A PASS device (Personal Alert Safety System) also known as a Distress Signal Unit (DSU) or ADSU (Automatic Distress Signal Unit), is a personal safety device used primarily by

firefighter A firefighter is a first responder and rescuer extensively trained in firefighting, primarily to extinguish hazardous fires that threaten life, property, and the environment as well as to rescue people and in some cases or jurisdictions als ...

s entering a hazardous or Immediately Dangerous to Life and Health (

IDLH The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent advers ...

) environment such as a burning building. The PASS device sounds a loud (95

decibel The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a ...

) audible alert to notify others in the area that the firefighter is in distress. On a fireground, the sound of an activated PASS device indicates a true

emergency An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...

and results in an immediate response to

rescue Rescue comprises responsive operations that usually involve the saving of life, or the urgent treatment of injuries after an accident or a dangerous situation. Tools used might include search and rescue dogs, mounted search and rescue ...

the firefighter(s) in distress. In the United States, the

National Fire Protection Association The National Fire Protection Association (NFPA) is an international nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards. As of 2018, the NFPA claims to have 50,000 mem ...

sets standards for PASS devices in NFPA 1982.NFPA 1982
(registration required) The PASS device is normally used in conjunction with breathing apparatus; it is a small, battery-powered device attached to the

self-contained breathing apparatus A self-contained breathing apparatus (SCBA), sometimes referred to as a compressed air breathing apparatus (CABA) or simply breathing apparatus (BA), is a device worn to provide breathable air in an atmosphere that is immediately dangerous to ...

(SCBA) harness which enables the firefighter to summon help by activating a loud, piercing electronic bleeper. Early models were only able to be activated manually, such as when a firefighter is lost or trapped. More recent PASS devices can also automatically activate if the device does not detect motion for 30 seconds, so that the alert will sound if the firefighter is seriously injured or otherwise incapacitated. Some devices use a ball bearing on a track to sense firefighter movement and others use an

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...

beam against a mirror mounted on a spring. 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. Older models of PASS devices required manual arming by firefighters prior to entering a dangerous environment. The unit was equipped with a key which, when removed, armed the unit. This key was left outside the hazard area with an entry control officer. When the unit activated, it could only be switched off by inserting this key. Current applications integrate the PASS device into the SCBA worn by firefighters so that it automatically arms when the SCBA air supply is engaged or when the SCBA is removed from its mounting bracket. This style devices are powered by

battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

, are easily activated while wearing gloves, and are intrinsically safe to operate in flammable or explosive atmospheres. It was reported that shortly after the events of

September 11, 2001 The September 11 attacks, commonly known as 9/11, were four coordinated suicide terrorist attacks carried out by al-Qaeda against the United States on Tuesday, September 11, 2001. That morning, nineteen terrorists hijacked four commerc ...

, the sound of many activated PASS devices could be heard beneath the rubble of the collapsed World Trade Center. 343 firefighters (including a chaplain and two paramedics) of the

New York City Fire Department The New York City Fire Department, officially the Fire Department of the City of New York (FDNY), is an American department of the government of New York City that provides fire protection services, technical rescue/special operations services, ...

(FDNY) were killed on that day.

References

External links

Personal Alert Safety Systems (PASS) ResearchPASS device sound
Firefighting equipment de:Totmannmelder {{Firefighting-stub

See also

References

External links