191 minutes how many hours

Download the free OSH Answers app. Search all fact sheets:. Occupational exposure limits OELs for noise are typically given as the maximum duration of exposure permitted for various noise levels. They are often displayed in exposure-duration tables like Table 1A and Table 1B. The OELs depend on two key factors that are used to prepare exposure-duration tables: the criterion level and the exchange rate.

The criterion level, often abbreviated as Lc, is the steady noise level permitted for a full eight-hour work shift. As the sound level increases above the criterion level, Lc, the allowed exposure time must be decreased. The allowed maximum exposure time is calculated by using an exchange rate, also called a "dose-trading relation" or "trading ratio.

There are two types of exchange rates currently in use: 3 dBA exchange rate or the "3 dB rule," and 5 dBA exchange rate or the "5 dB rule.

The 3 dBA exchange rate is more stringent. For example, the maximum permitted duration for a dBA noise exposure in the 3 dBA exchange rate is 15 minutes. With the 5 dBA exchange rate, it is one hour.

The following video will explain how to do this by doing an example problem:. Video Source mins Transcript. Step 1: Start with what you know is on top and bottom of the fraction numerator and denominator, respectively.

Step 3: Determine what conversion factor s to use. You will need more than one at least one for the top and one for the bottom. Step 4: Multiply by 1 in the form of the conversion factor that cancels out the unwanted units. We know that we need to change hours to minutes and miles to meters.

We need to decide which conversion factors will allow us to do that. Note that we chose the conversion factors that will enable us to cancel out the existing units and change them to the desired units ie. You are logged in. Switch accounts. Offers go here. Choose wisely! We won't share it with anyone else. If you forget it, you'll be able to recover it using your email address. The Hole Picture Sign up to receive a daily e-newsletter with a selection of local, state and regional news headlines from the Jackson Hole Daily.

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