AUTHOR: Brian O'Connor

Train at a station

Means of Egress with NFPA 130

NFPA 130 is the Standard for Fixed Guideway Transit and Passenger Rail Systems. It contains requirements for train stations, subway stations, the trains or subway cars themselves, and the tracks or paths these vehicles travel on. While NFPA 130 covers a wide array of topics this blog is going to concentrate on the unique means of egress requirements for fixed guideway transit and passenger rail stations. Means of Egress First, what is the means of egress? In layman’s terms the means of egress is the pathway out of a building or structure that leads to a point of safety and is comprised of three parts, the exit access, exit and exit discharge.    EXIT ACCESS - The exit access is the path that leads to the exit EXIT - The exit is the portion of a means of egress that is separated from all other spaces of the building or structure by construction, location or equipment as required to provide a protected way of travel to the exit discharge. Examples include an exit door that leads directly outside, an exit staircase, exit passageways, etc. EXIT DISCHARGE - Exit discharge is that portion of a means of egress between the termination of an exit and a point of safety. In NFPA 130 the point of safety can either be the concourse or a point of safety outside of the building. In general, the station needs to comply with the means of egress requirements in NFPA 101®, Life Safety Code®, for New Assembly Occupancies except where it is modified by NFPA 130. For more information on the means of egress check out this blog! The following sections discuss those modifications. Occupant Load Determining the occupant load is needed to figure out how quickly those occupants can egress the station. To determine the occupant load we need to assume that all of the trains are simultaneously entering the station full of passengers who need to disembark and that there is a full train’s worth of people waiting on the platform to enter the train. So, the occupant load includes both the people exiting the train as well as those waiting on the platform. This will give us a worst-case scenario of having all of the trains recalled to the station at once and having to evacuate both the vehicle and station. There is also the occupant load for each platform that must be calculated in order to make sure each platform can be evacuated in a timely manner. This number is based on peak ridership numbers, which can often require an analysis be done to determine peak ridership statistics. Similar to the station occupant load, the platform occupant load needs to assume a full train has pulled into the station and drops off an entire train load while there is another train load of people waiting on the platform. Evacuation Time When looking at evacuation times there are two main figures that must be considered. The first is the platform evacuation time which is required to be less than 4 minutes. The second is the station evacuation time, in which the occupant load needs to be able to reach a point of safety in under 6 minutes.  Travel Distance There are also limitations on travel distances and common paths of travel for platforms. Travel distance is your natural path of travel measured from the most remote point on the platform to the where the means of egress path leaves the platform. NFPA 130 requires that the travel distance is 100m (325ft) or less. There is also the concept of a common path of travel which is measured in the same manner as travel distance but terminates at that point where two separate and distinct routes become available. The common path of travel is not allowed to exceed 25m (82ft) or one car length, whichever is greater. Platforms Corridors & Ramps Many of the requirements for platforms, corridors and ramps are summarized in the table below. In addition to those limitations, when calculating available egress capacity on platforms, corridors, and ramps, 12 inches must be subtracted from each wall and 18 inches subtracted from the platform edge.   Capacity Travel Speed Minimum width Platforms 2.08 p/in.- min (0.0819 p/mm-min) 124 ft/min (37.7 m/min)   44 in. (1120 mm) Corridors 2.08 p/in.- min (0.0819 p/mm-min) 124 ft/min (37.7 m/min)   44 in. (1120 mm) Ramps 2.08 p/in.- min (0.0819 p/mm-min) 124 ft/min (37.7 m/min)   44 in. (1120 mm) Concourse   200 ft/min (61.0 m/min)   Stairs   48 ft/min (14.6 m/min)* 44 in. (1120 mm) Escalators 1.41 p/in.-min (0.0555 p/mm-min) 48 ft/min (14.6 m/min)*   Elevators carrying capacity for 30 minutes     *Travel Speed for vertical component of travel Escalators NFPA 101 typically doesn’t allow escalators to be used as a component in the required means of egress but because of the short evacuation timeframe, NFPA 130 allows it. When determining egress capacity for escalators there are a few rules that need to be followed. One escalator at each level must be assumed to be out of service and escalators cannot account for more than 50% of the egress capacity for a level unless they meet additional criteria. Elevators Elevators are another unique component of the means of egress that is allowed to be used in fixed guideway and passenger rail stations, but they also come with additional rules. One elevator must be considered out of service, elevators can’t account for more than 50% of the egress capacity and one elevator must be reserved for the fire service. The capacity of elevators is determined by calculating the carrying capacity over a 30-minute timeframe. Elevators also must meet certain construction requirements and they need to be accessed through holding areas or lobbies. Exit Hatches Exit hatches are another unique component of the means of egress permitted for fixed guideway and passenger rail stations. Exit hatches must be manually opened from the egress side with only one releasing operation requiring less than 30lb (130N) of force and have a hold-open device. It also needs to be clearly marked on the discharge side to prevent blockage. Fare Barriers Fare barriers are typically gate type or turnstile type, each of which have additional requirements that must be met to be allowed in the means of egress. Fare barriers are a unique characteristic of a station and have unique requirements. For a fare barrier to be allowed in the means of egress it must either be designed to release in the direction of travel during an emergency or be able to open by providing 15lbf (66N) of force in the egress direction. Platform Edge Provisions Finally, the platform edge is another unique feature of a station. Guards are not required along the trainway side of the platform edge. Certain horizontal sliding platform screens or doors are permitted to separate the platform from the trainway, but the doors or screens must open with less than 50 lb (220N) of force at any stopping position of the train and it needs to be able to withstand the positive and negative pressures caused by the passing trains. There are many unique fire and life safety elements found in Fixed Guideway Transit and Passenger Rail Systems. This blog discussed some of the unique means of egress characteristics, but NFPA 101 contains many more requirements that must be followed. 
Fire extinguisher on the wall

Fire Extinguisher Types

In the hands of a trained person, portable fire extinguishers are great tools to protect people and property from fire during early stages. When using an extinguisher or selecting an extinguisher to install, it’s important to know the characteristics of different fire extinguishers. This blog will address the different types of fire extinguishers by breaking them down by their extinguishing agent, which is the material inside the extinguisher that gets applied to the fire. Class of Fire Description Class A Fires Fires in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics. Class B Fires Fires in flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, alcohols, and flammable gases. Class C Fires Fires that involve energized electrical equipment. Class D Fires Fires in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium. Class K Fires Fires in cooking appliances that involve combustible cooking media (vegetable or animal oils and fats). Water Water is the primary liquid used in these extinguishers, although sometimes other additives are also included. A drawback for pure water fire extinguishers is that it is not suitable for use in freezing conditions since the water inside will freeze and render the extinguisher unusable. Certain types of water fire extinguishers contain antifreeze which will allow the extinguisher to be used in freezing conditions. Water type fire extinguishers can also sometimes contain wetting agents which are designed to help increase its effectiveness against fire. These extinguishers are intended primarily for use on Class A fires.  Water mist extinguishers are a type of water fire extinguisher that uses distilled water and discharges it as a fine spray instead of a solid stream. Water mist extinguishers are used where contaminants in unregulated water sources can cause excessive damage to personnel or equipment. Typical applications include operating rooms, museums, and book collections. Film-forming foam type AFFF (aqueous film-forming foam) and FFFP (film-forming fluoroprotein) fire extinguishers are rated for use on both Class A and Class B fires. As the name implies, they discharge a foam material rather than a liquid or powder. They are not suitable for use in freezing temperatures. An advantage of this type of extinguisher when used on Class B flammable liquid fires of appreciable depth is the ability of the agent to float on and secure the liquid surface, which helps to prevent reignition. Carbon Dioxide type The principal advantage of Carbon Dioxide (CO2) fire extinguishers is that the agent does not leave a residue after use. This can be a significant factor where protection is needed for delicate and costly electronic equipment. Other typical applications are food preparation areas, laboratories, and printing or duplicating areas. Carbon dioxide extinguishers are listed for use on Class B and Class C fires. Because the agent is discharged in the form of a gas/snow cloud, it has a relatively short range of 3 ft to 8 ft (1 m to 2.4 m). This type of fire extinguisher is not recommended for outdoor use where windy conditions prevail or for indoor use in locations that are subject to strong air currents, because the agent can rapidly dissipate and prevent extinguishment. The concentration needed for fire extinguishment reduces the amount of oxygen in the vicinity of the fire and should be used with caution when discharged in confined spaces. Halogenated agent types Halon The bromochlorodifluoromethane (Halon 1211) fire extinguisher has an agent that is similar to carbon dioxide in that it is suitable for cold weather installation and leaves no residue. It is important to note that the production of Halon has been phased out because of the environmental damage it causes to the earth’s ozone.  Some larger models of Halon 1211 fire extinguishers are listed for use on Class A as well as Class B and Class C fires. Compared to carbon dioxide on a weight-of-agent basis, bromochlorodifluoromethane (Halon 1211) is at least twice as effective. When discharged, the agent is in the combined form of a gas/mist with about twice the range of carbon dioxide. To some extent, windy conditions or strong air currents could make extinguishment difficult by causing the rapid dispersal of the agent. Halon Alternative Clean Agents There are several clean agents that are similar to halon agents in that they are nonconductive, noncorrosive, and evaporate after use, leaving no residue. Larger models of these fire extinguishers are listed for Class A as well as Class B and Class C fires, which makes them quite suitable for use on fires in electronic equipment. When discharged, these agents are in the combined form of a gas/mist or a liquid, which rapidly evaporates after discharge with about twice the range of carbon dioxide. To some extent, windy conditions or strong air currents could make extinguishing difficult by causing a rapid dispersal of agent. Clean agent type extinguishers don’t have a detrimental effect on the earth’s ozone so these are more widely available than Halon type extinguishers. Dry chemical types Ordinary Dry Chemical The fire extinguishing agent used in these devices is a powder composed of very small particulates. Types of agents available include sodium bicarbonate base and potassium bicarbonate base. Dry chemical type extinguishers have special treatments that ensure proper flow capabilities by providing resistance to packing and moisture absorption (caking). Multipurpose Dry Chemical Fire extinguishers of this type contain an ammonium phosphate base agent. Multipurpose agents are used in exactly the same manner as ordinary dry chemical agents on Class B fires. For use on Class A fires, the multipurpose agent has the additional characteristic of softening and sticking when in contact with hot surfaces. In this way, it adheres to burning materials and forms a coating that smothers and isolates the fuel from air. The agent itself has little cooling effect, and, because of its surface coating characteristic, it cannot penetrate below the burning surface. For this reason, extinguishment of deep-seated fires might not be accomplished unless the agent is discharged below the surface or the material is broken apart and spread out. Wet chemical The extinguishing agent can be comprised of, but is not limited to, solutions of water and potassium acetate, potassium carbonate, potassium citrate, or a combination of these chemicals (which are conductors of electricity). The liquid agent typically has a pH of 9.0 or less. On Class A fires, the agent works as a coolant. On Class K fires (cooking oil fires), the agent forms a foam blanket to prevent reignition. The water content of the agent aids in cooling and reducing the temperature of the hot oils and fats below their autoignition point. The agent, when discharged as a fine spray directly at cooking appliances, reduces the possibility of splashing hot grease and does not present a shock hazard to the operator. Wet chemical extinguishers also offer improved visibility during firefighting as well as minimizing cleanup afterward. Dry powder types These fire extinguishers and agents are intended for use on Class D fires and specific metals, following special techniques and manufacturer’s recommendations for use. The extinguishing agent can be applied from a fire extinguisher or by scoop and shovel. Using a scoop or shovel is often referred to as a hand propelled fire extinguisher. Conclusion & resources While there are many different types of fire extinguishers used for different applications it is also important to know the rating of each extinguisher which will let you know the types of fires it is meant to be applied to. For more information on portable fire extinguishers take a look at the following blogs, as well as our portable fire extinguisher fact sheet. Related blogs Guide to Extinguisher ITM Guide to Extinguisher Placement

Types of Water Supplies for fire protection systems

All water-based fire protection systems have one thing in common, they need water. Without access to an adequate water supply these systems will not be function properly. When determining a water supply you need to make sure it is automatic (when required), reliable, and has sufficient volume and pressure to meet the system demand. This blog will review the different options for water sources to supply a water-based fire protection system. Connection to Public Water Supply Commonly referred to as a waterworks system, this is typically a connection to a water main at the street level. These can be controlled or operated by a municipal or private water company. A connection to a public water supply is acceptable only if a water flow test or other approved method determines that volume exceeds peak demand. The pressure also needs to exceed the peak demand but that can be increased by installing a fire pump. The water supply tested should represent the supply that might be available at the time of a fire (in other words, at times of highest demand on the waterworks system and at times of the lowest demand on the waterworks system). This is critical because public water supplies can fluctuate widely from season to season and even within a 24-hour period. These can also be affected by things such as drought, interruptions caused by flooding, or ice in winter. Some cities are also dropping delivered system pressure as a means of water conservation. A system that is designed without taking into account fluctuations in the water supply could result in insufficient pressures or over pressurization of the system. Tanks Water storage tanks are tanks that supply water for water-based fire protection systems. Water tanks can be used for several different scenarios but most commonly they are used where an adequate supply of water is not available or reliable. There are several types of tanks that can be used as a water supply such as gravity tanks, suction tanks, and pressure tanks. Gravity Tank Gravity tanks are elevated water tanks that utilize gravity to provide pressure. They might be capable of providing the necessary pressure to operate a fire suppression system on their own, or they can be used to provide water to a fire pump. Gravity tanks are not typically used in private water supplies, but they're a common part of a reliable waterworks system. Suction Tank Suction tanks are mounted on the ground or below ground. Because of this they do not utilize elevation as a primary means to increase the pressure. Suction tanks typically provide water to a fire pump, which then boosts the pressure. Special consideration is needed for below grade tanks because they must either have a vertical turbine pump or a pump located below the tank. Pressure Tank Pressure tanks contain both water and air under pressure. When a system is actuated, the pressurized air pushes the water out of the tank. Because of this, a sufficient capacity of air must be available to discharge the water from the tank at the necessary rate. Pressure tanks are rarely used because they are typically no larger than 10,000 gallons (37,850 liters). Penstock, Flume, River, Lake, Reservoir Naturally occurring sources include penstocks, flumes, rivers, ponds, and lakes. Water supply sources such as these must be arranged to avoid mud and sediment being introduced into the fire protection system piping. These are thus required to include double removable screens or strainers on the water piping intakes. Their reliability and ability to meet system demand must also be verified and potential seasonal fluctuations taken into consideration. These naturally occurring sources need to be installed with a fire pump to provide adequate pressure for the system. The authority having jurisdiction (AHJ) should be consulted when considering the use of these types of water supply sources. Recycled or Reclaimed Water There is an increased interest in using recycled or reclaimed water as a potential water supply for fire protection systems, such as sprinkler systems, due to increased interest in green and sustainable water usage, and changes in weather patterns that result in drought. The source of the water and the treatment process (if any) must be analyzed to determine that any materials, chemicals, or contaminants in the water will not be detrimental to the components of the sprinkler system it contacts. Fire Pump Several of the water supplies discussed above utilize fire pumps to increase pressure. It’s important to understand that fire pumps cannot create more water than is available from a given source. As such, fire pumps on their own are not an acceptable water supply. They may be necessary, however, to make a water supply acceptable by increasing the available pressure. For information on the different types of fire pumps see our blog on fire pump types. Acceptable sources of water for a fire pump include reliable waterworks, water storage tanks, penstocks, flumes, rivers, ponds, lakes, or any combination of these as long as the supply into the fire pump has sufficient volume to meet the system demand. Other Considerations There are several other considerations that can help in the decision-making process of selecting an appropriate water supply, including the following: Corrosion – It is important to make sure the water supply doesn’t have any corrosive properties Zebra Mussels/Microbiological Corrosion or other harmful animal life – These can severely limit the flow of water though your system or affect access to the water supply. Dirty water - Mud and debris in the water will have a negative effect on the system. Pressure variances – It is important to ensure your system takes into consideration the possible pressure variances caused by droughts, flooding, freezing, and usage of the water supply by others. Automatic Water Supplies - Most water supplies are required to operate without human intervention. Reliability - Water supplies need to be able to supply water at any time. Multiple water supplies are not required but could increase the reliability of your water. Conclusion In conclusion there are several different options for water supplies. Depending on the needs of the system that the supply is supporting and the geographical and topographical location of the building, the type of supply that is available will vary. Comment below if you’ve worked on projects that used a water supply other than a waterworks system.

Fire Extinguisher Placement Guide

In the hands of trained personnel, portable fire extinguishers are the first line of defense against incipient fires, but in order to be useful they need to be accessible. This blog tackles the topic of portable fire extinguisher placement, both how portable fire extinguishers should be distributed and exactly where they are allowed to be placed. The first step is to choose the correct extinguisher based on the fire risk. Extinguishers are broken down into the following ratings: Class A: Ordinary Combustibles Class B: Flammable Liquids Class C: Energized Electrical Equipment Class D: Combustible Metals Class K: Cooking Media The distribution of portable fire extinguishers is a balance between having an extinguisher nearby when you need it but not being overly burdened by the cost and maintenance of having excessive extinguishers. Let us start off with what NFPA 10 Standard for Portable Fire Extinguishers requires. When NFPA 10 addresses extinguisher placement it uses the term “maximum travel distance to extinguisher”. This means that at any point inside the building you should never have to travel more than the maximum distance to reach an extinguisher. It is important to ensure the distance being measured is the actual distance a person would need to walk to get the extinguisher (as shown in Figure 1) and that occupants are not expected to walk through walls. The maximum travel distance is often the limiting factor but for certain Class A extinguishers there is an additional floor area limitation. This maximum floor area that a single extinguisher can cover is directly related to the numerical A rating and level of hazard occupancy but reaches a maximum of 11,250 ft2. It is important to know both the maximum travel distance and floor area per extinguisher since you need to follow the most restrictive of the two. The following table, along with Table and of NFPA 10, will help you determine the required travel distance and maximum floor area. Let’s look at a specific example of a 6-A rated fire extinguisher in an ordinary hazard occupancy. The maximum floor area is calculated by multiplying the maximum floor area per unit of A by the numerical A rating, which gives us the following:   This means that although the maximum travel distance is permitted to be up to 75ft, if you were in a wide open area such as a large warehouse you wouldn’t be able to take advantage of the entire 75ft travel distance because of the limitations that the 9,000ft2 maximum floor area would present. Check out the table below for a maximum floor area reference guide for Class A extinguishers. Let’s look at another example of an extinguisher with enough of an A-rating to have a 11,250 ft2 maximum floor area, one might think you could space the extinguishers every 150 ft since you would be 75ft from either extinguisher if you were in the middle, but because most rooms are rectangular this creates gaps where you would be further than 75 ft from an extinguishers (see sad faces in the figure below). Instead, portable fire extinguishers should be placed every 106 ft. to take advantage of the coverage area per extinguisher and conforming to the shape of most rooms (see Figure 4 below). This of course assumes that there are no dividing walls that would impede the path to an extinguisher. If Class A extinguishers are placed at the limit of their maximum travel distance then people might have to travel the entire 75 ft to get the extinguisher and then back another 75 ft to return to the fire in order to extinguish it. Let’s say the average person travels 3.5 mph, this means it would take them 30 seconds to travel the 150 ft it could take to grab the extinguisher and get back to the fire. A lot can happen in 30 seconds.   When distributing portable fire extinguishers an additional level of complexity is added when walls, obstructions and other structural features that limit movement are taken into consideration. Placement Extinguishers need to be located along normal paths of travel. This is because extinguishers should be available to occupants when evacuating. You do not want occupants to move away from an exit and risk being trapped by the fire when trying to retrieve an extinguisher. Extinguishers also need to be installed in places where they’re visible, but if an obstruction is unavoidable then there needs to be a sign provided to indicate the extinguisher’s location. Installation height Extinguishers need to be installed at least 4 inches off the ground up to a maximum of 5ft. The exception to this is for extinguishers heavier than 40 lbs, they can only be up to 3 ft 6 inches off the ground and wheeled fire extinguishers don’t need to be off the ground since the wheels already keep the cylinder from touching the floor. Cabinets & Hangers Extinguishers not on wheels are often installed on hangers or brackets, which need to be intended for the extinguisher, but they can also be installed in cabinets. Conclusion In my humble opinion portable fire extinguisher distribution and placement is the trickiest part of installation. There is a balance between efficiency and practicality that truly make a difference in the event of an emergency. I hope everyone found this helpful, let us know in the comments below what you think the toughest part of the job is. For more information check out our NFPA Portable Fire Extinguisher Fact Sheet. Annex E of NFPA 10 also has some more great information on fire extinguisher distribution if you want to learn more about the topic. Editor’s Note: I rounded to the nearest whole number for any calculations performed in this blog.

Fire Pump Types

Above credit: Hydraulics Institute Fire pumps are an essential part of many water-based fire protection systems. They are used to increase the pressure (measured in psi and bar) of a water source when that source is not adequate for the system it’s supplying. These are commonly found in buildings that tend to have a high-pressure demand such as high-rises or storage warehouses. This blog will review the different types of fire pump options available to designers. There are many types of fire pumps available. It is important to select the correct type of pump for the installation project to avoid excessive costs, and to avoid excessive pressures that might damage your system. If all the factors are not taken into consideration it could result in a pump installation that does not achieve the necessary pressure requirements which could require a new pump tobe installed. There are two main categories of pumps: positive displacement and centrifugal. Positive Displacement Pumps  Positive displacement pumps are characterized by a method of producing flow by capturing a specific volume of water per pump revolution and pushing it out through the discharge line. A bicycle tire pump is an example of a positive displacement pump we commonly see. Positive displacement pumps create very high pressures but have limited flow volume compared with centrifugal pumps. These are not as common because they have a specialized use, primarily with water mist and foam-water systems.  Centrifugal Pumps  Centrifugal pumps are the most common fire pumps and are used with most systems. With centrifugal pumps, pressure is developed principally by the action of centrifugal force or spinning. Water in centrifugal pumps enters the suction inlet and passes to the center of the impeller. The rotation of the impeller, in turn, drives the water by centrifugal force to the rim where it discharges. Centrifugal pumps can handle large volumes of water while providing high pressure boosts.  The following are different centrifugal type pump configurations: Horizontal Split-Case Pump With a horizontal split-case pump, the flow is split and enters the impeller from opposite sides of the pump housing. As the name implies, this is a pump installed with a split casing that can be opened for pump maintenance access and is connected to the driver by a horizontal shaft. They are very reliable, come in a wide range of rated flow and pressure capacities, are easy to maintain due to their relatively easy split-case access, and can be used with both electric and diesel drivers. However, these also typically need the most space of all types of fire pumps.  Credit: Hydraulics Institute    Credit: Grundfos Vertical Turbine Pump A vertical turbine pump is the only type of pump allowed by NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection that can start with negative suction pressure or take water under a lift condition such as from a below grade source such as a river or subgrade tank. These pumps can be used with raw water sources such as ponds, lakes, and rivers. Vertical turbine pumps come in a wide range of capacities and pressures, and they can be used with diesel and electric drivers.  In-Line Pump In-line pumps are useful where space is limited. These can be driven by both a vertical or horizontal shaft (end suction type). Vertical shaft types, which are the most common, have the driver located directly above the pump. These are typically one of the less expensive units and take the least amount of space but, they are also one of the more expensive to repair. Pump maintenance and repair can be difficult because the motor must be lifted off and removed to gain access to the pump, unlike a split-case unit. With these pumps, the suction flange and discharge flange are on approximately the same plane. In-line pumps have a limited capacity of typically no more than 1,500 gpm (5,678 L/min), and they can only be used with an electric driver which limits their potential applications.   Credit: Xylem - AC Fire Pump End Suction Pump An end suction pump has a discharge outlet perpendicular to the suction inlet. These pumps are typically limited to a capacity of approximately 1,500 gpm (5,678 L/min). Compared to horizontal split-case fire pumps, they are more compact and require less installation space in a fire pump room where available space is a concern. End suction pumps can be used with either an electric driver or a diesel driver. Multistage Multiport Pump Multistage Multiport pumps use a single-driver that can be either an electric motor or a diesel engine that connects to a pump with multiple impellers in series in a single casing driven by a horizontal shaft. The casing has multiple ports, or discharge outlets, delivering different pressures - each port has increased pressure from the consecutive series impellers. Credit: API International LLC / Western States Fire Protection Company For example, one multistage multiport pump could be installed in a high-rise building having 30 floors. The building may be divided into three zones where a multistage multiport pump equipped with three discharge outlets would use each outlet for a zone. The first has an outlet pressure of 100 psi (6.9 bar) and feeds lower floors or lower zone (ground to 9th), the second has an outlet pressure of 175 psi (12.1 bar) and feeds middle floors or mid zone (10th to 19th), and a third has a discharge pressure of 300 psi (20.7 bar) and feeds the upper floors or high zone (20th to 30th). Using multiport fire pumps could result in:  Fewer pumps required Less pipe work and fewer valves, as one pump could eliminate the need for some control valves and pressure reducing devices No requirement for water storage tanks on intermediate floors Lower structural loads and associated costs as only one pump may be required Energy conservation because less electricity and/or fuel will be consumed. Less pollution is also a potential benefit. Conclusion  Ultimately there are several different pumps that can be used in a variety of situations. When your system demand exceeds what your water supply can provide it’s time to look at what a fire pump can do to help bridge that gap. For more guidance see NFPA 20 for installation requirements and NFPA 25 Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems, for ITM requirements.   Let us know in the comments below what your experience is when working with these systems. 
Houses under construction

Types of Construction and Material Combustibility

It is important to understand how a building will perform in a fire. Minimum construction requirements are established to help maintain structural integrity for the time needed for evacuation or relocation to a safe location in the building. The combustibility of a material gives an indication of how quickly a fire will grow. Both of these aspects are essential to fire and life safety.  NFPA 220, Standard on Types of Building Construction, defines types of building construction based on the combustibility and the fire resistance rating of a building's structural elements. When we talk about fire resistance rating, we mean the time, in minutes or hours, that materials or assemblies have withstood a fire exposure as determined by specific tests.  NFPA 101 requires certain occupancies to meet minimum construction requirements, which can be found in section 1, subsection 6 of any of the occupancy chapter (XX.1.6). NFPA 101 isn’t the only code that specifies minimum construction types, other codes, such as a building code will also specify minimum construction types. Often times the type of construction that the building is permitted to be made out of correlates to how many stories the building will have and whether or not the building will have sprinklers installed.  NFPA Construction Types NFPA 220 breaks down building construction into five different types which relate to the material, each one of these types is numbered one through five (in roman numerals). When codes and standards refer to the type of construction required or permitted there are three numbers in parenthesis that follow the type of construction. These numbers indicate the fire resistance rating in hours of different structural elements that are required. The image below gives an example of how you might see this rating in a document and explains the different types as well as the following numbers.  Type I: Noncombustible (or limited-combustible) construction with a high level of fire resistance, typically concrete construction.  Type II: Noncombustible (or limited-combustible) construction with a lower level of fire resistance than Type I, typically this is steel construction with or without fireproofing.  Type III: Exterior walls and structural elements are noncombustible or limited-combustible materials, and interior structural elements, walls, arches, floors, and roofs are wood that is smaller than what is required for Type IV construction. This is usually called ordinary construction and an example of this is a mixed masonry/wood building.  Type IV: Fire walls, exterior walls, and interior bearing walls are approved noncombustible or limited-combustible materials. Other interior structural elements, arches, floors, and roofs are solid or laminated wood or cross-laminated timber. There are certain dimensional requirements:  Columns – 8in (205mm) x 8in (205mm) if supporting floor, 6in (150mm) x 8in (205mm)  if supporting roof Beams – 6in (150mm) x 10in (255mm) if supporting floor, 4in x 6in (150mm) if supporting roof Arches – Varies 8in (205mm) x 8in (205mm) to 4in (100mm) x 6in (150mm) Floors – 3in (75mm) or 4in (100mm) thick  Type V: Structural elements, walls, arches, floors, and roofs are wood or other approved material. Most residential construction is Type V. First Digit (X00): Exterior bearing walls Second Digit (0X0): Columns, beams, girders, trusses and arches, supporting bearing walls, columns or loads from more than one floor.  Third Digit (00X): Floor construction Material Combustibility Outside of the construction type and fire resistance rating of the structural elements there are also different designations for what is considered a combustible material, limited combustible material and noncombustible material. Noncombustible Material Materials that pass the criteria in ASTM E136 when tested in accordance with either ASTM E136 or ASTM E2652 are considered noncombustible. Also, any inherently noncombustible materials can be considered noncombustible without having to be tested. Although the standard doesn’t explicitly say exactly what is inherently noncombustible the associated annex material goes on to suggest that it consists of materials such as concrete, masonry, glass and steel.  Limited Combustible Material Material that is considered limited combustible needs to meet certain criteria.  It needs to be able to produce a heat value less than 3,500 BTU/lb when tested in accordance with NFPA 259. (For context paper has a heat value of approximately 7,000 BTU/lb, wood is about 10,000 BTU/lb while most plastics are in the 15,000 to 22,000 BTU/lb range) Tested in accordance with ASTM E2965 at an incident heat flux of 75kW/m2 for 20 minutes and meet the following conditions. a. Peak heat release rate doesn’t exceed 150kW/m2 for more than 10 seconds b. Total heat released is less than 8MJ/m2 Either one of the following a. Material has a noncombustible base with a surface that doesn’t have a flame spread index greater than 50 when tested in accordance with ASTM E84. The surface ontop of the noncombustible base can’t be thicker than 1/8th inch (3.2mm) b. Flame spread index is less than 25 when tested with ASTM E84 or UL 723, even if the material is cut.  An example of a limited combustible material is gypsum wallboard.  Combustible Material Defining combustible materials is done so by process of elimination. If the materials don’t meet the definition of limited-combustible or noncombustible then it is a combustible material. A common example of a combustible material is untreated wood.  Ensuring a building remains structurally sound and that materials react to fire predictably is important to overall life safety. Understanding and complying with construction type requirements is the first step in creating a safe built environment. We gave some common examples of each type of construction, what are some other examples? Let me know in the comments below. 

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