When calculating the number of negative air machines, what is the formula used?

The formula for calculating the number of negative air machines utilizes the total volume of the space being worked on and factors in the cubic feet per minute (CFM) that the negative air machine can handle. The correct choice incorporates both the dimensions of the area (length, width, and height) to find the volume and then divides by the air flow rate, which is essential for determining how many machines are necessary to achieve effective ventilation or maintain negative pressure.

Using the formula (Length x Width x Height)/15xCFM allows for calculating the total volume of the area in cubic feet and then adjusting for the CFM of the machines. The division by 15 is often used to represent the number of air changes required within a certain time frame to ensure that the air is continuously cycled and any contaminants, such as asbestos fibers, are adequately filtered out of the space.

This approach ensures thorough air quality management during asbestos abatement operations, thereby protecting both the workers and the environment from hazardous exposure.