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  • Jerry Schultz, P.E.

I will go back to solid shelving in my next blog post, but I thought we might need a break from such a highly technical concept to look at something fun. This post will take a brief look at firefighting robots and show how this concept promises to change the firefighting industry. Everyone is seeing more and more robots in the workforce and the warehouse field is no exception. Pulling boxes through an Automatic Storage Retrieval System (AS/RS) is such a common practice nowadays that one could envision a future where automation changes the world again, like the Industrial Revolution. One such advance that is receiving increased interest is robotic firefighting.

The first question always asked when we introduce a new technology is--How much is that going to cost? According to “Fire Loss in the US during 2011” collected by the NFPA, fire departments in the United States annually respond to about a half-million structure fires. These fires lead to more than 2,500 civilian fatalities, 15,000 injuries and property losses of approximately $10 billion. And if you consider that 70,090 firefighter injuries occurred in the line of duty that same year, robotics does make sense.

It is always interesting to go back and look at where we were at a given point in time and see how far we have progressed. In 2010, the Society of Fire Protection Engineers held a workshop on high-challenge warehouse fires during the Suppression, Detection and Signaling Research and Applications Symposium (SUPDET) in Orlando, FL. Six fire protection consulting engineering firms (including FPI) elected to participate and develop a protection scheme for a high challenge, high bay warehouse. We were given free reign and tasked with outlining how one could protect the presented scenario. The intent of the scenario was to “stimulate further discussion on a matter of critical importance to industry, insurers, the fire service, and standards development organizations.” It was intended to spark further work to create solutions that are both realistic and cost effective. The method of protection developed by each firm was summarized in a PowerPoint presentation made by Richard Gallagher and Mike Gollner of Zurich Services Corporation.

The PowerPoint presentation High Challenge Warehouse Case Study can be downloaded here:

And the article that appeared in NFPA Journal can be found here:

In the end, both FPI and Hughes Associates recommended High Expansion Foam as the primary extinguishing agent while several of the other firms ended up requiring ESFR sprinklers within the rack (which I have addressed in an earlier blog and FM Global is now pushing). However, what I found interesting is that several firms talked about tying a camera into the AS/RS system so that the actual fire location could be visually identified. This would allow for a more localized approach to extinguishment. Although the term wasn’t used, in my mind this led to thinking about robot firefighting. Why couldn’t we also add an extinguishing media to the AS/RS to achieve this localized approach?

I recently came across a company that is selling a system that combines a thermal camera with a monitor nozzle for outside use. They appear to have taken this “robot fire fighters” concept and developed it ( for the market. In researching the concept, I saw that the Navy is developing a robot fire fighter (SAFFiR-see photo 1) for ship board fires which resembles a human. Due to the unique nature of ship board fires, the robot must be able to open doors and step through bulkheads. (

Photo 1-SAFFiR

This is a unique application and the Fire Rover concept is probably more likely to occur. We are all familiar with robots being used for disarming bombs (see photo 2) and I can see the same type being used for fires.

Photo 2-Bomb Robot

A small wheeled robot with cameras mounted on the device and connected to a hose that can be directed at the fire with some type of joy stick control is likely. The potential to telescope up to reach the fire directly to cover high piled racking would complete the concept. Or, use the AS/RS system, connect a hose to it and with the camera we can reach the source of the fire and apply an extinguishing agent directed at the fire.

Although I have written about robots fighting the fires, the field is changing in other ways too. Drones are being used to review the fire scene and collect information for firefighting use.

But perhaps the biggest indicator of the firefighting robots can be found in looking at Playskool (the toy company) and recognizing that they have tied the fire station into Optimus Prime, who commands the “RESCUE BOTS” to respond to the fire.

It all ties together—remember the concept of fire protection prior to the introduction of the ESFR sprinkler. This was discussed in my first blog. The fire tests in the 1970’s spoke of the need for control of the fire, not extinguishment. Control is defined in NFPA 13 as holding the fire in check through the extinguishing system until the initial commodities are consumed or until the fire is extinguished by the extinguishing system or manual aid. The concept of firefighting robots allows for the manual aid without placing firefighters lives in jeopardy. It is only a matter of time.

As always, I welcome your comments:

  • Jerry Schultz, P.E.

As promised, we return to the original discussion on Solid Shelving. In my writings I have tried hard not to just reproduce the standard by copying sections and inserting them in the blog. However, in order to truly understand the solid shelving requirements, I am going to have to do that--present sections for you, the reader, to examine. The definition for Solid Shelving, as it appears in the 2016 edition of NFPA 13 under the subcategory, Storage Definitions is:

Shelving that is fixed in place, slatted, wire mesh, or other type of shelves located within racks. The area of a solid shelf is defined by perimeter aisle or flue space on all four sides or by the placement of loads that block openings that would otherwise serve as the required flue spaces. Solid shelves having an area equal to or less than 20 ft2 (1.9 m2) are defined as open racks. Shelves of wire mesh, slats, or other materials more than 50 percent open and where the flue spaces are maintained are defined as open racks.

In reviewing each line of the definition, it becomes evident that this is a game changer. "Shelving that is fixed in place, slatted, wire mesh, or other types of shelves located within racks." Right off the top, slatted or wire mesh or other types of shelves located within the rack can be classified as solid. (see Photo 1 of wire mesh shelving). Note that there is no reference to a shelving material being 50% open or 70% open. The definition applies to any shelving material. The product in Photo 1 is obviously greater than 50% open and yet by definition it can be considered as solid shelving. This is one of the main issues that we have to understand and it can be summarized by asking—wasn’t wire mesh developed to help eliminate solid shelving issues? Of course it did, but the standard has changed and now the material being stored determines if the shelf is solid or not.

Photo 1: Wire Mesh Shelving

The definition further states: "The area of a solid shelf is defined by perimeter aisle or flue space on all four sides or by the placement of loads that block openings that would otherwise serve as the required flue spaces." It is this part of the definition that starts to elaborate on how a shelf material that is obviously open can be classified as solid shelving. The area of a solid shelf is to be measured from opening to opening that surround the loads themselves. For example, take the shelf shown in Picture 1 and cover it with boxes spanning from side to side, now it has become solid shelving. The picture below shows small boxes on slatted shelves (which appear to be covered by a board) and would qualify as solid shelving whether the board was there or not. There is no defined flue being shown so one would have to measure from rack upright to rack upright.

Photo 2: Note the small boxes with no defined flue

So the next part of the definition gets even more interesting. "Solid shelves having an area equal to or less than 20 ft2 (1.9 m2) are defined as open racks." The 20 square feet is designed to represent a pallet load with openings on all four sides and this section is stating that pallet loads are not solid shelving so therefore if a shelf unit is 20 square feet, this shall not be considered solid shelving. Please understand that it is not the pallet load that is making this “not solid shelving” but the fact that there are openings on all four sides of the pallet. If we push two pallets together and do not maintain a flue around them then we measure from the opening to the opening and we are back to a solid shelf. As shown in Photo 3, the pallet loads have been pushed back to back such that a longitudinal flue is not provided therefore the area of the solid shelf would run from aisle to aisle in the one dimension and flue to flue (note there is a transverse flue shown) in the other dimension. (There is an exception to this requirement that we will discuss as we fine tune the actual definition).

Photo 3: Pallet loads eliminate the longitudinal flue leading to measuring the shelf from aisle to aisle

The final part of the definition states: "Shelves of wire mesh, slats, or other materials more than 50 percent open and where the flue spaces are maintained are defined as open racks." This is the section that I have had the most arguments about. Several individuals have taken this to mean as long as the rack component/material is 50 percent open (i.e. wire mesh deck) and a flue space is maintained somewhere then regardless of the area of the load, it is to be considered as open shelf. The argument is being made that this section reverses what is being said above and one can have a load that is over 20 square feet in area as long as flues (or aisles) are maintained around it and the shelf is not to be classified as solid shelving.

The argument above can be refuted by reviewing the Annex but there is another way to address it. In addressing it, we will complete the definition itself. The first line of the definition requires shelving material to be provided, and if there is no shelving material (i.e. cantilever racking as discussed in the first blog on solid shelving), then it does not appear to apply. NFPA 13, in Section defines Open Rack as:

Racks without shelving or with shelving in racks that are fixed in place with shelves having a solid surface and a shelf area equal to or less than 20 ft2 (1.9 m2) or with shelves having a wire mesh, slatted surface or other material with openings representing at least 50 percent of the shelf area including the horizontal area of rack members and where the flue spaces are maintained.

By definition, we cannot classify cantilever shelving with product that exceeds 20 ft2, nor can we classify a rack without shelving material where the loads exceed 20 ft2, as open racking so it falls back to solid shelving.

This is perhaps better explained by reviewing the Annex material. As one is aware, the Annex is not considered enforceable (I have seen ordinances which state that the Annex is adopted and is enforceable so watch yourself) but is “included for informational purposes only. This annex contains explanatory material, numbered to correspond with the applicable text purposes.” The Annex material for the definition on Solid Shelving in A. states:

The placement of loads affects the calculated area of the shelf. It is the intent to apply this definition to loads on the rack where 6 in (150 mm) nominal flues are not provided on all four sides, regardless of whether shelving materials are present. (underscore added)

At this point, it seems unarguable that the loads define the shelf area and therefore define the classification as solid shelving not some shelving material itself.

Further support for this interpretation can be found in the NFPA 13, 2016 Automatic Sprinkler Systems Handbook which includes the response to a Frequently Asked Question:

If the shelf material is considered open but the loads on the shelf, without the required 6 in. (150 mm) flue space between loads, are greater than 20 ft2 (1.9 m2) in area, do the shelves have to be protected as solid shelf? One of the most significant changes to rack storage in the 2010 edition was the new method to calculate the rack shelf area. The placement of loads on the shelf now affects the calculated area of the shelf. Previous editions only dealt with the shelf material alone and did not consider the loads on the shelf. With this definition, shelving material that had been classified as open, such as wire grate, which is more than 50 percent open, could be calculated as solid shelf if the loads on the shelf cover the required flue spaces to separate shelf area calculations. The intent was to have flues surrounding the load or shelf material that will not block more than 20 ft2 (1.9 m2) in area. Even though the shelf material (if any) is considered open, the distribution is blocked if the area of load or shelf is greater than 20 ft2 (1.9 m2) in area and solid shelf rack rules would apply.

This gets us to the understanding that the load (commodity being stored) and not the shelving material, determines whether to consider the arrangement as solid shelving or not. In the next blog I will address what happens when there is solid shelving present and what sprinkler protection method is required within those racks.

As always, I welcome your comments:

  • Jerry Schultz, P.E.

Prior to continuing the discussion on Solid Shelving I need to point out that I made a mistake in the last blog post. I used the photo below that I took off of the internet and referred to it as Cantilever Racking. This is an example of how as I age, my eyes are not as good as they used to be. I could clearly see the rack upright on the front part of the rack but could not see it on the back leg of the rack. If you look closely, you can see the rack upright on the back portion of the rack. It was pointed out that these are stacking frames that are individually transportable to any other location and does not represent cantilever racking. Cantilever racking is shown in Photo 2 below. Note the difference in that there is no front rack upright.

Photo 1: NOT Cantilever Racks

Photo 2: Cantilever Racks

I received comments from several individuals, and I appreciate them reaching out to me. In the final document I will correct the photo, but I found interesting the responses of two of the individuals who contacted me. One stated that sprinklers cannot be provided within the rack structure because of the stacking nature of the racks; while the other pointed out that the product is non-combustible, the racks are non-combustible and there is a general lack of combustibles in the building. Both gentlemen questioned the feasibility and the need for sprinklers in the racking. My response to both gentlemen was that the standard requires sprinklers in these racks (assuming that the building is required to be sprinklered) and that common sense or an equivalency/variance or alternate means is subject to negotiations with the official. (Contact your fire protection consultant for assistance).

As stated, the next blog post will return to the original discussion on solid shelving. Thank you to those individuals who reached out to me.

As always, I welcome your comments:

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