What code standard does this tool follow?

Ratings are based on the International Building Code (IBC) Table 601 and Table 602, which are derived from ASTM E119 fire resistance test durations. Always verify with your Authority Having Jurisdiction (AHJ) since local amendments may apply.

What does a "fire resistance rating" mean in hours?

It is the duration, in hours, that a structural assembly must withstand ASTM E119 standard fire exposure conditions while maintaining structural integrity, limiting temperature rise on the unexposed face, and preventing the passage of hot gases.

Does this tool cover exterior walls?

Yes. Exterior bearing and non-bearing walls are included. Their rating depends on fire separation distance as well as construction type — this tool uses the most conservative (zero separation) value; reduce for greater distances per IBC Table 602.

Can I use these values directly in construction documents?

Use these as a reference and starting-point check only. Final required ratings must be confirmed by a licensed architect or engineer of record using the adopted edition of the IBC and any local amendments.

What is the difference between Type I-A and Type I-B?

Both use non-combustible materials, but Type I-A has higher fire resistance requirements (e.g., structural frame at 3 hours vs. 2 hours for Type I-B), making it appropriate for the tallest and most critical occupancies.

Fire Resistance Rating

Name: Fire Resistance Rating
Availability: InStock
Author: Nham Vu

Select occupancy type, construction classification, and structural element to get the required fire resistance rating per standard building codes.

Parameters

Occupancy Type

Construction Type

Structural Element

Select parameters and click Calculate Rating

Quick Reference — Structural Frame (IBC Table 601)

Type	Frame	Ext. BW	Int. BW	Floor	Roof

BW = Bearing Wall. Values in hours. Source: IBC 2021 Table 601.

Summary

Select occupancy type, construction classification, and structural element to get the required fire resistance rating per standard building codes.

How it works

Select the building occupancy type (e.g. Assembly, Business, Residential).
Choose the construction type classification (Type I through Type V).
Pick the structural element you need the rating for (columns, beams, floors, walls, etc.).
Click "Calculate Rating" to get the required fire resistance rating in hours.
Review the code reference and notes for your specific combination.

Use cases

Verify fire resistance requirements during the schematic design phase.
Cross-check contractor submittals against code-mandated hourly ratings.
Quickly compare ratings across different construction type options.
Support code compliance documentation for permit applications.
Educate students and junior engineers on IBC fire resistance tables.
Estimate upgrade costs when changing occupancy or construction type.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu