Topic: Fire Protection Systems

Fire Alarm Pull Station Installation Height

Are you in the field installing a fire alarm system and need to know what the required fire alarm pull station height is? Or maybe you are working on a fire alarm design detail and want to know what the required height is for your fire alarm call point. You’re not the first one to ask this question, so I will get right into it. NEW! Download the Installation Heights for Wall-Mounted Fire Alarm Equipment graphic for free from NFPA What is the required height for a fire alarm pull station? The simple answer that the operable part of the pull station needs to be at least 42 in. (1.07 m), and not more than 48 in. (1.22 m), above the finished floor. Additionally, one pull station needs to be within 5 ft (1.5 m) of each exit doorway on each floor where required to be installed in a building. Both of these requirements are shown below. The code requirements NFPA 72®, National Fire Alarm and Signaling Code®, refers to a fire alarm pull station as a manually actuated alarm-initiating device, and defines it as a manually operated device used to initiate a fire alarm signal. Other publications may refer to a fire alarm pull station as a manual fire alarm station, pull station, fire box, call point, and so on. The requirements for the installation height can be found in Section 17.15 of the 2022 edition of NFPA 72. If you want to learn how you can easily find those requirements in the code using NFPA LiNK®, take a look at the video below.     It’s important to note that NFPA 72 does not require that manual initiating devices be installed in buildings. Instead, it provides the installation requirements when the devices are required by other codes such as NFPA 101®, Life Safety Code®, NFPA 1, Fire Code, or NFPA 5000®, Building Construction and Safety Code®. Mounting the back box When mounting the back box for a manual pull station it is important to know the make and model of device that will ultimately be installed. As you saw above, the measurements are taken to the operable part of the device, not the middle of the device. Additionally, these measurements are taken from the finished floor, so when installing back boxes prior to the installation of the flooring, the thickness of the flooring must be accounted for in the measurement. Tolerances NFPA 72 allows a tolerance for the installation of devices. This tolerance is noted in 1.6.5 and A.1.6.5. Where dimensions are expressed in inches, it is intended that the precision of the measurement be 1 in., which would be plus or minus 1⁄2 in. The conversion and presentation of dimensions in millimeters would then have a precision of 25 mm, which would be plus or minus 13 mm. Therefore, the maximum height of the operable portion of the manually actuated alarm-initiating device could be up to 48.5 in. (1.233 m) if you account for the allowable tolerances in NFPA 72. Other wall-mounted appliance and device heights Do you want to learn more about installation heights for other fire alarm devices, appliances, and equipment? The video referenced earlier in this blog outlines how you can use the direct navigation feature of NFPA LiNK (NFPA DiRECT®) to find the mounting heights not only for fire alarm pull stations, but also for other wall-mounted fire alarm equipment, as well as all of the supporting code requirements.  

Basics of Fire Sprinkler Calculations: Selecting the Design Area in the Density/Area Method

Automatic fire sprinkler systems have consistently demonstrated their ability to reduce the impact of unwanted fires.   But when a sprinkler system fails, many times it is due to insufficient water reaching the fire. An NFPA® research report titled “U.S. Experience with Sprinklers” found that when a system fails to contain a fire, 50 percent of the time it was because water did not reach the fire at all, and 31 percent of the time not enough water reached the fire.   These statistics underscore the importance of effectively calculating the water demand needed for the automatic fire sprinkler system; otherwise, the system may not be effective at reducing the impact of a fire.   This is the first in a series of blogs aimed at providing an overview of the basics of fire sprinkler design calculations (demand calculations) using the density/area design method found in the 2022 edition of NFPA 13, Standard for the Installation of Sprinkler Systems. Today we will focus on subsection 19.2.3, which addresses the water demand, and paragraph, which specifies the hydraulic calculation procedures specific to the density/area design method.   Density/area method   The density/area method can be generally defined as a given amount of water (sprinkler discharge rate) over a specified area. This given amount of water is known as the design density, which is intended to provide cooling and wet adjacent surfaces with the goal of controlling an unintended fire until it can be fully extinguished by emergency services. The area is the expected area of sprinkler operation, or remote area for which the given amount of water (design density) must be applied. For water demand calculations, it’s assumed all sprinklers in this area will operate. This area is often adjusted for things like quick-response sprinklers, sloped ceilings, dry-pipe, double interlock systems, and high-temperature sprinklers.   Remote area   When calculating the water demand needed for the system it is imperative that the correct location on the sprinkler system be chosen as the remote area. Although most fire sprinkler system calculations are done utilizing hydraulic calculation software, many are integrated into computer aided drafting (CAD) programs. The ability of the program to correctly calculate the water demand is directly related to the user’s ability to select the correct area.   The area selected should be the hydraulically most demanding, which is often physically the furthest point from the sprinkler riser on the system. However, in some instances, pipe sizes may make an area physically closer to the riser more hydraulically demanding. An example of this may be an instance closer to the sprinkler riser, which utilizes a more condensed spacing than the physically most remote portion of the system. When in doubt, it is best to calculate multiple areas.   Identifying the remote area   The steps in identifying the remote area involve determining the area (square footage or square meters) from the design criteria, applying the necessary adjustments to this area, calculating the shape, determining the number of sprinklers necessary in the area, and selecting those sprinklers that meet the remoteness and shape criteria. Let’s walk through a basic example for remote area selection on a system with a main line and branch lines (not gridded or looped).   The initial step is to determine the area (square footage or square meters) from Chapter 19. Since we’re utilizing the density/area method on a new system, Table applies. Determining the occupancy hazard classification is very specific to the area being protected and is a bit out of scope for this blog but certainly a topic we will cover in this series. For the sake of our calculation, let’s assume we determined the occupancy to be an Ordinary Group I hazard.     You’ll notice we’re given two options for each hazard. This is because areas adjacent to combustible concealed spaces present a unique challenge—the fire may establish itself in the concealed space and a greater number of heads may activate. Let’s assume we’ve determined we are not adjacent to a combustible concealed space, so the 0.15 gpm/ft2 (6.1 mm/min/m2) over 1500 ft2 (140 m2) applies, thus our area is 1500 ft2 (140 m2). Remember, this area may be adjusted for things like quick-response sprinklers, sloped ceilings, dry-pipe, double-interlock systems, and high-temperature sprinklers. For our example, let’s assume none of these adjustments applies.   After determining the size of the remote area, we’ll need to determine its shape. Paragraph indicates that “a rectangular area having a dimension parallel to the branch lines at least 1.2 times the square root of the area of sprinkler operation (A)” is utilized. As an equation that is:   L = 1.2√A Where:  L = the dimension parallel to the branch line (ft or m) A = the area of operation (ft2 or m2)   For the sprinkler operation area in this example, we get:   L = 1.2√(1500 ft2  (L = 1.2√140 m2) L = 46.5 ft (L = 14.2 m)   We’re going to assume we’re utilizing a sprinkler coverage area of 120 ft2 (11.1 m2), which is under the maximum allowable square footage for an Ordinary Group I hazard with standard-spray sprinklers of 130 ft2 (12 m2) with sprinklers spaced 12 ft (3.6 m) apart along the branch line and branch lines 10 ft (3 m) apart as shown below.     The next step is to determine the number of sprinklers in the area. To accomplish this, we’ll divide the area from Table by the coverage area per sprinkler.   1500 ft2 / 120 ft2 = 12.5 sprinklers   Since it’s not possible to activate half a sprinkler head, we round the number to 13 sprinklers.   Now that we have the shape and the number of sprinklers in the design area, we apply that to our layout and select the 13 most remote sprinklers that meet our remote area shape criteria.   To meet the shape requirement of 46.5 ft (14.2 m) long, we’d need to utilize five sprinklers along the branch line. To meet the number of sprinklers, we’d need an additional eight sprinklers, five along the next branch line and three along the third. We’re permitted to utilize any of the sprinklers along the third branch line. Most commonly, the ones closest to the cross main are selected as they will result in the greatest flow. This is shown graphically below.     As you can see, even in this simple example there are nuances to selecting the design. Keep in mind, this was one of many design options for new sprinkler systems in NFPA 13. Evaluation of existing systems has separate criteria. Make sure to utilize the correct option for your situation.   Wrapping up   Even when utilizing computer software, engineers and designers need to select these sprinklers correctly to ensure they accurately provide the water demand needed in the event of an unwanted fire. Next up in this series of blogs we’ll look at the K-factor formula for determining the flow of the starting sprinkler.   For more information about NFPA 13 sprinkler system design, check out the NFPA 13 Online Training Series. The training has been updated recently to reflect the most current 2022 edition of NFPA 13. Module 2 of this training provides users with a comprehensive overview of the calculations we discussed in this blog.

How To Maintain Building and Equipment Access for the Responding Fire Department

When facility managers and building owners think of fire department access, they typically think about keeping a fire lane clear, so the responding fire department has a place to set up their equipment in case of an emergency. While this is critical to an effective response, there are many other aspects of a building that need to be properly maintained to provide appropriate fire department access to the building, as well as crucial fire and life safety equipment.  Building Identification To assist emergency responders in locating properties, building address numbers must be visible from the street. Premises or building identification is covered in Section 10.11 of NFPA 1, Fire Code. Address numbers can be mounted either on the building itself or, if the building is not visible from the street, on a post located on the street. The numbers should be designed to contrast the background of the building or post and be large enough to be easily seen from the street. Fire Apparatus Access Road To provide effective manual fire suppression operations, the fire department must be able to gain reasonable access to a building. Chapter 18 of NFPA 1 provides requirements for fire apparatus access. According to the Fire Code, access roads must be provided and maintained to allow the fire apparatus to be able to get within 50 ft (15 m) of at least one exterior door and to be within at least 150 ft (46m) of all exterior portions of the first story—this is increased to 450 ft (137 m) if the building is sprinklered. These access roads should be kept unobstructed to a width of not less than 20 ft (6.1 m) and a height of not less than 13 ft 6 in. (4.1 m). Keep in mind that these widths and heights may be altered by the local authority having jurisdiction (AHJ) to accommodate responding apparatus. It is also important to maintain the proper turning radius needed for the responding apparatus and ensure that any required turnaround space is also kept clear. If the access road has a dead end that is greater than 150 ft (46m), a turnaround space is required. To ensure that your fire apparatus access roads are unobstructed from any parked vehicles or other obstructions, it may be a good idea to provide signs or roadway markings. This is something that may also be required by the AHJ. Access Boxes The fire department must be able to open any doors leading into the building that may be locked. This means an access box may be required by the AHJ to give the fire department the ability to obtain keys to unlock the building during an emergency. Typically, these access boxes are located near the front entrance of the building. If these access boxes are not provided, it is likely that the first responders may need to perform some forcible entry to gain access to the building, which means doors may be damaged or destroyed. If access to the premises is secured by a locked gate, then the fire department must be provided with an approved device or system to unlock the gate. This could be done with the installation of an access box on or near the gate that contains keys to the gate, or the responding fire department can be provided with an access card or other security device. Fire Hydrants The fire department also needs access to water. This is typically done by connecting to fire hydrants located on or near the property. All fire hydrants should be maintained so that a clear space of not less than 36 in. (914 mm) is provided all the way around the hydrant. Additionally, a clear space of 60 in. (1524 mm) needs to be provided in the front of a hydrant if it has a connection that is greater than 2 1⁄2 in. (64 mm). This clear space is provided to allow the connection and routing of hose lines. If you live in a cold climate, this means that all snow must be removed from around the hydrant after each storm. Fire Department Connection Your building may also have a fire department connection. This is a hose connection or series of hose connections located on the exterior of the building that connect either to a standpipe system or to the sprinkler system. Connections to standpipe systems allow the fire department to pressurize the standpipe system in the building so they can connect their hose lines to pre-installed hose connections within the building to fight the fire. Connections to the sprinkler system allow the fire department to pump additional water into the sprinkler system increasing the amount of available water and pressure within the system to control the fire. If your building has a fire department connection it is important to maintain proper access, which is outlined in Chapter 13 of NFPA 1. Most importantly, the code requires that a minimum of 36 in. (915 mm) of clear space be maintained to ensure the fire department can not only see the fire department connections but can also make use of them. This includes making sure any tree branches or vegetation are cut back and no other obstructions, such as trash cans, are present. Fire Alarm Control Unit If your building has a fire alarm and signaling system, it is important that the fire alarm control unit (FACU)—also known as the fire alarm panel—is accessible. The FACU allows the fire department to identify which initiating devices are in alarm to help them better locate the fire. If the fire alarm system also contains an emergency voice communication system, then the fire department can also use the system to communicate with occupants in the building to give them direction. Typically, the fire alarm control unit is going to be located near a main entrance in an area such as the lobby. It is also possible that the fire alarm control unit is in a different place and a fire alarm annunciator is placed near the main entrance. This fire alarm annunciator is connected to the fire alarm control unit and allows the first responders to see all of the displays on the fire alarm control unit from a remote location. Both the fire alarm control unit and any fire alarm annunciators must be free of any obstructions and must be visible at all times. If either the fire alarm control unit or the annunciator is locked, it is important to provide the fire department with keys so they can operate the system. Emergency Command Center If your building is a high-rise, meaning that it’s a building where the floor of an occupiable story is greater than 75 ft (23 m) above the lowest level of fire department vehicle access, then it is likely that your building has an emergency command center or a fire command center. This is a space that is separated from the remainder of the building with fire resistance–rated construction and provides a space for the fire department to set up their command if there is an emergency or fire in the building. The emergency command center may contain the following: ·      The fire department communication unit ·      A telephone for fire department use ·      Schematic building plans detailing the floor plan, means of egress, fire protection systems, firefighting equipment, and fire department access ·      A work table ·      The fire alarm control unit (fire alarm panel) or annunciator ·      Elevator location indicators ·      Emergency and standby power indicators ·      Fire pump status indicators ·      Smoke control system controls Typically, these rooms are located near the main entrance of the building or off the main lobby. It is crucial that these spaces remain accessible and are free from all storage or obstructions.  Fire Pump Room A fire pump may be required in your building to provide the required water pressure for a standpipe system or an automatic sprinkler system. Fire pumps are required to be in a room that is separated from the remainder of the building with fire resistance­–rated construction. If your building has a fire pump room, it is important that this room be properly identified and free of all storage and equipment that is not essential to the operation of the fire pump. Fire pump rooms are required to be accessed from a protected interior pathway or from an exterior door, so it is also important to ensure that the protected interior pathway or the path to the exterior door of the pump room is also free and clear of obstructions. Summary As you can see, there are many more aspects to fire department access than just keeping a fire lane clear. We want to make sure that the fire department and first responders can properly identify the building as well as access all of the building equipment that they may need during their response. It is important to get into a habit of regularly checking these items as you never know when you might need the fire department or first responders at your building, and in the case of an emergency, every second counts. Interested in learning more? Take a look at this video excerpt (below) from our Fire and Life Safety Operator Online Training, which goes over items that need to be maintained to assist the fire department.

Do You Travel with a Portable CO Alarm? If not, you should, and here’s why

Being raised by a volunteer firefighter, I was taught at a young age to always look for my 2nd exit, and when traveling to never to stay above the 4th floor because fire department ladders rarely reach above the fourth floor. It was also pretty “normal” for us to travel with a portable Carbon Monoxide (CO) alarm. Why? Because CO poisoning incidents in hotels are not uncommon and regulations on CO detection differ significantly from state to state. While there are multiple sources which provide CO incident data, each organization contains its own methodology for collecting information and providing statistics; However, it is not clear what specific information is being collected, disseminated, and represented for each incident type. The Fire Protection Research Foundation recently published a report titled: “Carbon Monoxide Incidents: A Review of the Data Landscape” which reviews and presents the CO incident data landscape to clarify the sources of information, how the data is compiled and what the data represents. Additionally, the report identifies, summarized, and analyzes case studies of non-fire carbon monoxide incidents specific to commercial-type occupancies to provide a greater understanding to the NFPA technical committees responsible for NFPA 101, Life Safety Code ® and NFPA 5000, Building Construction and Safety Code ®.  Be on the lookout for the Second Draft Reports from these committees in February of 2023 to see what changes have been made. A one-page summary of the Foundation report provides key takeaways. PS: If your CO alarm is your in carry-on bag, be sure you can access it quickly while going through TSA security, as mine is always “inspected”!  

Backflow Preventer Types

When a fire protection system (non-potable water system) is connected to the public water supply, the systems are said to be cross connected. In some localities, cross connections may be prohibited or closely regulated by health authorities.  Improperly protected water systems have the potential to lead to illness and even in some cases death. Federal regulations require states to provide quality water when it is intended for public consumption. Because of this, states and municipal governments have taken various steps to protect the potable water supply, such as requiring backflow prevention when the fire protection system will be supplied by a potable water source. Backflow preventers are installed to prevent contaminants from traveling from the non-potable source to the potable public drinking supply via back siphonage and back pressure.  Back siphonage is backflow caused by a negative pressure in the supply piping. This negative pressure in the supply piping is similar to drinking water through a straw. The water from the non-potable system is pulled into the supply piping. Backpressure is backflow caused by a pressure in the non-potable water system being greater than the pressure in the potable water supply piping. This higher pressure causes water in the non-potable system to be pushed back into the supply piping.  Its important to note here that the requirement for backflow prevention in a fire protection system comes from the local water authority and not from any NFPA standard. For example, NFPA 13 does not require a backflow preventer for an automatic sprinkler system, however, if one is required, it provides additional requirements to ensure it is installed in a manner that limits its impact on system operation and provides for a means to test the system.  There are a few different types of backflow preventers available, and the type of backflow preventer required by the water authority is going to be based on the degree of hazard posed by the cross connection. The degree of hazard may be classified differently, but the two main degrees include high hazard and low hazard. A high hazard is a system that could introduce waterborne disease organisms, or harmful chemical, physical, or radioactive substances into a public water system, and which presents an unreasonable risk to health. An example of this may be a system that contains an additive, such as a fire protection system with antifreeze, or a foam system. A low hazard is a system that could cause aesthetic problems or have a detrimental secondary effect on the quality of the public potable water supply, an example of this could be a fire sprinkler system that contains stagnant water or contains microbiologically influenced corrosion (MIC). The Double Check Valve Assembly (DCVA) and the Reduced Pressure Zone Assembly (RPZA) are the most used backflow preventers for fire protection systems, but I will discuss all the most common backflow preventers used in plumbing systems. An air gap is the most effective type of backflow prevention. This method utilizes a physical air space between the potable and non-potable systems. The most common example of this would be a faucet and a sink. This may be a backflow prevention method used to fill a water supply tank. Air gaps can be used to protect low and high hazards under both back siphonage and backpressure. An Atmospheric Vacuum Breaker Assembly contains an air inlet valve and a check seat. When water flows through, the air inlet valve closes, but when the water flow stops, the air inlet valve falls against the check seat and stops back siphonage, while at the same time letting air into the system. AVBs can only protect against a low or high hazard under back siphonage. The Pressure Vacuum Breaker Assembly is like an atmospheric vacuum breaker, but it contains a spring-loaded air inlet valve and check valve, two shutoffs, and two test cocks. When water is flowing, the check valve is open and air inlet valve is shut, when water stops flowing, the check valve shuts, and air inlet valve opens. The addition of the shutoff valves and test ports allows for this assembly to be field tested. The PVB only protects against low or high hazards under back siphonage. A Double Check Valve Assembly (DCVA) contains two spring-loaded check valves with two shut off valves and four test cocks. In the event of a backflow the first check valve will close, if that check valve fails then the other check valve will close. The addition of the shutoff valves and test ports allow this assembly to be tested. A DCVA can be used to protect against low hazards under both back siphonage and back pressure.   A double check valve detector assembly is the same as a DCVA, but it also includes a bypass for the installation of a water meter to monitor for incidental water use that is also protected with a smaller DCVA.   A Reduced Pressure Zone Assembly (RPZA) provides the maximum protection and along with the DCVA is the most common type of backflow prevention used in fire protection systems. This assembly contains two spring-loaded check valves with a differential relief valve between them and two shut off valves and four test cocks. The RPZA operates like a DCVA with the addition of a relief valve, if there is a backflow the check valves will close, and the relief valve will open, resulting in a reduced pressure zone and air gap between the check valves. The two shut off valves and four test cocks allow this assembly to be field tested as well. The RPZA can be used to protect high and low hazards under both back siphonage and back pressure.    A reduced pressure zone detector assembly is the same as a RPZA, but it includes a bypass for the installation of a water meter to monitor for incidental water use that is also protected with a smaller RPZA. As you can see, there are a few different types of backflow preventers, and the selection of the right preventer is going to depend on the requirements from the local water authority as well as the hazard. When the design of a fire protection system includes a backflow preventor, the designer must make sure that they account for the backflows impact on the available water supply pressure. If a backflow preventor is installed on a fire protection system, it is also important that proper inspection testing and maintenance (ITM) be performed (such as a forward flow test) to ensure that the backflow remains operational and does not seize up, which could impair the fire protection system.

What are the code requirements for haunted house attractions?

A version of this blog written by Kristin Bigda, publications strategy director at NFPA, first appeared in 2016. The article has been edited to reflect more recent code editions. With Halloween quickly approaching, thoughts of candy, ghosts, and haunted houses are surely on your mind. While haunted houses may be an entertaining way to spend an October evening, there can be devastating consequences if a fire were to break out and proper protections aren’t in place. What are haunted houses and special amusement buildings? Haunted houses may be temporary in nature or permanently installed. Sometimes, they are used only near Halloween, while others may be open year-round. This was the case in the tragic Haunted Castle fire that occurred at a permanently installed, year-round haunted house located at a Six Flags amusement park in New Jersey on May 11, 1984. Eight teenagers died in that blaze.  To prevent a similar tragedy to the Six Flags haunted house fire, provisions were added to NFPA 1, Fire Code, and NFPA 101®, Life Safety Code®, to address special amusement buildings—the category in which haunted houses typically fall. According to the 2021 edition of NFPA 1, a special amusement building is “a building or portion thereof that is temporary, permanent, or mobile and contains a ride or device that conveys patrons where the patrons can be contained or restrained, or provides a walkway along, around, or over a course in any direction as a form of amusement or entertainment, and arranged so that the egress path is not readily apparent due to visual or audio distractions, contains an intentionally confounded egress path, or is not readily available due to the mode of conveyance through the building or structure.” A special amusement building is an assembly occupancy regardless of occupant load. Special amusement buildings often use special effects, scenery, props, and audio and visual distractions that may cause egress paths to become difficult to identify. In haunted houses, in particular, the presence of combustible materials and special scenery can also contribute to the fuel load and, may result in rapid fire spread should a fire occur.   “ Haunted houses use special effects, scenery, props, and audio and visual distractions that may cause egress paths to become difficult to identify What does the code say? Code provisions for special amusement buildings are found in Section 20.1.4 of NFPA 1. The code requirements for haunted houses are summarized below: Haunted houses must apply the provisions for assembly occupancies in addition to the provisions of Section 20.1.4. Automatic sprinklers are required for all haunted houses unless it is less than 10 feet (3050 millimeters) in height and has less than 160 square feet (15 square meters) of aggregate horizontal projections. If the haunted house is considered moveable or portable, an approved temporary means is permitted to be used for water supply.  Smoke detection is required throughout all haunted houses.  The actuation of any smoke detection device in a mobile or temporary haunted house must sound an alarm at a constantly attended location on the premises. A fire alarm system is required in all permanently installed haunted houses.   The fire alarm system in all permanently installed haunted houses must be initiated by required smoke detection, the required automatic sprinkler system, and manual means at a constantly attended location under continuous supervision by competent persons when the haunted house is open to patrons. Actuation of sprinklers, or any suppression systems, as well as smoke detection systems (having cross-zoning capability) must provide an increase in illumination of the means of egress and termination of other confusing visuals or sounds. The one exception is for haunted houses that are in permanently installed special amusement buildings that use a ride (or similar device) that occupants are contained in and unable to evacuate themselves without the help of a ride operator and that meet specific criteria. Exit marking and floor proximity exit signs are required. Where designs are such that the egress path is not apparent, additional directional exit marking is required. Interior wall and ceiling finish materials must be Class A throughout. Per Section 10.8.1, emergency action plans are required. Other requirements, not specific just to haunted houses or special amusement buildings, may also apply, such as:  Permits (see Section 1.12) Seasonal buildings (see Section 10.12) Special outdoor events, fairs, and carnivals (see Section 10.14) As we move into the Halloween and haunted house season, it’s easy to get caught up in the fun and overlook the safety issues that may arise. Through the provisions in NFPA 1, which can assist code officials and fire departments in enforcing safe haunted houses, and NFPA’s Halloween resources for consumers, everyone can stay safe this season.
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