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Acoustic Testing & Certification

Performance Standards We Support

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ICD/ICS 705 compliant testing for SCIF/SAPF facilities (ASTC, NIC, OITC):

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  • 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+  -Very loud sounds within the SCIF, such as loud singing, brass music, or a radio at full volume, can be heard with the human ear faintly or not at all outside of the SCIF.

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Sentinel Field Acoustic Testing & Performance Report
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  • Measured sound isolation metrics by certified Class 1 equipment with laboratory verification (ISO/IEC 17025 Accredited)

  • Applicable performance criteria (e.g., FSTC targets)

  • Measured field sound transmission results (ASTC, NIC, OITC)

  • Calculated STC rating (single digit accuracy) to support accreditation review​

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Including Required Accreditation Deliverables

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Measurement Data & Analysis

  • Source and receiving room sound pressure levels

  • Background noise measurements and corrections

  • Reverberation time measurements

  • Averaging methodology and calculation summaries​

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Instrumentation & Calibration Records

  • List of all test instruments used (model and serial number)

  • Current laboratory calibration certificates

  • Documentation of field calibration performed before and after testing​

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Acceptance Summary Detailing:

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  • Measured performance meets specified requirements

  • Additional corrective action is required

  • Retesting is recommended following remediation

Instrumentation & Measurement Quality
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Accurate testing depends on professional-grade equipment and disciplined procedures.

Sentinel supports testing programs utilizing:

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  • Class 1 sound analyzers

  • Class 1 measurement microphones

  • Class 1 acoustic calibrators (94 dB / 114 dB)

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-All equipment maintains current laboratory calibration certificates traceable to national standards.

-Field calibration is documented before and after each test session to ensure measurement integrity.

Corrective Action & Retest Support (When Required)
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If field testing identifies deficiencies, Sentinel supports the project team by:

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  • Assisting with root-cause identification

  • Recommending targeted corrective actions

  • Verifying readiness prior to retesting

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This approach minimizes unnecessary rework and reduces schedule impact.

Field Test Methodology
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Testing is performed using recognized field procedures appropriate for high-performance secure spaces.

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Typical test activities include:

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  • Broadband excitation using a high-power omnidirectional sound source

  • Measurement of sound pressure levels in both source and receiving rooms

  • Background noise measurement and correction

  • Reverberation time measurement

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Measurements are taken at multiple microphone positions and averaged to ensure representative results. Transmission loss data is then reduced to a single-number Field Sound Transmission Class (FSTC) rating.

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