On-Site Acoustic Testing has provided (and continues to provide) acoustical testing and consulting related to the testing of secure facilities, to ICD-705 standards. We provide services that can take you from the inception of the project (including building plan review), through the construction phase, ending in the testing phase. We can also provide direction when spaces require acoustical remediation to bring them up to standard.

ICD-705 sets standards for all aspects of secure areas including access control, data security, and acoustical security. The document should be thought of much in the same way as the USRDA minimums as related to nutrition.

The acoustical security section of ICD-705 is based upon the ASTM-E336 standard, and all instrumented testing that is conducted must be compliant with ASTM-E336 dictates.

ASTM E-336 is the standard that covers airborne sound transmission.

There are two subsets of interior airborne sound transmission that are (commonly) used, and they are as follows:

ASTC – Apparent Sound Transmission Class – More accurate, but can be unsuitable for very large areas

NIC – Noise Isolation Class – Less accurate, but can be used in virtually all areas

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)

There is no difference in the testing method between Sound Group 3 and Sound Group 4, the only difference is in the expected result.

When testing a secure area, it is necessary to test all door and wall partitions individually that contact non-secure areas. Additionally, if the secure area is required to maintain security between multiple operations, all door and wall partitions between areas within the secure area must also be tested individually.

For example, a conference room that has two doors, three offices along one wall, a hallway along another wall, and an open area on two sides could require a total of eight tests to be conducted, to ensure that it meets Sound Group 3 or Sound Group 4 requirements.

Although ICD-705 is vague about ceiling, floor and exterior wall partitions, those are also required to meet the Sound Group 3 or Sound Group 4 standards. In the case of a building with CMU or other stout construction, it’s generally accepted that the exterior building facade will meet or exceed the Sound Group 3 and Sound Group 4 minimum standard, which means that only doors (or uncommon to most secure areas – windows) will need to be tested.

In order for us to be able to provide project pricing, we require either a marked up floorplan OR an accurate count of all wall and door partitions that will require testing.

Please use the form below to request additional information with regards to testing your secure area.


Please list the city and state where testing will take place.