In-Rack Sprinklers: What you need to know
- DURASTONE CONSTRUCTION LLC
- Apr 7
- 3 min read
When storing palletized commodities in high-density pallet racks, traditional ceiling-mounted sprinklers aren’t always enough. That’s where in-rack sprinklers come into play and can make a huge difference. These systems are designed to suppress fires directly at the point of ignition, especially in tightly packed racking configurations where ceiling sprinklers can’t reach effectively or when storing high-risk products.
In this post, we’ll explain how in-rack sprinkler systems work, when they’re required, the pros and cons of using them, and which types of products or warehouse setups benefit most from their installation.
What Are In-Rack Sprinklers?
In-rack sprinklers are specialized fire suppression systems installed within pallet racking structures to provide direct and immediate fire protection between levels of stored materials. They’re designed to activate more quickly and efficiently than ceiling-mounted systems in high-density storage areas, where smoke and heat may not reach the ceiling fast enough to trigger a response.
High-piled storage exceeding code thresholds
Narrow flue spaces
Plastic-wrapped or highly combustible products
Rack-supported storage systems that block vertical water flow
How In-Rack Sprinkler Systems Work
In-rack systems follow many of the same fire suppression principles as ceiling-mounted sprinklers but are strategically placed inside the racking system to ensure better coverage. They’re plumbed into the warehouse’s fire protection system and are designed to activate automatically when a certain heat threshold is reached.
Depending on the racking height, material type, and local fire codes, the system layout and number of sprinkler heads will vary.
Benefits of In-Rack Sprinklers
✅ Targeted Fire Suppression: They address fires where they start—right at the product level, reducing the chance of spread and damage.
✅ Improved Safety Compliance: In-rack sprinklers help meet the requirements of NFPA 13 and local fire authorities, especially for high-piled or plastic storage.
✅ Allows for Tighter Storage Layouts: Ceiling-only systems often require wider flue spaces and lower stacking heights. In-rack systems allow for denser storage configurations.
✅ Lower Risk of Inventory Loss: Faster fire response means less product damage and reduced downtime in the event of a fire.
Drawbacks to Consider
❌ Higher Installation Costs: In-rack systems are more complex and require precise design, installation, and routing, especially in multi-level racking systems.
❌ Maintenance and Repair Complexity: They are more prone to damage from forklifts or pallet handling, and regular inspections are needed to ensure all heads remain unobstructed.
❌ Reduced Flexibility in Reconfiguration: If you plan to regularly move or reconfigure your racking layout, the fixed plumbing for in-rack sprinklers may need to be adjusted or redesigned.
When Are In-Rack Sprinklers Required?
Fire codes such as NFPA 13 often require in-rack sprinklers when:
Storage exceeds certain height thresholds (depending on commodity class)
Stacked products are wrapped in plastic or stored in non-porous containers
Flue space requirements can’t be maintained due to product or rack design
The existing ceiling system is not sufficient to protect the type of commodity stored
Always consult with a fire protection engineer and your local fire marshal to determine if your planned storage system will require in-rack coverage.
Best Applications for In-Rack Sprinklers
In-rack sprinkler systems are commonly used in:
Distribution centers with high-piled storage.
Facilities storing Class III or IV commodities.
Rack-supported structures like pick modules or rack-supported buildings.
Warehouses with no sprinkler system or inadequate sprinkler systems.
If your operation involves densely packed, high-value, or combustible materials, in-rack sprinklers can be an essential investment in safety and compliance.
Conclusion
In-rack sprinklers are a powerful tool for protecting high-density pallet storage environments. While they add complexity and cost, they provide an extra layer of fire protection that can save inventory, time, and lives.
If you're planning to install new pallet racking or move into a warehouse with tight storage conditions, consider in-rack sprinkler requirements early in the design process. Your local fire code and your insurance provider may demand it.
Need help evaluating your racking system for sprinkler compliance? Contact us to get started with a professional assessment.
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