What is the concentration of xylene in this room? What is the flow rate of air moving through a portable blowers with a velocity of 120 FT/Min (3.048 m/min), through ha pipe of diameter 10 inches.

1. The lower explosive limit (LEL) of xylene is 1%.

In a room where xylene solution is being sprayed, an engineer uses a calibrate combustible gas meter to determine that the xylene concentration is 10% of the LEL.

What is the concentration of xylene in this room?
A. 1,000 parts per million (ppm)
B. 10,000 parts per million (ppm)
C. 9% great that the LEL of xylene
D. 11% greater than the LEL of xylene

2. What is the flow rate of air moving through a portable blowers with a velocity of 120 FT/Min (3.048 m/min), through ha pipe of diameter 10 inches (25.4 cm)
a. 0.425 ft3/min (o.0120 m3/min)
b. 7 ft3/min (0.198 m3/min)
c. 54 ft3/min (1.53 m3/min)
d. 9,420 ft3/min (267 m3/min)

3. An operator is working on a piece of machinery that is producing noise at 105 DBA. The company threshold level is at 85 DBA with 5 DBA exchange rate. The local authority is 90 DBA with 3 DBA exchange rate.
How long can this operator be exposed without any control and still respect both limits?
a. Less than 5 minutes
b. 15 minutes
c. 30 minutes
d. 1 hour

4. A company has decided to perform one random safety audit monthly of their 10 crews. The following are near miss points the crews accrued over the last year.
Crew 1 = 55
Crew 2 = 30
Crew 3 = 56
Crew 4 = 40
Crew 5 = 45
Crew 6 = 25
Crew 7 = 28
Crew 8 = 49
Crew 9 = 40
Crew 10 = 32

A crew is considered to be eligible for the safety audit if it accrued near miss points higher than 40
Which is the probability of a crew being selected for a safety audit?