ENCLOSED SPACED ENTRY CHECKLIST ON CHEMICAL TANKERS - CAPT AJIT VADAKAYIL

Capt. Ajit VadakayilJune 10, 2016 at 10:06 PM

http://timesofindia.indiatimes.com/india/INS-Vikramaditya-aircraft-carrier-accident-2-killed/articleshow/52693139.cms

INDIAN NAVY OFFICERS ARE POORLY TRAINED AND MOST TOP OFFICERS LACK CHARACTER-

FIRST STEP IS TO CHANGE THE COLOUR OF THEIR UNIFORM FROM WHITE TO KHAKHI

abcindiagogoJune 11, 2016 at 12:09 PM

Captain,

Why Khaki colour uniforms for the Navy Men ?

Is there an explanation for that ?

Or is it because white is impractical for their duty ?

1. Capt. Ajit VadakayilJune 11, 2016 at 12:16 PM

   hi a,
   
   THESE NAVAL OFFICERS ARE AFRAID TO GET A SPOT ON THEIR WHITE UNIFORM.
   
   THEY STRUT AROUND LIKE PEACOCKS -- ALL POMP AND SHOW -- THIS IS WHY NAVAL SHIPS HAVE TOO MANY DEATHS AND INJURIES
   
   PREVIOUSLY THEY USED TO HIDE IT -- NOW MEDIA REVEALS EVERYTHING
   
   capt ajit vadakayil
   ..

nobeatingroundthebushJune 11, 2016 at 1:11 PM

Every weekend in the Mumbai naval harbour u can see a fleet of naval ships sailing off with families of naval personnel for a picnic. This occurs every weekend. A few years back there was also an accident where two naval ships collided while returning back.

The army guys are constantly in war either in kashmir or north east.
The airforce is sometime or the other involved in rescue missions.

But these naval guys have been enjoying peace time since 1971 at our expense.....They have become Chalta hai....

They are not even patrolling our coasts properly....and of course no intelligence gathering....Otherwise who would Rascals like Kasab and his friends enter through the mumbai coast?

There is a lot of smuggling and pilfering of cargo and diesel etc going on off Mumbai and the konkan coast. These guys collect hafta!!!!

Capt. Ajit VadakayilJune 11, 2016 at 1:45 PM

hi n,

ALMOST ALL INDIAN NAVY OFFICERS BECOME SEA SICK AND PUKE THEIR GUTS OUT EVEN IN SLIGHT ROUGH WEATHER. 
I KNOW BECAUSE AT SEA ALMOST ALL OUR ELECTRICAL OFFICERS ( USLESS -PATHETIC IN WORK ) ARE FROM THE INDIAN NAVY--AT LEAST 70 OF THEM HAVE SAILED WITH ME .

AS A JUNIOR OFFICE IN SCI, I HAVE SAILED WITH SEVERAL COMMODORES, CAPTAINS, COMMANDERS AND LT COMMANDERS -- ALL MEN OF POOR CHARACTER AND COWARDS.

AS A YOUNG MAN I USED TO WONDER HOW OUR NATION IS BEING PROTECTED BY THESE MEN OF STRAW. 

AND MIND YOU THEY MADE MAX NOISE FOR OROP.    THE NAVAL OFFICERS WEAR WHITE UNIFORM AND STRUT AROUND LIKE PEACOCKS --AND SALUTE MAANGHTA HAI BHAIYYA .

WANT AN EXAMPLE OF INDIAN NAVY COMPETENCE?

check out my comment in the post below-- this is the PITS

http://defenseblog-njs.blogspot.in/2012/09/ins-vikramaditya-trial-malfunctions-to.html

TODAY MARINE ENGINEERS ALL AROUND THE PLANET PASS THEIR EXAMS USING MY SELF EXAMINER--THE QUESTIONS COME FROM THE POSTS BELOW

http://ajitvadakayil.blogspot.in/2011/11/marine-engineering-self-examiner.html

http://ajitvadakayil.blogspot.in/2011/10/marine-engineering-self-examiner-water.html

I AM NOT AN ENGINEER- JUST A DECK BOY

capt ajit vadakayil
..

Bhaskar SharmaJune 12, 2016 at 2:44 AM

Sir
The same Indian navy bombarded Pakistan port during indo pak war .I think sweeping comment because of few selective experiences is not expected from a person of your stature

Capt. Ajit VadakayilJune 12, 2016 at 2:47 AM

I KNOW PEOPLE WHO WERE PRESENT ON ON THE NAVIGATING BRIDGE OF THOSE NAVAL SHIPS.

INTERVIEWED DOZENS OF THEM . .

THERE WAS NO RESISTANCE FROM PAKISTAN 

WHOEVER PRESSED THE BUTTON , GOT PROMOTIONS AND MEDALS

I KNOW THE INSIDE STORY OF INDIAN NAVY

AT SEA, I DISCARDED THE OFFICIAL COMPANY SAFETY CHECKLIST AND USED MY OWN.

THEY THREATENED TO SACK ME –  SAYING SAFETY FORMS COME UNDER “SAFETY MANAGEMENT SYSTEM”

I REPLIED –  “ TRY SACKING ME – I AM DOING SO FOR SAFETY OF LIFE AND SHIP . I HAVE THE POWERS TO DO IT “

ENTERING ENCLOSED SPACES

Lack of oxygen should be suspected in all enclosed spaces.

Entry into an enclosed space or cargo tank with a known unsafe atmosphere with SCBA sets can be made only by the master after a risk assessement. 

This can be done only under exceptional circumstances, when no practicable and safe alternative exists. A written statement must be prepared by master declaring that there is no practical alternative to the proposed method of entry, and that such entry is essential to the SAFE operation fo the ship. 

The SCBA sets must be operated in the positive pressure mode, and ventilation must be provided where possible. Spare sets of SCBA must be available for rescue of the SCBA wearers.

When crew enters tanks to do squeegee of veg oil ,  continuous ventilation must be provided and atmosphereic checks of tank made as per ships SMS.

A space is SAFE FOR MEN when:

--the oxygen content of the atmosphere is not less than 20%,

--the concentration of flammable gas is less than 1% LFL,

--any toxic materials in the atmosphere associated with cargo, fuel, tank coatings or inert gas do not exceed permissible concentrations  any residues will not produce toxic vapours under prevailing conditions.

Tanks, holds, void spaces, double bottoms, duct-keels, pump rooms, cofferdams, chain lockers, CO2 rooms, sewage tanks, pressure vessels, battery lockers, inter barrier spaces, IG scrubbers, bow thruster room etc.

Entering any confined space is hazardous and can result in rapid death from harmful gases and or lack of oxygen. 

NEVER ASSUME A TANK OR ENCLOSED SPACE IS SAFE.  

It is the Master's responsibility to identify hazardous spaces and to establish procedures for safe entry.

Any tank, cargo hold or space which has contained a liquid or which has been sealed must be assumed to have a dangerous atmosphere and consequently be unsafe for entry without the protection of breathing apparatus. 

Unprotected entry should not be attempted until a competent person has made an assessment and taken the appropriate measures to ensure the space is safe for man-entry.

Any open tank which has NOT been "gas freed" should be secured against entry and a NO ENTRY notice hung on the hatch opening.

The Master or Chief Mate MUST ensure that it is safe to enter an enclosed space by:

1 Identifying potential hazards

2 Ensuring the space is prepared for entry and has been thoroughly ventilated by natural or mechanical means.

3 Testing the atmosphere of the space at different levels for oxygen deficiency and harmful vapour (where suitable instruments are available).

4 Ensure procedures are instituted before and after entry. If any doubt as to adequacy of ventilation or testing ensure breathing apparatus is worn by all persons entering the space

If, as possible on a cargo vessel, there is no suitable equipment to test the atmosphere within a tank/hold, it is absolutely essential that the respective tank/hold is adequately ventilated prior to entry and continuously thereafter.

The MSDS sheets should be consulted for further guidance when planning entry to holds or tanks containing cargo or residues of cargo.

In all cases and prior to entry, the enclosed space check list must be completed (see below). 

Whenever entry is first made into a recently opened tank/hold, there should be a qualified man positioned on deck tending the required lifeline and monitoring the situation.

SAFETY CHECK LIST

before entry into the enclosed space the appropriate safety checks listed below must be carried out by the Master or the Chief Mate AND by the person who is to enter.

XXXXX   XXXX

CHEMICAL TANKER ENCLOSED SPACE ENTRY PERMIT                                 

Ship:                                                           Date:                             Time:    

                                                      

Identity of Enclosed Space:

Reason For Entry:

Names of persons who will enter:

Validity of permit:                                          From:

 (cannot exceed 12 hrs )                                 To:

XX XX XX

CHEMICAL TANKER ENCLOSED SPACE ENTRY PERMIT

Ship:                                                      Date:                             Time:                                                            Identity of Enclosed Space: Reason For Entry: Names of persons who will enter: Validity of permit:                                          From:  (cannot exceed 12 hrs )                                 To:

	Question	Yes	No
1 .	Has space been isolated by  removing vapour return spools  or closing valves ?
2.	Are valves in (1) secured against accidental opening and a tag displayed ?
3.	Has the space been washed, cleaned ?
4.	Has the  space being ventilated ?
5.	Are you and the entry team familiar with the enclosed space arrangement?
6.	Have you and entry team read the MSDS  of chemicals the space last contained?
7.	Have you planned the work to be done in a safe and quick manner?
8.	Have you stopped ventilation for 10 minutes prior taking atmosphere readings?
9.	Has atmosphere in space been tested at different levels? Readings:   Oxygen              20.8%             Flammable Gas:        0                  Toxic Gas (1)            0      (specify gas , reading and TLV)                                     (2)
10.	Have you resumed ventilation after testing the atmosphere?
11.	Will the ventilation continue during work breaks?
12.	If there is any liquid inside the space, will it be sampled before starting work ?
13.	Is adequate illumination provided , with intrinsically safe lamps?
14.	Has a safe area been designated to monitor people inside the enclosed space ?
15.	Will frequent atmospheric checks be made while the space is occupied ?
16.	Are rescue harness , lines,  BA sets, oxy resuscitators and a fully charged intrinsically safe safety torch , ready for immediate use, at the tank entrance ?
17.	Has OOW (Bridge, E/R, CCR) been advised ?
18.	Has a communication system been established between work/ monitoring party who will be in constant attendance at the entrance?
19.	Are constant gas monitors ready for deployment ?
20.	Arrangements made for periodic atmosphere testing ?
21.	Are all portable equipment items intrinsically safe and of the approved type
22.	In the event of a breakdown of ventilation will you leave the space immediately ?
23.	Are you thoroughly familiar with BA set you are using ? (if to be used)
24.	Have you done the HP and LP checks for the SCBA sets?
25.	Are emergency and evacuation procedures established and understood?
26.	Have all persons involved attended an enclosed spaces rescue drill before, and trained in relevant emergency operations  ?
27.	Has the space been tagged as safe to enter?
28.	Has the reporting intervals on walkie talkie been agreed?
29.	If unable to report at the agreed interval will the entry party evacuate?

     

Master OR Responsible officer (name, signature, date , time):---------------

Responsible entry team supervisor ( name, signature, date, time ):---------------

Note: Separate permit must be made for each space.

1.This permit is rendered invalid should ventilation of space get interrupted or any condition noted in the check list change.

2.One copy of this form is to be posted at the entrance of the space to inform crew of the precaution being taken and of any restrictions placed upon the activities permitted within the space.  The other copy must be retained in the ships file.

A Permit Authoriser must temporary suspend a permit when the workscope or operation covered by the Permit has been or changed.

Where instructions have been given that a responsible person be at the entrance to the space, the persons entering the space should show him their completed card before entering.

The monitoring party at the entrance must record the names and times of entry on the permit posted at the entrance.

Those entering an enclosed space should always wear appropriate protective equipment and avoid loose fitting clothing which might snag on obstructions

If an empty or other confined space has been closed for some time the oxygen content may have been reduced by the rusting process. Lack of oxygen may occur in tanks. After discharge of volatile cargoes, sufficient vapours may remain in tanks to cause oxygen deficiency.

If Nitrogen or steam has been discharged into a space the oxygen content of that space will be depleted.

There is always a possibility of dangerous vapour from desorbing tank coating. Epoxy acts like a sponge for solvents.

Some putrifying cargoes emit Hydrogen Sulphide (H2S). Master shall take appropriate measures to protect crew against toxic H2S fumes .

The disturbance of  sludge residues of cargoes of animal, vegetable or mineral origin or of water that could be covering such substances may lead to the release of toxic or flammable gases.

When opening the entrance to a dangerous space care should be taken to avoid the effects of a possible release of pressure or vapour from the space.

The space should be isolated and secured against the ingress of dangerous substances by blanking off pipe lines or other openings or by closing valves. Valves should then be tied or other means used to prevent accidental operation.

The space should be thoroughly ventilated by either natural or mechanical means to ensure all harmful gases are removed. Compressed oxygen should never be used to ventilate a space.

The bridge, cargo control room and engine room duty officers should be kept informed and warning signs posted to warn against accidental use of equipment, valves or stopping ventilation etc. Where necessary, pumping operations should be suspended when entry is being made into a dangerous space.

All personnel must be well trained in the use of breathing apparatus and be aware of the dangers of removing their breathing apparatus while in the hostile atmosphere.

The number of persons entering the tank is kept to a minimum consistent with the work to be performed. 

Means of communication are provided and a system of signals is agreed and understood by the personnel involved. 

Spare sets of breathing apparatus (and resuscitators if available) are ready outside the compartment, and a standby party is in attendance in case of emergency.

Testing of a space should ONLY be carried out by persons trained in the use of the equipment.

Testing should be carried out from deck level. However on occasions, additional testing maybe required from within the tank/hold in which case the tester must use breathing apparatus and be secured with a life line tended by a qualified man positioned on deck. 

Communications should be maintained via portable walkie-talkies.

Where appropriate, testing should be carried out at different levels.

Personal monitoring equipment designed purely to provide a warning against oxygen deficiency and hydro carbon concentrations should not be used as a means of determining whether a space is safe.

Atmospheres contaminated with inert gas can contain toxic by-products (CO, SO2, nitric oxide and nitrogen dioxide) introduced during inerting. It is difficult to measure these gases without specialised equipment and trained personnel. To compensate the period of gas freeing should be considerably extended.

In all cases rescue and available resuscitation equipment should be positioned ready for use at the entrance to the space. 

Rescue equipment means breathing apparatus together with fully charged spare cylinders of air, life lines and rescue harnesses and torches approved for use in a flammable atmosphere, if appropriate.

 A means of hoisting incapacitated person from the confined space should also be readily available when appropriate.

The number of persons entering a space should be limited to those who actually need to work in the space and could be rescued should an emergency occur.

At least one attendant should be detailed to remain at the entrance to the space whilst it is occupied.

Ensure lifelines are long enough and be easily detachable should it become entangled.

Should an emergency occur, the Emergency Alarm should be sounded to summon the rescue team.

Where there is a possibility of hazard from contact with dangerous chemicals, protective clothing should be worn.

Regular drills simulating rescue of an incapacitated person from a dangerous space should be conducted to prove the rescue plan and familiarise personnel. 

The space selected should be made safe for the excercise. A drill should be held soon after signing new crew members. 

Each drill should be recorded in the log book. 

A heavy mannenquin or dummy must be used .

If an observer should notice or suspect that the person or persons in a space/tank/hold etc are experiencing difficulties or have become incapacitated, under no circumstances should rescue be attempted until a proper rescue party equipped with breathing apparatus has been assembled. If necessary, the observer should sound the Emergency Alarm to encourage rapid response.

ON NO ACCOUNT SHOULD THE PERSON STATIONED AT THE ENTRANCE TO THE SPACE ATTEMPT TO ENTER BEFORE ADDITIONAL HELP HAS ARRIVED. 

NO ONE SHOULD ATTEMPT A RESCUE WITHOUT WEARING BREATHING APPARATUS, RESCUE HARNESS AND A LIFELINE.

The following equipment MUST be kept as standard and in good order:--

Two portable oxygen analysers complete with spare sensors.

Two hydrocarbon gas analysers with supply of span gas for calibration.

Two Drager pumps.

All instruments must have extension leads and must be calibrated on board at monthly intervals and externally annually, or in line with manufacturers instructions. Dual (02/gas) type analysers are permissible. A service due "sticker" should be affixed to each analyser giving due date of next service  

 Displacement of oxygen can be by: 

Hydrogen in cathodically protected ballast tanks. 

Vapour generation (volatile substances).  

Use of oxygen absorbing chemicals to prevent rusting. 

Oxygen absorption by product carried in space.

NEVER RELY ON THE SENSE OF SMELL TO DETECT TOXIC GASES.   ALWAYS USE PROPER GAS MONITORING EQUIPMENT.

Tank signs are to be used as follows:

Fit for Entry – Green circle with “Tank Safe” on both sides.

Inerted Tanks – Yellow Triangle with “Nitrogen – do not enter on both sides.

Man in Tank-  Red Triangle with mans name written on it in waterproof pen. 

Crew members entering a tank for cleaning or maintenance are to leave their  personal tags at the tank entrance to indicate the number of persons in the tank.

Tanks that are inerted with Nitrogen are to flagged with the appropriate sign and are  not to be opened without the express permission of the Chief Officer or Nitrogen which is lighter than air will escape.

Tools should not be carried into enclosed spaces, but should be lowered in a plastic bucket or bag, to avoid the possibility of being dropped .

Unless a enclosed space has been cleared by a Hotwork permit as per SMS, the lights used inside must be intrinsically safe. 

When overhauling Framo pumps or opening up steam coils or valves inside tanks, it is recommended that personal monitors are used.

ENCLOSED SPACES, excluding the pumproom, include:--

 Cargo and slop tanks, Ballast, both double-hull and peak tanks, bunker, both heavy fuel, diesel and sludge/bilge tanks, fresh water tanks, lube oil tanks, void spaces, cofferdams, duct keels and trunkings, pipelines and fittings on cargo systems, inert gas lines and fittings, including scrubber towers and water seals, boilers and exhaust gas economisers, both on water and fire sides, sewage tanks, main engine crankcase, scavange spaces and exhaust trunkings, other items of equipment and machinery of which the internals are not routinely ventilated or entered. 

PUMPROOMS are enclosed spaces, which have fixed ventilation systems and a fixed gas detection systems, which give more control and monitoring of the internal atmosphere.

http://ajitvadakayil.blogspot.in/2014/05/hot-work-permit-on-chemical-tankers.html

  

     MEDICAL EMERGENCIES

No.	Action	Tick
1	Master informed
2	Name and rank of sick/injured crew-member
3	Nature of illness or cause of injury
4	Read MSDS sheets of cargo carried, Ems, MFAG if illness due to vapour exposure
5	Contact shore stations or ships with doctor on board for assistance using URGENCY GMDSS alert
6	Check for allergy
7	Date of last administration of medicine/ antidote and type
8	Specific assistance required
9	Prepare deviation statement if necessary
10	Inform the Company
11	If injury due to defective equipment keep part on board for inspection
12	Witnesses statements
13	Proper Illness / injury form to be completed
14	Prepare account of wages
15	Prepare personal effect inventory with witness
16	Enter facts in medical log and deck log book

Note:

Master must not hesitate to seek radio medical assistance for chemical poisoning and injury cases. If proper treatment is given in good time recovery will be faster.

Never give Morphine to a person who has been gassed  especially by irritant gases.. For all poisoning you can give a glass of milk. Milk should NOT be given for degreasing solvents and Chlorinated Hydrocarbon poisoning.

Carbon Monoxide poisoning makes the lips bright red and the face pink. Toxic and noxious gases have distinctive odours except Carbon Monoxide. CO causes chemical asphyxiation by restricting O2 in blood. TLV/ 25ppm

Pulmonary odema:  Fluid collects in lungs and you have difficulty in breathing or lying flat. Caused by inhalation of certain gases or by vomited matter going into lungs. It can be delayed by as much as 2 days.  Use a Guedel airway which can vacuum out froth from the airway. If the patient is conscious he must be kept in a sitting up position and if unconscious kept in the three prone position. The medicine used is Furosemide.

Anaphylaxis is allergy and swelling of tissue which can be fatal.

TDI and Nitriles enters blood and paralyses the nervous system and causes death. -

H2S gas has odour threshold Metallic taste in mouth, head ache , vomiting , diarrhoea, paralysis , difficult breathing

CAPT AJIT VADAKAYIL

     VENTILATION

Tank cleaning and gas freeing are the most hazardous aspects of chemical tanker operations. The risk is greater if the vapours are toxic.

First the tank has to be washed clean of residues.

The tank domes and butterworth covers should be kept closed until the ventilation of the  tank is about to commence.

Portable fans or blowers should be so constructed that no hazard of incendiary sparking arises if, for example, the impeller touches the inside of the casing. Dasic “Jet-Fan” impellers are specially coated to prevent static between impeller/casing. The capacity and penetration of portable fans should be such that the entire atmosphere of the tank can be made gas free quickly.

Venting of toxic and flammable gas during gas freeing should be through the vessel's approved gas freeing outlets.  No escape of cargo vapours should be allowed in the proximity of accommodation spaces and the velocity of venting should be sufficient to carry the vapours clear of the deck.

If the ship does not have fixed blower/de-humidifier, then portable fan must be used on a tank cleaning hatch venting through VCS pipework and p/v valve.  If  gas freeing is done through cargo pipelines , then the entire line system should be thoroughly drained before venting.

When the gas level within the tank has fallen below 30% LFL and below the relevant TLV, other deck openings of the tank in question may be opened and THEN ONLY discharge of the vapour mixture may continue at tank level.

Intakes of central air conditioning or mechanical ventilating systems should be adjusted to prevent vacuum inside the accommodation.

Ventilation outlets should generally be as remote as possible from the portable fans.

Portable fans should make an effective electrical bond to the deck.

Fixed gas freeing equipment may be used to gas free more than one tank simultaneously but must not be used for this purpose if the system is being used to ventilate another tank in which washing is in progress.

When a tank appears to have been completely gas freed, a period of about 30 minutes should elapse before taking final gas measurements .  This allows relatively stable conditions to develop within the tank space.  Tests should be made at several levels with the fan OFF at levels depending on the VD.

Gas vent riser drains should be cleared of water, rust and sediment.

After ventilation is completed, testing of the atmosphere should be carried out to determine its flammability, as a percentage of LFL, and its toxicity relative to the TLV.  Samples should be drawn from the inside of the ventilation pipe at its exit point.

Before venting ventable cargoes reduce trim and list to increase the surface area

Air contains a certain amount of moisture (vapor of water) depending on its temperature and surroundings. If the air contains the maximum amount of moisture allowed at the

temperature, the relative humidity is 100%. If the air contains no moisture, the relative

humidity is 0%.

Higher the temperature, more the air can contain moisture, which means if air containing a certain amount of moisture is cooled down, the relative humidity will increase. 

If air contacts a cold surface and gets cooled down below the temperature of 100% of relative humidity (so called "Dew Point") the amount of moisture contained in the air in excess of 100% relative humidity will condensed and become dew (sweat).

This is the reason why dew is generated on a cold surface within a cargo tank containing air of higher relative humidity. The cold surface can be a bulkhead between adjacent cargo tanks containing cold temperature of cargo, a shell plate of which the other side is immersed in the sea, etc.,

MEASURES IN CASE OF OCCURRENCE OF SWEAT

The sweat in an empty cargo tank can be generated when a cargo of lower temperature than atmospheric temperature is loaded in an adjacent tank, or a cargo loaded at a cold area is carried to a warm tropical area.

In the latter case, if the destination is far from loading port and will take long time more than 4 days, the problem of sweat in surrounding cargo tank will not happen because the temperature will be increased naturally. However in case of short voyage, it is not enough to increase the temperature naturally.

If sweating is expected to happen or has actually happened in the adjacent empty tanks, the followings are the possible measures to prevent or cope with:

The best way is to supply dry air into the empty tank, however this is not practicable because such system to supply dry air is not equipped on board.

If sea temperature is higher than cargo temperature, to ballast into concerned ballast tank in order to increase the temperature of cargo tank in the adjacent cargo tank.

If the cargo is not a polymerize cargo such as SM or MMA in surrounding tank, and not reactive at higher temperature, to steam into empty cargo tank to be loaded (the tank which is sweating). It is most effective method to increase indirectly the temperature of cargo within the shortest period (4 or 5 hours).

If the cargo is a polymerize cargo or reactive cargo for high temperature, Steaming into cargo tank should be avoided. Vessel can increase indirectly the cargo temperature by ventilation of surrounding empty cargo tanks with warm temperature, which heated by heating coil. The temperature of empty cargo tank should not exceed 35C.

During the above ventilation method, sweating in empty cargo tank is inevitable. After raising temperature of cargo to the necessary degree, Heating of empty cargo tank should be stopped and normal ventilation to be carried out after mopping up the sweat.

Prior to arrival loading port, the condition of the concerned empty tanks is to be checked to avoid any last minute surprises.

PREVENTION OF OCCURRENCE OF SWEAT

If vessel loads cargo in a tropical area at atmospheric temperature and carries it to a cold area. In this case, the sweat will not be generated in empty cargo tanks surrounding the loaded cargo tank. 

However some cargoes such as SM (styrene monomer) or MMA (methyl methacrylate), which react at high temperature, are loaded to cold temperature lower than atmospheric temperature at Tropical area. 

In case of parcel cargo, if vessel loads such cargo first, the sweat in cargo tanks which surrounded by such cargo tank will be generated.

Vessel should load cargoes of normal temperature first and then load cold temperature cargo last. It could be discussed with agent/charterer in advance.

For avoiding generation of sweat in empty cargo tank, it is necessary to find dew point. The sweat is generated when temperature in certain area is lower than dew point.

Therefore, if dew point of atmosphere is lower than that of empty cargo tank, ventilation into cargo tank is very effective, however dew point of atmosphere temperature is higher than that of empty cargo tank, ventilation should be stopped.

A tank which is having 100% relative humidity at 30c will have zero RH at -40 C dew point

Dew point= wet bulb reading on X axid/ diff between dry and wet on Y axis.

Ship sweat happens when ship travels from warm to cold place when tank temp is greater than dew point of outside air—ventilate and get rid of the sweat. 

Wait for temperature of air to be > 3 deg cooler than air inside. When tank temp is less than dew point of outside air—do not ventilate.

Warmer air can hold a lot more water than cooler air.  The rule of thumb is that raising the air temperature 10°C doubles its moisture capacity. 

If we cool air without changing its moisture content, eventually we'll reach a temperature at which the air can no longer hold the moisture it contains. Then water will have to condense out of the air, forming dew or fog. 

The dewpoint is this critical temperature at which condensation occurs Ordinarily the dewpoint doesn't vary much during a 24-hour period. Unlike temperature and unlike relative humidity, the dewpoint is usually the same at night as it is the daytime. 

A high relative humidity indicates that the dew point is closer to the current air temperature. If the relative humidity is 100%, the dew point will be equal to the current temperature 

The dewpoint temperature depends on the air temperature, since hotter air can hold more water vapor per unit volume than can colder air. The higher the dewpoint temperature, the higher the moisture content of the air.

Dew point is a better absolute measure of the air's moisture content. 

Here's a good example of why:-

Proforma: Temp/ DP/ RH

90/ 80/ 67%

100/ 80/ 47%

110/ 80/ 33%

RH=actual vapor density/ saturation VD x 100%

While relative humidity is a relative measure of how humid it is, the dewpoint temperature is an absolute measure of how much water vapor is in the air (how humid it is). In very warm, humid conditions, the dewpoint temperature can reach 75 to 77 degrees F, but rarely exceeds 80 degrees.

Dew-point does not change with temperature of the air; very much different from relative humidity. It is a measure of atmospheric moisture. It is the temperature to which air must be cooled in order to reach saturation

The closer the temperature and the dew point, the more humid the air is.

Accommodation entrances and air inlets to ER should not face cargo area.

Gas freeing fan 9000 m3/ hr which gives the purge pipes of 10 cm dia  an exit velocity of>30 Mtrs/ sec.

  

Cargoes such a styrene monomer and methyl methacrylate are loaded cold. So if MEG and styrene have to be loaded in adjacent compartments—load MEG first and styrene last.

Almost all chemical vapours are heavier than air and so remain at the bottom of tank.

Start gas freeing only after removing water from the bottom suction pit, or it takes too long.

Displacement method ( 1.5 air changes reqd )

entry velocity must be low to prevent short circuit.

entry from top via butterworth port using portable inlet blower. at 114 cum per minute

exit from bottom entering via drop line mouth  and eject via manifold..

Dilution method ( 4 airchanges with high entry velocity )

Method 1:

entry from top butterworth port

exit from top butterworth port.

Method 2 :

entry from bottom pump stack.

outlet from top butterworth port.

this will remove  few litres water or volatile cargo from suction pit.

use  blower fixed at manifold to put in air at 200 cum  “per minute..”

All modern chemical tanker pumprooms must have 45 airchanges “per hour”  as perCDI regulations.

Do not do too much of ventilation on a wall wash  earmarked tank to prevent salt in sea wind / dust / oil getting in.  The compressed air exhaust of the portable vent must be blown/ led  away (using a short pipe)  from the fan blades to prevent compressor carry over oil from getting into tank.

Products with low vapor pressure, or products which leave residues or contain inhibitors should never be cleaned by evaporation (ventilation). The non-volatile matter (NVM) content in the specification of the product is a good indication to determine, whether a product will leave residues

Gas freeing is most effective if 2 blowers are used in a single tank—with one on supply and the other on exhaust with a long duct leading to the bottom.

Ethanol which is not static can be removed by bubbling through the sump. Epoxy Paint resistance lists and Tank coating manufacturers give clear instructions on long term ventilation before water is introduced into the tank. Usually a  water wash is not necessary after a prolonged ventilation period unless there is NVM at the bottom or verticals/ sloping surfaces.

Venting after aggressive cargoes:

Epoxy absorbs solvents . The  problems are—damage to coating and contamination of next cargo. The cargo must be desorbed by ventilation.The release is faster if the steel temp is high  This steel temperature  increase must be from the adjacent compartment.. The ventilation for desorbsion must be devoid of moisture—the moisture takes the place of vapours which the air should have accepted and carried away. The ventilation must go to bottom of tank and exit from top from the other end,with the steam coils cracked open.

Don’t bubble through sump if the cargo is a static accumulator. Do not butterworth or even steam the tank without ventilation if the cargo is water mixable or water reactive.

A check is mandatory—will the next cargo be contaminated by the previous cargo. Say styrene monomer after benzene. Empty tanks must be ventilated during the voyage to ensure that the index is outside the flammability composition cup diagram.

Some of the water mixable/ reactive cargoes which are bad for epoxy coating and better off in SS or Zinc tanks are—

Acetone, Acrylonitrile, Ethanol, Methanol, IPA, MEK, Methyl acrylate, VAM, Butyl Acetate, Ekta Solve, Adiponitrile etc.

For many cargoes ventilation is the only acceptable means of removing the last traces from epoxy tanks. For such cargoes bottom flush with water is not a good idea. Read the paint manufacturers instructions for the next cargo. It may say—only warm organic cargoes.  Be very sure to read the footnotes.

The test is to shut off the tank and open the steam coils. Open the tank again and check for odour of last cargo. If the odour is still there then ventilation has to be done again.

Caution should be exercised when carry high MP heated products as the non-insulated ( from cold wind ) PV stacks can clog or the PV valve may stick. 

                INSTRUCTIONS FOR TANK ENTRY

In  XXX XX  there is a ZERO TOLERANCE POLICY for flouting tank entry procedures.

No tank entry is possible without permission of chief officer/ duty officer. A signed company enclosed spaces entry permit must be made for each tank.

No superior ship construction or company system can prevent accidents if the crew do not have safety culture ingrained in them.

You cannot enter a tank by just looking for cleanliness and using your sense of smell. Some gases like carbon monoxide have no odour.  Some gases choke the sense of smell and are therefore not detected in dangerous concentrations.

Read the MSDS sheets to find out the health hazard rating of the last chemical carried or even the tankcleaning chemicals used.

Man entry requires 20.8% oxygen , zero LEL HC and less than TLV ppm on Draeger / Kitagawa gas detector tubes and of course a running vent fan.

Organic face filters are of no use against inorganic gases. All organic chemicals have C on the formula of MSDS sheet. Nitric acid vapor or Hydrogen sulphide gas is not organic . Filtering masks are of no use in an oxygen deficient atmosphere.

Filter protection must only be used against gases which has a distinctive smell and there is no lack of Oxygen. If you can smell gas it means the filter is saturated and then it has to be discarded.

Class 1/ 1000 ppm

Class 2/ 5000 ppm

Mark X/ low BP products

Filter masks can be used only 3hrs in a working day.

Turbo filters have a battery powered blower which reduces the work on the lungs

Readings of tank atmospheres must be taken with the ventilation off. Most chemical vapors are heavier than air. Readings must be taken from top or bottom depending on vapor density of cargo

Know the VP and TLV of the last cargo. Couple of litres of colourless liquid in the sump need not be water, on the contrary it can be a toxic and flammable tankcleaning chemical either soluble or insoluble in water.

The tank must be isolated from the other tanks by blanking. Double valve segregation is not good enough on a parcel chemical tanker. This means the manifold elbow , vapor return elbow and manifold flexible jumper hose must be removed.

Nitrogen/ free steam inlet hose removed and heating steam coil  inlet manifold shut. Only chief officer REPEAT  only chief officer can authorize connection of one cargo tank to another by liquid or vapor.

While squeegeing veg oils the vent fans must be run and steam coils put off. Oxidizing and putrifying veg/ animal oils are dangerous for the sweeper.

Some gases are so acutely toxic that no exceeding of TLV is acceptable. They have been assigned with the letter C for ceiling. Some gases can enter the body through intact skin and have been assigned with letter S

Skin cream does not reduce the amount of chemicals absorbed through the skin—but they protect the skin itself.

Use harness not belt. Try hanging by your waist by 10 seconds to check this out ( don’t damage your spine while doing this )

Bow thruster room is an encl space.

It is possible to breathe in an atmosphere containing 17% oxygen provided the air is completely non toxic---such a condition is very rare.

When oxygen is used for combustion in the cells of the body Co2 is formed. The Co2 is removed from the body via blood and the lungs. Oxygen is absorbed in the blood inside lungs and Co2 is expelled from blood.

Brain superior centres:  thought, judgement, controlled movements, senses

Brain subordinate centre: ( self regulating )—control auto functions like breathing, heart rate digestion, temp regulation

Superior centres are affected first by toxic gases. Then subordinate centres get damage

All tank inspections must be done prior to hose connection. Tank can be entered by shore surveyor only in the presence of a ships officer.

Unless advised to the contrary all tanks must be cleaned to water white standards, dry and odour free. Unseen area checked by rubbing hands for residue. No loose scale or rust should be present. 

-------CAPT AJIT VADAKAYIL ( 30 YEARS IN COMMAND )