Question 1 of 270705eccef9ebacbc34ba4d465a6

The flammable limits of kerosene is 0.7% to 6.0% by volume in air. If a tank having contained kerosene is tested with the combustible gas indicator, shown in the illustration, and a reading of 50% is obtained, this means __________. See illustration SF-0002.

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Question 1 of 27070
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Q

The flammable limits of kerosene is 0.7% to 6.0% by volume in air. If a tank having contained kerosene is tested with the combustible gas indicator, shown in the illustration, and a reading of 50% is obtained, this means __________. See illustration SF-0002.

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🔍 Key Concepts

• Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL) for kerosene (0.7% to 6.0% by volume in air) • How a combustible gas indicator scale is usually calibrated (percent of LEL vs. percent by volume) • Difference between an atmosphere that is flammable, too lean, or too rich to burn

💭 Think About

• Is the meter in the illustration measuring percent of vapor by volume, or percent of the lower explosive limit? What does the scale labeling suggest? • If 100% on this meter corresponded to the lower explosive limit (0.7% by volume), what would a 50% indication represent in terms of safety and approximate concentration? • Which choice confuses "percent of LEL" with "percent by volume" of vapor in air?

✅ Before You Answer

• Check whether the indicator face in the illustration is marked in % of LEL or % gas by volume. • Confirm that 100% reading on this type of meter corresponds to the lower explosive limit, not to pure vapor. • Verify that a reading below 100% of LEL means the mixture is too lean to ignite, but may still be dangerous to enter without other tests.