Applying NFPA 101 in mission critical facilities
Mission critical facilities—including health care, industrial facilities, and other buildings—rely on NFPA 101: Life Safety Code to define fire and life safety strategies.
- Outline how NFPA 101: Life Safety Code should be used in mission critical facilities.
- Understand egress requirements versus defend-in-place requirements of the code.
- Assess the types of operational requirements needed for different building types.
In the engineering world, mission critical facilities can refer to a variety of different types of facilities. The first type of facility that tends to come to mind is a data center because the "mission" of the facility is critical and continuity of operations is essential.
However, from a life safety perspective, mission critical often refers to a facility in which the mission or operation of the facility is critical and the prompt evacuation of the facility is not possible. This can include health care facilities, detention and correctional facilities, and industrial facilities in which at least some operation or control personnel need to remain in place for a period of time.
Mission critical industrial occupancies
In December 1992, three workers at the O’Brian Newark Cogenerating Plant (Newark, N.J.) perished in a fire when they could not find a safe egress path. The employees were in a control center on the second floor with one means of egress, which was through the area where the fire occurred. The control center had exterior windows, but the employees were not able to break the windows. Given no other options, the employees entered the smoke-filled area and attempted to get to a stairway. Their bodies were found in the path of travel between the control center and the exit stairs.
When evacuation of personnel is likely to be delayed due to the need to initiate shutdown procedures, the most common life safety strategy is to provide one or more means of egress paths in which the available safe egress time (ASET) is greater than or equal to the required safe egress time (RSET). In this case, the required safe egress time includes the time necessary for the control personnel to initiate or, if necessary, complete plant shutdown procedures.
NFPA 101: Life Safety Code contains a requirement that ancillary facilities within a new industrial occupancy are to be provided with at least two means of egress arranged such that both egress paths are not likely to be compromised by a single fire event (NFPA 101-2015, Chapter 22.214.171.124.1). This general requirement applies to any ancillary facility, which could include administrative spaces, laboratories, and employee service areas.
The code also contains a requirement that if evacuation will be delayed, the ancillary spaces are to be separated from the industrial occupancy and at least one egress path shall be separated from the industrial occupancy by construction having a 2-hour fire-resistance rating (NFPA 101-2015, Chapter 126.96.36.199). Process-control centers are a common type of ancillary facility in which evacuation may be delayed to facilitate an orderly shutdown of the process or facility.
While the approach with ancillary spaces in industrial occupancies is to ensure that a safe means of egress will be available to occupants who may need to delay evacuation, there are other facilities in which the strategy is to "defend in place" or minimize the need to evacuate. This generally occurs in facilities providing medical care where moving fragile patients or residents could result in harm or in facilities needing to maintain security, which results in a desire to keep the occupants within the facility. In addition to requiring adequate staff ratios and training, the code requirements for these types of facilities address the construction, compartmentation, fire protection systems, fire prevention procedures, and emergency planning.
Whereas the scope of NFPA 101 involves life safety, the building construction type is not regulated for many of the occupancies addressed by the code. In these instances, the code presumes that adequate life safety can be provided without mandating specific types of construction. However, it is also recognized that the code presumes the building construction for those other occupancies will be addressed by building and fire codes (NFPA 101-2015, Chapter 1.1.6).
When a defend-in-place strategy is to be implemented, structural integrity is more critical. In such instances, NFPA 101 includes minimum construction types based upon the need to address the combustibility of the structural system as well as the fire-resistance rating. For example, NFPA 101, Table 18.1.6 requires that new health care occupancies be of noncombustible construction and have at least a 1-hour fire-resistance rating if the building is more than 1 story in height. Because buildings containing new health care occupancies must be protected throughout with an automatic sprinkler system, the construction requirements are in addition to the requirement for sprinkler protection.
In addition to structural integrity, such occupancies typically require some degree of compartmentation. With respect to the overall occupancy, NFPA 101 typically requires a fire barrier having 2-hour fire resistance to separate the mission critical occupancy from other occupancies in the building, when the separated occupancy approach is used. Unlike most other occupancies, the fire-resistance rating of the occupancy separation is not permitted to be reduced based upon the presence of an automatic sprinkler system. When compared with other occupancies with a similar fuel package, the mandate for the 2-hour separation is clearly intended to decrease the likelihood that a fire in an adjacent occupancy will impact the mission critical occupancy.
Within the mission critical occupancy, the compartmentation starts between the room and the corridor or common space. For example, NFPA 101, Table 22.3.8 contains specific requirements for separating the sleeping room within a detention and correctional occupancy from corridors and common spaces. As with health care occupancies, new detention and correctional occupancies are required to be protected throughout with an automatic sprinkler system, so the separation required is in addition to the protection provided by the sprinkler system. This separation provides protection for the occupant within the room of origin after they are removed from the room. It also provides protection for occupants in other rooms, thereby, reducing the need to relocate those that are not in the room of origin.
Should the fire continue to develop such that occupants outside the room of origin need to be evacuated, the mission critical occupancies are required to have smoke barriers, as indicated by NFPA 101. A smoke barrier typically has a fire-resistance rating of at least 1 hour and is designed to resist the passage of smoke. As such, moving patients, residents, or inmates across a smoke barrier should provide at least a temporary area of refuge, reducing the likelihood that those relocated will need to be evacuated to the outside or relocated vertically within the building. This horizontal relocation should require less staff than when evacuating the occupants or relocating them to other floors. However, it should also enhance the ability to continue to provide medical care in a health care occupancy or security in a detention and correctional occupancy.
In addition to regulating the travel distance to an exit, in the case of a health care occupancy, the code limits the travel distance to a smoke barrier. The travel-distance limit is based upon what the committee has determined to be an acceptable distance for staff to relocate patients across a smoke barrier. As such, considerations-such as the estimated time it will take to reach a smoke barrier as well as the physical challenges associated with relocating patients-have been considered. It should be noted that the travel distance to an exit door to the outside or an exit stairway is not to be considered when evaluating compliance with this requirement. The intent is that the occupants can be easily relocated to another part of the building on the same story.
Controlling the fire
In addition to compartmentation, NFPA 101 contains several provisions designed to manage the impact of the fire by controlling the fire. The provisions start with controls on the fuel package including the furniture and mattresses that are used. Two fire tests are referenced for such contents: one that evaluates the ease of ignition of the item and one that determines the heat-release rate for the item. In addition to addressing the fire-growth rate by requirements for certain furniture items, NFPA 101 also addresses the spread of fire with requirements for the interior finish materials. In this instance, the code does recognize the benefit of an automatic sprinkler system and establishes different criteria if automatic sprinkler protection is provided.
Another way that the fire is to be controlled in the mission critical occupancy is through the presence of an automatic sprinkler system. The 1991 edition of NFPA 101 was the first edition to mandate sprinkler protection in all new health care occupancies. Requirements also were added to sprinkler the portion of an existing health care occupancy involved in a major rehabilitation project. The combined effect of these two requirements is an increased percentage of hospitals that are protected by automatic sprinkler protection.
The basis of the requirement was fire modeling performed almost 30 years ago that illustrated the ability of fast-response sprinklers maintaining tenability at the bed level in a patient room in most fire scenarios. Subsequently, full-scale fire tests were conducted in mock patient rooms that validated the results of the computer modeling. In addition to protecting the patients, if the sprinkler system controls the fire, then staff can continue to provide medical care and treatment in other parts of the facility.
Whether one is talking about health care or detention and correctional occupancies, people often raise concerns about sprinkler protection in such facilities. Will babies drown in bassinets? Will patients be electrocuted due to the electronics of the bed? What about operating rooms and water discharge from the sprinkler system? Will inmates use the sprinkler as a means of committing suicide?
While there have been a limited number of incidents involving the sprinkler being used as something from which one can commit suicide by hanging, there is no data indicating that the other scenarios pose a risk to the occupants when the systems are properly designed. Even with respect to the suicide scenario, there are ways to properly design a sprinkler system to minimize the risk associated with any of these scenarios.
Despite the enhanced risk to life safety posed in these mission critical facilities, the fire record in the United States is very good. The benefit of sprinkler protection also is illustrated when comparing the fire experience in other countries where the compartmentation requirements may still exist but sprinkler protection is not as common. The multiple-death fires we read about in hospitals and detention and correctional occupancies in other parts of the world are occurring in buildings that are not protected with an automatic sprinkler system.
The defend-in-place concept used in these mission critical facilities also relies on the presence of adequate staff training and staff ratios. While staffing is not something that design professionals can typically address, there are design considerations that need to be addressed to assist the staff carrying out responsibilities during a fire emergency.
NFPA 101 addresses the need for visual supervision of suites and for spaces open to the corridor. The visual supervision is intended to provide one means of early detection of a fire. Another staff consideration that is not addressed by the code is the proximity of staff to the emergency situation. However, if the design team adequately addresses the efficient operation of the facility, staff members will most likely be relatively close to any emergency that occurs in an occupied area.
There are resources available to design professionals to address issues, such as reducing the number of steps staff must take while performing normal activities, including The Center for Health Design. Furthermore, the concept of distributive nurse stations throughout a patient care area is also placing the staff in closer proximity to patients for routine care and emergency situations.
Where design professionals can truly impact the ability of staff to perform during emergency situations is the coordination of the building design with the facility emergency plan. The following are scenarios from actual projects that were recently designed.
- The alarm notification appliance circuits in a new 20-story hospital are not aligned with the smoke barriers. While this is a requirement in NFPA 99: Health Care Facilities Code since 2012, it was not considered in the design of the fire alarm system for this facility. As such, the information needed for staff to properly implement the emergency procedures could not be provided using the fire alarm system. This has resulted in an expensive remediation project to correct the oversight.
- As permitted by the NFPA 101, 50% of the stairs in a hospital that opened within the past 2 years discharge through the level of exit discharge. However, all of them are on the same side of the building and require egress through the same atrium on the level of exit discharge, which is not permitted by NFPA 101. This issue was not identified until the facility started a project to evaluate their existing emergency plans. If a fire occurs in the atrium, which does not have smoke control and is not protected with a sprinkler system, it results in smoke spreading to adjacent floors where it can impact multiple smoke compartments on each floor. In addition, the egress from some of the smoke compartments requires vertical movement and evacuation through the atrium. In the short term, the facility is developing special emergency plans to identify specific areas to which patients are to be moved to prevent the reliance on the egress through the atrium. In the long term, a remediation project will be undertaken to address the fact that all the stairs that discharge through the level of exit discharge require travel through the atrium.
It is worthy to note that the NFPA Life Safety Technical Committee on Health Care Occupancies has appointed a task group to consider various fire alarm design issues in health care occupancies to be considered for the next edition (2021) of NFPA 101. In addition to coordination of initiating devices and alarm-notification appliances with the emergency plan, the group is expected to evaluate whether private-mode fire alarm systems should be required for all new health care occupancies. While currently a design option, many engineers continue to use public-mode fire alarm systems, and some regulatory officials are hesitant to approve private-mode fire alarm systems.
Another factor that will need to be considered with future designs is that many health care facilities are experiencing significant staff turnover. While the very nature of these mission critical facilities often results in complex designs, the design professional needs to consider staff turnover with regard to simplifying the design features associated with the emergency plan. In addition to staff turnover, when the Cleveland Clinic Abu Dhabi first opened, the staff included people from 50 different nationalities. The diversity of the staff further complicated emergency planning and training and clearly illustrated the need to make people aware of the building fire-safety features.
Mission critical facilities, such as health care occupancies and detention and correctional occupancies, present some unique life safety challenges. NFPA 101 addresses these challenges using a defend-in-place protection strategy. Proper implementation of the strategy requires designs that are coordinated with the facility emergency plan and protection strategies involving construction, compartmentation, fire control, fire protection systems, and adequate staff levels and training.
The U.S. fire experience has demonstrated that these can come together and provide an acceptable level of life safety from fire and similar emergencies. However, when one or more critical components is missed or fails, the fire may result in an unacceptable, but avoidable, outcome.
–William E. Koffel is president of Koffel Associates, a fire protection engineering design/consulting firm, and is recognized as an expert in the fire protection/life safety aspects of codes and standards. He is a member of the Consulting-Specifying Engineer editorial advisory board.