SCBA 2017 Flashcards
(38 cards)
In terms of exposure to toxic gases, what is the most hazardous stage of firefighting operations?
Overhaul
When should members don their SCBA?
When anticipating entry into an oxygen deficient, toxic, or otherwise hazardous atmosphere
Inspection of SCBA happens when?
Upon assuming duty, and after each use
Toxic atmospheres exceeding what temperature shall not be entered without full PPE and SCBA
120-130.
1 to 2 breaths of moisture-laden air would pose serious health consequences.
80% of fire fatalities are from what?
Inhalation of Toxic gasses.
Name the 7 gases that are listed as the primary cause of fire death due to inhalation.
CO, CO2, Hydrogen sulfide(H2S), Sulfur Dioxide(SO2), Hydrogen Cyanide(HCN, Hydrogen Chloride(HO), Phosgene(COCl2).
SCBA shall be placed in service at what concentration of CO?
35ppm
Also, the Has-Mat assignment should be requested.
At what concentration will CO cause unconsciousness after a 30 minute exposure?
3200ppm or .32%
At what concentration will CO cause immediate unconsciousness and death within 1-3 minutes?
12,800ppm or 1.28%
Hydrogen sulfide
Colorless gas with the odor of rotten eggs. Heavier than air, very poisonous, corrosive, flammable, and explosive. Caused by the incomplete combustion of material from living things- wool, rubber, and hair.
Exposure causes rapid breathing, followed by complete respiratory collapse.
Sulfur Dioxide
Caused by the complete oxidation of sulfur containing materials. Has an extremely irritating effect on the eyes and respiratory tract. The quantities produced by combustion are too low to be considered toxic.
Carbon Dioxide
Normal atmospheric concentration around 300ppm(.03%). 5000ppm will cause increased respiration, dizziness, excitement, and sweating. 100,000-200,00 (10-20%) may cause death within a few minutes due to paralysis of respiratory center of the brain.
Hydrogen Cyanide
Highly toxic colorless gas produced by the incomplete combustion of nitrogen containing materials (wool, nylon, polyurethane foam, rubber, paper). Bitter almond odor. Kills suddenly by interfering with the oxygen exchange at the cellular level.
Hydrogen Chloride
Colorless gas produce by the combustion of materials containing chlorine (PVC’s). Swelling of the upper respiratory tract, acting as an irritant to the heart and causes irregular heart rhythms.
Phosgene
Colorless gas produced when refrigerants come in contact with flame. Musty Hay odor.
Phosgene and Hydrogen Chloride have this in common.
They decompose/form Hydrochloric acid when they contact water or moisture. Causing burning and blistering to the mucous membranes of the nose, the linings of the lungs, and the tissue of the mouth and throat.
CO binds to the hemoglobin at what rate?
210 times more readily then O2. Forming Carboxyhemoglobin.
Name the major components of the Scott Air-Pak Fifty SCBA.
- Cylinder and Cylinder valve
- Harness and backframe, Dual EBSS(emergency breathing support system) with 3’ of hose, drag rescue loop(DRL) assembly, and RIC/UAC
- Pressure reducer assembly
- Breathing regulator: vibralert, purge, air saver switch, HUD
- Pak-Alert SE distress alarm: sensor module with pak-tracker locator/transmitter, and control console with remote pressure gauge
- Facepice
How is the air cylinder constructed?
An Aluminum shell over-wrapped with carbon fiber.
How often should a composite air cylinder be hydrostatically tested per DOT recommendations?
Every 5 years.
According to Scott, what is the weight of a charged, carbon wrapped SCBA cylinder?
17.1 pounds
A 60-minute SCBA cylinder contains how much air?
87 cubic feet when charged to 4500psi.
The pressure reducer is located where? Contains what?
On the left side of the packframe. Consisting of redundant dual path reducing systems (primary and secondary circuits), an automatic transfer valve, and over pressure relief.
The primary circuit reduces supply pressure to 100 PSI and sends it to the MMR.
What happens when the cylinder falls between 1200-1000 psi or when the primary circuit fails closed?
A transfer valve opens allowing the secondary circuit to function. Thus sending air at a pressure of 150psi to the MMR. The addition 50psi activates the Vibralert.
