Chapter 7 - Decompression Tables And Computers

Question 1

What are the decompression tables dependent on?

Answer 1

The theoretical tissue compartments

Question 2

What are some of the different decompression tables?

Answer 2

British RNPL table
United States Navy
Canadian diving tables

Question 3

What did Haldane do?

Answer 3

Examined the times for nitrogen in the various tissue compartments to half. He called this the half life

Question 4

What does the buhlmann tables show compared to US navy tables?

Answer 4

Shows saturated tissues in a different colour which returns to normal colour when the off gassing has reduced the nitrogen load sufficiently

Question 5

What does dive time mean?

Answer 5

Times from leaving the surface to returning to 6m or the first stop on the final ascent

Question 6

What does ascent check depth mean?

Answer 6

A pause is made to check that the dive has been conducted according to plan - usually 6m

Question 7

What does depth mean?

Answer 7

The deepest point of the dive - metres

Question 8

What does descent rate mean?

Answer 8

Maximum - 30 mins per meter

Question 9

What does ascent rate mean?

Answer 9

Maximum 15 meters per minute to check depth

Question 10

What does surfacing code mean?

Answer 10

The code just after surfacing from a dive

Question 11

What does current tissue code mean?

Answer 11

Before a second dive, the surface interval is applied to the last dives code to produce the current tissue code

Question 12

What does surface interval mean?

Answer 12

Time from arriving on surface after dive 1 to leaving surface on repetitive dive

Question 13

What does no stop dive mean?

Answer 13

Doesn’t require decompression stops

Question 14

What is a decompression dive?

Answer 14

One that requires a decompression stop

Question 15

What is a decompression stop?

Answer 15

Time spent at a specific depth for a specific duration during the ascent which allows the diver to unload excess nitrogen

Question 16

What are level 1 decompression tables used for?

Answer 16

> 984 mb atmospheric pressures at sea level

Question 17

What are level 2-4 tables used for?

Answer 17

Diving at altitude or reduced atmospheric pressure

Question 18

What is the repetitive dive depth?

Answer 18

A dive made within 6 hours of another dive - the deepest point of the dive in metres

Question 19

What is a pressure group?

Answer 19

A method of defining the amount of nitrogen in the divers system throughout a series of repetitive dives

Question 20

What does RNT mean?

Answer 20

The residual nitrogen time

Question 21

How do you calculate the total bottom time (TBT) when diving with PADI?

Answer 21

Residual nitrogen time + actual bottom time

Question 22

When must a safety stop be completed with PADI?

Answer 22

If the dive was to 30m or deeper
The pressure group st the end of the dive is within 3 pressure groups of the no decompression limit
The dive is up to the limit of the recreational dive planner

Question 23

What is a decompression schedule?

Answer 23

Description of the dive given as max depth/ bottom time

18 m / 20 mins

Question 24

What are the considerations that must be made for different conditions that may occur during diving operations?

Answer 24

Repetitive dives with deco stops
Short surface interval periods
Multi level diving
Diving at altitude
Incorrect ascent procedures followed

Question 25

What should you add to the depths when diving at altitudes of
100-300m
300-2000m
2000-3000m?

Answer 25

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