Which of the following is NOT a criterion for a valid breath sample?

A valid breath sample is essential for accurate breath alcohol testing using the Intoxilyzer 8000. The criteria ensure the sample accurately reflects the subject's blood alcohol concentration (BAC).

One key criterion for a valid sample is that it must be long enough, which allows sufficient air to be passed through the device for analysis. This ensures that a representative sample of the alveolar air is collected, as only this air gives an accurate indication of the individual's BAC.

The level slope criterion focuses on the breath sample's consistency throughout the collection phase, ensuring steady flow and quality of the sample. Any interruptions or significant changes in slope may indicate a less reliable sample.

The terminology surrounding the third option, "soft enough," may imply a breath sample that is not forceful or inadequate in volume or pressure. However, in breath testing protocols, what matters is the adequacy of the sample and the method of collection rather than the subjective term "soft." The requirement for the sample to be "hard enough" is also related to the idea that it must be forceful enough to be adequately processed by the device.

In summary, while the first two criteria directly correlate with the collection of a valid sample, the phrasing regarding "soft enough" does not represent