Cold Storage Fire Protection Solutions

Cold storage fire protection can pose multiple challenges, requiring the correct questions to be asked and addressed prior to selecting the sprinkler system and the best-suited sprinkler type.

The first question that needs to be answered is how is the freezer being constructed?

Is it a “box-in-a-box” type construction?

If the answer is yes, then as you will notice the deck of the freezer does not extend to the full building height. This type of construction provides a heated area above the freezer, and if this area is maintained at or above 40 degrees Fahrenheit a wet pipe sprinkler system is commonly provided in the building.

The best way to protect this type of freezer is to drop down from the wet pipe sprinkler system to directly above the freezer ceiling and install Viking dry sprinklers to penetrate the ceiling and extend down into the freezer to provide ceiling-only protection for the area.   Depending upon the ceiling and storage height, these dry sprinklers would be Viking ELO 11.2 K-factor dry sprinklers, or for higher ceilings, Viking’s ESFR dry sprinklers could be used for ceiling protection only up to a 50’-0” ceiling using the Viking VK512 K25.2 ESFR dry sprinkler.

A common method for supplying the Viking dry sprinklers is using a flexible sprinkler hose connection. This will help to maintain the integrity of the sealing method of the penetration into the freezer when maintenance is performed above the freezer ceiling, allowing the dry sprinkler connection to flex along with the ceiling. When a flexible sprinkler hose connection is used, additional support needs to be included to provide the stability of the connection, like that of a hard-piped connection. This can be achieved using Viking’s Cold Storage Bracket as shown below.

If the answer to the question above is no, and the walls of the freezer extend up to the deck of the building, in most cases making the building the freezer itself, then we need to take an entirely different approach to our protection scheme.

With this construction type we do not have a heated area above, and using a wet pipe sprinkler system is not an option. The system type of choice for this protection scheme would be to use a Viking Double Interlock Preaction System. Viking offers two types of Double Interlock Preaction Systems that are commonly used for this protection. Either a Double Interlock preaction System with Electric/Pneumatic Release, or Electric/Pneu-lectric Release.

Both system types require two actions to happen: activation of the detection and loss of air pressure from a sprinkler operating, prior to the deluge valve opening and introducing water into the system piping.

When protecting a freezer, this system type provides the added assurance that water will not enter the piping network unless there is an actual fire, preventing trapped water in the system piping, which could potentially lead to ice plugs.

Depending on the freezer/building height for this type of construction, there could be multiple sprinkler options selected, but the most common sprinkler used would be the Viking VK598, K25.2 Upright Sprinkler. The VK598 can be installed on Double Interlock Preaction Systems to protect ceilings up to 45’-0” with up to a Class III commodity.

When using a Double Interlock Preaction System, we also need to be sure that we are selecting the proper detection as well as the proper air supply. The detection that is commonly used in these environments is either linear wire heat detection or air sampling detection.

Selecting the proper air supply will prevent moisture from accumulating in the piping and eventually leading to ice plugs. There are a few options for air supplies for cold storage freezers, such as NFPA 13 provides a detail on how to pipe the air supply. A very common air supply for these applications would be using General Air’s Dry Air Pac.

General Air’s Dry Air Pac continuously provides a dry air supply to the piping network by using two desiccant towers which the air passes through to remove any moisture prior to being introduced into the system.

The next question we will need to find the answer to would be what the freezer height and storage height are that we are protecting. This will help to determine the best-suited sprinkler for the application. A good rule of thumb for sprinkler selection would be that the higher the ceiling height and storage height, the larger the K-factor of the sprinkler that will be used. We will also need to confirm that the sprinkler selected is listed for such ceiling heights, storage heights, as well as the commodity classification and storage arrangement.

Now that we have determined the freezer construction type, as well as the storage and building height, next we will need to determine what the commodity classification would be for the product that is being stored in the freezer.

To make this determination, we not only need to evaluate the product itself, but also the packaging and what it is being stored on. Often, the reason for higher commodity classifications ends up being required not by the actual product, but based upon the packaging used as well as the type of pallet that it will be stored on for rack storage arrangements. For example, the same product could be determined to be a Class I commodity if stored in non-plastic packaging, and in certain instances, up to a Class III commodity when stored on plastic trays.

The pallet type can also increase the commodity based upon whether it is a wood pallet or plastic pallet. If it is a listed pallet or non-listed pallet.

If the pallet being used is a plastic pallet, we also must determine whether it is a reinforced plastic pallet, or a non-reinforced plastic pallet, as this could potentially increase our commodity classification as well.

Another determining factor in how we approach our protection scheme for cold storage applications would be to determine what storage arrangement is that is being provided.

While there are multiple different types of storage arrangements e.g., bulk storage, palletized storage, solid shelf and solid piled storage. The most common type of storage arrangement for these applications would be rack storage.

Beyond just knowing that our storage arrangement is rack storage, we also need to know what type of rack storage. For traditional rack storage, you need to know whether it will be single, double, or multiple-row racks. There are also other non-traditional types of racks that could be used, such as push-back, flow-through, drive-through, and the ever more common ASRS (Automated Rack Storage System).

Lastly, we will also need to know which standard the freezer is being protected in accordance with. The two common standards used in the United States are NFPA 13 and FM Global FMDS 8-9. There could also be other applicable standards that are being used, depending on where in the world the project is located. As well as potential local or insurance regulations that exceed the minimum requirements of the standard.

There are different construction types, commodity classifications, system options, storage arrangements, and applicable standards that all need to be addressed prior to starting the design of the fire protection system. Providing the answers to these questions will help you to make sure that you are protecting your cold storage application with the best-suited fire protection.