Negative Air Machines For Your Abatement Project

What is a Negative Air Machine?

A Negative Air Machine is used to filter air and keep contaminated air from entering other parts of the building during a mold remediation or cleaning/restoration project.  Negative Air Pressure helps capture and contain airborne contaminates like dirt, dust, smoke, fumes, fungus and mold.



Did you know the Industry standard is to change the air 6 times per hour?

To create a negative pressure environment there has to be more air leaving the room than the amount that enters and the Negative Air Unit must be inside the containment with ductwork to exhaust the filtered air.

How to Calculate how many Negative Air Machines you need:

  1. Calculate the Cubic Square Footage of the room, house or building.  Multiply the total square footage by the height of the ceiling. (Length * Width * Height)

Ex. House: 2,679 sqft * Ceiling Height: 10Ft = 26,790 cubic feet.

  1. Divide the Cubic Square Footage by the Negative Air Machine’s CFM to determin
    e how long it takes to change the air 1 time.

Ex.  House Cubic Feet: 26,790 / 2,000 CFM = 13.40 minutes to change the air.

  1. Calculate how many times the air will be changed in an hour.  Divide 60 mins by the time it takes the machine to change the air 1 time.

Ex. 60 mins / 13.40 minutes to change the air = 4.48 times the air will be changed.

  1. Determine how many machines you need by dividing the industry standard of 4 by how many times your machine changes the air.

Ex.  6/4.48 = 1.35 machines needed.  So you would need at least 2 machines to meet the standard requirement to change the air 6 times per hour.


Future Environmental Designs created a Negative Air App that will calculate this for you if you have your measurements.  You can check it out here.