How egress is planned using NFPA 101
NFPA 101: Life Safety Code is one of the primary sources for the requirements of exit pathways
- Understand the requirements of egress that affect mechanical, electrical and plumbing designers.
- Know how other codes and standards affect NFPA 101: Life Safety Code.
- Learn how a project maintained required egress during a complicated remodel.
Some of the important aspects of building design and construction are related to building egress — the ability to exit a building safely, quickly and through protected pathways. While designers are experienced with developing a compliant building at the end of construction, the remodel process presents numerous opportunities for blocking required exits.
NFPA 101-2018: Life Safety Code is one of the primary sources for the requirements of exit pathways.
Protection of exits
Egress exit enclosures and exit passageways are required to be protected by fire resistance-rated assemblies to ensure the pathway is usable and not compromised by the failure of building systems. NFPA 101 Section 7.1.3 defines limitations to building systems that can be installed in or routed through exit passageways and exit stairways.
The intent of these restrictions is to prevent the exit enclosure from being used as a pathway for building systems, such as a vertical or horizontal chase, for systems that do not directly serve the exit enclosure. The exception to this restriction is listed in Section 220.127.116.11.1 (10) and includes ventilation, fire protection, heating and cooling systems.
Fire alarm and telecommunication systems also are allowed but are required to be installed in conduit. When designing systems, designers should pay careful attention to system routing to both avoid stairways during their project and to allow for future routing of systems around stairwells.
Delayed egress systems described in Section 18.104.22.168.1 allow for a short-duration impediment to the direction of travel for security reasons. These reasons may be to deter theft or limit use of the path except in emergencies. Building additions can impact the path of egress, resulting in egress through a sensitive area. A delayed egress system allows the building to meet code for egress pathway distance and location while promoting alternate travel paths.
This is not an ideal scenario, and the design team should try to avoid using delayed egress for this purpose when possible. This door system requires sprinkler systems and fire alarm systems be used for deactivation to eliminate impediments during an emergency. This requires fire alarm relays be located at the door controllers and programmed to unlock or bypass locking mechanisms.
Another electronic door control method is defined in Section 22.214.171.124.2, which includes requirements for locating a manual release device, a push-button with the words “push to exit” clearly identified. Both manual and motion sensors are required, however, a manual release is more secure than a motion-sensor release system, where the latter can inadvertently provide access to the secure area. Careful consideration as to the placement and coverage of the motion sensor may occur with secure locations.
Manual push–buttons are required to be within 60 inches of the door opening, which can be challenging with storefront construction, requiring careful coordination with the storefront manufacturer to install the pushbutton in the mullion. The design team should carefully consider arrangement and labeling of manual release buttons when multiple doors are grouped in an area.
A fire alarm interface is required at these doors as well, unlocking the doors upon activation of the sprinkler or fire alarm system. Typical applications for electronic door releases are for areas where public access is desired to be restricted or where the facility wants an electronic record of access. These areas can include electrical, technology and mechanical rooms and where panic hardware is required, the releasing requirements apply.
If the project requires electronic locking of doors separating an elevator lobby from the exit corridor, Section 126.96.36.199.3 has a long list of requirements and interfaces with other building systems, including requiring that the building have a sprinkler system and a fire alarm system in addition to the activation of those systems providing unlocking of the doors. Additionally, this section requires a two-way communication system to a continually attended location with trained staff, a requirement that is not suitable for buildings that are not staffed 24 hours a day.
The 2018 version added references to American National Standards Institute/Builders Hardware Manufacturers Association standards, requiring compliance for power-operated and power-assisted doors in Section 188.8.131.52. This section also defines the maximum amount of force required to manually open these doors upon loss of power. The maximum forces in Section 184.108.40.206.5 still apply, with a higher initial opening force allowed for power-operated and power-assisted doors.
It is important to note that the force required to open an egress door is affected by the heating, ventilation and air conditioning system. Buildings with negative pressure balancing will result in additional forces on exterior doors; designers should carefully consider how building pressure will affect egress requirements. Power–operated doors are required to be deactivated upon activation of the fire alarm in that area.
NFPA 101 has an extensive amount of information and requirements for stairs and stair enclosures. Minimizing water accumulation for exterior stairs is required in Section 220.127.116.11.5 and may result in the addition of exterior drains if the landscape cannot allow for natural drainage.
Engineers may be impacted by illumination requirements in Section 18.104.22.168.5.11, when installed, and smokeproof enclosure requirements in Section 7.2.3, where required by other sections of the code. Ventilation requirements of smokeproof stair enclosures are defined in Sections 22.214.171.124 and 126.96.36.199 and include both air change requirements of at least one air change per minute and an exhaust system that is 150% of the supply air.
This section also defines the physical location requirements of air intake and exhaust grills. The exhaust air discharge is required to be 2500 cubic feet per minute while maintaining at least 0.10 inch of water column pressure relative to the stair access doors and the occupied space. This pressurization requirement can vary based on building sprinklering and refers back to Section 188.8.131.52.5 for maximum door opening force.
These requirements require careful consideration to how the system is controlled to not exceed the minimum air pressure requirements to the point that the door opening force is increased beyond required maximums. One solution to this arrangement is using variable frequency drives to control the pressurization fans to maintain adequate pressure during balancing, but not to monitor actual pressure that would be affected by opening doors, thus causing the system to react in real time and overpressurizing the enclosure when doors are closed.
New to 2018 NFPA 101 is a requirement in Section 184.108.40.206.1.1 to comply with NFPA 92: Standard for Smoke Control Systems and the addition of survivability requirements for control and power wiring in Sections 220.127.116.11.2 through 18.104.22.168.4. These survivability requirements are similar to other sections of NFPA 70: National Electrical Code or NFPA 110: Standard for Emergency and Standby Power Systems where two-hour rated systems are required for power wiring.
These power systems are required to be on an emergency power supply system that complies with the requirements for a Type 60, Class 2, Level 2 EPSS, meaning power shall be provided within 60 seconds of utility failure and shall operate for no less than two hours.
Mechanical room egress
As mechanical rooms increase in size, the need for egress components need to be evaluated. Section 7.13 defines egress pathway distance limitation of 50 feet with distance extensions for sprinklered buildings, existing buildings or rooms without fuel-fired equipment. Egress pathways should be clearly identified, marked and illuminated in compliance with this section and other sections.
Mechanical rooms will commonly encounter restrictions to clear height, obstructions on the floor or obstructions raised off the floor. The designers should carefully consider the location and arrangement of mechanical room exits when the building systems are determined.
The requirements for elevators include American Society of Mechanical Engineers A17.1/CSA B44 Safety Code for Elevators and Escalators as well as NFPA 101 Section 7.15. The annex for Section 7.15 provides extensive information to support the requirements and share the findings in previous studies. Section 7.15 provides requirements and guidance for buildings where the elevators are desired to be used for occupant egress during an emergency.
Section 22.214.171.124 requires the fire command center to include a list of elevator information including location, direction of travel and occupied status. Additionally, the status of normal and emergency power and fire alarm status is required to be displayed. This information could be integrated into the elevator controller or provided by separate annunciators for transfer switches and the fire alarm, which are already required in International Building Code Section 911.
In addition to status, elevator override control is required at the fire command center. A voice-capable fire alarm notification system is also required, allowing the command center to provide verbal instructions per floor to indicate if/where elevators are available. This voice system shall comply with NFPA 72: National Fire Alarm and Signaling Code (Annex D) for speech intelligibility, especially in the elevator lobbies. A two-way communication system is required in the elevator lobbies to allow for communication with the command center.
Another important requirement is that elevator hoistways and elevator machine rooms shall not contain sprinklers if the associated elevators are used for occupant evacuation. The reason for eliminating sprinklers in these areas is because of shunt trip requirements, which would conflict with usage, as noted in Section 126.96.36.199 and described in the associated annex section.
Egress impacts during construction
Specific sections of Chapter 7 have been briefly discussed, yet this chapter is predominantly about requirements for egress pathways themselves. While the intent of this article is not to educate the reader on the entire chapter, it is important to understand how design and construction phasing will affect egress pathways and thus temporary occupancy challenges.
The distance travel limits, dead-end limits and common path limits in Table A.7.6 can be impacted during construction. Designers need to take both temporary and permanent impacts to building egress into consideration during remodels and building addition projects to ensure an unsafe condition is not created while the area is occupied. Additionally, NFPA 241: Standard for Safeguarding Construction, Alteration and Demolition Operations should be considered for compliance during these operations.
Consider a project where an exhaust duct is required and needs to be added to the space. While most of the project scope may be confined to a small area, the distance to a suitable exhaust system or vertical chase may result in ceiling removal outside of the project limits. It is important to note that NFPA 101 Chapter 43 should be reviewed in terms of additional areas outside the project scope that may need to be upgraded to comply with the life safety requirements.
Another example would be the addition of a sanitary drain on an elevated floor, where sloped pipe needs to be routed above the ceiling on the space below and that route may impact existing systems above those ceilings. It is likely this work will occur in or through existing corridors that will impact egress. The design team should consider how long the corridor will need to be closed off to execute the work. In some cases, only part of the corridor may need to be closed off at a time and while this phased installation increases the time and thus cost of the work, a temporary narrowing of the egress pathway may be tolerable.
For a school or office building this may be done after hours but for a hospital or 24-hour occupancy the work will trigger a review of alternate egress pathways. If the area in question is in front of an elevator or egress stair, the impacts are more substantial and the design team should consider if the area served by the egress pathway can remain occupied during construction. It will usually be considered unacceptable to tell a hospital client that your ductwork route requires they empty a patient wing.
For projects with a much larger impact to the building, phasing boundaries should be coordinated with adjacent egress requirements at each stage. Construction barriers that extend into corridors should be evaluated with adopted code and may require alternate options and pathways. When closing corridors is required, the team must assess the ability to continue to occupy adjacent areas. Depending on the project, the impact may be over hours, days, weeks or months.
The facility, the designers of record and the authority having jurisdiction should discuss the impacts during design and document the agreed approach, one that does not put occupant lives at further risk. One example of this effort is an addition and remodel of surgery department at a client’s hospital, where the entire surgery department would be replaced while the department remained active. The purpose of the building addition was to add operating rooms in the initial phase so the number of usable ORs remained constant during construction.
The engineering project manager and electrical engineer of record participated in many meetings and project phasing discussions that included the architect, owner, users and state health department to evaluate how each area would meet egress requirements during each construction phase. While the engineering team was focused on the impacts that both new and existing electrical, plumbing and HVAC systems would have on each phase, the team also considered the impacts to corridors and adjacent patient care areas.
For example, if the project was phased in a way that cut off the main HVAC duct serving areas outside of this phase, a temporary solution would be required and departments would not be occupied during system outages. Because this was a surgery department, the cleanliness of the temporary barriers further complicated the effort required and construction barriers that were durable, gasketed and cleanable. The HVAC air balance of the occupied areas required constant attention during each phase due the indoor air quality requirements and air pressure relationships.
The state authority required interim life safety drawings be submitted for each phase as part of the project approval process. It was clear from the beginning that our project phases were long enough to require egress solutions that would be suitable for a permanent condition.
One challenge was with the creation of dead-end corridors where construction barriers would be needed. Maintaining access to existing stairs became a requirement and the state would not tolerate temporary outages when the department was occupied.
In another project for this engineering team, existing ceilings were replaced in a surgical department. While the department was not physically large and only contained six ORs, the ceiling replacement required nine separate phases so that OR access and department egress was maintained at all times. Mechanical, electrical and plumbing designs should carefully evaluate impacts to existing egress when routing, removing or replacing ductwork, piping, plumbing, lighting and conduit in occupied areas. While MEP engineers may feel that egress requirements are the responsibility of the architect, the MEP design team must communicate expected impacts and not wait for the discussion to occur during construction.
Ensuring compliance with NFPA 101 throughout the construction process is not optional and can pose a series of challenges to the design team. Careful attention during design can prevent or alleviate concerns from the owner and the AHJ. A successful project can be measured by a number of metrics, but a project that takes future expansion egress into consideration will be looked upon more favorably in the future.
Similarly, paying careful attention to existing egress impacts during expansions or remodels will reduce the number of issues during construction and inevitably improve the relationship between the design team and the owner and construction team.