AUTHOR: Brian O'Connor

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. 

Smoke Control Systems

Studies have shown that most fire deaths are not caused by burns at all but instead by smoke inhalation. Smoke can be quite hazardous, and its effects stretch far beyond just being toxic. Smoke obstructs light and limits occupant visibility. This in turn diminishes travel speed so it takes longer for occupants to get to safety. Smoke can also be very hot, burning the interior of your lungs. Luckily, in the event of a fire, smoke control systems can help occupants avoid smoke when evacuating a building. NFPA 92, Standard for Smoke Control Systems, is the standard that contains requirements for the design, installation and testing of smoke control systems.  Fundamentals A smoke control system is a system that controls the movement of smoke and air in a building. It can be made up of multiple different components and use several methods to achieve its design objective, which is typically to maintain a tenable environment long enough for all occupants to egress the building. The design objective for a smoke control system can vary depending on the situation in which it is being used, for example a hospital might have a design objective of containing smoke to the zone of fire origin. These systems can also be part of the existing HVAC systems or they can be standalone systems. There are multiple ways to establish smoke control. NFPA 92 covers both types of smoke control systems: smoke management systems and smoke containment systems. Smoke containment systems keep smoke from entering specific areas using pressurization and are commonly found in enclosed stairwells. Smoke management systems maintain tenable environments in the means of egress from large volume spaces or prevent the movement of smoke into surrounding spaces. Smoke management systems are typically found installed in buildings with large multilevel atriums. Smoke Containment Systems There are several types of Smoke Containment Systems used for smaller enclosed spaces. Stairwell Pressurization Zone Smoke Control Elevator Pressurization Vestibule Pressurization Smoke Refuge Area Pressurization   Many of these smoke containment systems act in similar ways. They pressurize a certain area such as a stairwell, elevator, vestibule, or zone of a building by using a mechanical fan. This pressure difference across a barrier ensures that smoke does not migrate into certain areas of a building. This extends the period of time those spaces (usually egress routes) will remain tenable, allowing the occupants of the building more time to evacuate and emergency services to respond. Smoke Management Systems Types of Smoke Management Systems for larger areas such as warehouses or atriums include: Mechanical Smoke Exhaust Natural Smoke Ventilation   Natural venting removes smoke by taking advantage of the buoyancy of the smoke while mechanical smoke exhaust uses propellers to move the smoke and air outside of the building. Typically, the goal of these systems is to keep the smoke layer interface above the highest occupiable level that is open to the large space for a certain period of time. Mechanical smoke exhaust systems require a way for makeup air to be injected into the large space, otherwise the pressure could build up to be so high that it starts to negatively affect other building systems. For example, the pressure across a barrier must not result in a door-opening force that exceed 30 lbf (133N) or it might be too heavy for occupants to use. It Is also important to make sure the makeup air intake is clean fresh air and not located adjacent to where smoke could be exhausted. Activation Both smoke management and smoke containment systems are automatically activated by one or more fire detection devices including sprinkler waterflow, smoke detectors, and heat detectors. Manual pull stations should not be used for smoke control systems that need to know the location of the fire since the likelihood of someone activating the smoke control system in the area of fire origin is low. When do I need to install smoke control systems? NFPA 92 contains requirements on how to design a smoke control system but it doesn’t govern when a smoke control system is required. For that information the first place you should look is your locally adopted building and fire code to see if your facility requires a smoke control system. According to NFPA 101® Life Safety Code®, Section 9.3 outlines requirements for systems while the occupancy chapters (11 – 43) tell you when it is required. For example, in assembly occupancies with stages or platforms NFPA 101 requires a smoke control system that will keep the smoke level at least 6 ft (1830 mm) above the highest level of seating. Smoke control systems are also often installed in order to meet a certain performance objective when following a performance-based design approach or supplement a deficiency. To maintain tenability within a buildings egress path, smoke control systems must be properly designed, installed and tested in accordance with NFPA 92. This system is part of an overall life safety plan that helps ensure the wellbeing of building occupants. Smoke control systems not only need to be designed and installed correctly but they also need to be maintained. Let us know in the comments below what you think the most commonly cited deficiency is for a smoke control system.

Fire Apparatus Access Roads

Fire departments provide fire protection services to their jurisdictions as well as respond to a variety of other emergencies such as medical emergencies, motor vehicle accidents, hazardous material spills, electrical hazards, floods, and construction accidents. In order for these first responders to do their jobs effectively they need to be able to have access to the areas where incidents might occur, and this is where fire department access and access road requirements come in. Requirements for this topic come from Chapter 18 of NFPA 1, Fire Code. When we talk about fire apparatus access roads, this includes more than just the fire lane outside of a building, it encompasses roadways and parking lots that must be traveled in order to allow access and operational setup for firefighting and rescue apparatus. Fire engines not only need to be able to travel to their destination but when they get there, they need to be able to get close enough to any building to effectively deploy hose lines, access to fire hydrants and access fire department connections. Ladder trucks also need adequate room to setup rescue and laddering operations. Access Road Location Requirements Fire department access roads must be provided so fire apparatus can drive within 50 ft (15 m) of an exterior door that allows access to the interior of the building. This 50 ft (15 m) distance can be increased to 150 ft (46 m) for one- or two-family dwellings, or townhouses, that are protected with an automatic sprinkler system. The fire department access roads also need to be located so that any portion of the building or facility is not more than 150 ft (46 m) from fire department access roads as measured around the exterior of the building or facility. This requirement ensures that first responders can reach most parts of the building with their hose lines. This 150 ft (46 m) distance can be increased to 450 ft in buildings that are protected with an automatic sprinkler system because a correctly installed sprinkler system reduces the fire risk to the occupants and firefighters. If the AHJ determines that a single fire department access road can be impaired by through traffic, terrain challenges, climate conditions or anything else then multiple access roads might be required. Access Road Specifications Access roads need to allow adequate access to the building and room to setup and perform manual suppression operations. Fire department access roads require 20 ft (6.1 m) of unobstructed width, 13.5 ft (4.1 m) of unobstructed vertical clearance and an appropriate radius for turns in the roads and dead ends for the vehicles apparatus to turn around. The minimum 20 ft (6.1 m) width allows for two-way vehicular traffic and for one fire apparatus vehicle to pass while another is working at a fire hydrant or conducting aerial operations while the 13.5 ft  (4.1 m) vertical clearance ensures that fire apparatus can safely pass under power lines, bridges, and other obstructions. Bridges need to be designed to be able to support a load sufficient enough to carry a fully loaded fire apparatus and the vehicle load limits need to be provided at both entrances to the bridge. The grade of the road also must not exceed 1 ft (0.3 m) of elevation change every 20 ft (6.1 m) or whatever the design limits of the local fire apparatus dictate. As determined by the AHJ, certain parts of the fire department access road are required to be marked, these marked portions of the fire department access roads are called fire lanes. Obstructions This next requirement is one that most people have heard of because it is typically painted in large letters in front of buildings, but I’ll reiterate it here. If an area is designated as a fire lane, cars are not allowed to be parked there. In addition, the width of the rest of the fire department access road needs to be maintained and unobstructed. This means that parked vehicles need to be accounted for on roads or lots where they would normally park. Other obstructions might include gates, doors or any other security feature. First responders must be able to access these areas in an event of an emergency. Access can be granted by installing an access box which is a listed box that usually contains items such as keys, access codes, card keys, or a remote opening device for first responders. Fire departments must have adequate, unobstructed access to the buildings where incidents can occur in order for them to do their job properly. It is to everyone’s benefit to allow fire departments easy access and the requirements in Chapter 18 of NFPA 1 help ensure this happens. Do you have any experience with unique fire department access challenges? If so let us know about them in the comments below.

Sprinkler Protection for Flammable and Combustible Liquids

We live in a world where flammable and combustible liquids are all around us. Gasoline, rubbing alcohol, nail polish remover, hand sanitizer, and cooking oils are just a few common examples. When storing large quantities of flammable liquids, it's important to understand how to protect them properly because of their rapid rate of fire growth. This blog will dive into some of the requirements for the sprinkler protection of stored flammable and combustible liquids. Designers will often go to NFPA 13 Standard for the Installation of Sprinkler Systems for all sprinkler system requirements, but many don't know that flammable and combustible liquid storage is covered by NFPA 30 Flammable and Combustible Liquids Code. What is a flammable or combustible liquid? Before discussing sprinkler protection requirements for these liquids, the first step is figuring out what exactly we're talking about when we say flammable or combustible liquids. When defining these liquids, we often refer to their flash point, which is the temperature at which a liquid gives off enough vapor to form an ignitable mixture with the air. With that in mind we define flammable and combustible liquids as follows: Flammable liquid – flash point below 100°F (37.8°C) Combustible liquid – flash point at or above 100°F (37.8°C) NFPA 30 then further divides flammable and combustible liquids into classifications.  These will be used to determine the correct design criteria to your storage. Classifications of flammable and combustible liquids are as follows: Flammable Class IA = Flash Point <73°F (22.8°C) & Boiling Point < 100°F (37.8°C) Flammable Class IB = Flash Point < 73°F (22.8°C) & Boiling Point > 100°F (37.8°C) Flammable Class IC = Flash Point between 73°F (22.8°C) and 100°F (37.8°C) Combustible Class II = Flash Point between 100°F (37.8°C) and 140°F (60°C) Combustible Class IIIA = Flash Point between 140°F (60° C) and 200°F (93°C) Combustible Class IIIB = Flash Point above 200°F (93°C) Gathering information When determining when and how to protect the storage of flammable and combustible liquids it is important to gather information to make the correct design decisions. First it is important to know which standards to follow. For the storage of flammable and combustible liquids we should start in NFPA 30. There are certain requirements in NFPA 30 that will instruct users to follow the requirements for various commodities in NFPA 13 when necessary. To determine design criteria, you will first need to know the quantity of flammable or combustible liquids being stored. As well as how the liquid is being stored (whether it is rack storage, shelf storage palletized, or stacked.) Next, you need to be aware of what containers the liquid is stored in. The type of containers for flammable and combustible liquids can be stored in varies greatly; some examples of acceptable container material include metal, plastic, or glass. The material the container is made of will also dictate the volume of the container that the liquid can be stored in. A complete list of acceptable containers is located in section 9.4.1 in NFPA 30. How to protect it Fire protection system design criteria for protecting the storage of containers of flammable and combustible liquids are provided in Chapter 16 of NFPA 30. The design criteria are contained in 12 tables that address different storage situations and configurations and include both sprinkler and foam-water sprinkler systems. Three decision trees assist the user in identifying the appropriate table to be used. In these tables you will find maximum storage height, maximum ceiling height, required aisle width, required sprinkler arrangement as well as if in-rack sprinklers are required. It is important to understand that sprinkler systems are designed to protect against certain hazards and increasing those hazards can cause your fire protection system to be overwhelmed. This issue can be addressed by developing a change management plan that triggers safety and compliance reviews when certain changes occur. Although NFPA 13 usually contains all of the requirements for the installation of sprinkler systems for the storage of flammable and combustible liquids NFPA 13 and NFPA 30 work in harmony to help ensure sprinkler systems are designed in a way that can help save people and property. Check out the November/December 2020 issue of the NFPA Journal where the ‘In Compliance' column talks specifically about how to properly store and protect alcohol base hand rub. Have you recently worked on a project that included flammable or combustible liquids? Let us know in the comments below what you think the biggest or most common challenge is. If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety

Guide to Fire Extinguisher Inspection, Testing and Maintenance

Portable fire extinguishers are often times our first line of defense against small fires and chances are you aren't too far from one right now. Like any lifesaving equipment you want to ensure that it is operable at all times so it will work when you need it most. With proper inspection, testing and maintenance (ITM) protocols fire extinguishers can be long lasting, reliable options for combating a small fire early on. This blog will address the NFPA 10, Standard on the Installation or Portable Fire Extinguishers requirements that help ensure your extinguisher is ready. The requirements are broken down into three different sections on inspection, maintenance and testing. In each section there is information on what needs to be done (Procedures), who is allowed to perform the work (Qualifications), how often each step needs to be done (Frequency) and how to document the work (Recordkeeping). Inspection Procedures Performing an inspection is the easiest thing you can do to ensure your extinguisher can be used reliably and effectively in an emergency. At a minimum, inspection needs to consist of the following steps: Make sure it is located in its designated place Make sure the extinguisher is visible or that there is signage indicating where the extinguisher is located Make sure you can easily access the extinguisher Ensure the pressure gauge is in the operable range or position Make sure it is full, this can be done by just lifting the extinguisher or you can weigh it For wheeled extinguishers, make sure the condition of tires, wheels, carriage, hose, and nozzle are acceptable For nonrechargeable extinguishers, operate the push-to-test pressure indicators Qualifications You are not required to be certified in order to perform an inspection; any knowledgeable, competent person should be able to do it. Frequency NFPA 10 requires extinguishers be inspected when they are initially installed and once a month after that. You should inspect extinguishers more frequently if they are installed in locations where they are more prone to rust, impact or tampering. Recordkeeping Records of the monthly inspections need to be maintained by either putting a tag or label on the extinguisher or by having it recorded on paper or electronic files. The following items need to be recorded: The month and year of the inspection The person conducting the inspection These records need to be maintained for at least 12 months. Maintenance Procedures Maintenance procedures must include the procedures detailed in the manufacturer's service manual and a thorough examination of the basic elements of the fire extinguisher, including the following: Mechanical parts of all fire extinguishers Extinguishing agent Expelling means Physical condition This is completed by doing an external examination. An internal examination can also be required as part of your maintenance. Details on how to do an internal examination are located in your fire extinguisher service manual. Qualifications Maintenance needs to be performed by a certified person. Certification requires that a person take a test acceptable to the AHJ . A certified person needs to, at the very least, be familiar with the requirements in NFPA 10. Frequency Fire extinguishers need to have an external maintenance examination conducted on a yearly basis, at the time of hydrostatic test, or when specifically indicated by an inspection discrepancy. Extinguishers need to have an internal examination conducted at anywhere from 1-6 year intervals depending on the type of extinguisher. For example, a dry chemical, stored pressure fire extinguisher must have an internal examination every 6 years, see NFPA 10 Table for more details on other types of fire extinguishers. Recordkeeping Each fire extinguisher shall have a tag or label securely attached that indicates that maintenance was performed. The tag or label needs to identify the following: Month and year maintenance was performed Person performing the work Name of the agency performing the work Extinguishers also need a verification-of-service collar located around the neck of the container if an internal examination was conducted. That collar needs to have: Month and year the work was performed Name of the agency performing the work Hydrostatic Testing Procedures  A hydrostatic test always begins with an internal and external examination of the extinguisher as described in the maintenance section. The extinguisher then has many of its components removed so it is stripped down to pretty much just the shell and hose and is filled with water at a certain pressure for a certain time. The extinguisher must then be completely dried to get rid of all of the water and is then reassembled and recharged. If there is any leakage, distortion or permanent moving of couplings the cylinder fails the hydrostatic test and it must be condemned. Qualifications People who do hydrostatic testing need to know what they are doing because it can be dangerous if performed incorrectly. They need to be trained, certified, and have the correct equipment and facility to perform the testing. Frequency Like internal maintenance, hydrostatic testing is done at different intervals based on the type of extinguisher you have. These are done either every 5 or 12 years. See Table 8.3.1 in NFPA 10 to see which applies to your type of  extinguisher. Recordkeeping For low pressure cylinders a label is required to be attached to the extinguisher. It needs to contain: The name of the person conducting the test The date of the test The pressure at which the test was performed For high pressure cylinders the testers identification number and the date must be stamped onto the shoulder, top, head, neck or foot ring. This was intended to be a helpful guide to extinguisher ITM but it doesn't contain all the details that the requirements in NFPA 10 contain. Since there are many different types of extinguishers, there are slightly different requirements based on the extinguisher's characteristics. Electronic monitoring, which is a viable option as a replacement for your monthly inspections was also not addressed here.  If you're interested in more information about portable fire extinguishers check out these resources: Location and Placement of Fire Extinguishers - Fact Sheet Where are Fire Extinguishers Required - Blog Use the comments below to share your experience with fire extinguishers. What challenges have you faces when conducting inspections? What have you found to be the most common violation? If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety.

Airport Terminal Windows, More Than Just A Pretty View

During this era of Covid spending time at airports seems like a distant memory. Looking out those large  windows onto the apron, which is where aircraft are parked, you can see several fire protection measures at work. The surface of the apron is sloped away from the building in case of a fuel spill, the building itself is constructed of a certain level of fire resistance and the aircraft loading walkway has a pressurization system for safe egress, but what about that window you are looking through? NFPA 415, Standard on Airport Terminal Buildings, Fueling Ramp Drainage, and Loading Walkways, contains requirements for the protection of occupants and property for airport terminals, including their large landscape windows.  Glass vs Glazing? If you are looking in the standard one of the first things you might notice is that it doesn't use the term ‘window' or ‘glass'. Rather, the terms ‘opening', and ‘glazing material' are used. Glazing is used because most windows are not made from solely glass, they are usually made from a mixture of layers or laminated glass, fiberglass, acrylics, or other plastics and the term glazing material covers all of these. The term opening is used for much the same reason, it is more generic and can apply in more situations if the opening is technically not a window. For example, if the term window was used this wouldn't cover the use of a door, which would present many of the same hazards being addressed in NFPA 415. When do airport terminal openings need to be protected? If there is an opening in a wall that is within 7 ft of the floor and potential fuel spill points are less than 100 ft horizontally then the window needs to be protected with an automatic water spray system in accordance with NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection. There has been testing that has shown the radiant heat from a fuel spill fire can be expected to break glass windows 75 ft away and can potentially ignite combustible materials within the building. If the window is between the finished floor and 7 ft there is a greater potential for occupants to be injured and so that is the threshold for the application of this requirement. How do I provide protection? While NFPA 415 says to follow NFPA 15, additional guidance that is proposed for the 2022 edition of the standard explains the intent by adding that the user should follow the vessel exposure protection provisions of NFPA 15. This makes sense since we are providing the window with exposure protection from the fuel spill fire. Something to keep in mind when designing a system like this is that you can take water rundown into consideration, which allows you to increase the vertical spacing of your nozzles up to 12 ft. Another common question we get about design is whether protection is needed to be provided for the entire window or just the bottom 7 ft. A proposed change to the 2022 edition clarifies that it is the intent for the system to protect the entire opening. For more information on the design of glazing assemblies, please see Annex C of NFPA 415 which goes further into detail about glazing materials and the dangers aviation facilities can pose. Check out this ‘In Compliance' article which gives an overview of all fire protection features in an airport. Let us know if you have any experience with the fire protection of airport terminals or send us a picture of the next water spray system you find. If you found this blog helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, building and life safety.

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