How many negative air machines are needed for an 80' x 40' x 20' room if the effective capacity of one machine is 1,600 cfm?

To determine the number of negative air machines required for an 80' x 40' x 20' room, we first need to calculate the room's volume in cubic feet. The volume is found by multiplying the length, width, and height of the room:

Volume = Length x Width x Height

Volume = 80 ft x 40 ft x 20 ft

Volume = 64,000 cubic feet

Next, we need to assess the air exchange requirement. For asbestos abatement projects, a common standard is to achieve a minimum of 4 air changes per hour (ACH). To do this, we need to know how much air must be moved in a given hour.

1. Calculate the total air volume needed per hour:

Required airflow (in cubic feet per hour) = Volume x ACH

Required airflow = 64,000 cubic feet x 4 ACH = 256,000 cubic feet per hour.

2. Convert the effective capacity of one negative air machine from cubic feet per minute (cfm) to cubic feet per hour:

One machine capacity = 1,600 cfm

Convert to hourly: 1,600 cfm x 60 min/hour = 96,000 cubic feet