A stationary liquid oxygen system contains 80 lb of oxygen when ...

[FButt]

A stationary liquid oxygen system contains 80 lb of oxygen when full. A home care patient is using it 8 hours each day, during sleep, at a rate of 3 L/min. At this usage, how many days will the liquid oxygen last?
 
  a. 6 c. 19
  b. 8 d. 27

Question 2

Storage of a portable liquid oxygen system adjacent to a heat source will _____ the _____ of the oxygen.
 
  a. Increase; pressure c. Decrease; pressure
  b. Increase; venting d. Decrease; venting

[ebenov]

Answer to Question 1

ANS: C
Use the liquid oxygen duration formula as given previously.
A liter of liquid oxygen weighs 2.5 lb, so: 80 lb/2.5 = 32 L.
Gaseous oxygen occupies a volume that is 860 times the volume of liquid oxygen, so: liters of liquid  860 = liters of gas.
Duration of supply (minutes) = gas supply remaining (in liters)  flow (liters/minute).
Once you get the answer in minutes, you divide by 60 to obtain the number of hours. Then di-vide the number of hours by the usage, which is 8 hr/day; that gives you 19 days.

Answer to Question 2

ANS: B
Liquid oxygen units should not be located adjacent to heat sources, which can accelerate the venting of oxygen.

[FButt]

Thanks for the timely response, appreciate it

[brbarasa]

Great answer, keep it coming