NFPA Fire Terms That Industrial Tenants and Landlords Need to Know
Understanding NFPA 13: Key Fire Protection Terms for Industrial Properties
Fire protection codes are full of technical jargon that most people in industrial real estate don’t think about—until they have to. Whether you're a warehouse tenant, landlord, or broker, understanding NFPA 13 terminology can help you avoid costly fire code violations, insurance issues, or unexpected sprinkler system upgrades.
Here are some commonly misunderstood NFPA terms, why they matter, and how they impact industrial properties.
Encapsulated Storage
Definition: Products wrapped in plastic that covers the top and at least 75% of the sides.
Why It Matters: Plastic traps heat and prevents sprinkler water from penetrating the product, making fires harder to suppress.
Example: A pallet of boxed paper is a lower fire risk than the same pallet shrink-wrapped in plastic, which may require a higher sprinkler density or in-rack sprinklers.
Obstruction to Discharge
Definition: Any object that blocks sprinkler water from reaching a fire.
Why It Matters: Sprinklers are designed to spray water in a specific pattern—if racking, equipment, or solid shelving blocks that spray, fire protection is compromised.
Example: A warehouse with solid shelves in a rack system might require in-rack sprinklers because the shelves prevent water from reaching lower levels.
Commodity Classification (Classes I–IV & Group A Plastics)
Definition: NFPA 13 groups stored materials by how fast they burn and how much fire protection they require.
Why It Matters: The higher the classification, the more fire protection is needed.
Commodity Class Breakdown:
Class I – Noncombustible materials like metal parts (lowest fire risk).
Class II – Noncombustible products with limited combustible packaging.
Class III – Combustible products such as wood, paper, and natural fiber clothing.
Class IV – Class III materials with additional plastic or combustible content, such as cardboard boxes with foam inserts.
Group A Plastics – Highly combustible plastics, including plastic crates, shrink-wrapped goods, and synthetic clothing like polyester (highest fire risk).
Example: A warehouse storing cotton clothing (Class III) requires a different fire suppression system than one storing polyester clothing (Group A Plastics).
High-Piled Storage
Definition: Storage exceeding 12 feet for certain commodities or 15 feet in general cases.
Why It Matters: Once storage reaches high-pile classification, NFPA requires stricter fire suppression, which may include:
Higher sprinkler density
In-rack sprinklers
Additional water supply capacity
Example: A warehouse storing small boxes on floor pallets has fewer fire requirements than one using 20-foot racking for high-pile storage.
Solid Pile vs. Palletized Storage
Definition:
Solid pile – Goods stacked directly on top of each other.
Palletized storage – Goods stored on pallets with airflow between them.
Why It Matters: Solid pile storage burns hotter and faster than palletized storage, affecting sprinkler system requirements.
Example: A warehouse stacking clothing in solid piles may need a different fire suppression system than one using palletized racking with flue spaces.
Flue Space
Definition: Vertical gaps between stored goods that allow sprinkler water to flow down.
Why It Matters: Without proper flue space, fire suppression can’t reach lower levels, increasing fire risk.
Example: Fire inspectors may require a 6-inch transverse flue space between pallets in racks to allow proper water flow.
ESFR (Early Suppression, Fast Response) Sprinklers
Definition: High-output sprinklers designed to suppress fires quickly rather than just containing them.
Why It Matters: ESFR systems eliminate the need for in-rack sprinklers but may require higher water pressure than a standard system.
Example: A FedEx-style distribution center likely has ESFR, but a converted manufacturing building may not.
Limited-Combustible vs. Non-Combustible Materials
Definition:
Non-combustible – Does not burn (e.g., metal, glass).
Limited-combustible – Can burn, but not easily (e.g., fire-treated wood).
Why It Matters: Some materials appear fire-resistant but still contribute to fire spread.
Example: Certain fire-treated insulation materials may be limited-combustible rather than fully non-combustible.
Water Demand & Fire Flow
Definition: The amount of water needed to sustain sprinkler discharge for a required period (usually 20–90 minutes).
Why It Matters: If a warehouse lacks sufficient water pressure, it may need:
Fire pumps
On-site water storage tanks
Example: Older industrial buildings may not have enough water supply capacity to support modern sprinkler requirements.
Aisle Width & Fire Code Compliance
Definition: NFPA sets minimum aisle widths between racked goods to allow for:
Proper fire suppression
Emergency access
Why It Matters: If aisles are too narrow, fire code may require:
Layout adjustments
Additional sprinklers
Example: A warehouse reconfiguring racks may unknowingly reduce aisle width below fire code minimums, affecting compliance.
Why This Matters for Industrial Leasing
Fire codes play a key role in warehouse operations, affecting tenant approvals, insurance requirements, and long-term compliance.
Understanding fire protection requirements upfront helps tenants select the right space and avoid unexpected modifications.
Well-maintained sprinkler systems and proper fire suppression measures add value to a warehouse, ensuring it meets various storage needs.
Different commodities and storage heights require different levels of fire protection, making it important to match a space with the right tenant.
For businesses considering a warehouse, confirming that the fire suppression system aligns with your planned storage type ensures a smooth move-in process