Sound Proofing Fiberglass Door | STC and OITC | Plastpro Inc

Sound Proofing: STC and OITC Rating

Plastpro aims to provide safe doors that meet building codes and create a peaceful and comfortable living environment, which leads us to seriously consider soundproofing as we design our doors. Plastpro doors are tested for their soundproofing capabilities on a range of scales, including Sound Transmission Class (STC) and Outdoor/Indoor Transmission Class (OITC). Below you will find detailed explanations about these two testing classes, as well as more information about what to look for from a soundproofing perspective when choosing an entry door. Factors such as door model, door height, and the width and type of glass insert all effect the STC and OITC- use our search tool below to easily find the testing results for your door, based on these factors.

Sound Transmission Class (STC)

The STC is the most common rating used in North America for determining airborne sound transmission loss between 125 and 4,000 Hz. This range covers the majority of common noises we hear including speech, television, music, dogs barking, and other similar annoyances. This rating is essentially an average over the 16 frequency points tested. Look for a high STC rating for superior performance.

Outdoor/Indoor Transmission Class (OITC)

The OITC covers a wider range and lower frequency than the STC. The OITC is determined from testing between 80 Hz and 4000 Hz. Notably, road noise is a lower frequency sound, so depending on the proximity to busy streets and interstate highways, it is important to consider the OITC rating and look for higher numbers. A higher OITC demonstrates a door’s increased ability to prevent low-frequency sounds from entering the home.

Plastpro test results and search tool

Use our search tool below to easily find the STC and OITC for each Plastpro door, based on model, height, and glass type.


Please Note: This search tool is provided for your convenience. For any formal use of test results for Plastpro products, please refer to Plastpro Sound Proofing Test Results for more information. Additionally, if you are searching for Non-Plastpro Glass, these results are for a reference point only. Please confirm the results with your original glass manufacturer for more accurate test results. We reserve the right to update this information at any time.