Written by RAN Senior Fire Protection Consultant Sarah Swan.

“Royal Caribbean’s ‘Icon of the Seas’ is about as long as the height of the Empire State Building…” This was the lead sentence in an article written by the Cox Media Group National Content Desk to celebrate the world’s largest cruise ship setting sail in January 2024. It seems an innocuous comparison, to help people visualize just how BIG the new cruise ship is. But it got me wondering:

If a building is as long as a high-rise building, are the fire and life safety risks similar to those in a high-rise building?

Most people would say “No”. After all, even if a building is as long as a high-rise, that doesn’t necessarily mean that it will take longer for people to evacuate. And the fire fighters don’t need to haul hoses upstairs in order to reach a fire on an upper story. So how can the risks possibly be the same?

But consider the actual sizes of some of these mega buildings that have been built in recent years. Based on a list from Damotech, the first and largest warehouse rack safety solutions company and safety equipment supplier in the US and Canada, posted on April 16, 2025, the largest factory in North America is (the approximate maximum dimensions are as measured from Google maps):

The Tesla Gigafactory, Austin, TX

3,870 ft long x 1,144 ft wide

To put that into perspective, if you stood the Tesla Gigafactory in Texas on end, it would be approximately 276 stories tall – taller than the tallest building in the world, the Burj Khalifa in Dubai! In fact, if you laid the factory on its side, it would be nearly as tall as the (former) Hancock Building in Chicago!

Given that the maximum prescriptive travel distance in the model building codes for a factory or storage occupancy is only 400 ft, being in the center of this or many of the other top fourteen mega buildings would put you farther from an exit than is permissible. This means that prescriptive compliance is no longer possible with respect to egress. Alternative protections have to be proposed. Often fire modeling is required to demonstrate that there is still adequate time for evacuation prior to an occupant being incapacitated by the smoke and fire.

The problem with this method is that our model building and fire codes are largely written in the blood of those who perished in previous disasters. In fact, as a result of the World Trade Center attack on September 11, 2001, a number of high rise requirements were added during revisions of the International Building Code to address challenges identified with egress, communications, and fire fighter response. It seems foolhardy to me to wait for another accident to occur, this time in a mega building, when we could look at the reasons why a code change was put in place for high-rises and extrapolate whether similar conditions are present in these mega buildings.

So I did my favorite thing – I took to the code commentaries to understand the intent behind the high-rise code requirements. And I wasn’t surprised to discover that three code requirements for high-rise buildings, based on intent, should also be applied to mega buildings. I also discovered one requirement for high-rise buildings that, while not a requirement, should be strongly considered by any owner or designer of a mega building.

Should be Required – Water Supply at Required Fire Pumps

Fire pumps in high-rise buildings that are greater than 420 ft in height are required to be supplied by connections to two different water mains located in different streets (2024 IBC Section 403.3.2). This is required because fire fighting operations in extremely tall buildings cannot be supported from the ground. Therefore, additional consideration is given to the possibility that one of the fire pump supplies will be unavailable at the time of a fire due to a main break. The redundancy provides extra assurance that sprinklers will be able to control a potential fire on the upper floors, since fire fighters will not be able to use either ladders or ground-fed hoses to control the fire.

This same logic also applies to these mega buildings:

• The amount of hose line that would need to be laid to get to the center of the building is impractical and would require heavy large diameter hoses in order to overcome friction losses in the hose – just like reaching a higher floor in a high-rise building.
• Fire fighter hose streams from the exterior of the building are insufficient to reach a fire central to the building – just like reaching a higher floor in a high-rise building.
• Fire rescue operations in the center of the building require fire fighters to enter the building – exterior ladders cannot be used – just like the higher floors in a high-rise building.

Should be Required – Smoke Detection

Automatic smoke detection systems are required in high-rise buildings (2024 IBC Section 403.4.1). The smoke detection is required to ensure that a fire is detected in the early stages of development. This increases the chance that a) occupants will be able to safely egress from the building prior to degradation of the environment; and b) the fire department will be able to respond to the fire before it is fully developed and/or has flashed over. By egressing during the incipient stage, the occupants will be subjected to less potential health impacts from smoke or heat exposure. By getting there during the incipient stages, the fire department is able to (hopefully) use less water and limit the extent of the fire and water damage. It also improves the chances of successful rescue operations in the event people are unable to safely evacuate.

Again, this same logic applies to mega buildings:

• Early detection of fires will permit the fire department to respond before the fire becomes fully developed – just like in a high-rise building. Later arrivals risk fires growing larger than anticipated (and therefore exceeding the capabilities of the fire suppression system).
• Early detection of fires will permit the occupants who are not local to the fire to egress before the fire becomes fully developed – just like in a high-rise building. Later egress risks occupants being exposed to damaging levels of smoke and heat (and therefore increases the risks of them becoming incapacitated).
• By arriving early, fire departments will be able to achieve fire extinguishment prior to degradation of the environment. Later arrivals risk excessive smoke which requires opening of smoke and heat vents or doors, thereby introducing new oxygen into the space. This is a common cause of warehouse fire reignition.

Since it can take on average 5 minutes for a fire department to respond once a fire alarm is received and fire size increases exponentially with respect to time, the delay between smoke detector activation and sprinkler system activation can result in significant fire growth (Image courtesy of Xtralis)

Should be Required – Smokeproof Enclosures

Every interior exit stairway serving floors more than 75 ft above the level of fire department access are required to be a smokeproof enclosure (2024 IBC Section 403.5.4). Because total or immediate evacuation of the building occupants is not possible, these smokeproof enclosures provide occupants with a safe egress environment for the duration of time it takes for them to safely exit the building. It also provides responding fire fighters with a safe place to stage operations until the doors are propped open to accommodate fire hoses.

Although not tall, most mega buildings have egress distances that far exceed those prescriptively permitted by the code. This is often addressed by using a system of interior exit passageways (which must be constructed in a manner similar to interior exit stairways)  which are intended to provide the same function as the interior exit stairs: provide occupants with a safe egress environment and a staging place for responding fire fighters. And although the interior exit passageways are required to be building of fire-rated construction to protect against ingress of fire, no where are these passageways required to be smokeproof unless connected to a smokeproof stairwell.

Should be Considered – Emergency Voice Communication Systems

Emergency voice communication systems, which use speakers and voice recordings to direct evacuation rather than horns sounding “BEEP BEEP BEEP” pattern, are required for high-rise buildings (2024 IBC Section 403.4.4). As seen during the World Trade Center evacuation, having a total building evacuation of a high-rise building is not practical due to the excessively long travel times down the stairs. As soon as one person slows down due to fatigue, the entire stairwell slows down and either backs up or leads to trampling. In addition, fire fighters need to use those same stairwells to access the upper levels in response to a fire.

Emergency voice communication systems ease evacuation in two ways:

1. Phased evacuation. Only the actual fire floor and a select number of other floors (such as the one directly above and directly below the fire floor) are notified to evacuate. All others are directed to stay in place.
2. Voice commands. Humans are more likely to respond to voice commands than to the horns themselves. Also, emergency voice communication systems can be used to broadcast changes to the plan by the fire department if and when needed.

Although mega buildings are large, they often do not come with a significant number of occupants like a high-rise building does. In addition, floors in a high-rise building are usually isolated from a fire and smoke perspective, permitting those who are not on the actual fire floor to remain safe as long as they stay put; this is not typical for megabuildings. But…consider this from a different perspective.

From a business operations resiliency perspective, having a total evacuation of a mega building would be devastating. These buildings are as long as multiple city blocks – with a functional fire suppression system, a fire at one end of the building does not need to impact the other side of the building. If the buildings were subdivided into multiple segments, and an emergency voice communication system installed, operations could continue in one area of the building while another area evacuated. This would limit the impact of down time and be less of an impact to the bottom line.

Now, the good thing is, based on my experiences designing other mega buildings such as those discussed, the owners often do put these systems into place. Sometimes, they add a fire detection system for their own business resilience goals; sometimes, to increase the time available for egress from the center of the building in a fire model. Other times, they add a network of exit passageways to achieve prescriptive egress travel distances instead of performing fire modeling.

But the problem with this is owners of these mega buildings are not REQUIRED to do any of these items. Since it is optional they only have to provide a system if they can be convinced by their fire protection engineer and/or architect that it is in their best interest to go above and beyond code minimums. And if the project is over budget, guess what is often the first thing to be value-engineered off the table? That’s right, the non-required fire protection systems. I can’t count the number of times I’ve been asked “But what is the code basis for this? Do we REALLY have to have it?”