Fire Resistance Rating Calculator
Calculate fire resistance rating from material type and thickness, compare to IBC requirements.
Inputs
Results
Achieved Rating (hours)
2
Required Rating (hours)
1
Meets Requirement1
Rating Deficiency (hours)0
Additional Thickness Needed (in)0
Effective Thickness (in)4
How to Use This Calculator
- Enter Material Type, Thickness (inches), and Gypsum Layers.
- Set Occupancy Group.
- Review Achieved Rating (hours) and Required Rating (hours).
- Use Meets Requirement and Rating Deficiency (hours) to inform your decision.
How the result changes with Thickness (inches)
| Thickness (inches) | Achieved Rating (hours) | Required Rating (hours) |
|---|---|---|
| 2.85 | 1.4 | 1 |
| 8.72 | 4.4 | 1 |
| 16 | 8 | 1 |
| 22 | 11 | 1 |
What each input means
- Material Type
- 1=Concrete, 2=CMU, 3=Gypsum Board, 4=Protected Steel, 5=Wood.
- Thickness (inches)
- Total material thickness (ignored for gypsum — use layers).
- Gypsum Layers
- Number of 5/8-inch gypsum board layers (for gypsum type only).
- Occupancy Group
- 1=A(Assembly), 2=B(Business), 3=E(Educational), 4=F, 5=H, 6=I, 7=R, 8=S.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMaterial Type = 1, Thickness (inches) = 4, Gypsum Layers = 2, Occupancy Group = 2 = 4 input(s) provided
- Calculate Achieved RatingAchieved Rating2 = 2
- Calculate Required RatingRequired Rating1 = 1
- Calculate Meets RequirementMeets Requirement1 = 1
- Calculate Rating DeficiencyRating Deficiency0 = 0
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