What determines the air pressure maintained by the MMR?

The air pressure maintained by the MMR (Modular Mask Respirator) is specifically regulated to ensure that the pressure delivered to the wearer is safe and effective. This is set at 0.5 psi above atmospheric pressure, allowing for a steady and reliable flow of air. This slight increase above atmospheric pressure helps prevent contaminants from entering the mask while ensuring that the user has adequate airflow.

Setting the pressure at this level is crucial for effective respiratory protection, as it ensures that the air delivered to the user is properly controlled and consistent, enhancing both comfort and safety during its usage. This design feature is an essential part of the SCBA system, emphasizing the importance of maintaining a safe environment for firefighters and emergency responders who may be exposed to hazardous atmospheres.