Planned Maintenance

Alert: Due to planned maintenance, the HUD Exchange will be unavailable starting at 8:00 PM EDT today (4/25). The site will be available again on 4/26 by no later than 8:00 AM EDT.

Sound Transmission Classification Assessment Tool (STraCAT)

Part I - Description

Part II - Wall Components

Wall Construction Detail Area STC
Browse wall materials by their sketches.
{{getWallSTC(wall.material.stc)| number}}
  {{getWallAreaTotal()| number}} Sq. Feet {{getWallSTCTotal() | number:2|number}}
Window Construction Detail Quantity Sq Ft/Unit STC
Browse window materials by their sketches.
{{getApertureArea(window.material.area)|number}} {{window.material.stc|number}}
Door Construction Detail Quantity Sq Ft/Unit STC
Browse door materials by their sketches.
{{getApertureArea(door.material.area)|number}} {{door.material.stc|number}}

Part III - Results

Wall Statistics
Stat Value
Area: {{stracatCtrl.totalWallArea || "0"}} ft²
Wall STC: {{stracatCtrl.totalWallSTC|number:2|number}}

Aperture Statistics
Aperture Count Area % of wall
Windows: {{getApertureQuantityTotal('window')|number}} {{getApertureAreaTotal('window')|number:3|number}} ft² {{getApertureWallPercentage('window')|number:2|number}}%
Doors: {{getApertureQuantityTotal('door')|number}} {{getApertureAreaTotal('door')|number:3|number}} ft² {{getApertureWallPercentage('door')|number:2|number}}%

Evaluation Criteria
Criteria Value
Noise source sound level(dB): {{stracatCtrl.intro.noiseLevel}}
Combined attenuation for wall component: {{getCompositeAttenuation()|number:2|number}} dB
Required attenuation: {{calculateRequiredAttenuation()}}
Do Wall components meet requirements? {{getMeetsRequirements().value}}
Print

Part 4 - Tips

What do you do if the preferred wall design is not sufficient to achieve the required attenuation? Another wall design with more substantial materials will work, but may not be the most cost-effective solution. Try adding some other elements for just a little more attenuation.

For example:

  • Staggering the studs in a wall offers approximately 4dB of additional protection.
  • Increasing the stud spacing from 16” on center to 24” can increase the STC from 2-5dB.
  • Adding a 2” air space can provide 3dB more attenuation.
  • Increasing a wall’s air space from 3” to 6”can reduce noise levels by an additional 5dB.
  • Adding a layer of ½” gypsum board on “Z” furring channels adds 2dB of attenuation.
  • Using resilient channels and clips between wall panels and studs can improve the STC from 2-5dB.
  • Adding a layer of ½” gypsum board on resilient channels adds 5dB of attenuation.
  • Adding acoustical or isolation blankets to a wall’s airspace can add 4-10dB of attenuation.
  • A 1” rockwool acoustical blanket adds 3dB to the wall’s STC.
  • Filling the cells of lightweight concrete masonry units with expanded mineral loose-fill insulation adds 2dB to the STC.