• 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.

  • 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:

Jerry Schultz, P.E.

  • Jerry Schultz, P.E.

Throughout the writing of this blog, one subject that I have gone back to time and time again, is solid shelving. You would think that at some time, the issue would be resolved and the revisions would stop. The 2022 edition of NFPA 13, Standard for the Installation of Sprinkler Systems is proposed to be revised again to address solid shelving, but this time in multiple-row racking. The proposed changes have been approved by the committee and are out for final review by the general public. The only possibility to change the document now is by submitting a Notice of Intent to Make a Motion (NITMAM) and then have a floor vote at the annual meeting. NITMAM’s have to be filed by February 17, 2021.

In 2016, I wrote a blog post (Fire Testing, January 18, 2016) where I noted that there were no new tests presented to the committee as justification for the initial solid shelving changes to the standard that happened in 1999. In a nutshell, those earlier changes defined solid shelving and set an area limit for a solid shelf before requiring in-rack sprinklers. As time progressed and additional revisions took place, it became obvious that the committee was saying that the load itself defines if solid shelving is present and not whether or not shelving material is present. The committee reviewed tests that were conducted in the 1970’s and reinterpreted the results. This cycle, the proposed change to the solid shelving requirements once again is based on interpretation of a test conducted in the 1970’s. At that time, the test protocol only tested 16 foot deep racks. Not being involved with these tests, I do not know why that was what they tested. These racks could have been common in the industry or even more likely, that is the rack they had available. I cannot state why they only tested 16 feet deep racks.

The present committee reviewed that earlier test data and felt that since the test was limited to a given depth there was a need to change the standard. Hence the solid shelving requirements are being modified again. Three options are proposed -- provide transverse and longitudinal flues (longitudinal flues have never been required in multiple-row racking), limit the depth of a multiple-row rack, or provide in-rack sprinklers.

Several cycles ago, it was recognized that since a longitudinal flue was not required, we could have storage abutting each other with no limit on quantity. This was contrary to the direction that the committee was headed on solid shelving. In 2013, (see Solid Shelving Part 3) the standard was modified to state that if longitudinal flues are not provided in multiple-row racks, (remember they are still not required in multiple-row racking), a transverse flue would be required every 5 feet. A concern was expressed that if the rack were 100 feet deep, this could result in a solid shelf area of 500 square feet (5’x100’), but the general consensus appeared to be that transverse flues allowed for sufficient water penetration. Again, it is not just a solid shelf material that defines solid shelving, it’s the actual pallets of product abutting each other.

Seven years later (this cycle), the committee questioned if this was the right approach and went back to the test from the 70’s and proposed a limit on the depth of a multiple-row rack. The following change has been accepted by the committee and will be finalized in June of 2021, pending outcomes of any potential NFPA membership vote (NITMAM) and NFPA Standards Council action. The new requirement states (my editorial comments are in italics): Multiple-Row Racks

Unless the requirements of or are met, multiple row racks shall be considered racks with solid shelves. Note that you must meet one of the sections.

Multiple-row racks without solid shelves shall be considered open racks where both transverse and longitudinal flues are provided at a maximum of 5 ft. (1.5 m) intervals. Interesting that this provides a solid shelf of 25 square feet, yet for single and double-row racks, we are limited to 20 square feet.

Multiple-row racks shall be considered open racks where transverse flue spaces are provided at maximum 5 ft. (1.5 m) intervals and the rack depth does not exceed 20 ft. (6.1 m) between aisles that are a minimum width of 3.5 ft. (1.1 m). This option eliminates the deep 100 foot rack but provides for a solid shelf area without in-rack sprinklers of 100 square feet. Again for single and double-row racks we are limited to 20 square feet?

This section is stating that either a transverse flue and longitudinal flue is provided every 5 feet or the multiple row rack is a maximum of 20 feet deep and separated by a 3.5 foot aisle from your next multiple row rack or in-rack sprinklers are to be provided under every tier of storage.

FM Global has similar requirements but offers more clarity. Their Data Sheet 8-9, which is available right now, states the following: In multiple-row racks, maintain minimum 6 in. (150 mm) wide vertically aligned longitudinal and transverse flue spaces a maximum of every 5 ft. (1.5 m) throughout the height of the rack. For multiple-row racks not in accordance with Section

a) Provide minimum 6 in. (150 mm) wide transverse flue spaces a maximum of every 5 ft. (1.5 m) horizontally, and

b) Limit the depth of the multiple-row rack, as defined by minimum 8 ft. (2.4 m) wide aisles, to 20 ft. (6 m).

The big differences are that FM is mandating an 8 foot aisle, not the 3.5 feet that NFPA requires. Again, one can treat it as solid shelving and add in-rack sprinklers.

It must be recognized that the in-rack sprinklers are required (if one elects to go this route) even if an ESFR overhead system is provided.

These requirements are proposed for the 2022 edition of NFPA 13 and have already been added to FM Global Data Sheet 8-9. If in-rack sprinklers are not provided in a multiple-row rack, the allowable depth of the rack will be limited or transverse and longitudinal flues will be required. The requirement will more than likely be adopted into the 2022 edition. There is typically a delay in municipalities adopting the latest standard, so you probably will not start to see it enter the overall warehouse environment until at least 2022. FM insureds will have to take it into account immediately.

I have written numerous articles on solid shelving and they can be found on our web site (

As always, I welcome your comments:

Jerry Schultz, P.E.

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