Scuba Cylinder Part 1

Question 1

scuba tanks are manufactured from which two materials?

Answer 1

Aluminum or Steel.

Question 2

Dive clubs and resorts use a variety of tank sizes, but what is the most common tank size?

Answer 2

The most common tank size used is the aluminum 80.

Question 3

What are the terms “low”, “standard”, “mid”, and “high” used to describe in regards to dive tanks?

Answer 3

This term describes a dive tanks service pressures.

Question 4

What are the 4 things you should consider when buying your own scuba cylinder?

Answer 4

The 4 things you should consider when buying your own scuba cylinder are.

• that it fits your size,
• your air consumption,
• buoyancy
• your type of diving,

Question 5

Aluminum 80s are most popular rental cylinders. ​ but how buoyant are they when empty? __ Pounds / __ Kilo.

Answer 5

Aluminum 80s like the Luxfer S080, Catalina & Coltri-Sub S80. are roughly 4 Pounds / 1.8 Kilo buoyant when empty.

Question 6

What are your options if the standard aluminum 80’s (26 inches long) is too big for you.

Answer 6

the aluminum 80 can be too long at 26 inches for many divers. But there are options: Luxfer makes an 80-cubic-foot aluminum tank that is fatter than normal (8 inches diameter instead of 7.25 inches) but 3 inches shorter. It’s also a little heavier.

Question 7

What are the most common scuba cylinder pressure ratings?

Answer 7

The most common pressures are “Low” (2400 to 2640 psi), (160 to 180 bar), “Standard” (3000 psi), (200 bar) and “High” (3300 to 3500 psi), (220 to 240 bar).

Question 8

What are the three general scuba cylinder classifications?

Answer 8

The three classifications are Painted, Galvanized, and Uncoated.

Question 9

Remember, there is no _______ tank for all diving conditions and all divers.

Answer 9

Remember, there is no “perfect” tank for all diving conditions and all divers.

Question 10

Volume is defined by the internal dimensions of the scuba cylinder, how is it normally measured?

Answer 10

Internal dimensions of the tank, is normally measured in cubic feet of water.

❝A typical cylinder carrying 80 standard cubic feet of air, is enough to fill a phone booth❞

Question 11

How is Capacity defined?

Answer 11

Capacity is defined by the amount of breathing gas, the scuba tank will hold at its maximum rated service pressure.

Question 12

When would a Steel tank produce corrosion?

Answer 12

Steel tanks produce corrosion in the presence of water, they consist of iron oxide and iron hydroxide?

Question 13

When would an aluminum tank produce corrosion?

Answer 13

Aluminum tanks produce corrosion in the presence of water, usually in the form of aluminum oxide and aluminum hydroxide?

Question 14

What are the most common reasons both steel and aluminum tanks fail inspection?

Answer 14

Internal corrosion and line corrosion around the boot. These are the most common reasons both steel and aluminum tanks fail inspection.

Question 15

Why do steel tanks require fewer materials than aluminum during construction?

Answer 15

Steel is stronger and more ductile (less brittle) than aluminum, so construction of a tank requires less steel than aluminum.

Question 16

A steel tank total weight is less than an aluminum tank. What does a standard aluminum 80-cubic-foot tank weigh __ pounds? Or __ kilos? What does a similar capacity steel tanks weigh in at __ pounds? Or __ kilos.

Answer 16

The standard aluminum 80-cubic-foot tank weighs 35 pounds Or 16 kilos, while similar capacity steel tanks weigh in at 30 pounds. Or 14 kilos.

Question 17

How long is the service life of a properly cared for steel tank?

Answer 17

The service life for steel tank is widely considered to be at least 40 years.

Question 18

How long is the service life of a properly cared for aluminum tank?

Answer 18

The service life of a properly cared for aluminum tank is controversial, some reputable filling stations, won’t fill an aluminum tank manufactured before 1990

Question 19

During the manufacturing process, aluminum tanks are strengthened using what method?

Answer 19

During manufacturing, aluminum tanks are strengthened using a special heating and cooling process.

Question 20

When an aluminum tank is subjected to temperatures above ___ ℉? Or ___ ℃? the walls of the tank will lose their strength?

Answer 20

If subjected to heat beyond 350℉ or 180℃, the walls of the tank can lose their strength and the tank will fail at normal service pressures.

Question 21

Which type of scuba cylinder would an experienced diver prefer the buoyancy characteristics of?

Answer 21

most experienced divers prefer the buoyancy characteristics of a steel tank.

❝ A Steel tank will change from negative at the start of a dive to neutral buoyancy at the end of a dive, this means the diver can start a dive with less weight and still be adequately weighted at the end of the dive.❞

Question 22

Aluminum tanks will change from ________? to ________? buoyancy as the diver breaths the contents.

Answer 22

Aluminum tanks will change from negative to positive buoyancy as the diver breaths the contents down.

Question 23

Steel tanks will change from ________? to _______?buoyancy as the diver breaths the contents down.

Answer 23

Steel tanks will change from negative to neutral buoyancy as the diver breaths the contents down.

Question 24

Which initial purchase price would be the lowest? An aluminum tank or a comparably sized steel tank.

Answer 24

The initial purchase price of aluminum tanks is significantly less than comparably sized steel tanks.