpose is not to push the equipment into the building. But what happens when a worker extends the hose to the building and encounters multiple connections, one labeled "riser" and the other "sprinkler"? What happens when the order to "tap the standpipe" goes out and the staff lifts the tall building to clean up the stairwell? At that moment, we succumbed to one of our biggest failures on the fire-unable to communicate. If we can break the tradition (gasp!) and start to solve this problem correctly, we will be a bit more just.
According to the National Fire Protection Association (NFPA) 13, 2007 and 2010 editions of sprinkler system installation standards and NFPA 13R residential sprinkler system installation standards, almost all sprinkler systems installed require FDC. Four Stories from High Place, 2007 and 2010 editions. There are some exceptions. Considering that the building is too remote, the fire department is unlikely to intervene, and the building is too small to get any benefits. The vast majority of properties in our community do not reflect these conditions. What is certain is that we have all operated and will one day operate on properties protected by sprinklers or standpipes. According to a national standard, FDC aims to provide a way for sprinkler systems to receive supplemental water support from pumping equipment in the fire department. I think the term "supplement" is only related to whether a reliable and sufficient supply is automatically provided. In situations where buildings are closed or abandoned, we often find that public utility water services are demolished, even though such demolition is usually prohibited in the demonstration fire codes.
Events such as floods, hurricanes, tornadoes, earthquakes, and similar events can disrupt utility water supplies due to power outages at pumping stations or damage to water supply infrastructure pipes. If these events interrupt the water supply to the sprinkler system, the only possibility to supply water to the sprinkler system is through the FDC. Long before the restoration of the public facility system, the fire department is usually able to provide water through tankers, shuttles, and water diversion systems in such incidents. In this case, there is no replenishment of water; therefore, FDC should be fully considered because it may become the only water source for the system during a fire. After all, when will everything be all right on the fire?
In the event of a fire in a building equipped with FDC, it is most important to provide a reliable and adequate water supply, regardless of whether the connection is for sprinklers, standpipes, or both. It should also be mentioned that the attachment language of Section 6.8.1 in the 2007 edition of NFPA 13 strengthens the supplementary nature of FDC. They do not necessarily provide system requirements, nor are they intended to provide a specific volume of water, but on the contrary, FDC provides a Ideal auxiliary power supply to improve the reliability of the overall system. Later in this article, we will discuss the latest changes to the standard, which now limit the amount of supplementary support that FDC can provide.
Long before the building catches fire, we need to plan for the fire. Someone is responsible for ensuring that an accessible FDC is provided for responders and equipment. Regardless of how your local construction law enforcement and inspection systems operate, one (or more) person is responsible for placing and installing FDC. He may be called an inspector, plan inspector, construction officer, fire chief, etc., but does not necessarily have a firefighting background. The person may never have to find or establish contact on a dark snowy night, and he may not know how you will use the contact as a responding fire agency.
You need to go out and find that person. Introduce yourself and your organization; invite him to the station to see the equipment; or, better yet, invite him to observe the evolution of the pump or company exercises. If you really want to make an impact, pick him up at his office and drive him to the fire station or drill site; in the process, point out the FDC location and examples of good and bad locations on the building, And explain the reasons for these findings. You are not admonishing this person or process for past mistakes or omissions; you are opening a new chapter of collaborative understanding. It is entirely possible that no one has taken the time to establish any level of communication and understanding before this. I am willing to bet that things will improve for everyone involved. During the review and approval process, with "that person" on your side, moving or relocating the FDC on paper is more important than doing your first company inspection or pre-planning exercise and thinking after the building is completed. Much easier, "Who approved it?"
Location, location, location... I believe we have all heard of this phrase used many times in our careers. FDC is no exception: it must be in the "right" position from day one. According to the current regulations or standards in your jurisdiction, you should understand what documents are required to locate and place FDC. Learn to use the code, just like any other tool on the device.
The International Fire Protection Code (IFC), 2009 edition, provides extensive language in section 912 to ensure immediate access to everything needed for FDC. The code stipulates that the FDC (there may be multiple on the building) is located on the street side of the building and is fully visible and identifiable from the street or the entrance of the fire department vehicle. The specification extends this further, requiring the engine and its hoses to not obstruct other equipment from entering the building when connected to the FDC. The code language here is very clear. We have all seen damage, blockage or obstruction of FDC's positioning equipment more than once (Photo 1).
First of all, the most restrictive thing about the ladder company is its location in the building to achieve ladder access or air mainstream operations. There is no reason for the first expiration of the engine and its hoses to hinder or reduce the operability in this area. We least want engine companies to delay or abandon connecting to FDC while waiting for the ladder to arrive before blocking building passages or methods, but we see this situation time and time again. All of this, we have not even entered into other parts of the code that further restrict fences, trees, landscapes, or other fixed or movable obstacles. Will the correct location of the FDC pose a risk of physical damage to motor vehicles or forklifts? If it is, the part of the code that requires physical shock protection is applied. There is a fence requirement because the building has safety factors and requirements that must be considered; please remember that the access door must meet the specification requirements for cleaning and working space and the access requirements of the fire department, and the fire chief must approve the whole thing (photo 2) . When accepting any requests for discrepancies or deviations, always keep in mind the term "immediately accessible".
If your local organization does not implement IFC, you are not completely lucky, because the NFPA 13 (2007 edition) standard also contains language with the same purpose and intent, although it is not specific and leaves a lot of clear language in Section 8.17 In the attachment. If you happen to enforce these two documents legally, use them to implement an "immediately accessible" FDC to best serve your organization. It should be noted here that in the NFPA 13R standard (residential buildings up to and including four floors), there are no regulations or restrictions on the location or accessibility of the FDC. If you do not implement IFC, you may need to consider local amendments or other regulatory procedures to provide language to ensure that you can implement "immediately accessible" and other accessible FDCs on these residential systems. If you implement NFPA 5000, Building Construction and Safety Code®, 2009 edition as your building code, a similar situation will exist, which will send you directly to the reference standard required by FDC.
In addition to the above items, the location of the FDC on the building relative to the nearest fire hydrant or water source should also be considered for firefighting purposes. Sprinkler standards (NFPA 13 and 13R) have no regulatory requirements to regulate this, but usually anything less than 100 feet can achieve the purpose, and even limited engine personnel can effectively support FDC without difficulty. However, there is a requirement for riser systems (NFPA 14, Standpipe and Hose System Installation Standards, 2007 and 2010 editions) that fire hydrants must be located within 100 feet of the FDC. In this case, we have absolute power to adjust the location of the FDC or install new or additional fire hydrants to properly serve the building. Just as it is not advisable for the fire hydrant to be too far from the connection point, it is also undesirable for the fire hydrant to be located at the FDC. Although this seems ideal, please consider the impact of stopping or hindering the entry of the building by stopping the pumping equipment on the fire hydrant in front of the FDC (forbidden by regulations) and placing the equipment in the collapsed area of the building. When determining the best locations for fire hydrants and FDCs, it may be worthwhile to drive to the site to locate equipment and lay trunk lines. The code believes that FDC needs to be supported in a timely and effective manner, because personnel need to quickly ensure reliable water access to the connection before closing the building riser hose valve. In the planning phase, FDC must be monitored to adhere to the principle of "immediate availability" and the nearest fire hydrant to achieve continuous water supply.
The connection to the fire department must be marked with a minimum number of signs, which is clearly stated in the code. If we go back to IFC (2009), Section 912, we will find that a metal sign with raised letters at least one inch high is needed. The specification also requires specific wording, such as "sprinkler", "standpipe", "test connection" or a combination of them, depending on the actual building conditions (photo 3-4). Does it sound complicated? It shouldn't. Major fire protection equipment manufacturers have easily achieved regulatory compliance by stocking pipe keyhole rings that are properly constructed from metal, with raised letters that meet the exact requirements of the specification, and several other options, including contrasting red and white. Covers most common system installations. I wish I could tell you that I have never seen an automatic sprinkler ring installed on a building without sprinklers; obviously, someone does not know that they also make it with a riser. If the fire department inspector did not order the correct and corrected sign, the example in photo 5 would be catastrophic in an emergency situation (photo 6).
When the FDC connected system does not provide services for the entire building, there is also a language to provide supplementary signage. Again, this should seem obvious, but it is often overlooked and can lead to critical decision errors on the fire. In some cases, protection is only allowed in certain building areas or spaces. When a firefighter is facing a top-floor fire on a three-story taxpayer, the FDC used for the basement-only sprinkler system is of little value to the firefighter. Examples of such signs are shown in photos 7-8 and are not subject to specific regulations, so local officials must specify the size, material, color, and even content editing (photo 9) to avoid more confusion. necessary. As with the "immediately accessible location" requirement, please remember that the purpose of the code associated with the sign is to provide the respondent with specific system information to ensure appropriate support. It is completely impractical to expect staff to remember the weirdness of every FDC or building in the jurisdiction. There is no pre-planning procedure designed to compensate for failure to apply the correct code requirements.
Needless to say, the hose connection on the FDC must be compatible with the hose connection of the local response firefighting equipment; unfortunately, we have found time and time again that the thread type of the connection is not suitable for the thread of the local fire department. There are many explanations for how this happens during system installation, but the bottom line is that although the code requires compliance, if no one has checked it, you should not be surprised when the emergency finally exposes the problem. There is no explanation or excuse for not checking the installation immediately after the installation is complete. We know that all current codes and standards require these connections to be immediately accessible, so crew members who go out for training can easily pull over and check hose connections without disturbing any aspect of the site or the occupants of the building. Ensuring that connections are compatible with native threads also helps workers understand and familiarize themselves with the various attributes of their area. Even if the threads are compatible with the threads of your local fire protection agency, this type of continuous spot check will reveal that the connection is damaged or damaged and should be reported for repair.
In addition, all personnel need to know which end of the hose is stretched and connected to the FDC. NFPA 13 specifically requires internally threaded rotary joints on FDC; this is consistent throughout the fire department. When hoses are connected and pumped into the FDC, they are actually attack pipelines-even though we might think of them as supplying water to sprinklers or standpipes. The reason this becomes important on the fire scene is that some hose connections are similar to FDC, but are not actually used for fire department support. In buildings equipped with fire pumps, there is usually an external test connector that is almost similar to FDC, except that it has an externally threaded hose connection. If there is no clear and correct marking or label, the staff may try to use a pair of double female connectors to connect to the test connector. Although this is done with good intentions, it has no effect on the support system. Photo 10 shows an example of this potential confusion, where the left connection is used as an FDC and the right connection is actually a fire pump test connector.
Similarly, some places are equipped with wall fire hydrants very similar to FDC. Once again, the need for clear and legible signs is obvious. The staff should pay special attention to and discuss the main differences between these connections during the inspection. If you encounter an externally threaded hose connector at the connection when responding to an emergency, immediately suspect it is a fire pump test header or a wall hydrant, and seek more information before pumping to it.
In order to achieve effective support for the FDC, ideally, the location of the equipment should be such that the hose between the pump and the FDC does not exceed 100 feet. Since you will extend multiple lines to this connection, taking into account time and personnel factors, please do not choose the length of the hose you use arbitrarily. Generally, FDC manufacturers rate each 2½-inch hose connection as delivering 250 gallons per minute (gpm) to the system at a pressure of 100 pounds per square inch (psi). Depending on whether your equipment has a 2½-inch or 3-inch hose for connecting to the FDC, you can estimate the amount of water that will be delivered to the FDC. On average, a 100-foot long 2½-inch hose will have a friction loss of 12 psi @ 250 gpm, while a 100-foot long 3-inch hose will lose 5 psi @ 250 gpm. Under severe fire conditions, a 3-inch pipeline may be pressurized to 175 psi to provide 500 gpm, but this will cause a friction loss of approximately 20 psi. It is not recommended to use 2½-inch hoses for this type of flow and pressure because the friction loss exceeds 35 psi. These examples represent severe fire situations that could overwhelm a building's sprinkler system or multiple handles operating on a riser riser.
Problem: The higher the pump discharge pressure provided to the connection, the greater the friction loss, which reduces the actual water flow into the FDC.
Solution: For large-scale system requirements, you need an FDC with more than two hose connections. It is very difficult to deliver a large amount of water to the FDC at the necessary working pressure through only two 2.5-inch or 3-inch long hoses, especially above 1,000 gpm. When faced with vertically challenging buildings or large-area structures, it is beneficial to provide three or even four hoses to support the sprinkler system or riser system in terms of hydraulics. This will require the installation of FDCs with more than two 2½-inch connections and a more proactive approach during the planning review and construction phase of the project.
This is where the language of NFPA 13, 2010 edition, Section 6.8.1 may cause some difficulties. It says, "...The fire department connection should consist of two 2½" connections.... Prior to the 2007 version, the wording in this section required at least one hose connection, and local authorities were free to require two or more hose connections. The use of the mandatory "shall" language in the 2007 version may adversely affect the ability of the fire department's pump equipment to provide the required auxiliary power. This language now effectively limits the FDC to only two hose connections. Regulators should consider creating local amendments to revert to the previous language, or leave the final decision to the local firefighting agency that will deal with fire and public safety issues. Limited by the hard language that limits the amount of auxiliary support that the fire department's pumping equipment can provide to the building's sprinkler system, this is not in the best interest of fire operations.
Clarification is needed here: the above code section and its FDC restrictions only apply to stand-alone sprinkler systems installed in accordance with NFPA 13. If your project has a riser system or a combined sprinkler system, you will apply the requirements of NFPA 14. NFPA 14, 2010 edition, the FDC requirements in section 7.12.3 are more restrictive, specifically requiring FDC to be equipped with a 2½-inch hose connection for every 250 gpm of system requirements. Although it is fully allowed to install a combined sprinkler system and riser system that can be supported by an FDC in the site, the requirements of these two standards must be met, including those that require more stringent FDC capacity.
When discussing the specific requirements of NFPA 14 for the FDC of the riser system, it is also important to point out that multiple FDC-specific code languages may be required on the protected property. In Section 7.12, the specification states that "one or more FDCs shall be provided...", which can help local authorities determine that two or more FDCs are required on property protected by a standpipe. In addition, the code requires at least two remote FDCs on high-rise buildings. The current building codes adopted by your jurisdiction will define high-rise buildings (usually more than 75 feet above the fire department vehicle aisle) and when a riser system is required. Understanding the differences in code languages is the key to ensuring that all requirements are met, and where permitted, local authorities can establish the need for multiple traditional "conjoined" connections, which is usually not enough to provide the required water supply to these systems.
Traditionally, the fire department viewed the standard FDC as equipped with two 2.5-inch female swivel joints; I believe this gave way to the "Siam" name. However, there are many other connection configurations on the market, from single connection to four-way connection. Depending on site conditions, they can also be used for wall-mounted installation or as a base installation.
In recent years, the fire department has introduced genderless or quick-connect type fittings to the system FDC, usually with four-inch or five-inch hoses. The local fire department will make a choice because it needs to be compatible with hose fittings. However, there are a few things to consider when using these accessories and large diameter hoses (LDH) to power the system's FDC. These considerations should be part of any discussion about converting existing systems to LDH connections or using them for new system installations.
Compared with the traditional 2.5-inch or 3-inch water supply pipeline, LDH was introduced into the fire department as a means to provide large amounts of water over long distances and reduce friction losses. This advantage of large volume and reduced friction loss does not take into account the significant pressure loss caused by altitude, such as in risers of high-rise buildings. LDH provides the volume for the pump equipment, and then the pump equipment generates the necessary fire-fighting operating pressure. Fire sprinklers and riser systems rely on specific pressures of specific volumes to achieve effective sprinkler coverage or hose flow reaching and penetrating. The successful use of LDH to transport large amounts of water also depends on the design and piping of the pumping equipment. Installing an adapter to convert the existing 2½-inch discharge port to a 5-inch discharge port will create a choke point at the pump discharge port, where the water speed will greatly increase and cause additional friction losses as the flow rate increases.
You must also consider hoses. Since LDH is usually classified as a supply hose, its working pressure is 200 psi, while the working pressure of a three-inch hose is 300 to 600 psi. When looking at the requirements for the correct supply of riser systems in vertical buildings, especially multi-zone systems, you will encounter minimum pressures far in excess of 200 psi. Although the friction loss of a 100-foot hose between the pumping equipment and the FDC will be smaller in LDH, don’t ignore the fact that pumping 175 psi through LDH and providing up to 1,000 gpm is a good thing for companies that have closed operations. Does a completely inadequate riser system require 250 psi and 750 gpm to actually reach them and support their hose flow. Using three or more 3-inch hoses in the FDC will easily exceed 750 gpm; more importantly, it will provide it with the necessary pressure to overcome the height loss (gravity) when reaching these crew members. Large demand sprinkler systems or risers that require a flow rate of more than 750 gpm can still provide better service with multiple (three or more) hoses through three-way or four-way FDC.
When you consider the need to properly supply multi-regional buildings (discussed below), pumping equipment is rarely equipped to properly support two or more LDH emissions. The most basic engine equipment will have at least six drain ports for 2½-inch hose fittings, which can feed three lines into each FDC in two different areas. With the popularity of LDH, many organizations began to remove 3-inch hoses from their equipment and use LDH in their supply lines. This is not a question of using LDH as a supply between the fire hydrant and the equipment; it is about recognizing that although you may be "supplying" FDC, you are actually on the discharge side of the pump and you should use an "attack" grade hose Connect to FDC. Although it is not necessary to carry a 1,000-foot-long 3-inch hose in these situations, please consider your response area and its construction. Fire departments must still retain some three-inch hose supplements on their attack equipment to properly provide important functions to support FDC.
During the peak period of firefighting in riser buildings, internal staff relied on the water supply through the FDC for protection and safety. In a building equipped with a single large-diameter FDC, there is only one hose between the fire pump equipment and the building. If the hose is damaged by falling debris, knocked down by the wrong vehicle, or ruptured by pressurization, that unique hose will be lost and immediately endanger the insiders. It took a few minutes to stretch and reconnect the new hose, and internal staff scrambled to find cover and safety under deteriorating conditions. When multiple hoses (or even two) are in place and support FDC, it will provide a safety factor if one of the hoses is lost or damaged. Internal staff should use the remaining water in the additional FDC pipeline to evacuate to the protected stairwell with hose protection.
Traditionally, these codes require the FDC to be between 18 and 42 inches above the adjacent grade level. The lower measurement takes into account accessibility during snowfall and drift; the upper measurement takes into account easy access and connection, but also takes into account the weight of the water-filled hose at its fittings and kinks. In LDH, the weight and tension of the water have a significant increase in the impact of the joint, because a one-foot-long 5-inch hose weighs approximately 34.5 pounds when filled with water. The higher the FDC is installed, the longer the hose length that must be supported by the fittings before the hose touches the ground-at a height of 42 inches, approximately 121 pounds of water will hang on the connection (photo 11).
This will also increase the kinking of the hose, thereby reducing and possibly eliminating the hydraulic efficiency of the LDH. The charged 3-inch hose has sufficient rigidity, so it can be relatively self-supporting even at a height of 42 inches, but the charged 5-inch hose has no self-supporting characteristics and will immediately generate kinks and tension at the joint to FDC. Some agencies have stipulated the installation of pipe elbows to alleviate this situation (photo 12), but we must still remember that the height here is not good for us, and the regulations do not consider the use of LDH for FDC. A similar effect on FDC at low ground level (Photo 13). When you take the size of the hose joint into account, you will force a kinking under the connection, which again weakens the hydraulic throughput and undermines any advantages of LDH.
Early LDH couplings lacked a physical method to maintain their connection. They were only twisted together by friction, requiring only 1/4 to 1/2 rotation. Today, we have large diameter connectors with a ¼-turn twisting action and a safety latch to physically connect them. There is no doubt about the value or need of this safety latch, and we can check and maintain our hoses regularly. When using these connections on the FDC, we have much less control over the care and maintenance of this safety lock; if it breaks or becomes damaged, we have no reliable way to restore it in an emergency. This increases the possibility of hose connections failing or separating under pressure and depriving internal personnel of water. When using traditional hose sizes, we rely on hose threads, which make up their connection through a few turns instead of a few turns. If the threaded hose connection is found to be damaged, responders have multiple options for quick on-site repairs and timely connection of the hoses in order to provide support through FDC. A failed or damaged large diameter connection actually makes it unusable during a fire emergency and must be repaired by a service contractor.
Inevitably, you will encounter property whose FDC has been damaged or otherwise damaged. Finding these problems during the inspection can facilitate repairs, but we must know what we can do in an emergency to solve the problem and provide a certain level of support for the sprinkler or riser system.
Due to continuous exposure to external weather and susceptibility to impact damage, the rotating joint on the FDC may be damaged or fixed in place. It seems almost impossible to connect a hose-length male connector to a frozen female connector because the twisted hose will effectively cut off the water supply. There are two ways to overcome this situation in emergency situations that do not require special equipment or cause special time delays.
Measure 1. Install the double male connector into the refrigerated connector to form a typical hose seal connection. You now have a fixed male connector exposed; connect it to the double female connector and complete the connection with a hose seal. Although it may be unsightly, you now have a fully functional female swivel joint that you can easily connect to the male end of the supply hose.
Operation 2. Twist the hose and let it untie itself into the frozen rotary joint. After completing the stretching of the supply hose from the pump to the FDC, while holding the male connector and facing the FDC, twist the male end of the supply hose in a counterclockwise direction about three to four turns. This will cause the supply hose to twist, which is then alleviated by connecting the male connector to the frozen female connector and unwinding the supply hose in the opposite direction. This reduces twisting and completes the rotation required to screw the accessories together. This method may not achieve a leak-proof connection, but it provides an option when necessary. This method requires time and practice to develop so as not to become clumsy in an emergency. Considering that the reduction of lighting, temperature and time pressure is usually detrimental to us on the fire scene, I recommend using a set of double male and double female adapters to overcome the first method of stuck rotating joints. Most of the engine equipment has several sets of airborne, and firefighters are already skilled in connecting under different types of weather and light levels.
If the stuck or cross-threaded plug on the FDC internal threaded rotary joint cannot be removed, it will not be able to complete the hose connection on the FDC side, and will reduce the amount of water delivered to the system. Generally speaking, it is much less common to find that both plugs are stuck or frozen on the FDC. All this helps the support staff to fully check all the rotary joints and accessories on the FDC during the on-site inspection and activation of the alarm. need. These problems rarely happen overnight and are caused by long periods of negligence and lack of maintenance.
Measure 1. If the plug is really frozen and cannot be removed, it is better to leave it connected to it instead of trying to remove it and finding that the swivel is damaged or out of round and unable to make a hose. Either way, you cannot make hose connections, but at least FDC can still be used through other hose connections. Removal of the plug only complicates the problem, and it is found that the valve disc is also damaged or missing, and any attempt to provide hydraulic support will be blown across the exterior of the building. Connect all hoses as much as possible, and don't let the stuck plug cause you to give up all efforts to support FDC.
Measure 2. As an alternative to providing only one hose, you can connect a Y-shaped (gated or non-gated) with double male connector to the remaining good hose connections. You can then provide two hoses for the Y-shaped adapter and FDC, which have better flow results than using only one hose.
The worst case is that the FDC is truly damaged to an unusable level. Changes in national economic conditions have caused problems in areas where FDC components are recycled in exchange for scrap value, rendering many buildings unavailable for connectivity (Photo 14).
action. When faced with protected property with such FDC, officers and commanders need to conduct a risk-benefit analysis. If the protected property has an automatic sprinkler system, the fire department cannot provide supplementary support for the system. The purpose of this is not to consume the existing water supply into the building's sprinkler system. This will require additional equipment and hoses connected to fire hydrants in other parts of the underground distribution system to provide sufficient water for fire department operations. If sprinklers cannot be controlled, this may involve the main water flow. Continuously re-evaluate the fire attack plan, the progress of the fire, and the effectiveness of the sprinkler system. If there is no measurable progress, consider changing the attack pattern and predicting building damage.
In rare cases, the live FDC will suddenly and often violently loosen and separate from the pipeline in the building or underground, and operate in a building fire at the same time. Obviously, this poses a safety risk to people in the nearby area; it also endangers any internal staff who rely on sufficient hose flow for protection. Many times, this type of failure leads to the loss of the building. Military officers and commanders should be aware of this situation and evacuate personnel from places where they cannot be protected with sufficient water flow or cannot be used to support the sprinkler system to achieve control or suppression. These problems can often be traced to installation defects or undetected damage, rather than what the fire department did during the fire.
When installing the system, the inspector must pay special attention to the FDC and its related pipes to ensure that their installation complies with the specifications, especially the pipe supports and supports. Although the FDC pipeline is idle for most of its life, it is sometimes affected by the pressure and flow forces generated by the pumping equipment, resulting in pressures of 150 psi or higher. The movement of large amounts of water through system pipes under these pressures creates forces and movements that must be absorbed by mechanical supports and supports. If such support is not provided, the pipeline may shake or explode, resulting in damage to the system and failure to obtain support from the fire department. When the firefighter firmly grasps and shakes the FDC, it should not move in any way. If you can swing or move the connection with your hand, imagine what happens when water flows into the connection from the supported fire department equipment. FDCs, especially those far away from buildings, can be hit by vehicles and suffer damage that is not always obvious during visual inspection (photo 15).
During the response to the alarm failure of the property protected by the sprinklers, the staff took time to check the condition of the FDC. In the initial photo (photo 16), the connection looks normal and is in a state that does not normally facilitate any further investigation. When touching the FDC, it was found to be damaged, and the entire connection swings freely between the 10 o'clock and 2 o'clock positions (photo 17-18). This obviously requires further attention and repairs are ordered. This example highlights the need for officials and firefighters to use standard methods to check FDC during their response to protected property. Simple inspections of FDC, including swivel, thread compatibility, system identification marks, coverage area marks, overall accessibility, protective caps/plugs, supports and supports, can be easily performed in a few minutes. This simplified inspection also helps increase members’ familiarity with the FDC location and can trigger tailgate discussions about the future operations of the property.
When a disabled FDC serves the standpipe system, the situation becomes more urgent because it represents the water source for the internal hose. Command decisions must be based on the fact that dispatching personnel into a building to conduct a fire attack without properly supplying and supporting its ability to operate hoses is inherently dangerous. Alternative measures must take into account the reflection time and special resources required to propel the supply line vertically through the building-and it is not practical outside the third or fourth floor. The reason for installing the riser in the first place was that the code recognized that it was impractical to manually push the hose from the outside of the third floor of the building.
Options. Another uncommitted option is to lift the overhead device (preferably with a platform) to the floor below the fire scene and use it as a temporary external riser to supply internal hoses. This concept is immediately limited by the effective range of the antenna relative to the construction site, floor layout, and actual fire location. It also requires personnel to enter the lower floors from an open area, without the protection of an enclosed stairwell, where they usually rise. Once you enter the floor below, you may need an extra, possibly special hose stretch to find the internal stairs, and then rise to the fire floor to attack. This type of operation should only be considered when there is a legal life hazard above the fire floor and the personnel have sufficient pre-planned knowledge to enter the open floor area and effectively locate the internal stairs.
In addition to these considerations, external/defensive actions are the only reasonable plan that can be tried. This reinforces the requirement for high-rise buildings to be equipped with at least two remote FDCs. The possibility of both FDCs being damaged to be unable to work properly is reduced; at least a certain degree of support can be provided for the riser system.
For many years, it has been discussed that you can overcome the damaged FDC on the riser system by extending the supply line into the building and connecting it to a lower level hose valve and opening the valve-basically through a feedback riser soft Pipe valve. I am not denying this concept immediately; however, the concept has some inherent limitations and should not be regarded as a general solution to the problem of incapable FDC. This method has limitations. If it is generally acceptable and feasible to feed back each riser system through a lower level hose valve, then this will be taught and considered best practice!
An immediate limitation of this method is the volume that can be delivered to the system. Most riser systems are designed to be at least 500 gpm, usually 750 gpm to 1,250 gpm. These volumes represent the number of hoses that may be required to extinguish fires in different places. The maximum flow design is suitable for buildings without sprinkler protection, because we can expect the rapid development of fire, especially in open offices and professional uses. Residential land usually uses lower flow design, partly because the floor division design has fire-resistant components between the unit and the corridor. However, this does not mean that when vertical pipes are used in residences, especially in old buildings without sprinkler protection, the need for reliable hose flow support is reduced. Attempting to deliver enough water through a single reverse water supply hose valve to support more than one or possibly two operating hoses is impractical. This restriction severely restricts the crew from being able to advance to the exposed layer to cut off the extension while performing the main fire attack. It is not safe to arrange the staff to connect three or more hoses and push them to a situation where a fire is expected, while only providing enough water support to the riser to supply one or two hoses at a time of. None of the four water pipes has enough flow and water penetration. It is worse and more effective when preventing further extension when the main body of the fire consumes its available fuel and cannot spread. Danger.
When faced with multiple independent buildings in a city block that is involved or immediately threatened, we choose a defensive attack, that is, we log off the area that has been involved and focus our resources on preventing more exposed participation. When you cannot fully support enough hoses to safely complete an offensive attack on a fire, the same concept can be safely and effectively applied to internal building fires.
Another limitation that can sometimes be resolved on site is the presence of pressure regulators on the hose valve. Depending on the style of the device, it can be screwed on the hose valve or cast into the body of the hose valve. The key is to recognize the presence of the device and overcome its limited functionality if possible. You can do this easily when the device is screwed or screwed onto the hose valve, simply by removing it like any other hose coupling before connecting the supply hose. Remember to fully open the hose valve via the wheel or handle before charging your supply line. In an emergency, you can connect the hose to the valve and then charge the supply hose. The supply hose will harden and show its supply function; however, the water will not flow back to the riser riser. Since we are not used to opening valves when connected to FDC, please slow down and carefully consider the evolution process to ensure that you don't overlook things that seem so simple.
When you encounter a pressure regulating device built into the valve body, you must override the device to allow full port flow through the valve and into the riser riser. Depending on the type of pressure adjustment device in your jurisdiction, this may be as simple as removing the restricting pin (photo 19), or you may need on-site adjustment tools/wrenches/pins. There are still a large number of non-adjustable riser valves in existing buildings, and you cannot adjust them on site, which will severely limit your attempts to give back to the system or may make your efforts futile. Familiarization by pre-planning will help you identify these situations in advance; make them part of the record in your pre-planning document.
A pressure regulating valve. The built-in pressure regulators and check valves in the system piping can weaken or prohibit the less obvious conditions of the riser riser that are effectively fed back. When present, these devices can regulate system pressure without being visible or obvious at the hose valve or standpipe. Their purpose in the system is to regulate pressure and control flow under normal operating conditions. Attempting to overcome an incapable FDC through a feedback hose valve is by no means a normal operating condition; therefore, these valves can easily damage or prohibit such operations without your knowledge. Regulations may require check valves, depending on the piping configuration and the presence of multiple water sources (including overhead storage tanks) to prevent siphoning of the entire system during maintenance and repairs. Under normal operating conditions, they do not constitute an obstacle to normal flow and are usually hidden from sight. Even if you know they exist in the system, you cannot bypass or overcome them in an emergency unless you remove them and replace them with a straight pipe. Similarly, a large pressure regulating device can be located in the ceiling or service room to regulate downstream flow to multiple floors or the entire area of the building, rather than a single pressure regulating device at a single hose valve.
Your method of overcoming the incapable FDC and supporting the standpipe system should be guided by your knowledge and understanding, that is, there is really no silver bullet solution to these problems. The best way is to try each of the proposed remedies and observe the results. Taking into account your available resources, take more than one corrective action at the same time, as the fire continues to intensify and spread to other areas. The best measure of the progress or effectiveness of any emergency measures is direct feedback from the hose valve staff below the firefighting level. As long as internal attacks are still safe and feasible, you can get direct feedback on your efforts from these staff. From a relatively safe location within the fence of the stairwell, they can even operate the hose valve and observe the flow and pressure conditions before connecting the attack hose and considering entering the fire scene. Although this "indiscriminate" water flowing into the stairwell may seem like unnecessary property damage, remember that the fire is spreading uncontrollably throughout the building, and the best outcome of the event depends on Whether your emergency measures can be established to provide reliable water supply for internal staff.
Since our earliest fire school days, we have learned some very basic facts about operating in sprinkler protection facilities. I remember the emphasis on the piping from the FDC to the system riser is absolute, because even if the sprinkler water is deliberately turned off, water can be pumped into the system through the FDC. Well, now is a good time to realize the inherent limitations of this statement. First, regulations have banned the use of control valves in FDC pipelines for decades. It is absolutely forbidden to install any type of control valve in the pipeline between the FDC and the system. This means that no isolation or maintenance valve is provided for the FDC check valve. This is a special exception in that the check valve can be isolated for maintenance.
The statement that FDC will always provide water from the pumping equipment to the system even when the water supply valve is closed is misleading. The reality is that in a single standpipe sprinkler system, whether wet or dry, a properly installed FDC will allow the pump to supply water to the system even when the water supply valve is closed. This only applies to single riser systems, and generally applies to "most" installations. However, when the property is protected by a multi-riser system, these risers usually form a manifold between the water supply and the riser base, thereby placing a riser control valve between the FDC and any system risers. If the riser control valve is closed for any reason and a fire occurs in the protection area of the riser, water cannot be supplied to the operating area. Please note that FDC is not specifically designed to overcome system damage caused by closing the valve. This understanding further strengthens the need for emergency personnel to quickly enter the control valve or riser room and verify the operating status of the equipment in an emergency. This will be the only way to correct the closed riser control valve to allow water to flow into the fire area. These considerations should never be taken preemptively or delayed through response equipment to ensure reliable water supply and complete connection with FDC, in order to support the evolution of a complete system.
FDC location. In the event of a fire in a large-area recycling facility, IC chose to skip supplying power to the FDC because he was worried about locating equipment in the collapsed area of the building instead of selecting multiple air streams. The fire finally burned for long enough that the roof collapsed and the air flow penetrated and suppressed the fire. Although building collapse and firefighter safety are absolute priorities, there is no need to place equipment in a location that is dangerous to collapse. When you arrive, the hose can usually be safely connected to the FDC, and the equipment can be moved out of the danger zone well while maintaining the support of the system. If the construction method of the light-weight building raises the concern of early collapse, the FDC should be far away from the building or located in a lower corner. If such operations are considered during planning and construction, FDC can be effectively supported without putting equipment into the collapsed area. This also illustrates the value of remote or multiple FDCs located in large areas and high-rise buildings.
Multi-zone riser/sprinkler system. Delivering sufficient pressure and volume to buildings with special heights is far beyond the operation of the fire department. In buildings with 20 or more floors, the initial design and configuration of sprinklers and riser systems often require multiple "pressure" zones. These multiple areas can be independently equipped with separate fire pumps, or they can share equipment for pipeline pump configuration. The configuration of the building depends on the designer, who must act within the scope of various codes and standards. This brings us back to the question of developing a good pre-accident plan and ensuring that such information is available in an emergency.
From an operational point of view, buildings with multiple areas may create a "complex and chaotic" system appearance. We previously learned that each area in a high-rise building requires two or more FDCs, and a basic three-area building will have six FDCs, and hope to be divided into three groups and located in two remote parts of the building. The need for clear and understandable signage is essential to avoid confusion when making these connections. Although it is unlikely that a fire will require hoses to be connected to all three areas, it is likely that they will need to be connected to two areas.
Let us create a theoretical framework for our discussion to help illustrate the concept of multi-zone and how it affects your operations. Our building is a 35-story office center with a four-story parking structure underground and below the street. The automatic city water supply will go underground at one of these garage levels. This supply will have enough pressure to cover all garage floors and the first four floors above ground in the building to form the first area. Use fire pumps to increase the pressure of sprinklers and risers on floors 5 to 20 to form the second zone. The third zone uses a fire pump on the 20th floor to pressurize again to send the 21st floor to the roof. This fire pump configuration is similar to a relay pumping using two engine equipment, and is usually referred to as a "tandem pump" in the specification.
Each of these three areas will have at least two FDC installed outside the building, depending on the needs of the fire department and the building's available equipment access rights. Depending on the system area you need to support, the inlet pressure of these FDCs will vary. The first area obviously does not need as much pressure as the third area. The sign shall include clearly marked areas and their covered areas, as well as the maximum and minimum inlet pressure requirements for each area. Note: The area must be identified, not just the mark (photo 20); here only the high area and low area connections are identified. The firefighters did not specify the definition of the low and high zones, usually the floor number. The signs in photos 21 and 22 are more accurate and can provide useful information for firefighters. This additional information can help firefighters achieve the best results in an emergency.
Earlier, it was mentioned that the possibility of a single fire event that needs to be connected to all areas is very small. However, it is necessary to connect to two different areas in a fire, and there should not be any mentality that excludes this possibility. When operating near the interface floor near the adjacent area, there must be a hose connected to the FDC of the adjacent area.
Let's look at our example building again, assuming a fire on the sixth floor. The water flow automatic alarm on the sixth floor generates a response; when the smoke moves toward the stairs or elevators and the occupants activate the manual pull station, other signals will be generated during our response. An important adjustment factor is that the initial water flow warning came from the sixth floor-the initial attack plan should be concentrated in this area. When this information is broadcast to the responding device, the companies assigned to the two remote FDCs will find that the sixth floor is part of the second area, serving floors 5 to 20. This will be the correct FDC connected to the hose and ready to support operation.
Don't stop there. Although the fire may occur on the sixth floor, we know that our procedures require connection to the floor below the fire, which is the fifth floor. This is no problem, because the fifth floor also happens to be part of the second district. The pump operator may not immediately know that the missing part of this puzzle is the presence of scissor stairs in the building, and the hose valve under the sixth floor (fire floor) designated to attack the stairwell is actually a fourth-floor building. This means that the initial attack hose will pump water from the first system area and leave these crew members without the support of pumping equipment.
This scenario can also take another approach: the staff connects to a floor close to the upper limit of a given area. They are making progress and have not reported any water supply problems. Other companies have detailed instructions above the fire floor for exposure control; combined, they are now located on the lowest level of the next system area above the fire. When these workers start to work, they may suddenly report water supply problems, and only the workers on the one or two floors below have enough flow and pressure. When the pump operator starts to increase the pressure to overcome the problem, this may cause confusion or even injury to the fire, and continue to report low pressure and flow. When this happened, the lower area was under overpressure, and these crew members were suddenly faced with a surge of pressure.
The best way to overcome these two situations is to connect the hose to the adjacent area FDC whenever the staff is working in the three to five layers of the area interface. You don't have to pressurize the two areas immediately from the beginning of the event, but at least the hoses are in place and connected, if needed to support adjacent areas. Internal companies can also help prevent problems by communicating which floor they are connected to before launching an attack. The fire floor does not change in the scene, but if the staff reports that it is connected on the fourth floor because of the scissor staircase, the outer pump operator can immediately adjust the operation to supply the lower and upper areas (fire ground). Areas containing fire-resistant floors will always require FDC support, as you still have to provide any sprinklers that are running. If a water supply problem is suddenly reported, even if other nearby staff have not reported any water supply problem, the process of identifying that the operation will occur near the area interface and establishing a connection with the second area can also keep the pump operator in communication. In the event of an emergency , The necessary measures have been taken to take corrective measures. As a reminder: When you start to supply air to adjacent areas, please adjust your pump pressure to maintain the minimum required for each area, while not exceeding the maximum value for any area.
Pressure and flow requirements. Once the hose is dropped and connected, you need to know how much pressure you will provide. This is one of the times when too much is as bad as not enough. Pumping FDC requires some skill and skill. A few pounds more or less won't change the situation, but it certainly requires the application of theory and some mathematics to ensure that you are not below the system minimum and do not exceed the maximum of the pipes and components. Between these two extremes is the gray area where the pump operator must work to keep the sprinkler running and the hose flow generating sufficient flow and penetration.
When dealing specifically with the characteristics of sprinkler protection, the margin between the minimum and maximum values can be greater; performance is best measured by observing smoke and fire conditions from the outside. Observation from the inside will be very difficult, because the water-cooled smoke is dissipated to the floor; the best sign may come from the outside, because not only the color of the smoke is "cool", but its strength and pressure will also vary with the different openings of the building. reduce.
Note: Turning off the sprinklers in advance is inherently dangerous. This can improve visibility and the staff can launch attacks; historically, this practice has caused casualties and a large amount of property damage. Fire departments may have certain expectations about fires in sprinklers, which may lead to hasty or wrong decisions about shutting down the system and conducting internal attacks. Officials and commanders may expect that when the sprinklers in the building are working, the fire should have been extinguished by the time the fire department responds. However, the actual situation is quite different, which may lead to a mentality of thinking that something is wrong and that the sprinkler cannot control the fire. Therefore, they carried out internal attacks while turning off the sprinklers. During the large-scale testing of the fire sprinkler system, it was found that the sprinkler system usually requires more than 30 minutes of continuous operation to truly control the fire, especially in high-risk locations and storage rooms. Some of the best performance during the test was achieved by making the building relatively enclosed and providing continuous support for the system for up to 30 minutes before closing and natural ventilation. This is contrary to the operating mentality of the fire department, that is, you enter there and immediately put out the fire. In one such test involving liquids, the sprinkler system achieved significant control and the test effectively ended. When ventilating the area to release smoke and steam, the sudden influx of fresh air reignited the fire and burned violently until it was extinguished by the manual hose flow. Turning off sprinklers prematurely is just to allow the fire to spread throughout the residential area, forcing external defense actions to cause total losses, and there is nothing to save.
There are obvious and measurable benefits to pre-planned inspections of protected property long before the fire. Not only need to pay special attention to the building layout, but also to pay special attention to the protection system provided. It is not enough to find FDC and control valves in these buildings. Every effort must be made to review the building plans and design documents to understand how the system was designed and the level of fire department support required. In the absence of a design plan, look at or approach the sprinkler standpipe to obtain a certain type of hydraulic design data card. All sprinkler systems are designed to receive the minimum amount of water at the bottom of the riser while still operating as designed. In order to provide any supplementary benefits or support, the FDC must be supplied with at least that much water and pressure, and when there are signs that a fire is occurring, you should increase the water supply rate. When you increase the pressure in the sprinkler system, the operating heads themselves do not increase its coverage, but the area they cover increases the density or water consumption of the area while remaining basically unchanged. Think about how quickly you can fill the bucket with 40 pounds of water through the open hose, and repeat the test with 100 pounds. The water doesn't really flow further, but you will definitely pour more water into the drum in a shorter time. The increased density allows the sprinklers to absorb more heat generated by the fire, and cool and quench the nearby fuel packs to prevent them from catching fire. This will effectively starve the fuel to death from the fire, thereby controlling or suppressing the fire.
When the water supply of the sprinkler of the building is equipped with a fire pump, the FDC must withstand a pressure higher than that already generated by the fire pump. To avoid generating abnormal high pressure, the FDC on the fire pump system is connected to the discharge side of the pump. If it is not, the pressure supplied to the FDC by the pump will increase and may quickly exceed the maximum pressure rating of the system piping and components. The only way to understand these variables (such as minimum water supply and pump discharge pressure) is to develop information and plans in advance in non-emergency situations.
Some jurisdictions have taken a proactive approach, requiring FDC entrance pressure to be posted along with other required signs at the junction (photo 23). This eliminates the need for pump operators to calculate or locate critical system information in an emergency. The simple operation of publishing this information on FDC ensures that appropriate support is provided to the system in an emergency. By the way, the riser system (NFPA 14) has been requiring the entry pressure to be posted at the FDC for more than 20 years. One of the best times to develop information about the system design and required FDC support is during construction. When installing the system, plan and design documents can be obtained at any time in the building and permit documents. In addition, the installation contractor can be easily found, and the personnel responsible for installation and testing can answer questions about the system. This information can then be posted on the sign to make emergency operations more reliable. Even a few years after the project is completed, memories may disappear and documents may become difficult to find, which will hinder the development of advance plans. It is best to seize the opportunity to learn, and work is still fresh in everyone's mind.
Although all this pre-planning and signage sounds good, we still have to know what to smoke without any other building-specific information. If the normal operation of the sprinkler device does not require a pressure exceeding 175 psi, the connection does not require special markings or markings according to national standards. Therefore, the design pressure of all system components and piping is at least 175 psi, which means that the fire department can provide up to 175 psi pressure to the connection without causing excessive risk of system damage. Depending on the size of the supply hose and the distance from the pump to the FDC, you may need to adjust the discharge pressure of the pump; the final delivery pressure of 175 psi to the FDC is the maximum delivery pressure you should consider, and only if the fire spreads.
If you are dealing with a single-story or low-rise building with slight smoke or fire, you should of course reduce the water supply and increase the water supply as needed when the fire worsens. The initial operation should introduce a pressure of approximately 100 psi into the FDC inlet, and then gradually increase to 125 psi while continuously measuring the progress. Most sprinklers in low- and medium-rise buildings do not have building fire pumps to increase water pressure; therefore, sprinkler systems have been designed to work under the available city pressure, usually 65 psi to 95 psi. The complementary nature of the 125 psi FDC will greatly increase the density of the water delivered through the working sprinklers; only consider 125 psi when you are facing a large-area building or vertical residential area where the fire situation is obviously not controlled by the sprinkler system Up to 175 psi pressure. Take all precautions to avoid the sudden introduction of high pump discharge pressure into the FDC. The sudden influx of water into the system is of no benefit, and may damage the system pipes or cause system pipe failures.
Once a building's sprinkler system requires an FDC inlet pressure of more than 175 psi, specific signs need to be used to indicate the working pressure and maximum pressure that can be provided to the system. This usually occurs in high-rise buildings above 15 stories, where one or more fire pumps can be used to overcome excessive elevation loss. Failure to provide post pressure under these conditions may cause the equipment pump to simply agitate without water flowing into the system.
When using a property equipped with risers, the situation is slightly different and requires a deeper understanding of the support required. Although the sprinkler system requires sufficient automatic water supply, the riser system can be installed without water supply, and the water supply system can meet all the requirements for operating the hose flow. A riser system connected to a water supply system capable of providing the required hose flow is considered "automatic" and can be wet or dry. Other riser systems that do not provide water supply capable of supporting hose flow are considered "manual"; they can also be wet or dry. This information is critical because the code fully allows manual systems, because the urgency of providing full support for all expected hose flows becomes critical when you arrive at an event. Until you get a reliable water supply and pump that amount of water into the FDC, you cannot let the staff use the internal hose outside the standpipe. You can calculate the required volume by multiplying the number of hoses by 250 gpm, and make sure that you have all available hose connections on the FDC fed from the pumping equipment with their own hoses.
Establishing the correct minimum pressure for FDC requires pump operators to perform more calculations based on the length of the hose to the FDC, the vertical height to the fire floor, the length of the attack hose leaving the standpipe, and the working pressure of the specific nozzle. National standards once required The riser provides 65 psi of pressure at the hose valve at the top of the building. The 65 psi is based on the belief that the attack hose will be a 100-foot-long 2½-inch hose with a smooth 11⁄8-inch nozzle. The tragic One Meridian Plaza fire has raised concerns about the use of smaller hoses with automatic nozzles and the incorrect setting of pressure regulators on the hose valves. The lessons learned in this fire led to changes in the national standards for riser systems, including hose valves that deliver a pressure of at least 100 pounds per square inch to the top of the riser building. However, this change has no impact on any existing systems; today, some jurisdictions still allow riser systems to be designed at 65 psi. New Jersey’s current building codes even allow riser systems to not meet any residual pressure requirements when installed outside high-rise buildings with NFPA 13 sprinkler systems. These designs under the building code allow for the requirement that the response firefighting equipment should immediately and completely support the expected water flow before any internal attack is carried out. It is absolutely useless if only 20 psi or 30 psi attack hoses are provided under the permission of building codes. If there is no timely and reliable water supply, the appearance of a functional riser system in such buildings may lead to tragic results. Immediate development .
To calculate the FDC inlet pressure on a riser system, you must first understand the flow and pressure requirements of your institution's riser hose set (including nozzles). If you follow national standards, including systems prior to 1993, 65 psi (100 feet of 2½ inch hose and 11⁄8 inch smooth hole nozzle). For your organization, this becomes a fixed value. You must only calculate the distance between the equipment and the FDC, and then calculate the height from the FDC to the highest operating floor and the pipeline loss. Although we are likely to be connected to a riser or two on the floor below the fire site, we will still operate on the fire site board, so we must take into account the elevation loss. In addition, vertical operations may require hoses to run above the fire site to control internal extension and automatic exposure, all of which occur one or more layers above the fire site. It is necessary for the pump operator to consider this highest operating floor when estimating the elevation loss in the riser system. The pressure loss due to altitude is calculated as 0.433 psi per foot (for ease of memory and calculation, we rounded it to 5 psi/10 feet). Again, this is not an exact science. Our goal is to provide the crew with reasonably close water supply and allow them to control the slight pressure difference.
It is difficult to estimate the actual friction loss of the pipes and various fittings in the system. You must use your own experience and best guesses to determine the pipeline distance from the FDC to the riser where the staff is working. In large urban block buildings, the FDC may be connected to the staff at a horizontal distance of hundreds of feet. On the other hand, the FDC of a smaller building may be located on the opposite wall to the riser, and there are hardly any horizontal pipes to deal with. If your best guess is to pump 250 psi into the riser of the third-floor fire, then the internal staff cannot do anything to stop your severe overpressure. In the early stages of hose operations, it is reasonable to expect to communicate about pressure adjustments, but internal personnel are responsible for providing available information to the pump operator. Hopefully the running hoses are equipped with an online pressure gauge so that you can accurately hear their pressure as they flow out of the valve, and you can adjust your pump from there. There is no value in the report that more pressure is needed-do you need another 5 psi or 50 psi? The report should be short but provide useful information. The response to increasing the pressure by 15 psi is not "I have given you 145 psi". If the crew wants another 15 psi, that is what they want. The pump operator does not need to know how the building’s pipes are configured and where additional friction losses occur. It is your responsibility to always provide sufficient flow while maintaining the lowest operating pressure of the highest operating hose; changes of 10 to 20 pounds above the actual requirement are easily absorbed and gated on each floor.
In addition to all planning and construction inspections, there are unavoidable fires that must be mitigated professionally by the responding fire department. In this case, what you do and don't do in the early stages will have a significant impact on the results of you, your organization, and the community. This is the moment when your training and advance planning will pay off. Here are some things you need to keep in mind.
DAVID T. PHELAN has worked in the fire department for 18 years as a member of the Bergenfield (New Jersey) Fire Department. He is a certified Class I firefighter and a licensed fire/construction officer who has worked extensively in various public agencies in the field of fire protection and construction law enforcement. As a lecturer, he has developed a number of courses related to fire protection systems and taught in the fire licensing courses of local universities.