TOPIC: 1.2 SELF CONTAINED BREATHING APPARATUS (SCBA)

Enabling Objective OPERATE Self Contained Breathing Apparatus as defined in IFSTA and Scott Field Level Maintenance Training Manual (current series) while observing all applicable safety precautions.

SCBA The firefighter’s lungs and respiratory tract are more vulnerable to injury than any other part of the body. Because of this, SCBA’s play a major role in firefighting and rescue providing air supply and oxygen in an oxygen deficient atmosphere.

Protects the respiratory system from: Smoke Toxic gases Products of combustion

Provides an air supply in an oxygen deficient atmosphere SCBA Provides an air supply in an oxygen deficient atmosphere

Personal Alert Safety System (PASS) Provides an audible alarm for the fire fighter in the event he or she is trapped or unconscious.

Personal Alert Safety System (PASS) Attached to SCBA harness. After 30 seconds of lying motionless the alarm will sound. Manually activated when trapped in a hazardous environment. PMS should be at least weekly and maintained in accordance with manufacture instruction to ensure ready use.

Environments requiring respiratory protections: Oxygen deficient atmosphere 1 Internal Aircraft Cabin Fires. Fires consume large quantities of oxygen, and produce large quantities of smoke and toxic gases. Some areas may be oxygen deficient during overhaul. Assume all fire are oxygen deficient.

Physical effects Normal breathing air is 21% oxygen. OSHA determines that SCBA should be worn in atmospheres containing less than 19.5% oxygen. American National Standard Institute (ANSI) defines an oxygen deficient atmosphere as 18% or less. The body will increase its respiratory rate at this oxygen concentration.

Physical effects (CONT.) At 17% oxygen, muscle coordination is impaired. 12% causes dizziness. 9% causes unconsciousness. 6% causes death in a few minutes.

Elevated temperatures May be found in: Internal aircraft cabin fires. During backdraft. During flash over. Physical effects: Severe burns of the respiratory tract. Pulmonary edema (fluid pockets in lungs).

Smoke Physiological effects: Particles may effect alveoli in lungs. May shut down gas exchange. May cause alveoli to dilate and rupture. May result in nausea, vomiting , diarrhea, or lipid pneumonia.

Toxic atmospheres associated with fire. Exposure to combinations of irritants, toxicants and gases cannot be predicted accurately, but are potentially more serious that if each were inhaled separately.

Exposure to toxic atmosphere: May directly causes disease of the lung tissue. May have no direct harmful effect on the lung but pass into the bloodstream and to other parts of the body and impair the oxygen-carrying capacity of the red blood cells. Causes more deaths from carbon monoxide poisoning than any other toxic product of combustion.

The particular toxic gases given off at a fire, vary according to four factors: Nature of the combustible. Rate of heating. Temperature of the evolved gases. Oxygen concentrations.

Protective breathing apparatus limitations. Limitations of the wearer. The wearer must be in sound physical conditions. Wearing an SCBA may restrict the wearer’s movements. Shape and contour of the face will affect the wearer’s ability to get a good face-to-face piece seal.

Limitations of the wearer.(CONT) 4 The firefighter must be knowledgeable in every aspect regarding protective breathing apparatus use. The ability to maintain control in an excited or high stress environment. The harder a firefighter exerts themselves, the faster the the air supply is expended. The face piece reduces peripheral vision, and face piece fogging can reduce overall vision.

Limitations of the wearer.(CONT) Voice communication can be hindered. 9 Depending on the model and make, the protective breathing equipment adds 25 to 35 pounds of weight.

Description of Scott Air-Pak NOTE: THE AIR-PAK 2.2 AND 4.5 MODEL RESPIRATOR ARE INTEDED TO BE USED IN CONJUNCTION WITH AN ORGANIZED RESPIRATORY PROTECTION PROGRAM WHICH COMPLIES WITH REQUIREMENTS OF “ PRACTICES FOR RESPIRATORY PROTECTION” ANSIZ88.2 REQUIREMENTS OF OSHA 1910.134, OR OTHER PERTINENT NATIONALLY RECOGNIZED STANDARDS.

Cylinder (Scott Model 2.2, 3.0 & 4.5) 2.2 model has a rated duration of 30 minutes service time with 45 cubic feet of air when the cylinder is charged to 2216 psig. The 3.0 have a rated duration of 30 minutes with 59.1 cubic feet of air when the cylinder is charged to 3000 psig. The 4.5 Air-Pak has a choice of 3 cylinder types: Each type cylinder is available in three sizes for rated duration of 30, 45 and 60 minutes when cylinders are charged to 4500 psig. The 30 minute cylinder contains 45 cubic feet of air: 45 min. contains 66 cubic feet of air; and 60 min contains 87 cubic feet of air. These as well as other respirators are to be used only by persons trained in the proper operation of the respirator and not for any purpose other than those described in your commands Respiratory Protection Program.

NOTE THE DURATION OF THE RESPIRATOR WILL DEPEND ON SUCH FACTORS AS: THE DEGREE OF PHYSICAL ACTIVITY OF THE USER, THE PHYSICAL CONDITIONS OF THE USER, THE DEGREE TO WHICH THE USER’S BREATHING IS AFFECTED BY EXCITEMENT, FEAR OR OTHER EMOTIONAL FACTOR.

Face piece assembly The SCBA full face piece assembly is available in three color coded sizes: (a) Green – Small (b) Black – Large (c) Red - X Large The face seal is constructed of a blend of synthetic rubber. The single lens is a modified configuration, constructed of a polycarbonate material. Hard coated to resist scratching and designed to meet the impact and penetration requirements of a face shield. The head harness is a four point suspension with elastic straps to provide adjustment.

Regulator and Low Pressure Hose Assembly The positive pressure (constant air) breathing regulator supplies and maintains air to the face piece to satisfy the needs of the user. The breathing regulator maintains this positive pressure during flows of up to approximately 500 liters per minute. The breathing regulator outlet port is equipped with a doughnut-shape gasket. This provides the seal against the connecting surface of the face piece. The breathing regulator also contains a integral Vibralert alarm device which can be both heard and felt as a vibration of the face piece. This alarm device activates on both low cylinder pressure and primary first stage regulator failure.

LEAVE THE HAZARDOUS AREA IMMEDIATELY WHEN THE ALARM GOES OFF. WARNING LEAVE THE HAZARDOUS AREA IMMEDIATELY WHEN THE ALARM GOES OFF.

Regulator and Low Pressure Hose Assembly (cont.) A purge valve is arranged to direct the incoming air over the inner surface of the face piece for defogging purposes. A purge valve is situated at the inlet of the breathing regulator and can be adjusted to provide a constant flow of at least 125 liters per minute of air. The breathing regulator is arranged to direct the incoming air over the inner surface of the face piece for defogging purposes.

Back Frame and Harness Assembly Design to carry the cylinder and valve assembly and the pressure reducing regulator assembly on a lightweight adjustable lumbar support style harness. The harness is corrosion resistant, lightweight, and provides for adjustable lumbar support. It also has an adjustable aluminum band, coupled with a ramp adjustable toggle clamp. This clamp secures the cylinder and valve assembly to the harness. All load-carrying portions of the harness are constructed of a Kevlar sheathed polyester material for flame resistance. It includes a flexible waist belt and two shoulder straps. Waist belt has a quick release buckle for easy connection and separation, and two adjusters, one on each side.

Back Frame and Harness Assembly (Cont.) Each shoulder strap connects to the rear section of the waist belt at one end and to the rigid section of the back frame at the other end. It also contains pull up, push-to-release adjusters for quick adjustment and release of the shoulder straps.

NOTE: RESPIRATORS SHALL BE REGULARLY CLEANED AFTER EACH DAY'S USE OR MORE OFTEN IF NECESSARY.

Summary and Review Self Contained Breathing Apparatus. The function of the Personal Alert Safety System Environments Requiring Respiratory Protection Protective breathing apparatus limitations Description of Scott Air-Pak