Laboratory testing of different window design cases for noise transmission M A Maraqa, Y S Hawas, Md D Alam, J El Zarif and K N Aljunadi 2017 International Joint Conference on Civil and Mechanical Engineering Hong Kong, Dec. 15-18, 2018

Introduction Noise is a global issue, which requires precautionary action in any environmental planning situation. There is a need for a good acoustic environment that keeps the noise at levels of occupant comfort and well-being. Windows are the most crucial part when it comes to sound transmission into buildings. In general, the acoustic performance of a window is determined by its complete assembly.

Motivation and Objective There is no clear guidelines on window design and its specifications for noise in the Emirate of Abu Dhabi. The study intends to fill this gap by developing specifications for window design to control outdoor noise in the city. Developed specifications could then be incorporated in the Abu Dhabi International Building Code (ADIBC). Objective To investigate the effect of window design and window material on noise reduction.

Approach Review literature to identify factors Select factors based on practicality Identify cases for testing that cover selected factors Fabricate window cases Install cases in the laboratory and test for noise transmission Report results in terms of STC and compare among cases

Methodology Tested Cases Case Glazing Frame style Opening style Frame type 1 1.8x1.8 Single 6mm HU Hinge LA 2 Sliding 3 Single 8mm BU MA 4 Single 12.76 laminated 5 Single 12mm 6 Double 6mm-12mm-6mm 7 Double 6mm-12mm-12mm CW HA 8 Double 6mm-20mm-6mm 9 Double 12mm-12mm-12mm 10 uPVC 11 Single 6mm (wood shutter) 12 Single 6mm (aluminum shutter) 13 14 Double 6mm-12mm-6mm (wood shutter) 15 Double 6mm-12mm-6mm (aluminum shutter) 16 2.4x1.8 17 1.2x1.8 18 Single 6mm (tempered) 19 20 21

Methodology ASTM E90-09, Standard test method for laboratory measurement of airborne sound transmission loss of building partitions and elements. ASTM E413-10, Classification for rating sound insulation. ASTM C423-09a, Standard test method for sound absorption and sound absorption coefficients by the reverberation room method.

Methodology Test Rooms Points S1-S4 are loudspeaker positions Points M1-M4 are locations of rotating microphone.

Methodology

Results Reproducibility

Results Sound Transmission Class (STC) case 1

Results Case Glazing Frame style Opening style Frame type STC, dB 1 Single 6mm HU Hinge LA 29 2 Sliding 23 3 Single 8mm BU MA 21 4 Single 12.76 laminated 24 5 Single 12mm 20 6 Double 6-12-6 7 Double 6-12-12 CW HA 25 8 Double 6-20-6 9 Double 12-12-12 26 10 uPVC 31 11 Single 6mm (wood shutter) 32 12 Single 6mm (aluminum shutter) 34 13 14 Double 6-12-6 (wood shutter) 15 Double 6-12-6 (aluminum shutter) 16 17 18 Single 6mm (tempered) 19

Results Effects of Glass Thickness Case Glazing Frame style Opening style STC, dB 2 Single 6mm HU Sliding 23 20 Single 8mm 21 Single 12mm No improvement in the STC value with increasing glass thickness from 6 to 12 mm.

Results Effects of Lamination Case Glazing Frame style Opening style STC, dB 4 Single 12.76 laminated HU Sliding 24 21 Single 12mm 23 Only 1 dB increase in the STC value using a laminated layer of 0.76 mm.

Results Effects of Glazing and Air Gap Case Glazing Frame style Opening style STC, dB 5 Single 12mm BU Sliding 20 6 Double 6mm-12mm-6mm 7 Double 6-12-12 CW Hinge 25 8 Double 6-20-6 29 Single and double glazed windows with similar glass thickness result in the same STC value for a small air gap of 12 mm. An increase in the air gap from 12 to 20 mm between glass panes results in a 4-dB increase in STC.

Results Effects of Frame Material Case Glazing Frame style Opening style Frame type STC, dB 1 Single 6mm HU Hinge LA 29 10 uPVC 31 Compared to aluminum frames, a 2-dB increase in the STC value could be obtained using uPVC frames.

Results Effects of Frame Style Case Glazing Frame style Opening style STC, dB 3 Single 8mm BU Sliding 21 20 HU 23 Compared to box umbrella frames, half umbrella frames result in 2-3 dB increase in the STC value. Compared to curtain wall frames, half umbrella frames with hinge result in 4 dB increase in the STC value.

Results Effects of Shutters Case Glazing Frame style Opening style STC, dB 2 Single 6mm HU Sliding 23 11 Single 6mm (wood shutter) 32 12 Single 6mm (aluminum shutter) 34 Wood and aluminum shutters when completely closed result in an increase of 9-11 dB in the STC value compared to similar windows without shutters.

Results Effects of Window Area Case L (m) H (m) Glazing Frame style Opening style STC, dB 2 1.8 Single 6mm HU Sliding 23 16 2.4 17 1.2 Changes in window area do not change the STC value.

Results Effects of Window Opening Style Case Glazing Frame style STC, dB 1 Single 6mm HU Hinge 29 2 Sliding 23 Hinge windows result in about 6 dB increase in the STC value compared to sliding windows.

Results Effects of Glass Type Case Glazing Frame style Opening style STC, dB 1 Single 6mm HU Hinge 29 18 Single 6mm (tempered) No effect on STC between tempered and float glass.

Conclusion Glass thicker than 6 mm does not show any improvement in sound insulation. Laminated glass with 0.76 mm PVB layer does not cause a significant improvement in sound insulation. Double glazed windows with air gap of 12 mm or less does not cause any tangible effect on sound transmission. Air gap of 20 mm in double glazed windows causes a moderate improvement in the STC value. PVC frames results in a slight improvement over aluminum frames. Box umbrella and curtain wall frames result in lower STC values compared to those of half umbrella frames. Shutters result in a significant improvement in sound insulation when completely closed. Hinge, not sliding, windows cause a good improvement in sound insulation. Use of tempered glass did not cause any effect as compared to float glass.

Acknowledgement This study was undertaken as part of a scientific collaboration between ADM and the Roadway Transportation and Traffic Safety Research Center (RTTSRC) at the UAE University. Funding was provided by ADM

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