STC Requirements
Calculator
Direct answer: for the stated IBC 2021 dwelling and sleeping-unit separation scope, the built-in target is laboratory STC 50 or field NNIC 45. Choose the matching test basis below, then compare it with a documented rating. For every other project type, enter a target verified from the applicable owner criteria, contract, regulation, or sector standard.
Who it is for: architects and acoustical consultants checking a documented acoustic test rating against one confirmed target at construction documents. It does not select an assembly, predict field loss, or determine requirements for schools, healthcare, offices, hotels, façades, impact sound, or local amendments.
| Adjacency | Typical target | Source |
|---|---|---|
| Residential party wall | STC 50 lab / NNIC 45 field | IBC 2021 §1206.2 |
| Residential floor/ceiling (airborne) | STC 50 lab / NNIC 45 field | IBC 2021 §1206.2 |
| Hotel room to room | STC 55–60 | Industry practice |
| Office conference room | STC 45–50 | Industry practice |
| Classroom party wall | STC 50 | ANSI/ASA S12.60 |
| Hospital patient room | STC 45–50 | FGI / HTM 08-01 |
Rows other than the IBC residential scope are owner-criteria or sector benchmarks. Enter the verified target for your project in the calculator above.
How to use this calculator
The formula
A nonnegative difference means the entered rating equals or exceeds the selected numerical target. It does not establish assembly construction, installation quality, field performance, or whole-project compliance.
Worked example
When this estimate will be off
- The built-in IBC condition applies only to the §1206.1/§1206.2 dwelling and sleeping-unit separation scope.
- The calculator does not predict a rating from materials and does not recommend an assembly.
- Impact sound, IIC/NISR, exterior OITC, low-frequency noise, mechanical vibration, and background-noise criteria are excluded.
- A user-entered target is not validated as a legal, contractual, healthcare, education, or certification requirement.
Frequently asked questions
A common mistake: The built-in IBC condition applies only to the §1206.1/§1206.2 dwelling and sleeping-unit separation scope.
No. Enter a target verified from the applicable owner criteria, contract, regulation, or sector standard.
Not under the built-in IBC option. The code text distinguishes laboratory STC 50 from field NNIC 45.
No. Applicability, documentation, construction, penetrations, installation, and amendments remain separate checks.
Sources
- ICC — 2021 IBC §1206.2 — Airborne-sound requirement for the scoped dwelling and sleeping-unit separations: laboratory STC not less than 50 under ASTM E90, or field NNIC not less than 45 under ASTM E336.
Sources and review record
Sources and method basis
- IBC 2021 §1206.1 and §1206.2; ASTM E90 laboratory STC and ASTM E336 field NNIC references
- https://codes.iccsafe.org/
Limitations
- Built-in targets cover only the stated dwelling/sleeping-unit separation scope; assembly prediction, impact sound, other sectors, local amendments, and compliance are excluded.
This free STC Requirements Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.