top of page
  • corey877

By: Sarah Swan


Solar panels. Lithium-ion battery energy storage. Exterior cladding. Rooftop gardens.

What do these seemingly diverse items all have in common?

They have all been identified as important pillars in the race to be more eco-friendly with the impact to the fire safety of users and first responders lagging behind their adoption.

You may be familiar with the hazards of the first three items. Solar panels cannot be disconnected, leading to issues during fire-fighting operations. Lithium-ion battery fires are a fairly regular presence in the news. And everyone watched the exterior cladding on Grenfel Tower in London burn.

Does my inclusion of rooftop gardens in that list seem out of place to you? I wouldn’t be surprised if it did. Many people were surprised by a proposed change for the 2024 International Building Code which would require the height of an occupiable roof (if provided) to be considered when determining whether the building is a high rise structure or not.

The argument I heard most often stating that this should not be the case was that the occupants on the roof are outdoors, and therefore are not exposed to the heat and products of combustion during a fire as occupants inside the building envelope are. Therefore, there wasn’t an increased risk for the people on the roof if the roof was more than 75 feet above the fire department access as there is for those inside the building envelope at that height.

I disagree. I’m happy to say that the Code Council disagreed as well.

And so, in the 2024 IBC, a high-rise will be a building where either an occupied floor or an occupied roof is located more than 75 feet above the level of fire department access.

This change doesn’t mean much for those who own or design low rise buildings. And building that were already intended to be high-rise buildings won’t be impacted either. But those who own mid-rise buildings? Including a rooftop area for tenants to use could force the entire building to comply with high-rise rules.

What Makes High-rises Special?

High-rise buildings historically have stricter rules when it comes to fire and life safety requirements than other buildings. This is because there is significant physical effort associated with both occupants exiting the building and the fire department accessing the fire floor.

The typical fire truck ladder is approximately 100 feet. Allowing for the building to be set back from the street and potential obstructions to use of the ladder such as parked cars or overhead wires, the generally agreed upon effective length of use for these ladder trucks is 75 feet. Once a building is taller than that, ground-based fire-fighting operations will not be sufficient for either fighting the fire or rescuing occupants. Why? Stairs, water pressure, and communications.

Stairs represent a major choke point in a high-rise building, especially during a fire. The stairs are needed for people to exit the building and for the fire department to both fight the fire and rescue occupants. And since the stairs represent a mostly unusable and unleasable area, they are typically as narrow as possible. This limits the ability of faster people to pass slower people, particularly if the fire department is also using the stairs for their operations. If traffic in the stair slows too much, doors into the stairwell will be held open during exiting activities. This allows smoke and heat to enter the stair, opening up a pathway for the fire and its effects to spread throughout the building.

Water is pretty heavy stuff. It takes 4.33 psi of pressure to lift water 10 feet. When a building is 75 ft tall, that’s a minimum of over 30 psi that is needed to get the water to the top of the building. Add in other sources of friction loss such as air resistance or the interior of the fire hose, and there can be significant pressures associated with getting water up near the seat of the fire. Since a conventional fire hose nozzle requires 100 psi of pressure to operate, and fire pump trucks can be rated for as little as 120 psi, these tall buildings can easily require more pressure than is available to effectively fight the fire.

Fire fighters use radio signals on the fire ground for a variety of purposes – to coordinate attack strategies, to notify others of changing conditions, to call for help, etc. But radios, like cell phones, work best when there is a clear line-of-sight between the antenna and the radio/phone. The more that comes between these two items, the more the signal gets distorted. Radio is particularly susceptible to metal interference. Unfortunately, high-rises are full of metal. There are steel structural elements, metal pipes, metal conduit, metal HVAC equipment, etc. So it can be quite easy for radios to be ineffective when used in a high-rise. When the radio can literally make the difference between life and death, this is not an acceptable situation.

Because of these and other challenges, it was decided that high-rises required special attention. So the International Building Code has an entire section dedicated to the protection of high-rise buildings. From mandatory automatic sprinkler systems and standpipe systems to smoke removal systems; from remote stairs to emergency fire fighter communication systems, the requirements in this section are focused on three things – provide a safe path for people to escape the fire affected floors, reduce the reliance on ground-based fire fighting equipment, and improve fire fighter safety.

Why is this a problem for mid-rise buildings

Let’s consider a mid-rise office building. While the building is 80 feet tall when measured from the ground to the roof line, the highest occupied floor is only located at 70 feet above the ground. Therefore, this building is not currently a high-rise building.

The building owner is looking to do some remodeling in order to entice new tenants and existing tenants to sign leases. With the increased push for remote work, the building owner has decided that additional benefits are required to sweeten the deal. When consulting with you, his architect, for suggestions for the remodel, your attention turns to the roof. This is a large, unused space, perfect for a vegetative roof to get some extra LEED points. But it can be so more than that.

Put in a patio with tables and umbrellas where people can eat lunch. String up some lights so the space can be used after dark. This could even be an event space that could be rented out at night for office functions! The owner is excited for this new benefit to offer to existing tenants during lease renewal and to offer to potential new tenants – for a premium rent of course.

The plans are drawn up. Everything seems to be moving along. The owner has even gotten some early signatures on lease renewals based on the plans for this perk.

But then, during permitting, disaster strikes.

For years the definition of a high-rise had been the same – A building with an occupied floor located more than 75 feet above the lowest level of fire department vehicle access. Since the definition of floor area is based on the area enclosed within the perimeter of exterior walls, your understanding was that this did not pertain to the roof. But the building code official has different ideas. The official is of the opinion that a floor is also defined as a walking surface. And since the roof is now planned to be occupied and can be walked on, it becomes the highest occupied floor. Since it is more than 75 feet above the ground, this means that the building would now be considered a high-rise.

You try to argue this point with the code official, but it is in vain. The official points to the new definition of high-rise in the 2024 International Building Code as proof that their interpretation is correct and the previously understood interpretation is no longer valid.

So you put together a breakdown of the rules for both the project-specific mid-rise and for high-rises, along with an evaluation of how the differences apply to the project. The results are eye opening.

The building owner and architect are now left with two choices – give up the rooftop garden or increase the cost and scope of the project to address the high-rise rules that are now applicable. Since leases were already signed with the promise of this new amenity, the owner is stuck between an expensive rock and a costly hard place.

What Next?

The last thing we in the AEC community want is to have surprise costs appear late in the project. These surprises either lead to expensive redesigns (which often cannot be charged to the client) and pricey change orders from the installing contractors (which upset the “blindsided” owners). Surprise costs have never resulted in anything on a project other than annoyance and frustration for all involved.

I’ve experienced for myself how clients react when we have to inform them that their building which met code when the building was designed is now under protected due to changes in a standard resulting in the need for a costly retrofit. Retrofitting to accommodate the new definition is exceedingly costly and often exceptionally difficult. The earlier they are able to plan for this eventuality, the better for everyone involved.

Need help staying on top of the ever-changing codes and standards that shape our world? Contact us!

  • Jerry Schultz, P.E.

My last blog spoke about high-piled permits and the potential to correct deficiencies in a sprinkler system due to occupancy changes. It seems natural for me to move this into a discussion on retroactivity, and how can one get a sprinkler system updated to reflect more current requirements when it was designed to meet an earlier code or standard. Before I proceed, let me say that I believe in the concept of the code of record and that we should not be attempting to bring all sprinkler systems up to current standards. I believe that the concept of retroactivity is defined adequately by NFPA and recognize that there are certain items that need to be applied retroactively and others that were designed to a given standard based on the state of knowledge when it was designed and installed and may remain that way. It is a judgment call on the part of the code official or the consulting engineer that has to be judiciously applied. I address retroactivity here for discussion purposes but recognize that I don’t have the answers. It really comes down to what you are comfortable with.

NFPA has long recognized that fire protection levels may change based on new information and data coming forward whether it’s from fire loss experience, fire tests, or other evidence that changes might be necessary. However, that does not mean we should have to review our existing sprinkler system every 3 years and bring it up to the current standard. The Retroactivity requirement appears in Chapter 1 and states:

1.4 Retroactivity.

The provisions of this standard reflect a consensus of what is necessary to provide an acceptable degree of protection from the hazards addressed in this standard at the time the standard was issued.


Unless otherwise specified, the provisions of this standard shall not apply to facilities, equipment, structures, or installations that existed or were approved for construction or installation prior to the effective date of the standard. Where specified, the provisions of this standard shall be retroactive.


In those cases where the authority having jurisdiction determines that the existing situation presents an unacceptable degree of risk, the authority having jurisdiction shall be permitted to apply retroactively any portions of this standard deemed appropriate.


The retroactive requirements of this standard shall be permitted to be modified if their application clearly would be impractical in the judgment of the authority having jurisdiction, and only where it is clearly evident that a reasonable degree of safety is provided.

Just as an aside, I find it interesting that these four sections are found in numerous codes and standards that NFPA publishes but NFPA 72, National Fire Alarm and Signaling Code modified the requirements and addressed retroactivity a little bit differently. They stated the following:

1.4 Retroactivity.


Unless otherwise noted, it is not intended that the provisions of this document be applied to facilities, equipment, structures, or installations that were existing or approved for construction or installation prior to the effective date of the document.


In those cases where it is determined by the authority having jurisdiction that the existing situation involves a distinct hazard to life or property, retroactive application of the provisions of this document shall be permitted.

I see the difference but have a difficult time understanding why there is a difference.

Staying with the NFPA 13 definition, it is obvious that it was not the intent to require the continual upgrade of an existing system HOWEVER, they give a lot of discretionary authority/responsibility to the authority having jurisdiction (AHJ). By NFPA 13, if the AHJ believes that the existing situation presents an unacceptable degree of risk, they can elect to have the building/system upgraded to meet the new requirements of the standard. Note that NFPA 72 mentions a “distinct hazard to life or property” but basically grants the same power to the AHJ.

What presents an unacceptable degree of risk is a judgment call. Two examples are obvious in my mind. In the 1996 edition, NFPA 13 added a requirement that sprinklers in a light hazard occupancy are required to be quick response. Prior to that edition of the standard, sprinklers in a light hazard occupancy were standard response sprinklers (the quick response sprinkler was not available for much of that time). Do you, if you were the AHJ, feel that all sprinklers in a system installed prior to 1996 should be changed out because the lack of quick response sprinklers represents “an unacceptable degree of risk”?

Another example is that prior to the 2016 edition of NFPA 13, expanded exposed Group A plastics in racks was outside the scope of Chapter 17, and therefore outside the scope of NFPA 13. Does this mean that people were not storing expanded exposed Group A plastics? There were no couches, upholstered furniture, coolers, mattresses on racks in warehouses? Perhaps the building was just not being sprinklered.

Figure Decision Tree.

Of course not. The protection scheme was being developed by fire protection engineers, insurance companies, contractors and others and accepted by the AHJ. In 2016, protection criteria for rack storage of expanded, exposed Group A plastics appeared in the standard for the first time. In 2019, additional protection schemes were added to the standard giving the designer a lot more flexibility. I ask you again, do you, as the AHJ, believe that the protection scheme provided for an expanded, exposed Group A plastic in a rack should be retroactively upgraded to the protection scheme outlined in the newest edition of NFPA 13?

I have my opinion on each of these scenarios, but I really believe that you have to make up your own mind. You need to identify what is an unacceptable degree of risk, and that is going to vary depending upon a variety of contributing factors. For the quick response scenario, let’s modify the scenario a little bit and say that we are dealing with a memory care facility where residents are not capable of evacuation, and we recognize that the residential sprinkler is now available. Does this change your opinion? Let’s add the fact that the memory care facility is providing excellent care to residents but is barely getting by and the cost of the change out would impact them greatly. Where are you now?

Let’s go one step further and review the Life Safety Code (NFPA 101), specifically Section (6) of the 2021 edition of the code. This section states:

Standard-response sprinklers shall be permitted to be continued to be used in approved existing sprinkler systems where quick-response and residential sprinklers were not listed for use in such locations at the time of installation.

What is interesting is that I had to go to the Life Safety Code to find this requirement.

For the exposed, expanded Group A plastic scenario, let’s say that the current design uses k5.6 in-rack sprinklers discharging at 15 gpm and the overhead system is designed for a 0.24 gpm density over the most remote 2400 square feet. The commodity is 18 foot high foam mattresses standing on end in racks to a height of 18 feet on end and wrapped in plastic with no longitudinal flue and transverse flues every 10 feet. Do you now require an upgrade to the newest criteria?

The last issue is an issue that I don’t understand and relates to Section 1.4.1. This section states:


Unless otherwise specified, the provisions of this standard shall not apply to facilities, equipment, structures, or installations that existed or were approved for construction or installation prior to the effective date of the standard. Where specified, the provisions of this standard shall be retroactive.

I have reviewed NFPA 13 by searching for the word “existing” and have identified retroactive requirements. Certain sections that appear to have a solid basis for a retroactive classification are not being pushed as retroactive. An example is found in ESFR sprinklers in a 40’ high building. This scenario was allowed to be protected with a k14 sprinkler in the 2010 edition (and earlier) but is not allowed in the 2013 (and later) editions. The committee was informed that in certain instances, the k14 sprinkler did not work in a 40 foot high building. The 2013 NFPA 13 Handbook states:

The original ESFR criteria allowed K-14 ESFR sprinklers to protect ceilings 40 ft (12.2 m) in height without in-rack sprinklers. However, subsequent fire tests have shown that, given a certain combination of fire ignition points between sprinklers and 40 ft (12.2 m) ceilings, the K-14 ESFR sprinkler might not provide fire suppression for all storage commodities.

So we know that “given a certain combination”, the k14 ESFR sprinkler will not work and the committee was so concerned that the design option was removed from the standard BUT you are not required by NFPA 13 to change the sprinkler if it was installed under the 2010 standard. Is the committee stating that this sprinkler is acceptable for an existing installation and perhaps although not a “suppression” sprinkler it still functions as a “control” mode sprinkler. Or is the committee stating that whether or not the sprinkler should be changed out is strictly up to you based on your research? In my opinion, it is a complicated decision because the tests that led to the decision to not allow this sprinkler in a new installation are not available (if someone can locate them, please let me know).

To go back, the decision to apply the standard retroactively is not an easy decision but it is a critical one. This is the stuff that keeps all of us up at night. Good luck!

If you have any comment, questions or want to talk with me, please email me at

My next blog will discuss Automatic Storage/Retrieval Systems specifically identifying NFPA 13 and FM Data Sheet 8-34. This may end up being a two part discussion.

  • Jerry Schultz, P.E.

By now, if you have been following my blog, you know that I have worked in the storage field for years. I am an Alternate on the NFPA 13 Technical Committee and teach the three-day NFPA seminar. I regularly speak on items impacting the industry and have been blogging for several years on this web site. A long way to go in an attempt to prove my bona fides for identifying THE SOLUTION!

High Piled Storage

One thing that all of us in fire protection speak of and recognize as an industry wide problem (or opportunity) is that things change. It may be as simple as the plasticization of society— what was metal is now plastic— Tonka trucks, car bumpers, snow shovels, hose reels, the list goes on and on. Or it could be the introduction of a new unknown exposure in the warehouse (expanded exposed foam or lithium-ion batteries). Should a fire occur, the sprinkler system, which was designed for some other hazard, is now under-designed for the new hazard. As I travel throughout the country, I consistently hear the same story:

"Our department is understaffed due to cutbacks and I cannot do all of the inspections. We have just had 5 million square feet of warehouse open up in town so how can I ensure that the buildings are properly protected, when I can’t get out there?"

I named this blog THE SOLUTION so I better provide one. To the basic question “How can I ensure that the buildings in my jurisdictions are properly protected in an environment where I cannot do as many inspections as I previously did?” THE SOLUTION is a high-piled storage permit. Section 105.5.24 of the 2021 International Fire Code states

An operational permit is required to use a building or portion thereof with more than 500 square feet (46 m2), including aisles, of high-piled combustible storage.

High-piled combustible storage is defined in Chapter 2 as:

Storage of combustible materials in closely packed piles or combustible materials on pallets, in racks or on shelves where the top of storage is greater than 12 feet (3659 mm) in height. Where required by the fire code official, high-piled combustible storage also includes certain high-hazard commodities, such as rubber tires, Group A plastics, flammable liquids, idle pallets and similar commodities, where the top of storage is greater than 6 feet (1829 mm) in height.

Now let’s look at what is required by the International Fire Code in Chapter 32, High-Piled Combustible Storage. Specifically Section 3201.3 Construction Documents:

At the time of building permit application for new structures designed to accommodate high-piled storage or for requesting a change in occupancy/use, and at the time of application for a storage permit, plans and specifications shall be submitted for review and approval. In addition to the information required by the International Building Code, the storage permit submittal shall include the information specified in this section. The construction documents shall include all of the following:

1. Floor plan of the building showing locations and dimensions of high-piled storage areas.

2. Usable storage height for each storage area.

3. Number of tiers within each rack, if applicable.

4. Commodity clearance between top of storage and the sprinkler deflector for each storage arrangement.

5. Aisle dimensions between each storage array.

6. Maximum pile volume for each storage array.

7. Location and classification of commodities in accordance with Section 3203.

8. Location of commodities that are banded or encapsulated.

9. Location of required fire department access doors.

10. Type of fire protection systems.

11. Location of valves controlling the water supply of ceiling and in-rack sprinklers.

12. Type, location and specifications of smoke removal and curtain board systems.

13. Dimension and location of transverse and longitudinal flue spaces.

14. Additional information regarding required design features, commodities, storage arrangement and fire protection features within the high-piled storage area shall be provided at the time of permit, where required by the fire code official.

I think it is obvious that THE SOLUTION is geared to the authority having jurisdiction. As an AHJ, the requirements above provide you with the fundamental information you need to review and assess the sprinkler system adequacy. You are being given the storage arrangement, height, commodity and design criteria. What else would you need to determine if the sprinkler system can protect your hazard (I have assumed that the reviewer has the prerequisite knowledge). It should also be noted that Section 3201.3.2 requires that a legible drawing be provided, mounted and protected from damage be present at the facility. This drawing is required to have much of the information above available. No longer should your inspector walk into the building and have to determine if the protection is adequate. They can look at the drawing and see if what is shown is what is present.

Now, like all good consultants, let me provide the caveats. These are issues that strengthen THE SOLUTION and ensure that the information is adequate and especially correct.

  • The steps below show a process that should be followed for an occupancy permit. Drawings should not be collected and thrown in a drawer without someone looking at what is being provided.

  • At some point you still need to get into the building to make sure that the drawing accurately reflects what is present, however, your time spent on site is greatly reduced when verifying information versus collecting the data.

  • The information provided is only as good as the firm or individual that submits the information. I personally would like to see some rules spelled out surrounding the qualifications for who can do this work. A registered fire protection engineer would provide the knowledge and independence to complete this task.

In order to turn your annual warehouse inspections into quick 15-minute visits, you should implement a Storage permit process. The steps to be taken to accomplish this are:

1. Require an annual Occupancy Permit as outlined in the IFC, when buildings are used for the storage of High Piled Storage as defined by the Fire Code.

2. Provide a guide to owners/engineers for the development of High Piled Storage drawings. This will include qualifications required to complete the permit.

3. The drawings must be submitted for review for approval, and updated and resubmitted when the use, height, configuration, or commodities change.

4. The Approved High Piled Storage drawings shall be kept onsite for verification and use by inspectors. The inspector then only needs to verify that the building and storage are the same as what is on the approved High Piled Storage permit drawings and then they can move onto the next inspection.

The bottom line is that you have the authority in the code to require an operational permit. Uncle Ben told Peter Parker “With great power, comes great responsibility.” You have the power, now use it responsibly.

Next blog, I will talk about retroactivity which ties into this.

As always, I welcome your comments:

Featured Posts
Recent Posts
Search By Tags
Follow Us
  • LinkedIn Social Icon
  • Facebook Basic Square
bottom of page