Case studies

The challenge

A client at a military installation had been told that its walls and doors were falling well short of their required acoustic ratings. The reported findings included an STC of approximately 30 for a 16-inch-thick solid concrete wall. That result raised questions about how the measurements had been taken.

OSAT was initially brought in to check a few walls and doors. The immediate task was to establish whether the earlier results could be relied upon before the client committed to corrective work.

The testing and corrective work

OSAT reviewed the earlier agency’s approach and found that the testing did not follow the applicable ASTM procedures. The methods were inconsistent, leaving the client without a dependable account of the assemblies’ performance.

The assignment grew to approximately 100 doors. OSAT tested the installed assemblies and worked with the client through adjustments and retesting. The work continued until all of the doors in the program met their required acoustic ratings.

The result

Government personnel subsequently conducted their own testing. Of the approximately 100 doors, only one failed to meet its rating, and that door showed apparent damage.

For the client, the work resolved two problems: uncertainty about the original test results and the need to verify a large number of installed doors. The subsequent government testing provided a separate check on the condition OSAT had documented.

The challenge

OSAT was retained to verify newly installed acoustic doors at a secure facility on a military base. During the initial visit, every door tested failed to achieve the required performance.

Problems with the seals were a major part of the failure. The client needed specific guidance on the installed condition and a way to organize repairs across a substantial number of doors.

The testing and corrective work

OSAT provided advice on seals, caulking, and door fitment, along with installer training. The guidance showed the repair team what to address and how installation details affected the measured result.

OSAT also demonstrated a basic field-screening method the client could use between visits. This helped personnel check their progress during repairs, while formal acceptance remained dependent on OSAT’s verification testing.

The client mobilized an all-hands repair effort. OSAT returned two weeks later and supplied real-time feedback during testing. Some doors passed immediately; others needed further adjustments and another test.

The result

By the end of testing, 100% of the more than 60 doors met their required rating. The project moved from universal failure at the initial visit to verified passing performance for every door in the program.

The result came through installation corrections and repeated measurement. Training and immediate feedback helped installers connect their work to the acoustic requirements and resolve remaining deficiencies.

The challenge

A major U.S. defense contractor retained OSAT to evaluate multiple secure areas within a principal headquarters facility. Some of the SCIFs were believed to date to the 1990s.

The rooms were being used for secure conversations, but their installed sound isolation had not been established by the assessment now required. OSAT’s testing found acoustic deficiencies in several of the areas evaluated.

The assessment

OSAT tested the perimeter of the selected spaces, including doors, floor-to-floor transmission, and demising walls between adjacent areas. The scope examined different parts of the acoustic separation rather than treating door performance as a substitute for the whole perimeter.

OSAT prepared a report documenting the measured performance of the tested areas. It gave the client a record of the existing condition and the deficiencies that required attention.

After remediation was completed, OSAT returned to test the spaces again. The follow-up measurements addressed whether the modifications had achieved the required acoustic performance.

The result

The retested areas met the applicable ICD 705 acoustic requirements. The client had measurements documenting both the original condition and the performance after corrective work.

The assignment demonstrated why existing secure rooms need assessment of their actual construction. The age and continued use of a space did not establish its sound isolation; the testing supplied that information.

The challenge

A law firm representing a data center retained OSAT after neighboring property owners alleged excessive noise on adjacent properties. The neighbors had engaged their own counsel, and the dispute also involved local police enforcement of a county noise ordinance.

The law firm needed an independent measurement of the noise and a review of the information being presented as evidence of exceedances.

The measurements and review

OSAT conducted additional testing to determine the noise levels at relevant property boundaries and advise the law firm on their relationship to the applicable limits.

OSAT then examined the opposing measurements and the methods used to obtain them. The review identified concerns with the meter’s suitability, a lack of recent calibration, an inappropriate measurement scale, and inconsistent procedures.

Video footage recorded during the police officer’s testing was available for review. It allowed OSAT to examine the collection process directly and identify errors in how the readings had been obtained.

The result

The law firm received independent measurements and a technical assessment of the evidence supporting the allegations. Those were separate questions: what noise was present, and whether the earlier readings had been collected in a way that supported their stated conclusions.

The principal legal action was subsequently withdrawn. At the time of this account, a limited matter involving the local noise ordinance remained open.

The challenge

A large apartment developer wanted to know which floor-ceiling constructions performed best before adopting them for future buildings. The choices involved underlayment, insulation, framing or stud type, and finished flooring materials.

The question concerned the assembled construction. Selecting an individual material did not, by itself, answer how a completed floor-ceiling system would perform.

The comparison

OSAT tested multiple samples across several buildings for both airborne and structure-borne sound transmission. The work compared the combinations of materials and construction details the developer was considering.

Measuring both types of transmission allowed the developer to assess the different performance concerns within the same program. The results identified the combinations that performed best under the tested conditions and gave the client a basis for selecting preferred assemblies.

The findings were then used to standardize building methods for new construction. Instead of making each material choice independently, the developer could specify combinations informed by measurements of the assembled systems.

The result

The testing influenced methods intended for use in future apartment buildings. Its value extended beyond the sampled properties because the developer was establishing a repeatable approach to new construction.

OSAT understood from the client’s experience that the approach also helped avoid tenant complaints about sound transmission. Fewer complaints and improved tenant retention were practical goals of the work.

The challenge

A leading television direct-to-consumer marketer supplied OSAT with multiple handheld blowers intended for leaf cleanup and household use. The units produced excessive noise, including a high-pitched whistle that made the sound particularly objectionable.

The client wanted to establish the product’s noise output, understand how it compared with competing products, and identify the source of the whistle.

The investigation

OSAT used sound intensity testing to evaluate the supplied units. Competitor products were obtained and tested as part of the comparison.

The investigation identified the rear grille as the source of the high-pitched whistle. This narrowed the problem from a general complaint about a loud product to a particular feature that could be changed.

OSAT modified a sample by replacing the original rear grille with a screen-style grate. The modification addressed the component identified during testing and gave the client a specific alternative to incorporate into the product design.

The result

The grille change was subsequently implemented in production units. The revised design reduced the overall noise level by more than 10 decibels.

The assignment linked measurement to a manufacturing decision. Competitor testing provided context, source investigation identified the component responsible for the objectionable sound, and the sample modification led to a change in the units sold to customers.

The challenge

A regional airline operating services for a major U.S. airline retained OSAT to investigate cabin announcements that were difficult to understand at different flight levels.

The airline made an aircraft available with a pilot, co-pilot, and supporting personnel. This allowed the announcement system to be assessed under the conditions in which the problem occurred.

The testing

OSAT performed speech intelligibility testing using an NTi TalkBox and actual aviation headsets. Several headsets were evaluated, including Bose and David Clark models.

Ground testing included different aircraft systems operating, including HVAC. OSAT then conducted testing during a two-hour flight at multiple flight levels. The combination allowed evaluation of the announcement system beyond a stationary aircraft with its systems switched off.

OSAT assessed headset selection and announcement volume and discussed gain staging to minimize distortion. The recommendations addressed how the equipment and system settings worked together, rather than relying on a volume increase alone.

The result

OSAT identified preferred headset choices and appropriate announcement settings, with guidance on gain staging. The airline subsequently applied the recommendations throughout its fleet of similar aircraft.

The work translated a problem experienced during operation into settings and equipment choices the airline could use consistently. The ground and flight evaluations supplied the operating context for those recommendations.

The challenge

A client suspected a leak in a large section of low-pressure, high-volume piping. Several other methods had already been tried without successfully isolating the location.

Access was a significant part of the problem. The underside and other portions of the installation were normally difficult to reach, and the suspected leak could not be investigated as a readily accessible, localized defect.

The client described a sound associated with loss of pressure. OSAT used that description as the starting point for an acoustic search.

The survey

OSAT developed a plan to scan the piping with a parabolic microphone, including the underside and the normally inaccessible areas.

The purpose was to locate the sound associated with the suspected leak and narrow the search to a repairable defect. The survey approach was selected around the size of the installation and the access limitations that had complicated the earlier attempts.

The investigation used sound to find the source rather than requiring the client to first identify a visible defect along the piping.

The result

OSAT successfully located the defect, which was subsequently repaired.

The completed work provided the client with a specific repair location after previous approaches had left the leak unresolved. This was a source-location assignment: the immediate value was finding where corrective work was needed within a large, difficult-to-access installation.

The challenge

A manufacturer of pods used by broadcasters at major sporting events retained OSAT to verify their acoustic performance. The pods were intended for events attracting national and international audiences.

The manufacturer also needed assistance with the door assembly. Its performance needed to match the surrounding construction materials so the opening would not undermine the enclosure’s intended sound isolation.

The testing and design support

OSAT verified the pods’ STC performance and assisted with the door assembly design.

The work considered the door as part of the completed enclosure. The main construction and the opening had to be addressed together when evaluating whether the pod provided the required acoustic separation.

This combined verification with a specific design question. The manufacturer received information about measured performance and assistance with the component that needed attention, rather than an acoustic rating without guidance on the door.

The result

The pods have been used for national and international broadcasts. The manufacturer plans to deploy them at additional major global sporting events.

OSAT’s role was to establish acoustic performance and help align the door assembly with the rest of the construction. The manufacturer could use the findings to address the opening as part of the pod’s overall design.

The challenge

A luxury waterfront hotel operated by an international hospitality company retained OSAT to assess noise in indoor and outdoor areas and light levels in public walkways and other guest spaces.

The beachfront was also habitat for nesting turtles. The lighting question involved competing needs: suitable visibility for guests and limiting light that could interfere with the turtles’ natural cycles. Simply increasing or reducing lighting throughout the property would not address both objectives.

The surveys

OSAT measured light levels in the relevant public areas and identified locations that were overlit and others that were underlit. These findings gave the hotel information about where lighting needed attention, rather than treating the property as uniformly too bright or too dark.

OSAT also assessed noise throughout indoor and outdoor areas. The survey identified locations where sound levels interfered with speech intelligibility and guest comfort.

The two assessments addressed different aspects of the same property. Walkway visibility, comfortable communication, and the sensitive beachfront setting all formed part of the recommendations delivered to the hotel.

The result

OSAT provided a set of recommendations for a more balanced lighting approach and identified noise conditions requiring attention.

The hotel received a documented basis for planning changes in its public areas, with attention to both the guest experience and the sensitive beachfront setting.