Note: I know I should have had this out yesterday, and I do apologize. With everything going on I never had the opportunity to put everything together and get this posted. A day late, but here is “letter D”
An important part of a firefighters gear is the PPE or Personal Protective Equipment, which will be discussed later in letter P. A key part of the PPE, and more specifically the SCBCA (which will be discussed in letter S), is a small device known as the the DSU or Distress Signal Unit
The DSU or ADSU (Automatic Distress Signal Unit) more commonly known as the PASS (Personal Alert Safety System) is a small device used, mainly by firefighters, when entry will be made into an environment that could be potentially dangerous or hazardous (ie a burning building). It is often times an integral part of the SCBA but can also be separate.
In early years, DSUs had to be turned on before entry into a dangerous situation and required manual activation. Devices that are attached to a SCBA unit are designed to automatically turned on when the air bottle for the SCBA is opened. Modern models are designed to go off when there is a period of time without movement. When activating for a lack of motion, the PASS device will typically emit a few seconds of a muted warning that activation is about to occur, so that a firefighter who has simply been motionless for a time but is otherwise safe will be able to move slightly and thus reset the activation timer before a false activation occurs. The DSU can also be activated manually in situations where a firefighter has found himself trapped or otherwise in trouble.
In 1982 NFPA developed a standard for personal alert safety system (PASS) devices. When activated, the PASS/DSU device must emit a high-pitched audible alert of at least 95 decibels.
On a fire-ground, the sound of an activated PASS device indicates a true emergency and results in an immediate response to rescue the firefighter(s) in distress.
Another feature of modern DSU/PASS devices is to transmit how much air is in the bottle to a receiver in the face mask.
- PASS device
Join me on an A to Z Journey of firefighting tools throughout the month of April. I appreciate feedback. Please keep in mind that I am not (nor do I pretend to be) a firefighter or a member, either volunteer or paid, of the fire service. My purpose here is to pass on knowledge that I find in hopes to both bring awareness to the fire-service and to help those in the profession do their job safer and better.