Equipment Covered by the EU Machinery Directive
For equipment covered by the European Union’s Machinery Directive (Updated) 
, you can use the specified sound power level as a baseline criterion. The EU Machinery Directive specifies sound power level noise emission limits for equipment manufactured or sold in the EU. These limits are considered to represent the state of the art and take into account the state and availability of technology for controlling noise, particularly at the source. The EU Machinery Directive contains sound power level noise emission limits for a variety of outdoor equipment.
If the equipment to be purchased is included in the EU Machinery Directive, the published sound power level noise emission limit should be selected as the baseline criterion. Furthermore, the equipment should not produce a peak sound pressure level greater than 130 dBC at any time during operation. This criterion applies to the “total machine” under all typical operating conditions.
Note: EU Machinery Directive limits merely represent the state of the art in noise control design and technology, but they are emission levels, not immission levels and do not guarantee safe exposure for the operator of the equipment. If the equipment includes (or offers an option to include) an operator cab or enclosure to control the operator’s noise exposure, the requirement for the enclosure should be added to the specification, and the sound level at the operator position should be addressed by listing it separately in the specification and/or by other hearing conservation program methods.
A simplified version of the Table from Article 12 of the Directive gives Baseline Sound Power Level Criteria for Selected Equipment Types as a function of equipment power.
All Other Equipment
For all other equipment, the baseline noise emission criterion is 80 dBA at 1 m and at the operator position. This sound pressure level is often achievable, pushes the state-of-the-art standard, and is broadly compatible with NASA’s hearing conservation goals. This criterion applies to the “total machine” under all typical operating conditions. The equipment should not produce a peak sound pressure level greater than 130 dBC at any time during operation.
You may find, based on your research, that neither of these criteria is appropriate. In that case, you may need to adjust the criterion.