To: Steelform Building Products Inc. Wednesday, 2007 May 7 4104 69 Avenue Edmonton, AB, T6B 2V2 Attn: Mr. Marty MacDonald aci Acoustical Consultants Inc. Suite 107, 9920-63Ave Edmonton, Alberta, Canada T6E 0G9 Phone: (780) 414-6373, Fax: (780) 414-6376 www.aciacoustical.com re: Acoustical Testing Results of Steelform Products Dear Marty, Thank you for retaining aci to conduct STC field testing at the Park One Condominium Building. The results and discussion of the testing are attached. We trust the information provided is sufficient. Please contact us if you have any questions. Yours very truly, aci Acoustical Consultants Inc., CJ Buma Corjan Buma, M.Sc., P.Eng. Associate Consultant APEGGA Permit to Practice # P7735 1
INTRODUCTION aci Acoustical Consultants Inc. of Edmonton was retained by Steelform Building Products Inc. to conduct standarized acoustical measurements of some of its stud and joist products as installed at the Park One condominium located at 111 Street and 68 Avenue in Edmonton, AB. The purpose of this study was to determine the STC (sound transmission class) performance across a party wall and one floor/ceiling assembly within the building. Site work was conducted for aci by Corjan Buma, M.Sc., P.Eng., on Friday, 2007 Febr. 2. MEASUREMENT METHODS STC TEST The STC testing was done using the ASTM E336 standard Standard test method for measurement of airborne sound insulation in buildings as a guideline. The general procedure involves producing a loud source of sound on one side of the measured partition with a loudspeaker, as shown in Figure 1, producing pink noise. Sound level measurements are conducted on the source side at several locations (to be averaged in post-processing) and on the receiver side at several locations. The difference in sound levels between the two locations is known as the Transmission Loss (TL). Finally, a measurement of the reverberation time within the receiver space is conducted to allow for adjustment of the receiver sound pressure levels in accordance with the ASTM standard. The results are used, along with the area of the tested partition and the volume of the receiver room to calculate the adjusted TL values in each of the measured 1/3 octave band frequencies. Finally, a standardized STC curve is fitted to the adjusted TL curve according to the fitting criteria outlined in the ASTM standard. The resultant value of the standard curve at 500 Hz is known as the STC value. This value, being measured in a constructed building, is known as the Apparent STC (ASTC). The ASTC value is generally lower than the laboratory achievable STC value (known as the rated STC ) because there are typically (1) additional noise flanking paths around the partition and (2) mechanical and/or electrical components that allow noise transfer through the partition; both of these are intentionally minimized or prevented in laboratory testing. As such, the reported ASTC value is a measure of the overall construction performance. Table 1 shows a range of STC and ASTC values and typical subjective response. 2
Table 1. Subjective Performance of Various STC Values STC Lab Apparent STC Subjective description of effectiveness 26-30 22-26 Most sentences clearly understood Many phrases and some sentences understood without 30-35 26-31 straining to hear Individual words and occasional phrases clearly heard and 35-40 31-36 understood 42-45 38-41 Medium loud speech clearly audible, occasional words understood 47-50 43-46 52-55 48-51 Normal speech audible by straining to hear. Loud speech audible, music easily heard Normal speech unintelligible, Loud speech audible by straining to hear; music normally can be heard and may be disturbing 57-60 53-56 Loud speech essentially inaudible; music can be heard faintly but bass notes disturbing 62-65 57-61 Music heard faintly, bass notes "thump"; power woodworking equipment clearly audible 70 65 Music still heard very faintly if played loud. 75+ 65+ Effectively blocks most air-borne noise sources The measurement equipment for the STC testing consisted of a Brüel and Kjær Type 2250 Precision Integrating Sound Level Meter, collecting data in 15-second L eq samples measuring the broadband A-weighted and 1/3 octave band frequency sound levels. The sound level meter was calibrated at the start of the measurements to ensure accurate results. The sound source consisted of a NTI Minirator MR1 generating pink noise and a JBL EON-G15 loudspeaker. Reverberation time measurements were conducted with the loudspeaker (used for room excitation) and the Sound Level Meter as both the source and measurement system. Refer to the Appendix for calibration certificates for the Sound Level Meter. 3
BACKGROUND SOUND LEVEL CONSIDERATIONS Note that during all tests the sound level in each of the pertinent 1/3 octave bands is required to be at least 10 db above the ambient sound level (with the source signal turned off). This ensures that the measured sound is loud enough to not have interference from the other constant sources such as ventilation and other equipment. As such, measurements in the receiver room are conducted with the source sound both on and off and then compared after the test. Some of the STC tests occurred with receiver room levels less than 10 db above ambient in several of the 1/3 octave bands; this was due to either low-level sound due to Contractors still at work in the building or the in-suite air-handling equipment being on. In general, the deficient 1/3 octave values were not responsible for determining the resultant ASTC value. However, where the ASTC value did appear to be affected by higher-thandesirable background sound level, the results are reported with the ASTC value followed by a + sign, indicating that the actual ASTC would have been slightly higher had background noise not interfered with the result. TEST LOCATIONS An up-down assessment of a floor/ceiling assembly was conducted from Unit 203 to Unit 103 and a side-to-side assessment of a party wall was conducted from Unit 405 to Unit 404. The suites tested were all unoccupied, having been finished to the degree of painting, baseboards, millwork and most doors in place. Some of the bedrooms had been equipped with finish flooring (in the form of carpet or lino or laminate). There were no obvious holes/leaks between any of the units though typically party-walls did have an electrical box into the room on either side. Some doors had not yet been equipped with handles (resulting in a 50-mm open hole) and none were equipped with perimeter seals. Subjective listening/assessment during side-to-side STC testing (Unit 405 to Unit 404) verified that the lack of perimeter seals and lack of some doorhandles was not the determining factor in STC results. Unit 203 to Unit 103 The STC assessment from Unit 203 to Unit 103 was done in the living room area and assessed the performance of Steelform joists in a floor/ceiling construction. 4
The floor/ceiling assembly consisted of 22-gauge metal deck, filled with concrete topping (minimum thickness 38 mm), on 150-mm Delta joist, 50-mm Spider insulation applied to underside of deck, furring bar ( hat channel ) below Delta joist and one layer 16-mm Type X drywall attached below furring bar. Unit 405 to Unit 404 The side-to-side STC test was done from Unit 405 Bedroom and Unit 404 Bedroom. The composition of this party wall was Delta stud on both sides of 25-mm gap (no board material within 25-mm gap), common batt insulation in stud-cavities on both sides of gap and one layer of 16-mm Type X drywall on one side and two layers of 16-mm Type X drywall on the other. (Note that there is acoustically no difference whether the sound source is on the 2-layer or the 1- layer side of the party wall.) RESULTS OF STC TESTS The results of the STC tests are shown in Table 2 and Figures 2 & 3. The value of ASTC 58 is considered very good (an ASTC value of 55 or more would qualify as superior sound isolation ). The value of ASTC 53 is considered good. Table 2. Derived ASTC Values Source Receiver ASTC Unit 203 Unit 103 58 Unit 405 Unit 404 53 For reference, the Alberta Building Code states (in Section 9.11): every dwelling unit shall be separated from every other space in a building in which noise may be generated by a construction providing a sound transmission class rating of at least 50, measured in accordance with Subsection 9.11.1 or as listed in A-9.10.3.1. in Appendix A 5
The test method discussed in Subsection 9.11.1 refers directly to ASTM E 336 (which was followed as part of this test). Thus, the tested value of ASTC 58 appreciably exceeds the requirement of the Alberta Building Code. For the fourth floor result, had Spider insulation been used on fourth floor, the ASTC may well have gone above 53 (assumes Spider insulation is more dense than common batt insulation). CONCLUSION The results of the ASTC in-situ testing of the Steelform products indicate that building code requirements can be met, and even exceeded, with the use of the Steelform products. 6
Figure 1. Sound Source Used for STC Testing (Unit 203) 7
100 90 80 Sound Transmission Loss (db) 70 60 50 40 30 STC 58 20 10 0 125 250 500 1000 2000 4000 Frequency (Hz) Figure 2 ASTC Result For Floor/Ceiling Between Living Rooms of Units 203 & 103 100 90 80 Sound Transmission Loss (db) 70 60 50 40 30 STC 53 20 10 0 125 250 500 1000 2000 4000 Frequency (Hz) Figure 3 ASTC Result For Party-Wall Between Bedrooms of Units 405 & 404 8
APPENDIX 9
B&K 2250 Calibration Certificate(s) 10
B&K 4231 Calibrator Calibration Certificate 11