If you’re new to loose-fitting respirators, the whole concept can be a bit confusing. How can a loose seal stop the hazardous air from entering your headtop? Well, this all comes down to positive pressure.
Air is supplied to the respirator headtop either via a battery powered air purifying respirator (PAPR), which draws in and filters ambient air from the environment, or via a supplied air respirator (SAR), which will be connected to compressed breathing air with an airline hose.
The clean breathing air is then passed through to the breathing zone via a breathing tube.
Respiratory hazards are prevented from entering the respirator because the air is being supplied to the headtop at a greater rate than ambient air is able to enter. This is called positive pressure and is the reason why a loose-fitting respirator doesn't need a tight-fitting seal to provide quality respiratory protection.
Benefits of a Positive Pressure Respirator
No fit testing: A loose-fitting positive pressure respirator does not rely on a skintight seal to provide respiratory protection, this removes the need for fit testing which can be significant cost saver.
Facial hair friendly: The loose-fitting design enables you to have facial hair without compromising safety or breaching compliance requirements.
Promotes safer breathing: Positive pressure also allows you to breathe as you normally would as the lungs are not labored to manually filter the air as they breathe. This is especially helpful with preexisting health conditions, such as asthma or COPD, as it supports breathing.