What pressure must be checked by firefighters before donning an SCBA?

Before firefighters don their self-contained breathing apparatus (SCBA), it is crucial to check the air cylinder pressure to ensure that there is sufficient air supply for safety during operations. The standard practice is to check for a minimum of 90% of the cylinder's rated pressure. This preparatory step is important because it ensures that the firefighter has an adequate amount of breathable air available to potentially face smoke or toxic environments, allowing for safe and effective firefighting and rescue operations.

A cylinder with pressure below this threshold could lead to an insufficient air supply, which poses significant risks during emergency response. Proper pressure checks help to prevent situations in which firefighters may become incapacitated due to low oxygen levels or equipment failure. Thus, confirming a pressure of 90% or more allows firefighters to operate confidently and safely.