Nov 3, 2019 · To satisfy the normal security standards of SCIFs, the following transmission attenuation groups have been established: Sound Group 3 - STC 45 or better. Loud speech from within the SCIF can be faintly heard but not understood outside of the SCIF. Normal speech is unintelligible with the unaided human ear. Sound Group 4 - STC 50 or better.

Jan 7, 2013 · The ability of a SCIF structure to retain sound within the perimeter is rated using a descriptive value, the Sound Transmission Class (STC). To satisfy the normal security standards of SCIFs, the following transmission attenuation groups have been established: Sound Group 3 – STC 45 or better.

Oct 28, 2024 · The AO will determine the Sound Transmission Class (STC) requirement based on if amplified sound will be used within the facility. Your facility will either need to be built to STC 45, also referred to as sound group 3, or STC 50, also referred to as sound group 4, in the case of amplified sound.

Dec 2, 2019 · Sound Group 3 – STC 45 or better. Loud speech from within the SCIF can be faintly heard but not understood outside of the SCIF. Normal speech is unintelligible with the unaided human ear.

Nov 3, 2019 · Learn the intricacies of STC ratings and the practical approach to ensuring your SCIF or SAPF meets the necessary soundproofing standards. POAM, SCIF upgrade mandate, ICD 705 upgrades, DCID 6/9, SCIF compliance, SCIF upgrade risk assessment.

Mar 30, 2023 · When people are evaluating building materials and acoustical products for sound reduction, they rely on the sound transmission class or STC rating of the product. By understanding this rating of materials, we know how much sound will be blocked from going through those materials.

A SCIF structure and its ability to retain sound within the perimeter is rated using the Sound Transmission Class (STC). Sound group ratings are divided into two groups: Sound Group 3 and Sound Group 4.

ICD-705 offers two levels of acoustical security: Sound Group 3 – Sound Group 3 compliance requires rooms to have a minimum STC or NIC rating of 45 (40 when field tested) Sound Group 4 – Sound Group 4 compliance requires rooms to have a minimum STC or NIC rating of 50 (45 when field tested)

Sep 12, 2023 · STC is a score that indicates how much sound is stopped by a partition like a wall or door. The ICD 705 also mentions a Noise Isolation Class (NIC) score, which is a measurement of the total sound insulation between two rooms rather than just measuring the partition.

Whether using Sound Group 3 (STC 45) or Sound Group 4 (STC 50), these ratings are used in nearly all Type 2 or Type 3 SCIFs. Ensuring your door meets the required acoustic specifications is a key part of compliance and performance.