You must select a noise emission limit for the equipment, which the supplier must meet. The noise emission criterion you select should reflect the state of the art in available low-noise equipment. This will result in the selection of the product you need without making the project too expensive or unpracticable. The noise emission criterion should be inserted into the NASA Noise Emission Specification.
If the criterion you choose is too high (loose), the resulting product or facility will be louder than necessary. This is especially critical because an overly loose requirement will typically result in lower-priced proposals. If the requirement is too stringent, it will be difficult to secure responsive proposals from suppliers.
The first step is to select a baseline criterion that is appropriate for the class of equipment you wish to purchase.