CHAMBERS & REGS Flashcards
What is the maximum voltage allowed in DDCs?
24V D/C
What is the minimum number of life support personnel permitted per shift?
2
What is the Maximum batter size allowed in the chambers?
500mA/Hr
What is the maximum PPO2 allowed in the chamber?
2.8bar
What is the maximum PPCO2 allowed in the chamber for long exposure?
5000ppm or 5mb
IMCAs maximum recommendation for PPO2 in diving?
1.6Bar
DESIGN for saturation diving (bell) system is what document?
IMCA D024
DESIGN for surface supplied mixed gas diving system is what document?
IMCA D037
‘Code of practice on the initial and periodic examination, testing and certification of diving plant and equipment’ is what document?
IMCA D018
Minimum internal diameter of Saturation chamber is?
1800mm (1.8m)
What are the ideal conditions for Soda Lime?
20C at 70% or more
Damp not Wet
Below what O2 percentage will fire not be able to start?
6%
The O2 percentage should never be allowed to rise above what in a chamber?
23%
How many compartments must an air chamber have?
Two
IMCA D050 states that there must be sufficient compressed air available to….
Pressurise both locks of the deck decompression chamber to maximum possible treatment depth (usually 50msw)
Plus sufficient air for three complete surface decompression cycles
And 90m3 of breathing quality oxygen needs to available for emergency treatment procedures
How many people need to be in chamber when used to deliver therapeutic treatment?
Two
Patient and attendant that knows the symptoms and treatment for acute oxygen poisoning
A chamber hull penetration must have a valve where?
On both sides of the chamber to allow the valve to be closed off in an emergency or for maintenance
Pressurisation connection usually made up of?
Quarter turn valve on the outside and non return valve on the inside (or quarter turn with a silencer on inside)
Exhaust connections are usually made up of?
Quarter turn valves on the inside and outside
Should be a T-piece on inside to prevent suction injuries or small objects being sucked into exhaust line
Depth gauges should be checked and calibrated every?
6 months
In an air chamber BIBS is used to supply what?
Pure Oxygen or a rich O2 mix
Principally used for surface decompression or therapeutic treatments
When not in use the external and internal BIBs and dump valves are normally closed to prevent O2 leakage into chamber (fire risk)
In a saturation system the BIBS is used to supply what?
Pure Oxygen, an O2 rich mix or bottom mix
Principally used as an emergency breathing supply so a suitable bottom mix should be connected at all times
Medical and Equipment locks must have what?
Pressure gauge visible to person operating the lock
A safety interlock system to the clamping mechanism making it impossible to open if there is still pressure inside the lock
How often should viewports be replaced?
Complete renewal within 10 years of fabrication
Environmental Control Units (ECU) for saturation systems circulate the atmosphere to maintain safe, healthy and comfortable levels of?
Oxygen
Carbon Dioxide
Temperature
Humidity
How is carbon dioxide removed from the chamber?
Soda Lime
How are trace gasses and odours removed from chamber atmosphere?
Purafil or activated charcoal
How is Moisture extracted from chamber?
Cooling the gas passing into ECU, which is then reheated to desired temperature for chamber living
Minimum quantities of gas is covered in which document?
IMCA D050
As per IMCA D050, Before commencing saturation diving operations there should be:
- Enough gas to allow 4 hours of BIBS per diver
- Sufficient treatment gas for depths involved
- Sufficient mixed gas to pressurise the system to maximum intended storage depth, plus equal amount as reserve
- Sufficient oxygen to allow for metabolic consumption, any O2 make prior to decompression and required O2 to maintain ppO2 during decompression (doubled for safety)
- Three weeks minimum supply of cal and zero gas
In addition, sufficient mixed gas should always be available at the start of the bell run to carry out full bell run plus the same amount in reserve
How to preventative ear drops work?
The increase the acidity of the ear canal making it inhabitable for the bacteria
Environmental parameters for Oxygen in Heliox saturation chamber
Around 400mb
Environmental parameters for nitrogen in heliox saturation chamber
Less than 1000mb (1atm)
Environmental parameters for humidity in heliox saturation chamber
50-70%
Environmental parameters for temperature in heliox saturation chamber
25-33C (77-92F)
Saturation chamber allowable depth can be within what of the specified depth?
0.3msw (1fsw)
How often should chamber parameters be logged?
Every hour
Oxygen analysers should have what alarms?
High and low
After decompression what should be avoided?
Physical work for at least 12 hours
Very hot showers or saunas
How long must a diver stay close to a chamber after decompression?
Within 20 minutes of a chamber for 4 hours and within 2 hours for the following 8 hours
How long after a decompression can a diver fly?
Flights below 600m (2000ft) are allowed after 12 hours
Flights above 600m after 24hours
What DMAC document gives recommendations for flying after diving?
DMAC 07
Which DMAC covers the Medical equipment to be held at the site of an offshore diving operation?
DMAC 15
Which DMAC outlines the provision of emergency medical care for divers in saturation
DMAC 28
Which IMCA document outlines the ‘use of battery operated equipment in hyperbaric conditions’?
IMCA D 041
If there is a sudden loss of pressure in a saturation chamber the divers may suffer from?
Barotrauma
Decompression illness
Hypoxia
Minimum specifications for DMAC 28:
- Minimum internal diameter of 1.8m but preferable 2.15m
- The ability to remove/move bunks out of the way
- A waist high bunk for a patient
- A tray or working surface for medical instruments
- Suspend IV drips overhead the patient
- Medical lock of at least 300mm diameter
- Good communication system
- Suitable extra lighting for the area of the casualty
- Sufficient additional gas and electrical hull penetrations
At what O2 percentage can you get complete combustion?
16%
How often do the chambers and bells have a MWP leak test?
Every 2 and a half years
Diving plant and equipment test certificates are normally in force for?
2 years
There must be enough room for two adults to lie down in a 2 compartment DDC with over 1.75m internal diameter if continuous occupancy under pressure will be?
12 hours or more
DMAC 07 recommends not flying after an air dive requiring stops for?
12 hours
Depth gauges must be tested to what British standard?
BS 1750
In an O2 analyser a micro fuel cell works by?
Polarography
In the UK all plant and equipment used in a diving operation must be checked?
6 hours prior to a dive
In Norway who is responsible for ensuring that diving regulations are adhered to?
Client
In Norway certificates relating to chambers and pressure vessels must be kept for at least?
10 Years
A diving bell must have a pressure leak test every?
2 years
Under UK legislation who has the final responsibility for all the checks on plant equipment?
Supervisor
How often must gas cylinders on the outside of hyperbaric lifeboats be tested?
2 yearly
In a life support system, how is a sudden loss of gas prevented in the circuit from the chamber to the life support system?
By a flow fuse
The zone of complete combustion is?
16%
The oxygen percentage during decompression should not be allowed to rise above what?
25%
Paramagnetic Oxygen analysers works by?
Reflecting light beams
What is usually the first filter in a. Chamber Regen system?
Soda Lime
What is the maximum permitted level of CO allowed in the chamber?
0.02mb
During the initial stages of saturation decompression the PPO2 does what?
Decreases
(The increase of PPO2 before starting decompression is not counted here)
What is the minimum amount of personnel required to conduct a safe surface supplied mixed gas dive?
6
