The following is guidance on how to manage the potential risk of health from working with devices that generate ultrasonic frequencies.

• Ensure compliance with Control of Noise at Work Regulations 2005 . Ensure there is no direct contact, or indirect via a solid or liquid medium, with ultrasonic generating devices.
• Manufacturer’s information should include noise levels at 1m from the ultrasonic device when operating under normal conditions. Ensure the measured audible noise levels are below the exposure action values as specified in the control of noise at work regulations.

• Use the preliminary noise risk assessment, if required a competent person can carry out monitoring of audible noise (Safety Adviser).

Important information to consider when conducting a risk assessment

• The energy from ultrasonic waves dissipate rapidly in air
• Attenuation for ultrasound is similar to that for audible noise.

o Reduce the energy at source.

o Block the path of the energy

o Protect the worker

• Attenuation for ultrasonic frequencies is simpler and easier than for audible noise energy.

o Ultrasonic frequencies are more readily absorbed and reflected inwards by enclosures.

o Ultrasonic frequencies are less liable to diffraction.

o A barrier of 3mm cardboard reduces SPL by 70dB between 20kHz and 50kHz.

o Attenuation offered by hearing protection is usually referenced up to 8kHz, according to published information it is likely that attenuation in the ultrasonic region will be at least that offered at 8kHz.