AUTHOR: Kristin Bigda

People walking up and down stairs

Basic of Egress Stair Design

For many of us, walking up and down stairs is a routine part of our day. We may use stairs at work, at entertainment venues, and in our home without thinking twice about how their design and function contribute greatly to life safety in both emergency and non-emergency situations. Recently, I wrote about the details and the importance of handrail design for safe and efficient stair use. Here I will focus on other details of stair design including riser height, tread depth, stair width, stair landings, and construction uniformity that are mandated in order to create a safe path of travel when using the stairs to move throughout the building. These standard stair design details are mandated for egress stairs in the exit access, exits and exit discharge. (Where you have other than standard stairs such as curved stairs, spiral stairs or winders within a means of egress, consult NFPA 101, Life Safety Code, Chapter 7 for further details on their design.) Construction All stairs serving as required means of egress must be of permanent fixed construction (unless they are stairs serving seating that is designed to be repositioned, such as those in theaters, for example, where seating sections are added, removed, or relocated and it is impractical for stairs associated with that seating to be of fixed, permanent construction). In buildings required by NFPA 101, Life Safety Code, to be of Type I or Type II construction, each stair, platform, and landing, not including handrails and existing stairs, are required to be of noncombustible material throughout. Stairs can be of combustible construction if the building is not required by that occupancy to be of Type I or Type II construction. For example, an occupancy might not have any requirements related to minimum building construction type, or the occupancy chapter might permit Type III, Type IV, or Type V construction. If the building is required to be of Type I or Type II construction, the materials used for new stair construction (stairs, platforms, and landings) must be noncombustible. Dimensional Criteria and Uniformity Providing adequate width is one of the most important features of egress stair design as the width ensures that the stairs can accommodate enough people safely and efficiently during an evacuation.  Providing appropriate stair riser height and tread depth ensures that stairs are safe, usable, and presents tripping and discomfort when traveling up or down the stairs.  The minimum required width as well as other dimensional criteria for both new and existing stairs is summarized in the tables below (reference: Chapter 7 of NFPA 101).  It should be noted that in some cases, the egress capacity will require a stair to have a greater width than the minimum specified here. The minimum width of new stairs is 36 in. (915 mm) where the total occupant load of all stories served by the stair is fewer than 50. Where new stairs serve a total cumulative occupant load (assigned to that stair) of 50 or more people but less than 2000 people the minimum width is 44 in. (1120 mm) and where the total cumulative occupant load assigned to the stair is greater than or equal to 2000 people the minimum width is 56 in. (1420 mm).  Riser height is measured as the vertical distance between tread nosings. Tread depth is measured horizontally, between the vertical planes of the leading projection of adjacent treads and at a right angle to the tread’s leading edge. Measuring both riser height and tread depth needs to represent the actual space available to those using the stairs. It cannot include any part of the tread that is not available for someone to place their foot.  Installing floor coverings to existing stairs might also reduce the available space for use on the stairs. Irregularities in stair geometry, either from one step to the next or over an entire run of stairs, can cause accidents, tripping and falling when using the stairs. When many people are using the stair at once, just one accident can cause delays and disruptions in movement and use of the stairs, and increase the overall time of evacuation. There should be no design irregularities. Very small variations due to construction are permitted between adjacent treads and risers and the overall different over the entire flight of stairs. The variation between the sizes of the largest and smallest riser or between the largest and smallest tread depths shall not exceed 3∕ 8 in. (9.5 mm) in any flight. Stair Landings As a general rule, stairs must have landings at door openings because it is unsafe to move through a door opening and immediately begin vertical travel on a stair. In existing buildings, a door assembly at the top of a stair is permitted to open directly to the stair, without first providing a level landing, provided that the door leaf does not swing over the stair (rather, it swings away from the stair) and the door opening serves an area with an occupant load of fewer than 50 people. Stairs and intermediate landings must continue with no decrease in width along the direction of egress travel. A reduction in width of a stair landing could reduce the overall capacity of the stair.  In new buildings, every landing will have a dimension, measured in the direction of travel, that is not less than the width of the stair. Landings are not required to exceed 48 in. (1220 mm) in the direction of travel, provided that the stair has a straight run. Intermediate stair landings serve as effective breaks in runs of stairs, which allow persons who slip or trip to halt their fall.     Stair Tread and Stair Landing Surfaces Surface Stair treads and landings must be solid, without perforations, except for noncombustible grated stair treads and landings as otherwise provided in the following occupancies: assembly, detention and correctional, industrial and storage. Solid treads and solid landing floors provide a visual barrier that shields the user’s view of the vertical drop beneath the stair. People with a fear of high places are more comfortable using these stairs. Grated and expanded metal treads and landings could catch the heel of a shoe and present a tripping hazard. Noncombustible, grated stair treads are permitted in areas not accessed by the general public, such as catwalks and gridirons in theaters, resident housing areas in prisons, factories and other industrial occupancies, and storage occupancies. Projections Stair treads and landings must also be free of projections or lips that could trip stair users. The tripping hazard occurs especially when someone is traveling down the stairs, where the tread walking surface has projections. The installation of a surface-mounted stair nosing or a strip of material onto an existing stair tread might produce a projection that creates a tripping hazard. Tread nosings that project over adjacent treads can also be a tripping hazard. (Additional considerations for minimizing tripping hazards for accessibility is also addressed in ICC A117.1, Accessible and Usable Buildings and Facilities.) Traction Stair treads and landings within the same stairway must have consistent surface traction. This means that slip resistance is reasonably uniform and sufficient to minimize risk of slipping across the treads. Consistency is important because misleading a person’s expectation of the surface they will be walking on is a major factor in missteps and falls involving slipping. Materials used for floors that are acceptable as slip resistant generally provide adequate slip resistance where used for stair treads. If stair treads are wet, there is also increased danger of slipping, just as there is an increased danger of slipping on wet floors of similar materials. The many details of stair design may seem minute and unimportant in the overall picture of fire and life safety, but stairs can be dangerous and an impediment to egress if not designed correctly.  Tripping, falling, and a lack of confidence by those using egress stairs can interrupt efficient egress travel and building evacuation.  Paying careful attention to stair design will greatly contribute to occupant safety during both day to day and emergency conditions

Basics of Fire and Smoke Damper Installations

Heating, ventilating, and air-conditioning systems and other components that support the movement of air throughout buildings are necessary for the day-to-day function of buildings in order to properly heat, cool and (re)distribute air throughout them. Air is distributed in air-conditioning and ventilating systems by ducts and plenums and for the system to reach everywhere it needs to within the building, it may require penetrating fire-resistance rated assemblies or assemblies protected against the transfer of smoke. Like fire doors protecting openings in fire-resistance rated construction, dampers also protect openings where ducts pass through or terminate in or at fire rated assemblies in order to maintain the integrity of the assembly and to prevent fire and smoke from spreading to and contaminating other areas of the building that might be otherwise unaffected. During a fire, the air distribution system may transport deadly smoke and products of combustion instead of breathable air. If proper design and installation precautions are not taken, smoke, fire gases, heat, and even flame can spread throughout the area served by the duct system. Improper plenum locations, lack of detection equipment in the system, and lack of required fire and smoke dampers in appropriate walls, ceilings, or partitions can lead to tragic situations. What are fire and smoke dampers and where are they installed?  Fire dampers are installed in ducts passing through or in air outlet openings terminating at shaft walls, fire barriers (such as an occupancy separation wall, horizontal exit walls, corridor walls, corridor ceilings, floor-ceiling assemblies) and other fire resistance–rated assemblies as required by a building or life safety code and other applicable standards.  Under severe fire exposure, a duct may eventually collapse or significantly deform, creating an opening in the fire barrier. Fire dampers provide a method of protecting such penetrations and openings.   A fire damper is designed to, and required to, close automatically upon detection of heat (such as a fusible link or heat detector) and to interrupt airflow and to restrict the passage of flame.  Fire dampers are required to close against the maximum calculated airflow of that portion of the system in which they are installed. Those that are intended to close under airflow are labeled for use in Dynamic Systems (A dynamic systems is an HVAC system designed to maintain the movement of air within the system at the indication of a fire); those that are intended to close after airflow has stopped by automatically shutting down the fan or airflow in the event of a fire are labeled for use in Static Systems (a static system is an HVAC system designed to stop the movement of air within the system at the indication of a fire). Fire dampers are provided with an hourly fire rating.    Smoke damper’s primary function is to control the movement of smoke in dynamic air distribution systems, and they reduce the possibility of smoke transfer within ductwork or through wall openings. They are installed in ducts passing through, or air outlet openings terminating at, smoke barriers, shaft walls, horizontal exit walls, corridor walls, corridor ceilings, and other barriers designed to resist the spread of smoke as required by a building or life safety code and other applicable standards. Smoke dampers operate automatically on detection of smoke and must function so that smoke movement through the duct is halted.  Their activation can be by area detectors that are installed in the related smoke compartment or by detectors that are installed in the air duct systems. Smoke dampers are provided with leakage and temperature ratings.   A combination fire/smoke damper is used when a barrier is both rated for fire resistance as well as designed to restrict the transfer of smoke and will meet both the fire damper and smoke damper requirements.   What standards area applicable?  Multiples codes and standards are applicable to the installation of fire and smoke dampers.  Knowing what each document addresses can help map out the provisions for a safe and successful damper installation.  It is suggested that these documents be reviewed for further details beyond the summary that is provided here.  NFPA 101®, Life Safety Code® mandates where smoke dampers are required as well as their ratings, access and identification requirements, and activation requirements. Smoke dampers are required in air-transfer openings (an opening designed to allow the movement of environmental air between two contiguous spaces) in smoke partitions and in air transfer openings and duct penetrations in smoke barriers.  Where a smoke barrier is also constructed as a fire barrier, a combination fire/smoke damper must be used.  There are multiple exemptions where smoke dampers may not be required in smoke barriers such as where ducts or air-transfer openings are part of an engineered smoke control system and that smoke damper will interfere with the operation of a smoke control system or where ducts penetrate floors that serve as smoke barriers. NFPA 5000®, Building Construction and Safety Code® mandates where fire dampers are required and their required ratings as well as access and identification requirements for fire and smoke dampers. Fire dampers are required in the following locations:  Ducts and air-transfer openings penetrating walls or partitions having a fire resistance rating of 2 or more hours, Ducts and air-transfer openings penetrating shaft walls having a fire resistance rating of 1 or more hours, Ducts and air-transfer openings penetrating floors that are required to have protected openings where the duct also is not protected by a shaft enclosure, Air-transfer openings that occur in walls or partitions that are required to have a fire resistance rating of 30 minutes or more.   NFPA 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems also mandates additional locations where fire and smoke dampers are required, working in conjunction with the building code and life safety codes. In addition, it mandates the minimum required rating of the fire damper based on its location.  Compliance with NFPA 90A is mandated by NFPA 101, NFPA 5000 and NFPA 80.  NFPA 80, Standard for Fire Doors and Other Opening Protectives and NFPA 105, Standard for Smoke Door Assemblies and Other Opening Protectives apply after it has been determined where a damper is required and how to access and identify it.  Users are directed to NFPA 80 and NFPA 105 for additional installation details as well as all requirements for the inspections, testing, and maintenance of the dampers. NFPA 80 covers fire dampers as well as combination fire/smoke dampers and NFPA 105 addresses smoke dampers.  Fire dampers are tested and listed for use in air-conditioning and ventilating ducts by UL in accordance with UL 555, Fire Dampers. These dampers include single-blade, multiblade, and interlocking-blade types, all actuated by fusible links. Smoke dampers require compliance with UL 555S, Smoke Dampers.  Combination fire and smoke dampers will meet the applicable requirements of both UL 555 and UL 555S       Fire and Smoke Damper Installation  First and foremost, dampers must be installed in accordance with the manufacturer’s installation instructions and in accordance with their listing. For new installations, retaining the installation instructions on site can help verify that a damper has been properly installed.     Access to both fire and smoke dampers is required for inspection, testing, and maintenance. Smoke and combination fire and smoke dampers in new construction must be provided with an approved means of access large enough to allow inspection and maintenance of the damper and its operating parts.  Access cannot affect the integrity, continuity, or rating of the assembly where its located and must also comply with any access requirements in the mechanical code. Access points must also be provided with permanent identification indicating the type of damper (fire damper, smoke damper, fire/smoke damper). In some situations, where space constraints or physical barriers in new construction restrict access to a damper for periodic inspection and testing, the damper is required to be a single- or multi-blade-type damper and must comply with remote inspection requirements (found in NFPA 80 or NFPA 105.)   After a damper has been installed, an operational test much be completed. This test ensures that the damper has been installed correctly within the air distribution system, is fully functional, closes completely without obstructions and contains all the correct components and devices as part of its assembly. The operational test may be required be conducted under normal HVAC airflow and non-airflow conditions. The damper shall fully close under both test conditions.   Conclusion  Both fire and smoke dampers are important building and life safety equipment that protect people and buildings from the effects of fire. It is critical that they are installed, and accessible, where required throughout buildings and installed properly so that they will operate when required under fire conditions. Without them, fire and smoke could travel throughout the building to spaces otherwise untouched by the fire. Check back for future blogs where we will address the requirements, both in-person and remote, for inspection, testing and maintenance of fire and smoke dampers.  For more information on fire and smoke dampers as well as other opening protectives, you can check also out our various training offerings here.  
Door lock

Swinging Egress Door Operation: Permissible Egress Door Locking Arrangements

Every component in the means of egress (an unobstructed route from any point in a building to a public way) must be operable by, and under the control of, the occupants attempting egress. One of the biggest obstacles a person can encounter, preventing them from free egress, is a locked door. Approaching a noncompliant locked door unexpectedly and without the means necessary to operate it is an example of when egress becomes outside of an occupant’s control. This can hinder evacuation time and prevent occupants from getting to their point of safety.  I recently wrote about the basics of swinging egress door operation, and we will continue that discussion here by focusing on some of the specifics of permissible door locking arrangements, so that we can better understand if door locking is permitted and what is required to do it safely. An unfortunate increase in hostile events, and similar threats has also increased the presence of security features on door assemblies within the means of egress to prevent unwanted entry. This added security, particularly where door assemblies to exit stairs and main egress routes are involved, could be disastrous in the event of a fire or other emergency. The provisions of NFPA 101 Life Safety Code are aimed at preventing locked door assemblies in means of egress in the event of fire. The Code has attempted to balance this objective of free and unobstructed egress while also maintaining features that are essential to security within the building. Where locked doors are permitted, additional requirements are often mandated to achieve an equivalent level of life safety as would be provided if the means of egress system were fully under the control of the building occupants and did not contain locked doors. For example, in health care occupancies locked door assemblies are permitted if it is necessary for specialized protective measures or the clinical needs of the patients.  In this case, there are a number of additional requirements that need to be met, that include requiring staff to carry the keys needed to unlock those door assemblies at all times. DOOR OPERATION To achieve free and unobstructed egress, there are several general concepts to consider in all buildings regarding swinging egress door locking and latching: Door leaves must be arranged to be opened readily from the egress side whenever the building is occupied. This requirement is consistent with the concept that all components in the means of egress must be under the control of the occupants. When an occupant approaches a door within their means of egress, they cannot be met with unexpected obstacles outside of their control that would prevent them from passing through the opening. The use of key locks or complex devices, such as door handles or latches covered with glass that must be broken, is prohibited. Locks and latches cannot require the use of a key, a tool, or special knowledge or effort to operate from the egress side. Locks that require the use of a key, a tool, or special knowledge or effort to open the door leaf from the egress side are prohibited unless meeting one of the recognized locking arrangements discussed later in this blog. It cannot be assumed that an occupant has access to the key, or device that is required to operate the door from the egress side. It takes much longer to operate a door that has been equipped with additional locking/unlatching components which is time that an occupant may not have available to them when trying to evacuate a building during an emergency. This also prohibits doors being locked via a keypad or card reader on the egress side without additional protection measures. To prevent unauthorized entry, door assemblies are generally permitted to be locked from the non-egress side. All locks, latches, and all other fastening devices on a door leaf must be provided with a releasing device that has an obvious method of operation and that is readily operated under all lighting conditions. Examples of conventional devices used release locks and latches include knobs, levers, and bars. Unfamiliar methods of operation, such as a blow to break glass, would not be acceptable. Switches integral to traditional doorknobs, lever handles, or bars, and that interrupt the power supply to an electrical lock are permitted if they are affixed to the door leaf. Where a latch or other similar device is provided, the method of operation of its releasing device must be obvious, even in the dark. The method of release must be one that is familiar to the average person.  Panic and fire exit hardware is another example of hardware that has an obvious method of operation and is readily operated under all lighting conditions (While not required for all situations, it meets the other conditions we talk about here as well.) The operation of the releasing mechanism must release all latching and all locking devices of the door leaf with not more than one motion in a single linear or rotational direction. An example of a releasing motion in a single linear direction could be pushing on a panic bar to release the locking/latching hardware to allow a door to be opened. An example of a releasing motion in a single rotational direction would be turning a lever-operated handle of a door lockset in either a clockwise direction or a counterclockwise direction (but not both directions) to unlock/unlatch the door. Multiple motions to unlock or unlatch a door, again, takes time and can delay a person from getting to their point of safety.  There are several situations that do permit additional motions, such as in residential occupancies and school and daycare classrooms. These are permitted to balance unique security needs as well as to recognize situations where occupants are, themselves, locking the doors (such as a hotels and apartments) and the operation of the door during egress is under their control. Swinging exit door that meets all door operational criteria PERMISSIBLE DOOR LOCKING ARRANGEMENTS There are situations where a locked door within the means of egress is necessary and permitted.  But to do this, additional measures must be in place to ensure that, while meeting security needs, the locked door does not become an obstacle to a person’s egress travel and prevent them from getting to their point of safety quickly and efficiently.  When providing egress door locking arrangements, pay careful attention to the details for how to achieve the door locking safely and when and where these locking arrangements are permitted.It is not a one size fits all installation. Many permissions to lock doors are dependent on the type of occupancy and the location of the door within the building. Key-Operated Locks – Doors equipped with key-operated locks, such as a deadbolt, are an exception to the rule that locks and latches cannot require the use of a key, a tool, or special knowledge or effort to operate from the egress side to open. Doors equipped with key-operated locks may be found on the exterior of a store or office where added security is required after-hours, for example. Stairway Reentry – Some stair enclosure door assemblies are permitted to be locked to prevent reentry to the building on selected floors. This arrangement provides flexibility in buildings that, perhaps for security reasons, do not want occupants to enter certain spaces of the building, while at the same time ensuring that one can reenter the building if necessary, without having to travel up or down too many flights of stairs. Delayed egress electrical locking systems. This type of locking system delays egress through the door by preventing the door leaf from opening for 15 or 30 seconds. Doors with this type of locking system are commonly installed where there are concerns for internal security, such as theft from a store. Delayed-egress electrical locking systems might also be installed where occupants might benefit by being protected from their actions, such as a specialized patient care floor in a nursing home. Swinging egress door with a delayed egress electrical locking system Sensor-release of electrical locking systems. Doors with this locking arrangement are intended to be locked against access from the outside of the building and require a magnetic card or similar tool for entry. In order to provide free egress a sensor is provided on the egress since to electrically unlock the door leaf in the direction of egress when an person approaching the door is detected. Where the sensor fails, a manual release device, such as a push button, is also provided as a backup. Elevator lobby exit access door locking. This locking arrangement permits door assemblies that separate the elevator lobby from the exit access to be electrically locked. The locked door between the elevator lobby or landing and the exit may be an obstruction to egress but with the twelve criteria that must be met in order to apply this locking arrangement, it balances the security need with safety of the occupants. The criteria blend a host of provisions for fire detection and alarm systems, sprinkler systems, occupant and staff two-way communication systems, and automatic lock release systems Door hardware release of electrically locked egress door assemblies. Doors utilizing this locking arrangement are locked with an approved electrical locking system that is released by door hardware that is affixed to the door leaf itself..  The door leaf is typically held locked to its frame with an electromagnet. The biggest difference between this type of locking arrangement and that described in condition (2) is the location of the releasing hardware (affixed to the door leaf vs sensor).Doors with this arrangement operate very similarly to a traditional door assembly. Electrically locked swinging egress door with door hardware release CONCLUSION Leaving a building or relocating to another point of safety during an emergency should not present obstacles to occupants trying to do so. One of the greatest impediments to this free egress is an unexpected and noncompliant locked door.  Fundamental door operation requirements ensure that doors are readily openable, easy to operate and available for use when the building is occupied. However, when security needs also dictate a need for additional protection, balancing that security need with additional life safety measures will help to ensure occupants continue to be offered safe and reliable means of egress during emergency situations.

Strategies for Crowd Management Safety

A return to crowded, full capacity sports events, concerts, festivals, and performances seemed unimaginable early on in the COVID-19 pandemic as large venues such as stadiums, arenas, ballparks, and music halls remained closed or operated at a very limited capacity. However, here in the US we are now seeing these locations begin to open to larger crowds and even some to full capacity. But, in doing so, we must not overlook the safety challenges that come with the presence of large crowds. On April 30, 2021 what should have been a celebration turned into a tragedy as 45 people were killed and over 150 more people were injured at a religious festival. It was estimated that almost 100,000 people attended the event. As the celebration ended, attendees began to exit through passages that could not accommodate the crowds. It was reported that some people may have lost their footing, tripped, and then caused the people behind them to be pushed ahead, crushing people as they were forced ahead by the crowd. Provisions are in place to ensure the safe and orderly movement of people during an emergency. When these safety protocols and features are overlooked, it can have a drastic impact on the efficiency of egress response during events such as fire or other related emergencies. This blog summarizes a few of the code requirements from NFPA 101, Life Safety Code, which are unique to assembly occupancies with large crowds. Occupant load Large assembly venues have a high number of occupants - in some cases, tens of thousands of people - for which they are designed to accommodate safety both entering and egressing the facility. In general, the occupant load is determined utilizing factors that are based on how the space is used or is determined as using the maximum probable population of the space under consideration, whichever is greater. However, in areas of assembly occupancies in excess of 10,000 ft2 (930 m2), the occupant load cannot exceed a density of one person in every 7ft2 (0.65 m2).This occupant load limit exists in order to avoid overcrowding. When overcrowding occurs, walking becomes a shuffle, and then further crowding can lead to a complete “jam point” such that all movement by occupants comes to a stop. Life Safety Evaluation (LSE) Where the occupant load of an assembly occupancy exceeds 6,000, a life safety evaluation must be performed. The required life safety evaluation recognizes that fixed protection and suppression systems alone do not ensure safe egress where large numbers of people are present. Expected crowd behavior is part of such an evaluation, as is consideration of techniques to manage any behavioral problems. The evaluation must include an assessment of all the following conditions and related appropriate safety measures: Nature of the events and the participants and attendees Access and egress movement, including crowd density problems Medical emergencies Fire hazards Permanent and temporary structural systems Severe weather conditions Earthquakes Civil or other disturbances Hazardous materials incidents within and near the facility Relationships among facility management, event participants, emergency response agencies, and others having a role in the events accommodated in the facility A new assembly venue subject to the LSE must be assessed prior to construction to ensure that the needed physical elements are part of the design. Also, facility management must be evaluated prior to building occupancy. The LSE provisions help to facilitate better communication among the designers and those who manage the facilities after construction. The goal is to provide managers with safety systems that are compatible with actual building use. Similarly, the LSE provisions for existing assembly occupancies include requirements for building systems and facility management assessments, a life safety narrative, floor plans, engineering analysis and calculations, operational plans, and a systems reference guide. Extensive details regarding the LSE, including factors that should be considered in an LSE, crowd behavior, and performance-based design approaches can be found within Annex A material in NFPA 101, Life Safety Code, which should be followed when completing an LSE. Main Entrance/Exit Every assembly occupancy, new or existing, is required to have a main entrance/exit. This concept is to accommodate for occupants that are likely to egress the facility though the same door(s)/opening they used to enter it and will be most familiar to them. In some types of new assembly occupancies, the main entrance/exit must accommodate up to two-thirds of the total egress capacity, while in other assembly occupancies it can account for 50 percent.  In assembly occupancies where there is no well-defined main entrance/exit, exits are permitted to be distributed around the perimeter of the building, provided that the total exit width provides not less than 100 percent of the width needed to accommodate the permitted occupant load. This concept acknowledges that some assembly occupancy buildings, such as a large sports arena, have no well-defined main entrance/exit. Occupants enter the building by doors in multiple walls, via one of multiple main entrances/exits. Under emergency egress conditions, all occupants will not attempt to use one common group of doors, because some occupants are familiar with their entrance/exit and others are more familiar with a different one. In such cases, it is the intent that egress width be distributed among the various exits without any one exit being required to provide 50 percent of the egress capacity. Auditorium and Arena Floors In new assembly occupancies where the floor area of auditoriums and arenas is used for assembly occupancy activities/events, not less than 50 percent of the occupant load can have means of egress provided without passing through adjacent fixed seating areas. This may occur where a large arena that is usually host to sports games switches to host a concert event and uses the floor area to put additional, temporary seating to accommodate additional occupants. It is intended to reduce the amount of merging and sharing of means of egress by persons in fixed seating areas and those who are forced to travel from the arena floor up into the seating sections to egress the building.  Regardless of where in the assembly occupancy someone might be located, access and egress routes must be maintained so that crowd management, security, and emergency medical personnel are able to reach any individual at any time (floor seating, fixed seating, theater seating, festival seating, etc.), without difficulty.   Emergency Action Plans (EAP) Emergency Action Plans (EAP) must be provided in assembly occupancies and are a critical component of assuring life safety in buildings. These plans must include at least a minimum of 18 different items, some of which include the following: Building details Designated building staff responsible for emergency duties Identification of events that are considered life safety hazards and the specific procedures for each type of emergency Staff training Documentations Inspection, testing, and maintenance of building facilities that provide for the safety of occupants Conducting drills Evacuation procedures The facility’s EAP must be submitted to the AHJ for review and should be reviewed and updated as required by the AHJ. Following any drill or actual emergency or reported emergency occurring in the building, an after-action report should be prepared by the building owner or designated representative to document the function of the building’s life safety hardware, procedures, and occupant emergency organization. Crowd Managers Assembly occupancies must be provided with a minimum of one trained crowd manager or crowd manager supervisor. Where the occupant load exceeds 250, additional trained crowd managers or crowd manager supervisors are to be provided at a ratio of one crowd manager or crowd manager supervisor for every 250 occupants in most facilities. Those designated as a crowd manager or crowd manager supervisor are required to receive approved training in crowd management techniques, as they need to clearly understand the required duties and responsibilities specific to the venue’s emergency plan. Training should be comprehensive of all aspects of crowd management including, but not limited to, the specific actions necessary during normal and emergency operations, and include an assessment of people-handling capabilities of a space prior to its use, the identification of hazards, an evaluation of projected levels of occupancy, and the adequacy of means of ingress and egress.  The procedures for providing trained crowd managers must be made part of the written emergency action plan as well. In conclusion, controlling crowds is a critical aspect of life safety in large assembly occupancy venue. Designers, owners and facility personnel, as well as inspectors and local AHJs all play an important role in ensuring a safe environment for occupants when crowds are present. With due diligence from all parties, the necessary life safety features for crowd management will not go overlooked.
Exit doors

The Basics of Swinging-Type Egress Door Operation

Door assemblies serve multiple purposes that relate to the comfort and safety of building occupants. They provide protection from weather, reduction of noises from adjoining areas, prevent trespassing by unauthorized persons and slow or stop the spread of fire and smoke. While seemingly so commonplace, door assemblies can become an impediment to occupants if they are locked or inoperable.  Doors within a means of egress include those non-fire-rated, fire-rated and smoke-resisting door assemblies. None of these will perform properly if left open during a fire. There are many examples of fires where fatalities resulted because of doors that were left open. There are also examples of fires where lives were saved because a door leaf was closed. Unfortunately, there are those fires in which door openings needed for escape were blocked or locked, resulting in devastating losses. Just this week, an eight-alarm fire in Queens, New York City, displaced 240 residents and injured people, including 16 firefighters. The fire was reported to start in a unit on the top floor.  An occupant fleeing the building left the door open to the apartment unit, causing the fire to spread into the hallway and to other areas of the building.    To help ensure safe door operation during an emergency, considerations must be given to the type of door, width of opening and door leaves, door swing direction, encroachment, the force required to operate the door, and the locking and latching devices. Here we will focus on those fundamental operational features only for side-hinged or pivoted-swinging type egress doors as these include the majority of doors an occupant will likely face while egressing a building. Other door types may be permitted in lieu of swinging doors but these will be addressed separately.   Minimum Width Door openings must be of sufficient width to ensure that enough people can pass through the openings quickly and safely during egress. Too narrow of an opening, or not enough total available capacity can create bottlenecks, and obstruct the flow of occupants leaving as they move towards a safer area.   Minimum door width is prescribed as (1) clear width, (2) egress capacity width, or (3) leaf width and when a specific minimum width is required by the Code, the specific width will be refenced. Specifying a door leaf width (the width of the door leaf, not the opening) is the least common case, and more often a minimum clear width or egress capacity width is mandated. Door width measurements might be used in calculating egress capacity or in determining if a minimum door width requirement is met. Depending on the purpose for which the door width measurement is used, the allowable encroachments on opening width vary.   Measuring egress capacity width for a new door leaf that opens 90 degrees (Credit: NFPA 101 Handbook, 2021 edition)   Measuring egress capacity width for a new door leaf that opens 90 degrees (Credit: NFPA 101 Handbook, 2021 edition) Clear width of a door opening is used for meeting minimum door-opening requirements, not for determining egress capacity. In some cases this minimum clear width value is based on the need for occupants traveling in a wheelchair to be able to move the wheelchair through the door opening. The egress capacity width, used to determine how many occupants can be credited with passing through the opening safely, will be less than the actual door leaf width because deductions in width are made for certain encroachments that extends into the door opening. Note: This describes the types of various door width measurements, but users should reference Section of NFPA 101 for further details about how to obtain these measurements in both new and existing conditions. Door Swing Direction Door leaves are required to swing in the direction of egress travel only if any one of the following three conditions exist:   The door serves a room or area with an occupant load of 50 or more,   The door assembly is used in an exit enclosure,  The door opening services a high-hazard contents area.    These three conditions address situations where it is undesirable for an occupant to take time to pull the door open in the direction they are moving from. This could be due to the higher number of occupants, or where conditions exist that could require instant and immediate access to the path of egress travel due to extreme fire or explosion risk.   Ideally, all door leaves in a means of egress would swing in the direction of egress travel. However, because of operational concerns, there are cases where door leaf swing in the direction of egress travel is not desirable. For example, a classroom door leaf that swings into a corridor serving as an exit access for several classrooms might open against another door leaf or against the flow of people and possibly restrict the width available as corridor exit access. The Code recognizes this danger and permits the classroom/corridor door leaf from a room with an occupant load of fewer than 50 persons to swing against the direction of egress travel.  Encroachment To minimize the risk of a door restricting the width available of other egress components, the Code establishes maximum encroachment allowances. During its swing, any door leaf in a means of egress is required to leave not less than one-half of the required width of where it is opening. When the door is fully open, is cannot project more than 7 in (180 mm) into the required width of the aisle, corridor, passage or landing unless the door is equipped with a proper self-closing device and swinging in the direction of egress travel. These two conditions help to ensure that the door leaf does not become an obstruction in the egress path onto which it opens which could reduce capacity and delay egress travel. There are no encroachment limitations for a door opening that provides access to a stair in an existing building. Door leaves capable of swinging a full 180 degrees have a greater utility than door leaves capable of swinging only 90 degrees. The 180-degree-swinging door leaf can be fully opened into a corridor without significant intrusion on corridor width. The 90-degree-swinging door leaf, however, might have to open into an unusually wide corridor, be set into an alcove, or otherwise be recessed so as not to exceed the maximum encroachment. Door leaf swing into a corridor (Credit: NFPA 101 Handbook, 2021 edition)   Door leaf encroachment on landing in new building. (Credit: NFPA 101 Handbook, 2021 edition) Unlatching Force  Several movements are necessary to move a door leaf from its closed to its fully open position. The force needed to unlatch the door assembly cannot exceed 15 lbf (67 N) for hardware that may push pull or slide and 28 in.-lbf for hardware that requires rotation. Additional limits are placed on the force to start the door leaf in motion and on the force necessary to move the door leaf to its required open position. Consideration must be made for persons with severe mobility impairment, such as someone using a wheelchair, who might find it difficult or impossible to exert excessive force to unlatch the door and put it in motion. Additional scenarios may render others incapable of exerting larger forces, so values as high as 50 lbf which were recognized in earlier editions of the Life Safety Code, are now only acceptable for existing installations.     Locking and Latching Doors within an occupant’s means of egress cannot be locked beyond their control but must also be designed to accommodate building’s and occupant needs for security.  If done incorrectly, door locking and latching can become a severe impediment to free and safe egress. The details and permissions for door locking and door latching are extensive, and must not be overlooked. We will address this subject in its entirety in a future blog (stay tuned!)    In conclusion, leaving a building or moving within a building to a point of safety in the event of an emergency is almost guaranteed to include using doors to get there. Proper door operation is critical to occupants being afforded a safe and efficient means of egress. Adequate door opening width, correct door swing direction, minimal encroachment, and appropriate opening and unlatching forces, combined, will work together to provide occupants with reliable and safe door operation.  (Note: Additional details and requirements related to door operation can be found in NFPA 101, Life Safety Code, Section 7.2.1.)
Fire ratings

How to determine the required fire protection rating of an opening protective?

Depending on the construction type and use, buildings may be designed and constructed with fire resistance-rated walls, floors and ceilings for structural integrity as well as to prevent fire and smoke from spreading throughout the building. However, openings in these fire rated assemblies are necessary for egress, communication, security, everyday travel throughout the building, and building services and equipment. Openings in fire rated assemblies must be protected accordingly so as to not compromise the fire resistance of the assembly in which they are located. Unprotected or improperly protected openings can void the rating of the wall, floor or ceiling by leaving ways for fire and smoke to spread unintentionally to adjacent fire compartments.    Fire rated components in buildings have either a fire resistance rating or a fire protection rating. It is important to understand the difference in the two ratings and to understand how to determine the required ratings of assemblies both when designing a building and also when determining compliance of existing installations. Although often used interchangeably, the terms are different.  Fire resistance rating vs. fire protection rating When a building assembly, such as a fire barrier, is required to be fire rated it must be reasonably airtight under increased air pressure on the fire side due to heated air expansion and must prevent the passage of heat and flame for a designated time. Fire barriers also must be capable of withstanding direct impingement by the fire, as determined by large-scale tests, either ASTM E119 or ANSI/UL 263. The ASTM E119 and ANSI/UL 263 test standards determine fire resistance ratings, in hours, based on exposure to the standard time-temperature curve and provide the rating of the construction of the particular assembly and the actual testing of the assembly in the test furnace. Assemblies protecting openings, such as doors and windows, located in fire resistance-rated assemblies must be capable of withstanding the effects of fire, as determined by large-scale tests such as NFPA 252, NFPA 257, ANSI UL10B, ANSI/UL 10C or ANSI/UL 9. The acceptance criteria for these fire protection-rated assemblies, differ from those for fire resistance-rated construction, such as a wall or floor/ceiling assembly. The limitation of temperature rise through a fire door is not normally a measure of acceptance, although it is a measure of acceptance for a fire resistance–rated assembly such as a wall.   Some openings may also be protected with products that have a fire resistance rating where they have been tested as, and passed criteria as required for walls, floors or ceilings.  Fire resistance rating, glazing, is an example of this. It may be installed and used as a wall in some cases if permitted and tested accordingly. Determining the required fire protection rating To properly protect an opening in a fire resistance-rated assembly, the proper fire protection rating is required. The following steps should be followed when determining the appropriate fire protection rating of an opening protective:   Step 1: Determine the required fire resistance rating of the component under evaluation.  Components include, but are not limited to, vertical shafts, horizontal exits, exit access corridors, and smoke barriers.  Codes, such as NFPA 101, Life Safety Code, NFPA 5000, Building Construction and Safety Code, mandate where a building component is required to have a fire-resistance rating.    Step 2: Utilize the tables, “Minimum Fire Ratings For Opening Protectives in Fire Resistance-Rated Assemblies and Fire-Rated Glazing Markings”, found in Chapter 8 of both NFPA 101 and NFPA 5000 to determine the minimum fire protection rating of the opening protective based on the fire resistance rating determined in Step 1. It should be carefully noted that this table DOES NOT mandate the fire resistance ratings of components, other provisions in the Code will require it.    Step 3: Confirm through footnotes, other code text associated with the component, and through occupancy specific provisions, that no further modifications to the general fire protection ratings are permitted.  In some cases, there may be exemptions for some opening protectives in existing installations or for certain conditions in some occupancies.     Example Let’s look at an example: What is the required fire protection rating for a corridor door in an exit access corridor in a new, non-sprinklered, office building?     Per NFPA 101, most new, non-sprinklered, business occupancies require exit access corridors have a minimum 1-hour fire resistance rating (step 1).  Next, by going to the referenced table in NFPA 101 (table it can be determined that a 1-hour fire resistance-rated exit access corridor requires a minimum 1/3-hour, or 20-minute, fire-protection-rated door. It can then be confirmed that no further modifications are permitted (step 3).    Why can the fire protection rating be less than the fire resistance rating? The required minimum fire protection ratings of opening protectives are sometimes permitted to be of a lower rating than the fire resistance rating of the fire barrier in which they are located. For example, a 2-hour fire barrier enclosing an exit stair is permitted to have fire doors protected by 1½-hour fire protection-rated door assemblies.  The test procedures on which the ratings are based, discussed above, are different. Although combustibles placed against a fire resistance–rated wall expose the wall to a considerable fire challenge, a fire protection-rated door assembly does not usually have combustibles placed against it, because the opening must be clear to use the door and kept free of obstructions for proper operation of the door. Such a scenario suggests that, if a door is not to be used and combustible storage is to be placed at the door opening, the door should be removed and the opening replaced with solid construction to restore the wall to its required fire resistance rating.   Fire rated components are a critical piece to the comprehensive protection strategy that buildings use to protect people and the building itself from the effects of fire.  The success of passive fire protection methods such as the use of compartmentation requires careful compliance during design and installation as well as effective and consistent inspection, testing and maintenance to ensure the system will perform as intended during a fire.    What challenges have you faced when designing buildings with fire rated components?  In what role have you worked with applying code requirements for opening protectives?  Please share your feedback in the comments below!
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