Question

activity 6: question
a confined space has a volume of 75,000 ft³. the ventilation fan has a cfm rating of 2,500 cfm. seven air exchanges are needed. what will the total purging time be? select the best option.
○ 21 minutes
○ 210 minutes
○ 240 minutes
○ 300 minutes

Explanation:

Step1: Find time for one air exchange

To find the time for one air exchange, we use the formula \( \text{Time (minutes)} = \frac{\text{Volume (ft}^3\text{)}}{\text{CFM (ft}^3\text{/minute)}} \). Substituting the values, we get \( \frac{75000}{2500} = 30 \) minutes.

Step2: Find total purging time for seven exchanges

Multiply the time for one air exchange by the number of air exchanges. So, \( 30 \times 7 = 210 \) minutes.

Answer:

210 minutes (Option: 210 minutes)