NAICS & SIC Code Guidance
Introducing Submission Triage and Orchestrate: Agentic AI for Modern Underwriting. Learn More >
An ISO fire-protection rating is a score assigned by the Insurance Services Office (ISO), a third-party organization that provides data and analytics to the insurance industry. ISO ratings are used to assess the quality of fire protection services in a given community.
This score is part of the Public Protection Classification (PPC) system, which assigns a rating between Class 1 and Class 10. A Class 1 rating represents the highest level of fire protection, while Class 10 indicates that the community's fire protection capabilities do not meet minimum criteria.
The ISO score is based on the evaluation of multiple factors, including the fire department's staffing and equipment, the availability of water supply, emergency communications systems, and community risk reduction efforts.
ISO ratings help insurers evaluate how likely a fire department is to effectively respond to and control a fire in a specific area, directly impacting potential property losses.
The Insurance Services Office uses the Fire Suppression Rating Schedule (FSRS) to evaluate communities. This system examines three primary components, each weighted differently:
Communities can also earn up to 5.5% in bonus credit for community risk reduction efforts, including code enforcement, public fire safety education, and fire investigation programs.
Evaluators examine:
Robust computer-aided dispatch (CAD) systems, redundancies, and well-trained personnel enhance this component score.
Water availability is critical and accounts for 40% of the total ISO fire-protection rating. Key elements include:
Evaluators assess whether sufficient water is accessible throughout the community to support effective fire suppression.
Accounting for 50% of the score, ISO evaluates:
ISO determines whether the department can meet response requirements for structural fire risk across the geographic area served.
ISO classifications significantly impact property insurance pricing. Better ratings (lower numbers) typically result in lower premiums, reflecting reduced risk of fire loss.
Underwriters incorporate ISO classifications to assess the local fire protection environment. The PPC score informs estimates of emergency response effectiveness and water availability, key determinants of fire-related loss severity.
Actual premium impacts vary by carrier, line of business, and property characteristics; the above ranges are illustrative only.
Some carriers use the ISO classification directly as a discount/surcharge factor; others embed it in multifactorial pricing models alongside construction type, exposure data, and proprietary risk scores.
For commercial lines, the pricing impact is often greater. A manufacturing facility in a Class 9 area may face markedly higher premiums and potentially reduced capacity compared to an identical facility in a Class 3 area.
ISO ratings are not the sole fire-related factor. Distance to the nearest station or hydrant, building materials, and on-site suppression systems also play significant roles.
Strong ISO scores (Class 1 to Class 4) signal high-quality community fire protection. These ratings correlate with lower fire loss potential and better insurance terms.
National ISO Class Distribution:
These communities typically feature:
Insureds benefit from maximum premium discounts.
Most communities fall in this range. Characteristics may include:
Insurance pricing varies based on exact classification and other risk modifiers.
These scores indicate fire protection gaps:
Properties in these areas often face:
Modern underwriting platforms integrate ISO data directly into risk evaluation workflows. When reviewing a submission, the property’s address is automatically geocoded and matched to the ISO classification.
ISO ratings are applied in:
Platforms with more advanced capabilities ingest not only the overall PPC class but also component-level FSRS scores (e.g., water supply, fire department, emergency comms). This enables deeper underwriting insight, particularly for complex commercial risks.
For example, a property might be in a Class 4 area but located 10 miles from the nearest fire station. Combining ISO class with local distance-to-protection data yields a more accurate fire risk profile.
The fire risk assessment landscape continues to evolve. Leading insurers increasingly combine ISO data with real-time property attributes, claims histories, and geographic hazard data.
Unified underwriting platforms such as Federato’s RiskOps integrate ISO fire-protection scores with these additional signals to support more consistent, high-fidelity risk evaluation.
Key benefits of integrated fire risk assessment:
Rather than applying blanket rate adjustments, insurers can now analyze the drivers behind an ISO score and act accordingly, targeting mitigation efforts, prioritizing inspections, or refining appetite strategy.
This progression represents a step forward in aligning technical fire risk data with underwriting judgment and business goals.
Carriers combine ISO scores with property characteristics, claims history, and geographic risk in underwriting platforms to produce composite risk scores and pricing decisions.
Platforms like Federato’s RiskOps present ISO data alongside construction type, occupancy, and loss history in a unified interface for faster and more accurate risk assessment.
Typically every 3–5 years. However, significant infrastructure changes may prompt interim evaluations at the request of local fire officials.
ISO ratings apply to entire communities and are not subject to individual appeal. However, property-specific mitigation (e.g., sprinklers, alarms) may result in underwriting credits or premium discounts even in poorly rated areas.