Equipment - Metric Flashcards
Deciphering Cylinder Hieroglyphics
Which of the following cylinder markings designates the type of metal used to construct the scuba cylinder?
a) 3AL
b) 7@89
c) 675432
d) 3000
a) 3AL
Deciphering Cylinder Hieroglyphics
Which of the following cylinder markings designates the hydrostatic test date?
a) 3AL
b) 7@89
c) 675432
d) 3000
b) 7@89
Deciphering Cylinder Hieroglyphics
The (+) designation that appears on _____________ cylinders denotes that the cylinder may be overfilled to ________ beyond its working pressure.
a) steel/15%
b) aluminum/10%
c) steel and aluminum/10%
d) steel/10%
d) steel/10%
Cylinders – Materials
A steel cylinder whose capacity is 2016 litres at 168 bar and an aluminum cylinder whose capacity is 2265 litres at 203 bar are both filled to 133 bar. Which cylinder contains more air?
a) The steel cylinder
b) The aluminum cylinder
c) Both would hold equal amounts.
d) The answer cannot be determined from the information given.
a) The steel cylinder
The steel cylinder contains more air. To answer this question, you need to compare how much capacity each “bar” accounts for. In steel cylinders each “bar” accounts for 12 litres (2016 litres divided by 168 bar = 12 litres per bar). In an aluminum cylinder each “bar” accounts for 11.15 litres (2265 litres divided by 203 bar = 11.15 litres per bar). These constants can now be used to quickly determine how much capacity remains in a cylinder of a certain pressure. In the question, a steel 2016 litre cylinder filled to 133 bar contains 1596 litres (12 litres per bar x 133 bar = 1596 litres). An aluminum 2265 litre cylinder contains only 1482.95 litres (11.15 litres per bar x 133 bar = 1482.95 litres).
Cylinders – Materials
Aluminum cylinders were introduced because aluminum is a stronger metal and enables higher working pressures than in steel cylinders.
True
False
False
Cylinders – Features
What are the advantages of a DIN connector over the standard yoke screw system? (choose all that apply)
a) A better seal between the cylinder and regulator
b) Less expensive
c) Stronger connection
d) Less likely to freeze
a) A better seal between the cylinder and regulator
c) Stronger connection
Cylinders – Features
To prevent a scuba cylinder from rupturing due to overpressurization, a burst disk is installed in the _____________, and is designed to rupture when the cylinder pressure rises above about _____________ of the cylinder’s rated pressure.
a) regulator/200%
b) cylinder neck/225%
c) valve/140%
d) submersible pressure gauge/125%
c) valve/140%
Cylinders - Features
A burst disk only needs to be replaced if it ruptures.
True
False
False
Cylinders - Features
Why does a burst disk vent to the sides rather than straight out?
a) Venting straight out takes longer.
b) Venting to the sides takes longer.
c) To prevent the cylinder from potentially spinning.
d) To prevent condensation in the valve.
c) To prevent the cylinder from potentially spinning.
Scuba Cylinder Care and Maintenance
Why is it important to avoid any process involving heat treatment when having a scuba cylinder painted or refinished?
a) To avoid weakening the cylinder’s metal.
b) Painting a cylinder is unnecessary.
c) To prevent the cylinder from rusting.
d) To avoid contaminating the cylinder’s interior.
a) To avoid weakening the cylinder’s metal.
Scuba Sylinder Care and Maintenance
To ensure the structural integrity of a scuba cylinder, it should be _____________ anytime it is _____________.
a) destroyed/at an age of twenty years
b) hydrostatically tested/exposed to temperatures above 82°C/180°F
c) visually inspected/left unused for more than two years
d) All of the above are correct
b) hydrostatically tested/exposed to temperatures above 82°C/180°F
Scuba Cylinder Care and Maintenance
During a hydrostatic test a scuba cylinder is placed in a water-filled chamber. The cylinder is then filled with compressed air and the amount of expansion that occurs in the cylinder is measured by the amount of water that is displaced.
True
False
False
Scuba Cylinder Care and Maintenance
To what pressure is a scuba cylinder filled during a hydrostatic test?
a) 340 bar
b) 200% of its working pressure
c) 5/3s of its working pressure
d) The exact pressure depends upon what happens to the cylinder once it is pressurized.
c) 5/3s of its working pressure
Scuba Cylinder Care and Maintenance
Under what circumstances should a scuba cylinder be visually inspected?
a) If loose material is heard rolling around inside the cylinder
b) If a red or green accumulation is seen on the filter of the regulator first-stage
c) Once every year even if the cylinder appears in good condition
d) All of the above are correct.
d) All of the above are correct.
Scuba Cylinder Care and Maintenance
During a visual inspection on a scuba cylinder, what it the technician looking for? (choose all that apply)
a) Hydrostatic pressure.
b) Severe exterior damage.
c) Severe interior corrosion.
d) Galvanic action between the cylinder and valve.
b) Severe exterior damage.
c) Severe interior corrosion.
d) Galvanic action between the cylinder and valve.
Regulators
The term “open circuit” refers to the fact that:
a) electricity is used to test the regulator’s air-flow rate.
b) the regulator is made from nonmagnetic metal.
c) the exhaled air is released directly into the water.
d) All of the above are correct.
c) the exhaled air is released directly into the water.
Regulators
The term “demand valve” refers to the fact that the regulator will provide air:
a) during both inhalation and exhalation.
b) only upon inhalation.
c) only upon exhalation.
d) at a constant flow regardless of the inhalation effort.
b) only upon inhalation.
Regulators
What are the primary advantages of the open-circuit, demand valve regulator? (choose all that apply)
a) More efficient gas use versus a free-flow system.
b) Requires no care or maintenance.
c) Helps avoid carbon dioxide buildup by reducing dead air spaces.
d) Simpler to use than closed-circuit systems.
a) More efficient gas use versus a free-flow system.
c) Helps avoid carbon dioxide buildup by reducing dead air spaces.
d) Simpler to use than closed-circuit systems.
Regulators - Features
The function of the first-stage of a scuba regulator is to
a) deliver high-pressure gas to the second stage.
b) supply air on demand.
c) connect all hoses to the cylinder.
d) take high-pressure gas from the cylinder and reduce it to an intermediate pressure.
d) take high-pressure gas from the cylinder and reduce it to an intermediate pressure.
Regulators - Features
The function of the second-stage of a scuba regulator is to take the intermediate pressure gas delivered by the first stage and break it down to ambient pressure for the diver to breathe.
True
False
True
Regulators - Features
A pilot valve refers to a second-stage design that:
a) uses a small valve to assist the opening of the main valve.
b) directs the air flow more directly to the diver.
c) requires the use of an ultra-high pressure cylinder.
d) All of the above are correct.
a) uses a small valve to assist the opening of the main valve.
Regulators - Features
Fail safe refers to a regulator’s tendency to _____________ because of the use of a(n) _____________ valve in the second-stage.
a) breathe easily/open circuit
b) free-flow/downstream
c) breathe easily/closed circuit
d) free-flow/upstream
b) free-flow/downstream
Regulators - Features
The primary advantage of the fail-safe design of regulators is that in the event of a malfunction, air is still delivered to the diver.
True
False
True
Regulators - Features
An environmental seal operates by:
a) not allowing water to directly contact the first-stage piston or diaphragm.
b) not allowing water to directly contact the second-stage piston or diaphragm.
c) increasing the temperature of the first-stage.
d) causing increased turbulence in the air flow of the first-stage.
a) not allowing water to directly contact the first-stage piston or diaphragm.
Regulators - Features
What are the advantages of an environmental seal of the first-stage?
(choose all that apply)
a) Protects the regulator from sun damage.
b) Prevents regulator freeze up.
c) Encourages diving in a conservative manner.
d) Prevents dirt and debris from entering.
b) Prevents regulator freeze up.
d) Prevents dirt and debris from entering.
Regulators - Features
A valve that tends to open in the direction of flow is referred to as _____________ while a valve that tends to close in the direction of flow is referred to as _____________ .
a) open circuit/closed circuit
b) closed circuit/open circuit
c) upstream/downstream
d) downstream/upstream
d) downstream/upstream
Regulators - Features
The primary advantage of balanced first-stages over unbalanced ones is that:
a) they breathe easier at greater depths even at low cylinder pressures.
b) they provide greater air flow.
c) they are better able to supply a second diver breathing from an octopus.
d) All of the above are correct.
d) All of the above are correct.
Dive Computers
Two divers may use a single dive computer provided they are careful to remain together and dive the exact same profile.
True
False
False
Dive Computers
A buddy team exits the water. Both divers are using dive computers. After a short surface interval, they plan another dive to 18 metres. One device allows 38 minutes of bottom time at 18 metres, the other allows only 32 minutes. Based on this information how should they plan their dive?
a) Plan a maximum bottom time of 38 minutes because computers are intentionally designed to be more conservative than dive tables.
b) Plan a maximum bottom time of 32 minutes because computers are intentionally designed to be more conservative than dive tables.
c) Plan a maximum bottom time of 38 minutes but be sure to make a safety stop before surfacing.
d) Plan a bottom time of somewhat less than 32 minutes and make a safety stop before surfacing.
d) Plan a bottom time of somewhat less than 32 minutes and make a safety stop before surfacing.
Instrument Specifics
A capillary depth gauge works by using:
a) a simple system of pressure sensitive gears.
b) a mechanical pressure transducer.
c) Boyle’s Law.
d) Archimedes’ Principle.
c) Boyle’s Law.
Instrument Specifics
While on a dive in a mountain lake at an altitude of 3000 metres, a diver checks his depth. He is using a capillary depth gauge which indicates a depth of 14 metres. If he actually measured the linear distance to the surface from where he is, he would find that
a) he is exactly 14 metres beneath the surface.
b) he is actually more than 14 metres below the surface.
c) he is actually less than 14 metres below the surface.
d) The answer cannot be determined from the data provided.
c) he is actually less than 14 metres below the surface.
Instrument Specifics
The oil-filled bourdon tube analog depth gauge works by ___________________.
a) pressure causing a sealed coil tube to coil tighter
b) pressure causing a diaphragm to flex
c) pressure causing the transducer to vary its electrical transmission
d) pressure pushing water up an air filled tube.
a) pressure causing a sealed coil tube to coil tighter
Instrument Specifics
In terms of equipment considerations, avoiding the maximum limits of the dive tables is wise because:
a) dive tables are imprecise.
b) it’s hard to read dive tables while underwater.
c) depth gauges can malfunction and/or be read inaccurately.
d) you can get nitrogen narcosis more easily.
c) depth gauges can malfunction and/or be read inaccurately.
Instrument Specifics
What special considerations are important in terms of equipment when planning a deep dive?
a) The diver will use air more quickly than at a shallower depth.
b) Breathing will become more difficult than at a shallower depth.
c) The diver may have difficulty controlling his descent/ascent.
d) All of the above are correct.
d) All of the above are correct.
