Occupancy of Buildings Under Construction

Buildings that are constructed today can often hold many challenges to firefighters that legacy buildings do not, writes John Walser.

BY JOHN WALSER

You are responding to a high-rise residential building for an activated fire alarm in your district in the middle of the night. As you prep your crew for arrival, your driver reminds you that the building is under construction but is almost finished. As you arrive, you notice construction equipment and trailers remaining on the property, so this picture fits with your prearrival knowledge.

Once you get to the front entrance, you see what appear to be residents exiting the building, still waking up as they mill around. As you make your way to the fire control room, a residents let you know he smelled smoke when he left his apartment. Your size-up has significantly changed from a fire alarm in a building under construction to a potential fire in an occupied building, forcing you to quickly adapt your response. You begin to formulate a plan to handle the immediate problem and include a longer-term goal to learn more about how buildings get released for occupancy.

Buildings that are constructed today can often hold many challenges to firefighters that legacy buildings do not. Modern construction techniques, coupled with technological advances in materials, may lead to unexpected building performance under fire conditions compared to previous experiences in buildings constructed in earlier eras. Another change in modern building construction is the occupancy of buildings still under construction. When you respond to the new residential building that is still being built but has residents fleeing a growing fire at 2 a.m., it should not be the first time you find out the building is occupied.

To start, is this even allowed? How can a building still under construction be occupied, either for residential or business purposes? We know that buildings under construction or rehabilitation are at higher risk for incidences of fire. Both the International Building Code and National Fire Protection Association 5000, Building Construction and Safety Code, allow building officials the authority to grant approval for occupancy of a building or portion of a building prior to approval of the completion of the entire building. Although this approval is granted with the knowledge that not all the building components are finished, the building can be safely occupied. Minimally, for the area to be occupied, all required means of egress should be available and usable with fire protection systems approved and active.

At its core, a partial or temporary certificate of occupancy must ensure the safety of the occupants while inside a partially completed structure. A benchmark to consider during the planning phases is to apply how the safety of occupants of a building being renovated is afforded and maintain that same level. Beyond this basic premise, what are some considerations that can be incorporated into an approval for partial occupancy of a building under construction?

Although the building official does have the authority to allow this type of temporary occupancy or partial certificate of occupancy, a collaborative process with the fire department can yield the best result for both the occupants and the firefighters during an incident. What are some considerations that go into the final approval?

Fire resistive and noncombustible construction (Types I and II, respectively) is less challenging to develop a phased construction plan than buildings using combustible construction for the structural components. When combustible construction is used, the framing should be concealed for all levels and areas of the building. Any fire-rated assemblies, including the opening protectives and fire dampers, must be in place and approved. For large-area buildings or buildings in close proximity to others, consider of how an external fire may impact the target building. When there is a radiative exposure problem, the external cladding required by the building code should be installed prior to any occupancy. This will limit the fire spread problem from radiative exposure and assists the responding fire department by providing a measure of passive fire protection. Photo 1 shows what appear to be three separate buildings, but they are connected underground by a parking garage. Since the portions aboveground were occupied as each was completed, the construction phasing incorporated the concern for a construction fire exposure problem to the occupied building.

(1) Photo courtesy of Fairfax County (VA) Fire & Rescue Department; all other photos by author.

Adding passive protection to divide a building can serve to limit the fire spread problem within the building. The fire barrier installed in photo 2 (the unpainted portion of the wall to the right) was temporary, dividing the lower portion of the building in photo 1, which extended under different towers aboveground.

(2)

This wall was removed after all portions of the building were completed.

Even using noncombustible construction that incorporates separation floors or unoccupied floors between the areas remaining under construction and the occupied areas can benefit occupant safety and enhance firefighter operations. For instance, the lower 10 floors of a 20-story high rise may be occupied, with floors 11 and 12 complete but unoccupied. The floors above 12 would remain under construction.

Ensuring adequate egress for occupants of a building under construction is fundamental when any building is issued approval for occupancy, let alone one that has the risks associated with being under construction. When considering a phased occupancy approach, this is no different. Affording occupant egress also protects firefighter access and safety. In large-area buildings, as often seen in modern-style apartment buildings, the egress must not pass through a portion of the building under construction. This concept may prove the most challenging to developers since the minimum number of stairs usually only accounts for travel distance from the entire completed building, not a portion of the building. Contractors often want to control the access to areas under construction, which limits the choice of exits.

We must also consider oversight of the material and waste handling. Any stored materials must not block any egress facility, both inside and outside the building. Any decision to allow occupancy in a building under construction or renovation requires careful planning early in the design process to ensure the occupancy plan is coordinated with the egress facilities.

Where fire sprinklers are required, sprinklers should be installed and inspected for all levels of the building. Although other life safety measures can be considered for very large buildings, there is no substitute for the protection that sprinklers afford to occupants and firefighters alike.

When ceilings are not yet in place, the sprinkler heads should be the upright type and installed within 12 inches of the deck. Although this may pose challenges for the sprinkler contractor and the timing of the overall project, the protection the sprinklers provide is significant since occupants are now in a building under construction. Incorporating this need into the project timeline early in the design process can overcome many of the initial hesitation.

Additionally, any sprinkler installation must meet the listing requirements of the piping and sprinkler heads. Flow switches and tamper switches should be connected to the fire alarm system and report to a monitoring company.

Often, there is a desire in large wood-frame buildings to have occupancy of one portion of a building while the other portion remains under construction. For this type of construction, a partial sprinkler system may not be sufficient to control a rapidly spreading fire in a construction area. An unchecked fire has the potential to overwhelm the sprinklers in the occupied portion. Strongly consider the implications of allowing occupancy in a wood-frame building before all sprinklers are installed and operational in the entire building. The fire pump room access should be in the building’s a completed phase so firefighters can safely access this vital fire protection equipment.

If standpipes are required in the building, the standpipes and fire hose valves should be completed and approved for the area intended to be occupied. Access to these valves must be unimpeded so the fire department can access the valves and easily stretch handlines from these valves to the fire area. Photo 3 shows how early design consideration allows access to one area of a building for occupants, while firefighters would have access to both sides of a firewall from the standpipe- equipped stairwell.

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Considerations for fire alarms often revolve around the construction type. In Type I and II buildings, there may not be as significant of a need for completion of the fire alarm system throughout the entire building. It may be desired that the “core and shell” fire alarm be completed for the entire building or up to a certain threshold, but not every detection and notification appliance may be needed in areas remaining under construction. Using a “buffer floor” or separation floors as described previously between the occupied area and the construction area where the fire alarm system is complete provides an additional level of occupant protection. For combustible construction, completing the fire alarm for the whole building ensures adequate detection and notification for occupants and firefighter response.

When smoke control or stair pressurization is required, these systems must be fully operational and approved (photo 4). These systems protect the egress paths for occupants and protect the shafts where firefighters will be initiating a fire attack. The smoke control system design engineer must be involved in any decision to isolate areas of the system temporarily so the system can be designed to accommodate any changes over time.

(4)

Elevators designed for fire service use should all be approved for use and operational by the time any occupancy is allowed. This would include elevators sized for ambulance stretchers and fire service access elevators. The firefighter’s service function must be operational in all of these cars, which would mean the tie-in to the fire alarm system would need to be completed. When construction hoists are still being used on the building’s exterior, the fire-rated assemblies must be complete, and any combustible framing must be enclosed.

The building’s exterior should be completed to allow the safe ingress and egress of occupants. Specific concerns can be mitigated through overhead protection to ensure the tenants and visitors can safely access the building. All fire department access should be in place and appropriately marked. Emergency key boxes should be installed with the appropriate keys in place to allow first responder access to the building and any critical locked areas. All the construction materials that could pose a fire exposure hazard or would otherwise impede firefighter access should be removed from the exterior.

These are a few considerations from a fire department operational perspective that would affect the decision to allow occupancy of a building under construction. A building official may want in place many other considerations. These largely address the minimal safety concerns that could impact building occupants or firefighters when responding to a fire in an occupied building that is still under construction. Make every effort to develop a relationship with your building official to understand what he is approving and communicate the impact on the firefighters who respond to these buildings. Building officials work very hard to ensure firefighter safety in addition to that of the public. Many times, they do not recognize the needs of firefighters or the tasks that they need to complete during a fire. Taking the time to work with your building official is beneficial to everyone who would ever enter the building, especially firefighters who are in the building when it is on fire!

JOHN WALSER joined the fire service in 1993 and is a deputy chief with the Fairfax County (VA) Fire & Rescue Department, assigned to the Office of the Fire Marshal. He is responsible for the oversight of life safety inspections, engineering plans review, fire protection systems, and fire investigations. He has a bachelor of science degree in mechanical engineering from Lehigh University and a master of science degree in fire protection engineering from Worcester Polytechnic Institute.