If you store products on pallet racks higher than 12 feet in Clark County, you need a high-pile storage permit from the fire marshal. For certain materials like plastics, rubber, and aerosols, that threshold drops to just 6 feet. This is separate from the building permit for the rack structure itself, and it catches a lot of warehouse operators off guard.
High-pile storage permits exist because fires in racked storage behave differently than fires in open floor storage. The vertical channels in a rack system act like chimneys, pulling fire upward faster than sprinklers can respond if the system is not designed correctly. The permit process ensures your sprinkler system, flue spaces, and aisle widths are adequate for what you are actually storing.
Commodity Classification: It Starts Here
The fire code classifies stored materials into commodity groups based on how they burn. This classification drives every other requirement, from sprinkler density to maximum storage height.
- Class I: Non-combustible products on wood pallets. Metal parts, glass, ceramics. Lowest risk.
- Class II: Class I products in corrugated cardboard packaging. The cardboard increases fire load.
- Class III: Wood, paper, leather, natural fiber products. Moderate fire load.
- Class IV: Class I through III products containing some plastics in packaging or content. Higher fire load.
- Group A Plastics: Products made primarily of plastic (ABS, polyethylene, polypropylene, foam). Highest fire load. Burns fast, burns hot, produces toxic smoke.
- Group B Plastics: Plastics with lower heat release rates (PVC, fluoropolymers). Less aggressive than Group A but still regulated.
Why Commodity Classification Matters So Much
A warehouse storing Class I metal parts on wood pallets has very different fire protection requirements than one storing Group A plastic products on plastic pallets. The difference can mean thousands of dollars in sprinkler upgrades.
Getting the classification wrong is one of the most expensive mistakes we see. A warehouse operator tells the fire marshal they are storing Class III goods, gets a permit, and then starts stacking pallets of plastic-wrapped consumer goods that are actually Class IV or Group A. The fire marshal finds out during an inspection. The permit gets pulled. Now you are shut down until you upgrade your fire protection system to match what you are actually storing.
Be honest about what you store. It is cheaper to design for the right commodity class from the start than to retrofit after a violation.
Sprinkler Requirements for High-Pile Storage
Clark County follows the International Fire Code (IFC) and NFPA 13 for sprinkler design in high-pile storage areas. The requirements vary based on commodity class, storage height, storage method (rack vs. solid pile), and whether you have in-rack sprinklers.
- Ceiling-only sprinklers: May be adequate for Class I through III commodities at moderate heights with proper flue spaces.
- In-rack sprinklers: Required for most Group A plastic storage and for high-rise storage configurations where ceiling sprinklers alone cannot control a fire within the rack structure.
- ESFR sprinklers: Early Suppression Fast Response heads are designed for high-pile storage and can sometimes eliminate the need for in-rack sprinklers, depending on storage height and commodity class.
Flue Space Requirements
Flue spaces are the gaps between pallets and between rack rows that allow sprinkler water and cooling air to penetrate into the rack structure during a fire. Maintaining flue spaces is one of the most frequently violated and most important fire code requirements.
- Transverse flue spaces: The gap between pallets stored side by side on the same beam level. Typically 3 inches minimum.
- Longitudinal flue spaces: The gap between back-to-back rack rows. Typically 6 inches minimum.
- These are not optional. Blocking flue spaces with oversized pallets or product overhang defeats the sprinkler design. A fire that the sprinkler system was designed to control can become uncontrollable if flue spaces are blocked.
Aisle Width and Access Requirements
The fire code also specifies minimum aisle widths for fire department access in high-pile storage areas. Aisles must be kept clear at all times, and there are limits on dead-end aisle lengths.
Your rack layout design needs to account for these requirements from the beginning. Retrofitting aisle widths after the rack is installed means removing and relocating rack rows, which is expensive and disruptive.
The Permit Application Process
The high-pile storage permit application in Clark County requires:
- A site plan showing the rack layout, aisle widths, and building dimensions.
- A commodity classification statement identifying what materials will be stored.
- Sprinkler system documentation showing head type, spacing, density, and in-rack head locations if applicable.
- Maximum storage height for each area.
- The fire code edition being applied (Clark County currently enforces IFC 2018 with local amendments).
Source 4 Handles the Fire Marshal for You
We coordinate with Clark County Fire Prevention on every rack installation we do. Our permit packages include the fire protection details the fire marshal needs, formatted the way they want to see them. This is not our first time through the process. It is our thousandth.
If you are planning a new rack installation or reconfiguring an existing system, call us at (702) 734-8848. We will make sure the fire code requirements are built into the design from day one, not discovered after the install is done.