Planning multifamily dwellings: Fire and life safety
Fire and life safety systems are of utmost importance in multifamily dwellings.
Kris Cotharn, PE, LEED AP
Wayne Griswold, PE, CFPS
Principal Fire Protection Engineer
Randall V. Moss, P.E., LEED AP
Joseph Russo, PE, LEED AP BD+C
Rafi W. Wartan, PE, LEED AP BD+C, CQM-C
CSE: What are some of the unique challenges regarding fire/life safety system design that you’ve encountered for such projects? How have you overcome these challenges?
Griswold: Sprinkler requirements and the applicable design and installation standard are not always obvious to the design team or even the awarded contractor in multifamily buildings. The cost associated with installing the wrong type of system is drastic, so coordination with the design team, AHJ and contractor is often necessary to resolve the issue. This coordination is also useful to ensure the design team is taking advantage of building code allowances permitted when a building is sprinklered (i.e., travel distances, building construction, etc.).
Recently we had a project where a project fell under the jurisdiction of the 2015 edition of International Residential Code and there were basement bedrooms using egress window wells. The issue was that the middle unit of the townhouse (i.e., three-unit cluster with separated garages) did not have compliant egress within its own lot lines to a public way as required by IRC Section R311.1. Previous editions of the IRC simply stated the egress route couldn’t be through a garage and had to be continuous and unobstructed; however, no mention was made to a public way.
As a result, two options were given to resolve the issue: provide a path between the garages to the public way or orient the basement bedrooms so that the egress window well was on the street side. This is an important change in the 2015 IRC edition as the intent is to ensure that each unit is capable of exiting to a public way without needing adjacent properties, which prevents potential entrapment issues associated with neighboring fences.
Russo: The challenge in assisted living projects is to alert the proper personnel to the alarm without upsetting the residents. To address this challenge in 24–hour occupied areas, we would recommend a private notification system, which allows personnel to escort the residents out of the building in a controlled fashion.
CSE: In assisted living facilities, how have the trends in fire/life safety changed?
Russo: Fire/life safety systems are not only a code requirement but are an expectation of those living within these facilities as well as their loved ones. These facilities are no longer the simple residences; they include theaters, pools, atriums, etc. Assisted living facilities have required more intricate fire protection design considerations in large part due to ornate, “cloud” ceilings (requiring multiple levels of sprinklers). In addition, atriums and corridors with glazing, requiring specific wall ratings, mandate the installation of listed window sprinklers. Theaters also are becoming more significant, further increasing the complexity of fire protection systems.
As a result of the high demand and enormous size of these facilities, fire standpipe systems can be required. Aesthetics, including custom color and welded piping, also has been desired. Technology rooms are being considered vital rooms, as such, owners are evaluating the need for preaction and gaseous systems. Due to the overall fire protection demand, fire pumps (either electric or diesel) also are becoming more common.
Griswold: Historically, assisted living facilities have been set up similarly to a hospital with a central fire–rated corridor and various care function rooms on either side. Recently, assisted living facilities have evolved toward a more open concept to aid in patient wellness and sense of community. The intent is for the patient to spend more time outside of their rooms, while also providing staff members with a less intrusive means of monitoring patients. The 2018 edition of the International Building Code has accommodated this design feature and now permits shared living spaces, group meeting spaces and multipurpose therapeutic spaces to be open to fire-rated corridors if certain conditions are met, including being provided with sprinklers and a smoke detection system.
CSE: What fire, smoke control and security features might you incorporate in these facilities that you wouldn’t see on other projects?
Griswold: Assisted living facilities are unique from the standpoint that the patrons have varying degrees of self-preservation ability and capacity. Additionally, depending on the number of patients for the facility, the occupancy classification can be either R-4 or I-1 as regulated by the IBC. Similarly, NFPA 101 regulates these types of facilities as Residential Board and Care Occupancies, with “small” facilities being defined as not more than 16 residents and “large” facilities having more than 16 residents. Unique features to this type of occupancy may include any of the following: smoke compartmentalization, areas of refuge with two-way communication, delayed egress, mandatory sprinkler and smoke detection systems, accessibility requirements and reduced exit travel distances.
Russo: For high–rise multifamily buildings that meet the criteria indicated in the IBC, stair and vestibule pressurization systems are to be provided. The system shall be independent and all wiring and controls shall be located either on the exterior of the building, within the smokeproof enclosure or in the building separated by another two-hour fire barrier. Control and power wire may be excepted if using two-hour rated cables, encased in 2 inches of concrete or protected by a circuit system with a fire-resistance rating of two hours. The stair pressurization ductwork shall be located inside the two-hour rated enclosure to minimize the need for fire smoke dampers and additional rated shafts. The fan shall be provided with a variable frequency driver for balancing and wired with two-hour rated cables. Outlets shall be located on every other floor (including intermediate landing locations) and away from operable doors so not to interfere with the doors closing and opening.
CSE: What types of systems have you put in place to guard against natural disasters such as hurricanes, wildfires, floods, earthquakes, etc.?
Griswold: Systems specific to guard against natural disasters are location dependent. Different fire/life safety systems warrant varying degrees of protection. As an example, NFPA 13 has incorporated seismic bracing for piping into Chapter 9 for areas of the country that are prone to seismic activity. The International Fire Code requires an automatic secondary on-site water supply for high-rise buildings where located within a Seismic Design Category C, D, E or F zone as determined by the IBC. Other examples of guarding against natural disasters include using weatherproof audible/visual notification devices on exteriors of buildings and the enforcement of defensible space in wildland-urban interfaces and the use of ignition resistant building materials as required by NFPA 1144.
Wartan: Hurricanes cause damage along their path, but the impact to a lot of facilities is limited to loss of power only. In assisted living facilities, we’ve been designing larger emergency power systems that allow the residents to maintain a safe living environment until utility is resumed. In Florida, providing emergency power to HVAC equipment is not just good practice, it is required after Hurricane Irma hit the state and the governor issued a rule (58A-5.036) making it a requirement.
CSE: Describe unique security and access control systems you have specified in such facilities.
Griswold: Gated access to multifamily areas has become increasingly commonplace for new construction projects. Despite presenting unique challenges for response fire departments, this orientation is often preferred by prospective buyers as it enhances security and safety while promoting a community environment. Fire department specific Knox boxes are typically installed on the security gate pedestal or other approved means to ensure that fire department response is not delayed in these types of settings. Assisted living centers tend to implement some sort of access control system to provide varying levels of access for both patients and staff members. These systems present unique egress challenges and need to be interfaced with a fire alarm system to ensure mechanical free egress in the event of a fire event.
CSE: Do you see any future changes/requests to the structural design of these buildings regarding fire/life safety systems?
Russo: The recent push for larger and taller wood structures may seem like an architectural fad; however, construction companies around the world are starting to use more large-scale structural wood systems. These buildings can already be seen throughout Europe and Canada. Fire protection systems for these buildings will be mandated to reach the desired heights and square footages. Protecting any potential combustible concealed spaces also may be a challenge.
Griswold: Structural member features of these types of buildings will follow the ebbs and flows of construction material costs. In general, I would anticipate Type V construction to continue to be the norm for the low-rise and midrise applications, with Type I and II construction being used on high-rise facilities due to allowable area and height restrictions. While not structural member specific, I would anticipate changes to exterior façade requirements based on the lessons learned from recent high-rise façade fires across the world. Additionally, how we protect the building from a passive system (i.e., firestopping) standpoint at the exterior wall and floor/ceiling interface needs to be improved to better resist passage of heat and smoke vertically.
CSE: How has the cost and complexity of fire protection systems involved with multifamily dwellings changed over the years? How did these changes impact the overall design process?
Griswold: The fire protection community has taken strides since the publication of America Burning – The Report of The National Commission on Fire Prevention and Control, which recognized that the majority of fire deaths occurred in residential occupancies. Since that time, NFPA 13D and NFPA 13R have been developed and codified in an effort to reduce the financial burden and complexity of fire/life safety systems in multifamily construction. These systems are considerably cheaper to design and install than traditional NFPA 13 systems and are much less demanding from a hydraulic standpoint, generally not requiring a fire pump. The intent of these systems is to extend fire department response and occupant egress times that have been reduced over the years due to increased use of synthetic materials (i.e., plastics) in homes, which have higher release and more toxicity characteristics.
Russo: As a result of the architectural detail and overall size of these facilities today, fire protection costs have increased for new multifamily facilities as well as renovated facilities. Fire safety is no longer simply based on code, it now includes insurance carriers and owner’s requirements, all of which inform the design process. Furthermore, the public tends to expect this higher level of safety.
CSE: How have changes to codes, BIM and wireless devices/systems impacted fire and life safety system design for these projects?
Russo: Wireless fire alarm devices allow for location flexibility to address changes in construction with regard to space programming. Wireless devices have become more reliable and, when allowed by the jurisdiction, they can eliminate some conduit/wiring, which allows the limited ceiling cavity to be freed up. The code, building and fire officials, as well as the public are less tolerant of nonprotected buildings, thus prompting an increased need for fire protection systems throughout the entire building. BIM has allowed closer coordination with all trades and stakeholders from early schematic design, right through construction to assist in providing a coordinated product to the owner.
Griswold: Fire alarm systems have been and will be the most impacted systems from a wireless technology standpoint. While not readily on the market, wireless fire alarm components are in development and are likely to enter the marketplace sooner than later. To date, monitoring of fire alarm systems per NFPA 72 Chapter 26 has been the most impacted by wireless technology. Historically, monitoring redundancy (i.e., two means) was established via two separate phone lines. More recent versions of NFPA 72 now permit a single phone line with an accompanying system consisting of one of the following: one-way private radio alarm system, two-way radio frequency multiplex system or performance-based transmission means.
BIM technology continues to evolve in more complex buildings and designs where clash detection is desirable to avoid construction delays associated with uncoordinated trades. Comparatively speaking, fire and life safety systems are not generally intrusive when compared to overall mechanical/electrical/plumbing designs. Caveats to this are sprinkler and smoke control systems where shaft enclosure space and/or ceiling space can be limited. We’ve experienced varying degrees of success with BIM projects, although I would expect this to improve as the technology is refined and use is more commonplace.