Exam CFPS topic 1 question 1 discussion

Actual exam question from NFPA's CFPS

Question #: 1
Topic #: 1

It was determined that a total-flooding carbon dioxide suppression system installed in a process room requires an overpressurization vent. The system will flow 156 pounds of carbon dioxide per minute, and the enclosure strength has been calculated to be 9 lb/ft2 (71 kg). What is the minimum vent size recommended for this application?

A. 35 in2 (226 cm2)
B. 40 in2 (258 cm2)
C. 45 in2 (290 cm2)
D. 50 in2 (323 cm2)

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Suggested Answer: C 🗳️

by howmany at April 10, 2023, 3:55 p.m.

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AhmedEbrahim

2 months ago

Selected Answer: B

p.g. 17-14

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afa188f

10 months, 2 weeks ago

To calculate the minimum vent size, we need to consider the flow rate of carbon dioxide and the strength of the enclosure. First, let's convert the enclosure strength from pounds per square foot (lb/ft²) to pounds per minute (lb/min) to match the flow rate of carbon dioxide. 9 lb/ft² * (156 lb/min) = 1404 lb/min Now, we compare the flow rate of carbon dioxide (156 lb/min) to the strength of the enclosure (1404 lb/min). The higher value, which is 1404 lb/min, represents the required vent size. Now, we convert this value to square inches: 1404 lb/min ÷ 30 in/min (since 1 lb/min equals about 30 in² of vent area) ≈ 47 in² So, the minimum vent size recommended for this application would be closest to option: C. 45 in² (290 cm²)

upvoted 1 times

AhmedEbrahim

2 months ago

wrong answer

upvoted 1 times

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Leelo

11 months, 3 weeks ago

The Answer is B

upvoted 2 times

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howmany

1 year, 8 months ago

The answer is B - 40 in2

upvoted 1 times

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