FSTC / ASTC Field Sound Transmission Class testing services / Apparent Sound Transmission Class – ASTM E336 – 14

FSTC (ASTC) Testing Services –Field / Apparent Sound Transmission Class Tests

FSTC (ASTC), or as it’s formally known Field / Apparent Sound Transmission Class is a double digit number that refers to the sound transmission properties of a wall structure. It may also be applied to measure the sound transmission properties of a window or door unit. Virtually all states and municipalities have set guidelines for the minimum FSTC / ASTC test rating that a building may have, and it’s a vital part of the International Building Code.  It’s not at all uncommon to find well-above-minimum FSTC / ASTC  test (and related FIIC / AIIC) ratings inserted into requests for proposals from architects and other designers especially for luxury housing. The most common standards for testing in the United States include the ASTM E90, ASTM E336 and ASTM E413 standards, while in European Union countries the ISO 140 and ISO 717 standards are used.

Performing a FSTC / ASTC test requires some specialized equipment, the first being an omni-directional sound source. This just means a sound source (speaker) that radiates sound in all directions equally, quite unlike a typical speaker which radiates most of its sound to the front. This ensures that the room is equally driven by sound pressure in all directions. Typically this is achieved by utilizing a multi-driver speaker systems that resembles a large soccer ball…think of each of the black sections as a speaker! The Bruel & Kjaer 4292 speaker is probably the best known of the current crop of omni-directional sound sources, and our personal reference unit. This unit is placed in what is called the sending room and then switched on, in order to excite the wall structure (and other structures that comprise the room) so that the resultant noise may be measured on the other side.

Secondarily, a sound level analyzer is required to accurately measure the sound in the room on the other side, which is named the receiving room. We utilize a  Bruel & Kjaer 2260 and 2270  sound level/analyzer meters running building acoustics software BZ 7204 and BZ 7229 which is capable of providing results compliant with ASTM, ISO, DIN, BS, and NBE among others.

We provide commercial and residential tenants, building managers, architects, contractors, insurance companies, and governmental agencies STC testing services and  ratings for any building. Call us today to talk about your noise transmission sound problems.

Contact us at 1-800-665-0080 to speak with a consultant today, or email us at: sales@onsiteacoustictesting.com

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