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Kenneth C. Crocco
Senior Member
Username: kcrocco

Post Number: 122
Registered: 04-2003
Posted on Monday, January 14, 2008 - 11:13 am:   Edit PostDelete PostPrint Post

I am looking for information regarding the specification of Apparent Sound Transmission Class (ASTC) for high rise residential applications. My understanding is that this is a field test of installed conditions that incorporates assumptions about the room acoustics and background noise.

PS: I am assuming a division one section and don't know the best number to use at this point. I am thinking along the lines of 018853 Apparent Sound Transmission.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 604
Registered: 03-2003
Posted on Monday, January 14, 2008 - 11:33 am:   Edit PostDelete PostPrint Post

Actually, it's called a "Field Sound Transmission Class," or FSTC. The building code (IBC) does not prescribe a method to test for an FSTC, but you can use ASTM E 336, Standard Test Method for Measurement of Airborne Sound Insulation in Buildings. The minimum rating needs to be 45 for a field test.

If your building code is the IBC (or even the UBC), you'll need to include requirements for an "Impact Insulation Class," or IIC, for floor-ceiling assemblies. The IBC requires a rating of 50. Like the STC, the IIC can be tested in the field (FIIC). Again, the IBC is silent regarding the test method, but you can use ASTM E 1007, Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures (Can you get a longer title than that?!). Also, like the FSTC, the rating for the field test needs to be a minimum of 45.
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick

Post Number: 828
Registered: 03-2002
Posted on Monday, January 14, 2008 - 11:46 am:   Edit PostDelete PostPrint Post

And I assume you are talking about sound transmission between units. If your talking about exterior noise sources, you need to look at OITC--Outdoor Indoor Transmission Class.
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre

Post Number: 695
Registered: 07-2002
Posted on Monday, January 14, 2008 - 01:31 pm:   Edit PostDelete PostPrint Post

Ken-
I have a section called "General Acoustical Requirements" that covers floor/ceiling sound, and also room to room sound protection. in the 95 numbering, I use a 01400--- series number. we consider it part of quality control in this office, since the with sound control you have to have ongoing quality control during the construction process. if you measure only at the end of the assembly, there is no fix other than ripping the wall out and starting over. We ask for the contractor to hire the acoustical consultant for ongoing observation during critical installation times, so in many ways, its like ongoing testing.

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