L safety Flashcards
What is the procedure for electric shock?
1) LVA
2) Isolate supply if possible
3) If 2 is unavailable then use a safety hook to move the causality
4) Check for response
5) Check Airways are open
6) Check the causality is breathing
7) Call for help (HQ1)
8) Start CPR
Define Electric shock
Electric shock is where an external current is passed through the body
3 causes of electric shock
Equipment Failure (non-direct contact) Human Error (direct contact) Combination
Another way of describing equipment failure
Non direct contact
What cause of accident is direct contact?
Human error
At what value of current would you have an INVOLENTARY REACTION
1mA
What are the causes of human error?
Over familiarity Failure to inspect equipment Shoddy work Working in damp conditions Failure to observe relevant safety
Give an example of equipment failure?
Casing of equipment becoming live
Give an example of a combination cause of electric shock
Failure to repair damaged leads
Using untested equipment
What would a 10mA electric shock do?
Cause you to be unable to release the grip on the supply
What value of current would cause physical damage?
20mA
What value of current would have the potential to kill
30mA
What “safe” voltages do the RN use?
24VDC
What is the resistance of the human body
1000 Ohms (although this can be reduced due to dampness)
What procedure would be followed in the event of an electric shock?
1) LVA
2) Isolate supply either by switching fuses or breakers
3) If 2 is not possible use a safety hook/insulative PPE to move the causality away from the source of the current
4) Check for response
5) Check their airways are open
6) Check that the causality is breathing
7) Call for help (Notify the HQ1)
8) Start CPR
How often is the earthing of cased electrical equipment checked?
Every 3 months
What hazards are associated with Tantalum Capacitors?
What mitigating actions should be taken when working on them?
1) They contain sulphuric acid and are liable to explode
2) You should wear a face covering
What hazards are associated with Selenium Rectifiers?
They contain selenium dust which is toxic.
Care should be taken to prevent its inhalation or ingestion
What is Lotoxane?
Lotoxane is the only cleaning agent used on RN ships for electrical equipment
What hazards are associated with lotoxane and what mitigating precautions should be taken when using?
It has a low flash point.
It should not be sprayed on live equipment or hot surfaces
The user should wear gloves
It should be used in well ventilated areas
What PPE should be worn when working in the galley?
DMS Boots
Coveralls or No. 4’s with sleeves rolled down
Chefs Hat
When would you work on LIVE electrical equipment?
NEVER ON HV.
Only when there is no alternative
What is required when working on live electrical equipment?
Must be approved by the MEO
Must be supervised by an ME senior rate
Appropriate measure taken to prevent shock (PPE, Standing on a thick rubber mat, having a safety number
What precautions can be taken when working on LIVE electrical equipment?
Stand on rubber mating Wear rubber gloves Wear insulating boot covers Use insulated tools Avoid leaning on bulkheads Be aware of the voltages present Take care not to cause short circuits with tools Don't take unnecessary risks Don't rely on interlocks or other safety devices
What is the procedure for working on DEAD electrical equipment?
1) Isolate the equipment and carry out LOTO
2) Prove the circuit is dead by using GPTME (test between phases and between phase and earth, looking for a 0V reading)
3) Discharge any capacitors using GPTME set to voltage shorting across the terminals until V reads 0
4) Fit the required shorting straps to prevent the capacitors recharging
What are the 4 parts (Paper work) of LOTO?
LOTO Index sheet
LOTO safety certificate
Red LOTO label
LOTO display board
Where does part B of a LOTO label go?
On the LOTO display board
What would you need to find from the LOTO index sheet
The next sequential LOTO serial number
What are the 8 stages for the APPLICATION of LOTO?
1) Obtain permission
2) Identify all isolation points
3) Inform the user
4) Fill out the LOTO index sheet (LOTO log sec. 3) and collect the safety certificate serial number
5) Complete the relevant sections of the LOTO safety certificate
6) Complete LOTO log parts A, B and C
7) Ensuring the circuit is switched off, the isolation switches/breakers are open. Remove the fuses. Replace the empty fuse holder with “part A” attached
8) Place part B in the LOTO Board and Part C on the fuses in the fuse board
What is the correct procedure for REMOVING a fuse?
Ensure the load is removed
With a finger in the centre of the fuse casing. Use a fuse key to slacken the screws and then fully loosen the screws
Looking away (in case of arch flash), smartly remove the fuse
Remove the fuse from the fuse housing
Replace the fuse housing to maintain a dead front and attach part A of the LOTO label to the front
What is the correct procedure for REPLACING a fuse?
Remove one empty fuse holder from the fuse way
Using a piece of GPTME (set to V) across the empty fuse way check for dead (0V) - If voltage indicated do not replace the fuse
Using a correctly rated fuse, replace the fuse into the empty casing
Averting eye locate the fuse carrier smartly onto the bus bars
Whilst holding the carrier in place tighten with a fuse using a fuse key
What is HV?
High Voltage
1000V AC
1500V DC
What are the 3 specific terms used to describe the ships state in terms of HV?
HV Live
HV Dead
HV Safe
What does a ship being HV Live mean?
Its capable of generating HV
Its generating HV
Its connected to a HV Shore supply
What does a ship being HV dead mean?
The ship cannot generate, distribute or receive HV
All sources of HV are disconnected and isolated
The circuit main earth is applied
What does a HV safe mean?
This refers to an area not the entire platform
The area is safe to enter
The HV power source is disconnected
The HV decay period has been elapsed
Who is a competent person in regards to HV?
A person who has sufficient technical knowledge or experience to enable the person to avoid danger from electrical hazards.
What documentation would be needed to control HV?
Permit to work (PTW)
Sanction for test (SFT)
Limitation of Access (LOA)
Switching Schedule (SS)
What does arch flash cause?
- Heat up to 20,000oC
- Plasma Discharge
- Very intense, blinding light
- Pressure wave - Vaporized copper expands 67,000 times
- Shrapnel - molten copper, insulation, pieces of switchboard
- Sound 140-165 db. (permanent hearing damage)
- Smoke
Where can arch flash occur?
At a breaker or at the fuse
What is the procedure for REMOVING LOTO?
1) Obtain permission to remove
2) Sign the LOTO certificate for the remove of LOTO request
3) Collect the right fuses and part B And C of the the LOTO label
4) Ensure the circuit isolation switches are open
5) Remove Part A and empty fuse holder, test across the fuse way for 0V, if dead replace fuse
6) Return all 3 parts of the LOTO labels to approving senior rate
7) Sign the LOTO safety certificate for LOTO removal and closure
8) Close LOTO index sheet entry (date and sign)
9) Destroy all LOTO labels, Transfer LOTO safety certificate to sec. 6 of Log
What are the 6 main causes of accidents?
Over familiarisation Lack of skill or ignorance Laziness or fatigue Preoccupation Physical Hazards Horseplay
When would additional testing for DEAD be done?
1) When there has been a break from work
2) When handing over to other personal
3) If inspections are required.
