NEMA Publishes Test Procedure for Compatibility of Hearing Aids, Ultrasonic Lighting Control Devices - NEMA LC 1-2007
April 3, 2008 // Published as a news service by IHS
The National Electrical Manufacturers Association (NEMA) published NEMA LC 1-2007 - Test Procedure for Compatibility of Hearing Aids and Ultrasonic Lighting Control Devices.
This standard provides a basis to evaluate the possible interactions between ultrasonic lighting control devices and hearing aids using a set of test procedures.
This evaluation can be used as the basis for specifying performance criteria for both hearing aids and occupancy sensors to eliminate interference.
According to Bob Erhardt, former chairman of NEMA Lighting Controls Section, NEMA LC 1-2007 addresses compatibility between hearing aids and ultrasonic lighting control devices (occupancy sensors).
Some occupancy sensors may occasionally interfere with acoustic signal processing in some digital hearing instruments causing audible noise and distortion of the signal.
"This publication provides a basis to evaluate the possible interactions between ultrasonic lighting control devices and hearing aids by specifying a set of test procedures," Erhardt said.
"This evaluation can be used as the basis for determining performance criteria for both hearing aids and occupancy sensors to eliminate objectionable acoustic interference."
NEMA LC 1-2007 establishes test procedures for use with a small acoustic chamber to evaluate potential interactions between hearing aids and occupancy sensors. The test procedures are designed to simulate and test occupancy sensors at three typical, specific frequencies (25 KHz, 32.7 KHz and 40 KHz) and one type of hearing aid.
"If there are multiple hearing aids," Erhardt said, "the test procedures are repeated as many times as necessary."
Source: National Electrical Manufacturers Association (NEMA).