• 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.

  • Jerry Schultz, P.E.

Walmart, Amazon, Lowes, Target and numerous third party logistic (3PL) firms are shifting to pick modules as their warehouse arrangement. A pick module consists of an arrangement of racking with catwalk levels supported from the racking supports on about 10 foot vertical increments so that employees (or robots) can pick the product from a shelf and transport it to the shipping area.

Photo 1: Pick Module Top Level

In the photo above, the “floor” (more properly designated as a catwalk level) of the pick module is supported from the racking shown and the rack system is designed to support the catwalk levels. The photo shows the top level of the racking system, and there can be multiple levels below. This allows for an employee to walk the level and select product from the shelf to transport to the packaging and shipping areas. Most of these installations have conveyors running on the levels so that the product is moved to the packaging and shipping area by itself.

Having provided fire protection engineering and code consulting for numerous pick modules, FPI provides the following for those individuals that are dealing with their first pick module. We believe there are several issues that need to be addressed and understood by all.

  • Occupant load is higher than normally anticipated in a storage occupancy. This will require a careful evaluation of the design strategies for fire alarm, exiting and fire fighter access.

  • The catwalk levels are not to be classified as a story so they do not impact the height and area limitations.

  • Nor do they fall into a floor classification. They do not provide a true separation in that the walking surface is typically a product called Resindek and provides no fire resistance. The module itself is open to the warehouse on the sides.

  • There is typically a lift provided to move products from the ground level to the appropriate upper level. This lift is not an elevator but instead is a vertical reciprocating conveyor. No recall functions are provided and employees are not supposed to be on the lift.

  • Exiting from upper levels is via stairs. The rack designer initially tries to only provide these open stairs within the pick module and take into account vertical travel distance down the stairs to the outside. On all levels, it is important to be aware of any conveyors as traveling around a conveyor will add travel distance. If an exit cannot be reached within the allowable travel distance (which may be as small as 250 feet depending upon the year and interpretation of the code), interior fire rated stair enclosures will be needed.

  • Sprinklers are required on every level. The sprinkler system must be designed to current code, which may include barriers within the shelving units.

  • The shelves will be provided with open face boxes to allow for “picking” the product. If plastic boxes are provided for durability reasons, the sprinkler system design must take this higher hazard material into account.

  • Each client that we have worked with has their own set of fire protection requirements. At the current time, there is no one set of answers.

  • The local official has to be part of the design efforts starting with an initial kick off meeting where the concept of a pick module is explained and fire protection features are discussed. Even though the community is happy to get one of these buildings in their area and it typically provides a nice tax base, the code official has to worry about the fire protection and the life safety of the employees. The input from the official on the front end eliminates the need for critical revisions when the building is trying to get its Certificate of Occupancy. FPI identifies this as “No surprises” and we consider this a fundamental role of the consultant.

  • The fire alarm system and building management system must be carefully coordinated. This is not a typical warehouse occupancy with a limited occupant load, no air conditioning, no or limited conveyors throughout the building, and occupants at grade level, therefore additional life safety considerations must be incorporated into the design. Notification appliances should be provided. The fire alarm system may need to tie into an HVAC system and shut the system down. Conveyors should probably be shut down. Travel distances have to take into vertical distances down the stairs.

As fire protection engineers that have worked on numerous pick modules, The Fire Protection International Consortium, Inc. believes that this sector of the marketplace requires the full involvement of a Fire Protection Engineer as a consultant throughout the entire project. It is the involvement of the fire protection consultant that can ensure that all life safety systems are addressed early on in the project. This will ensure that all design issues are addressed and reviewed by all stakeholders. It will also serve to reduce change orders as a result of plan review comments or surprises at the end of the project when trying to get the Certificate of Occupancy.

It wasn’t one of our projects, but we are aware of a code official requiring additional stairs before he would issue the Certificate of Occupancy because he felt that more were needed. This resulted in a delay in the go live date along with a loss of storage capacity.

Pick module projects require a Fire Protection Engineer to ensure NO SURPRISES!

As always, I welcome your comments:

Jerry Schultz, P.E.

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