Cylinders Flashcards
K Factor - O2 HK
3.14
K Factor - O2 E
0.28
Liquid to Gas - O2
1L liquid o2 = 860 L gas o2
Liquid to Weight - O2
1L liquid o2 = 1.136kg or 2.5lbs
Liquid to Gas - N2O
1L liquid n2o = 669L gas n2o
K Factor - heliox HK
2.5
3AA
steel alloy, heat treated, tested every 10 years
3A
carbon steel, non heat treated, tested every 10 years
3AL
aluminum alloy, tested every 5 years
CR-MO
chrome molybdenum cylinder
two types of cylinder valves
- direct acting (over 1500psi)
- diaphragm (under 1500psi; better with leaks)
cylinder safety features
- colour code
- labeling
- safety relief valve
- indexed inlet/outlet
types of labels for cylinders
- barcode (similar to cylinder markings)
- TAG (type, DIN, distributor, precautions, purity, status)
- WHMIS label (green=gas, red=flammable, yellow=oxidizing)
- Hazards (type, warnings, high pressure, precautions)
safety relief valves
- frangible disc (H/K); copper bursts at 150% pressure test
- fusible plug (E/D); metal alloy melts at given temp (150% pressure test)
check for … during cylinder tests
- leaks (bubbles on: weld spots, valve stem assembly, or areas of corrosion)
- internal/external corrosion
- bulging
- evidence of rough usage
- pitting
- exposure to fire
disposal/destruction process
- discharge contents slowly
- cut up steel
- torch off marking
** perforate noxious gases from long distance or bury**
duration equation
Duration = K (P - 500) / flow
define critical pressure
the pressure required to convert a gas to a liquid at its critical temperature
define critical temperature
the temperature above which a gaseous molecule cannot be converted back to a liquid, regardless of the pressure
oxygen information
colour: white or green (usa)
features: odourless, colourless, tasteless
supports combustion
critical temp = -118 celcius
purity = 99%
indications: hypoxia, hypoxemia
medical air information
colour: black and white
features: odourless, colourless, tasteless
supports combustion
purity = 99%
indications: deliver meds, provide humidification, provide second gas source to ventilators
helium information
colour: brown
features: non-flammable, inert gas, least dense
critical temp = -267 Celcius
purity = 95%
indications: PFT, mix with o2
heliox information
colour: brown and white
either 80:20 (x1.8 for flow) or 70:30 (x1.6 for flow)
indications: upper airway obstructions
carbon dioxide information
colour: grey
features: non-flammable, colourless, slight odour & taste
critical temp = 31 celcius
purity = 99%
indications: specimen preservation (MLS) and cardiopulmonary bypass machine (CVP)
carbogen information
carbon dioxide + oxygen = carbogen
either 98/2, 97/3, or 95/5
indications: may eliminate hiccups or encourage tachypnea
nitrous oxide
colour: blue
features: colourless, odourless, tasteless
supports combustion
critical temp = 36.5 celcius
purity = 99%
indications: CNS depressant
nitronox/entonox
nitrous oxide + oxygen = nitronox
indications: pain relief
nitric oxide
colour: teal
features: colourless, metallic odour, nonflammable
supports combustion
purity = min 99%
indications: pulmonary vasodilator; treats infants with hypoxic respiratory failure (INOMAX DSIR PLUS)
forms brown fumes in presence of oxygen; forms nitrous oxide and nitric acids in presence of moisture which are corrosive
carbon monoxide
colour: red
either 0.1%, 0.2%, or 0.3%
indications: combination with other gases for PFT
methods to prepare oxygen
- fractional distillation of liquid air
- cool/compress/warm until 99% pure o2 - physical separation of oxygen (concentrators)
- molecular sieve
- semi permeable membrane (only 40% oxygen)
bulk liquid system pressures
head pressure > 150psi = gas leaves to vaporizer
head pressure < 150psi = liquid leaves to vaporizer
head pressure < 125psi = pressure building circuit converts liquid to gas through second vaporizer
bulk pressure relief vent at 1.5x pressure
bulk liquid system alarms
- indicate when liquid 1/3 volume
- high/low line pressure (40 and 60 psi)
- switch to reserve system
portable liquid system pressures
vents when pressure > 20psi; safety relief opens when pressure > 30psi
when pressure < 20psi liquid is vaporized to fill gas head pressure
flow 5-15 LPM
compressors
rotary vane, piston, diaphragm
must have: cooling coil, means to dry gas, filter
- vacuum compressor only needs condensation trap
hospital: min 26 LPM at 50psi
portable: min 8 LPM at 20psi
concentrators
- molecular sieve
- 87-95% o2 purity up to 10 LPM; must be over 90% to be put in service in Ontario
- alarms: accumulator pressure decrease; power failure; fio2 decrease at output - semi-permeable membrane
- can only produce fio2 = 0.4
