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Posted by Stephanie on May 27, 2024

Modern warehouses must follow numerous industry-wide regulations to ensure their buildings are up to code. If you store any combustible materials in your warehouse, you’ll have strict limitations about the height of the storage. If your products are stacked too high, you’ll be tasked with applying for special permits and making sure your facility adheres to fire code regulations.

When you store products at significant heights, safety and compliance are of the utmost importance. If the products are improperly stacked, they could tip over, which would likely cause damage to the items and injuries to personnel who were in the area at the time. While storing your products vertically allows you to save space, you’ll have more comprehensive fire safety requirements to follow. This guide tells you everything you need to know about high pile storage and how to maintain compliance in your facility.

Pallet Racking with Column Guards

What is High Pile Storage?

High pile storage refers to products that are stored in a warehouse above 12 feet high. However, the products must be combustible for them to be part of these regulations. Keep in mind that most products are at least partially combustible. If you store items that are made entirely with metal or brick masonry, they won’t receive this classification. 

The purpose of these regulations is to make sure that pallet racks don’t block the fire sprinklers in your facility. If you’d like to store combustible items vertically, you’ll likely need to apply for a permit that grants you the right to do so. On the other hand, each jurisdiction can have unique requirements for this type of storage. Make sure you’re aware of the local regulations in your area before finalizing your layout or applying for a permit.

When Do You Need a High Pile Storage Permit?

This type of storage permit is almost always required in warehouses that are storing combustible items at a height of 12 feet or more. However, you don’t need a permit if your storage area has a floor plan of 500 square feet or less. In this scenario, you can store combustible products at a height of 12 feet or higher without needing to acquire a permit. 

Some situations require stricter regulations. For example, let’s say you’re storing high-hazard products like rubber tires or batteries. You may be tasked with applying for a permit if these products are stored at a height of six feet or more. 

Anything in your facility that can burn is combustible. Nearly every type of product that you might store on a wooden pallet is combustible. In most cases, the local fire marshal is responsible for making sure these permits are issued to the appropriate warehouses.

High Pile Storage Requirements

There are many requirements you must consider when planning your facility’s layout. If you intend on storing your items vertically to save space, there’s a good chance that you’ll meet the requirements that necessitate getting a permit.

Fire Safety Considerations:

All warehouses that need to apply for this type of permit will also be required to install the right fire sprinkler systems. The system must have a specific density and flow rate to comply with regulations. Most warehouses use an automatic fire-extinguishing system, which can include a ceiling unit with in-rack sprinklers or an ESFR system. As for fire detection systems, you may need a beam-type smoke detection unit

ESFR sprinklers provide a high water density without increasing the discharge pressure by a significant amount. By using this type of system, you should have more flexibility when designing your facility’s layout. When you’re stacking items, it’s crucial that you don’t obstruct fire sprinklers. The clearance between your sprinkler and the top of your storage needs to be at least 36 inches.

Building and Storage Specifications:

As touched upon previously, you may be able to bypass the permit requirement if your storage space is less than 500 square feet. If the ceiling in your facility has a height of less than 30 feet, you’ll need to install a heat detector. For ceilings that are more than 30 feet above ground, spot-type heat detectors are often required. You could also obtain a pneumatic rate-of-rise or linear cable heat detection system

If you don’t want to apply for a permit, you’ll need to use the right storage accessories. For example, most pallets are combustible. The types of storage containers that are regulated with this permit include the following:

  • Wood or plastic pallets
  • Crates
  • Wooden spools
  • Paper or cardboard boxes

When you apply for a permit, you’ll need to submit scale drawings and provide in-depth descriptions of the types of items you’re storing.

Pallet Racking

Commodity Classes and Their Impact on Requirements

There are five distinct commodity classes that are part of the permitting requirements, which include Class I, II, III, IV, and High Hazard. You can find this information As part of the International Fire Code in part 3203.8

Class I Commodities: This classification includes noncombustible items that are stored in paper wrappings or on wooden pallets. Dry insecticides and gypsum boards are two types of products that fall under this category. 

Class II Commodities: All Class I products that are kept in combustible packaging are viewed as Class II commodities. 

Class III Commodities: Paper, natural fiber cloth, and wood are Class III commodities. This classification also covers food that’s stored in plastic containers as well as fertilizer that’s kept in bags.

Class IV Commodities: These commodities include level 2 aerosols and any solid metal products that are able to catch fire. Oil-based paints also qualify. These items must be stored properly to prevent damage to property and accidents that might harm employees. 

High Hazard Commodities: This category involves only the most combustible items, which include everything from rubber tires and idle pallets to flammable liquids and certain plastics.

Process of Obtaining a High Pile Storage Permit

The permit process begins by filling out an application and submitting it to the fire marshal. You’ll also need to submit specific documents alongside the application, which include the following:

  • Scale drawings
  • Ceiling heights
  • Measurements
  • Comprehensive descriptions of the items you’ll store in your facility
  • Specifications of your fire suppression systems

You may be asked to provide more information if you store highly combustible items.

Potential Delays and How to Avoid Them

Like any permit process, there are certain events or factors that could delay approval. If your initial application is denied altogether, you could face lengthy delays while you get everything up to code and make sure your facility is compliant.

There might also be a backlog of permit applications that the city or county needs to sift through. If you comply with building codes and implement adequate fire safety measures, you should be fine. The most common reason for permit applications to be denied involves an inadequate fire sprinkler system. Updating to a modern one can resolve this issue.

Compliance and Consequences of Non-Compliance

Like all fire code regulations, there will be consequences for not complying. Your local fire department will perform routine inspections. While they can notify you before this happens, they often perform surprise inspections to make sure warehouses are complying with all guidelines.

If you don’t comply, the local fire marshal can issue a citation. Your business might also be held liable for any injuries that occur because you’re not complying. If problems are detected during an inspection of your facility, you’ll be given some time to make the necessary corrections. If you don’t, the warehouse could be shut down altogether

When a permit application is denied, you can take steps to fix it and receive the necessary permit. The purpose of this process is to make sure your warehouse operations are safe. The fire marshal should detail what you need to do to receive a permit. They’ll hand you a list of requirements, after which you can make the necessary changes. This might mean hiring a professional who has experience with fire sprinklers and can make sure you have the right system.

You may also need to change your storage plans completely to ensure your products are stacked below a height of 12 feet. While you could change your storage space to ensure it’s not larger than 500 square feet, the most cost-effective option is usually to limit how high you stack items.

warehouse layout design

Best Practices for High Pile Storage

The requirements for this type of storage don’t remain static for long. The national fire code can be updated at any time to include stricter guidelines. Review any changes to make sure your facility stays compliant. Staying informed about local fire codes and regulations should allow you to avoid any surprises. 

You should also regularly update the fire suppression systems that are installed in your facility to make sure they are outfitted with the most advanced and effective features. If you store any highly flammable products in your warehouse, never pile them higher than six feet. 


To keep your employees safe and mitigate potential penalties, you must comply with high pile storage requirements. Prioritize fire safety and regulatory adherence in your warehouse to avoid hassles and worker injuries. Consider implementing a training program that helps your personnel learn how to comply during warehouse operations. Review your storage practices to ensure they meet all necessary guidelines.

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With over 32 years of experience in material handling, QMH is committed to providing end-to-end solutions for companies with distribution, logistic and warehousing needs. From permit approval management to full-service execution from the ground up, QMH delivers unique solutions providing distinct value in record time.