One thing that makes SHOEBOX unique is that it has been optimized for hearing testing outside of a sound-proof booth. However, that doesn’t mean that any location will be acceptable for testing. OSHA provides detailed guidelines for how to test outside of a booth as long as you stay within the prescribed sound levels or Maximum Permissible Ambient Noise Levels (MPANLs). More on these can be found in the OHSA document 29 CFR 1910.95 Appendix D.
SHOEBOX offers two methods to help with MPANL compliance. First, it uses a built-in Type 2 Sound Level Meter to perform a room scan prior to beginning a hearing test. This scan will assess your space and indicate if the noise levels in your testing room are within the maximum allowable limits. It also comes with a calibrated Class 2 external microphone that plugs into the lightning port of the iPad. This can also be used for room scanning and assessment prior to beginning testing to ensure the test location meets the OSHA-defined MPANLs.
For those who may need to manage a large fleet of SHOEBOX devices but are worried about compliance, the system can be configured to ensure that a room scan produces a passing result prior to being able to proceed to a test. You can also enforce that the room can be completed before beginning a day of testing, ensuring that this step can not be skipped.
After a room scan has been completed and the hearing test has started, you can configure the system’s built-in sound level meter to continuously monitor the room to detect any changes in background noise. If problematic noise is detected, the test will pause if the MPANLs have been exceeded. The individual being tested will be alerted, and action from the Test Examiner will be requested from the software. They will be asked to check for common sources of noise, such as people talking, phones ringing, etc. If the noise persists, the Test Examiner will need to decide if testing should be moved to a new room. In the event that a test is interrupted by noise, the system will prompt to retest any affected frequencies to ensure the noise does not affect the overall results.
Testing can be performed in any reasonably quiet room, such as a conference room, office, or lounge. Depending on your available testing areas, you may be challenged in finding a suitable testing space — one that meets the OSHA MPANLs. If your facility has a permanent space that can be designated for testing but slightly exceeds the OSHA MPANLs, it is possible to install noise-dampening panels in the room, which can be economical and easy to source. Mufflers applied to overhead fans or ventilation systems can be quite effective. These are known to be common sources of low-frequency noise. If you are required to utilize more than one testing room, it would be important to turn off common noise sources such as fans, printers, or power generators. If these options aren’t effective enough, it is possible to source cost-effective portable testing spaces that are as insulating as a soundproof booth without the high cost and need for regular calibration maintenance.
If you are a service provider and travel frequently, you may wish to bring a portable testing space, which includes noise-dampening fabric or panels such as those used in vocal recordings. These are easy ways to block out noise while also being compact and lightweight.
As the Test Examiner, there are a few things you should keep an eye out for. Once a test is complete, verify the results screen to see if any frequencies have been affected by noise and need to be retested. The room scan result will also be displayed below the audiogram; verify that you have a passing result. Noise measurements that exceed the OSHA MPANLs will be displayed in red, as opposed to compliant measurements, which will be displayed in black. This data is also exportable in CSV format should this be required for record-keeping.