BITUMEN OPERATIONS

Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, entirely soluble in carbon disulphide, and composed primarily of highly condensed polycyclic aromatic hydrocarbons.

Bitumen is the residual (bottom) fraction obtained by fractional distillation of crude oil. It has a specific gravity range between 1.00 to 1.04 and average volatility. It is the heaviest fraction. The bitumen or Asphalt (Roofer’s Flux) is also known as Tar in some countries. In British English, the word ‘asphalt’ refers to a mixture of mineral aggregate and bitumen (or tarmac in common parlance). Most bitumens contain sulphur and several heavy metals such as nickel, vanadium, lead, chromium, mercury and also arsenic, selenium and other toxic elements.

The penetration number of a particular grade of bitumen is a measure of its consistency and is determined by laboratory tests.

The main characteristic of this compound is the high loading, carriage and discharge temperature

USES OF BITUMEN

It is transported in bulk by sea, and on land by special rail cars which are equipped to handle it, but in some cases it is blocked and shipped as solid.

Bitumen is mainly used for paving roads and for general waterproofing products, including the use of bitumen in the production of roofing felt and for sealing flat roofs. It is also the prime feedstock for petroleum production from tar sands currently under development in Alberta, Canada. Bitumen from tar sands is projected to account for 80% of Canadian oil production by 2020.

CARRIAGE OF BITUMEN

Loading temperature for Bitumen is normally about 1400C, carriage about 1500C and discharge temperature 1500-1600C. These high temperatures are necessary for the cargo to flow. Precautions are necessary to keep the cargo in liquid state. For this reason heating system has to be in good order. The heating should be done in such a fashion, so as not to allow wide temperature swings in the range.

Due to the high temperatures as above, steam is not suitable as heating media. To maintain the high temperature range the tanks have hot oil (thermal) heating coils.

Bitumen ships are specially built to handle this product at high temperatures. Not only are the ships equipped with double bottoms, the tanks are designed and insulated on all sides to retain the high temperatures to prevent thermal loss. The heating coils are rather more elaborate than in the normal ship. In addition to the coils covering the bottom of the tanks, additional mattresses or layers of coils are provided at different levels in the tanks. Piping and pumps in the pump-room as well as deck are provided with lagging, and the deck lines are often provided with a steam trace in addition to this. Most grades of bitumen are handled at temperatures that exceed 1200C and below this temperature they become hard to handle.

Bitumen carriers are usually fitted with two screw pumps. The double bottom water ballast tanks are served by the ballast pump.

KEY ISSUES IN CARRIAGE OF BITUMEN

There are a number of key aspects in storing and handling bitumen as given below:

1) Condensation in empty tanks is extremely dangerous. Dangerous amount of steam can be created when hot liquid Asphalt is introduced into a tank that has been empty for a while and accumulated moisture from condensation. To circumvent this, cargo tanks should be pre-heated prior to arrival at load port,

2) Extreme caution should be exercised when loading, unloading and sampling, due to the high temperatures involved. Failure of cargo tank insulation may create some hot spots on the vessel’s weather deck and direct contact of hot surfaces can cause severe burns e.g. handling manual tank valves etc.

3) Protective equipment should be made available and used by all personnel involved in cargo operations.

4) Use catwalks, screens, barrier Guards and shields to protect from steam, hot asphalt or other hot surfaces.

5) Bitumen being a high density cargo, due consideration should be accorded to the above whilst planning for the cargo. The density of the grade being loaded must be compared with the permissible Load Density of the cargo tanks and appropriate handling precautions must be in place. The cargo should be loaded at a very slow rate initially to prevent high velocity impact of cargo flow on the tank structures , the operation of the valves and pumps must be gradual to avoid pressure surges from being set up in the lines

RISK OF EXPLOSIONS IN BITUMEN TANKERS

A vessel laden with asphalt had suffered an explosion on one of its cargo tanks while sailing from Algeciras to Tarragona (Spanish coast). As a consequence of the explosion there was an opening on the main deck of approx. 2 x 1 metres. Fortunately there was no injury, casualty or pollution resulting from this incident.

LIKELY CAUSES OF CARGO EXPLOSIONS

Whereas we are all aware of dangers associated with carriage of Bitumen at high temperature (about 1500C), there is a misconception, that product is always below its flashpoint even at such high temperature. The following to be followed for ensuring the safe carriage of bitumen:

a) High Temperatures

Bitumen is handled at temperatures in excess of 1500C and contact with the skin must be avoided or serious burns will result. Systems must be designed to minimise this exposure and in addition protective clothing and protective equipment should be used to prevent this. The carriage temperature is even becoming higher these days (nearly 2200C) due to advanced extraction / refining techniques.

b) Water

The temperature of bitumen and blends is almost always above the boiling point of water so WATER SHOULD NOT BE ALLOWED TO CONTACT THESE PRODUCTS AS THIS WILL CAUSE BOIL OVER OR EXPLOSION. Most Bitumen ‘explosions’ in ship’s tanks are often Boil Over, where water enters the bitumen and turns into steam. The expansion ratio is 1400 to 1. This phenomenon was bad enough when ships were loaded open, but of course these days most ships load closed so the sudden pressure increase is contained within the tank, thereby increasing the possibility of an explosion due to over-pressurisation.

c) The Flammable Nature of the Product

At or below the recommended maximum handling temperature bitumen will remain below its flash point, however, bitumen cutbacks are usually handled at temperatures above their flash points and so the vapours, mixed with air are often explosive. All they need is a source of ignition and they can explode into flames. The same applies to over-heated bitumen. It is essential to keep all sources of ignition (e.g. naked flames, smoking, etc.) well away from areas where flammable vapours may be present. This is likely to be at loose or open manhole covers, vents, hose ends and the like.

d) Vapours in High Concentration

Vapours from bitumen and related products can be hazardous in high concentrations. For example, they can displace oxygen and cause suffocation or affect breathing and the eyes. Persons entering confined spaces, where these products have been stored will require full protective clothing and fresh air breathing apparatus. These operations require stringent precautions controlled by an authorized person under a work permit. Confined spaces including the ones adjacent to cargo tanks must not be entered without a permit and procedures must be followed.

e) High H2S

H2S is a becoming a significant toxic vapour present with many bitumens and as such these carriers should have specific procedures and risk assessments to mitigate the risks. This is due to the Crude feedstock in use where H2S levels are rising as wells become aged. Port Jerome in France has always had significant problems with H2S. Refer to PTOM section 7.1 for H2S handling precautions

LIKELY CAUSES FOR EXPLOSIONS IN ENGINE ROOM

Cargo heating on Bitumen Tanker is conducted by thermal oil.

a) Carry out a thorough risk assessment prior carrying out any maintenance.

b) Routine maintenance to be carried out only as specified by maker and as per maker’s procedures

c) Conduct regular inspection to ensure good and tight condition of the thermal oil pipelines in the engine room. Check shielding of thermal oil line also.

CAUTION IN STORAGE AND HANDLING

When handled properly, bitumens may be reheated or maintained at elevated temperatures without affecting their properties adversely. However, if bitumens are thermally abused in storage or application, the bitumen can harden (or in some cases soften) and will produce poor performance in service.

The quality problems that may be encountered in storage relate to:

· Temperature

· Presence of air

· Surface to volume ratio of the bitumen

· Method of heating

· Duration of exposure

Safety problems that may be encountered in storage relate to:

· Exceeding maximum storage temperature

· Contamination with light products

· Contact with water

· Accumulation of flammable vapours

Quality problems that may be encountered in handling relate to:

· Overheating or poor heating procedures

Safety problems encountered in handling relate to:

· Danger of burns danger of water ingress

· Danger of overheating

HEATING OF CARGO

Bitumen is a very good insulator with a low heat capacity. Figure shows typical values for heat capacity.

Specific Heat of Bitumen

Heating of Bitumen is accomplished by circulating high temp thermal oil from a heater into the cargo tanks via heating coils.

Hot oil heaters are preferred for a number of reasons:

· There is no opportunity for corrosion; the heating may be precisely controlled.

· Oil, unlike water or steam, will not cause an explosion if it leaks into the bitumen.

Prior to commencing heating operations, the following checks should be carried out:

a) Air in expansion tank is properly purged and bled-off and oil is not in contact with air.

b) There is enough oil in the reserve tank

c) Check that oil level in the expansion tank is at the correct level

d) Cooling-water levels (if required) for circulating pump checked

During operation of the heating system the temperature difference between thermal heater inlet and outlet temperature should, ideally, be 250 to 500C. If temperature difference between the inlet and outlet is more than 500C or if differential pressure is more than 4kg/cm2, then adjust load bypass valve accordingly.

Thermal oil takes a long time to cool down especially when the load temperature is high. Keep circulating pump in operation for apprx. 30 minutes so as to gradually bring down the oil temperature.

Operational checks to be done on daily basis during transit of cargo:

a) Check that oil level in the expansion tank is at the correct level.

b) Check the thermal valves for normal operation.

c) Check for thermal oil leaks in the system.

Annual inspection and testing of thermal oil is recommended.

Heating of asphalt cargoes should be brought up ideally not exceeding 300C in a period of 96 hrs. However, not less than 54 hrs should be taken to bring cargo temp up to 1800C (if needed).

Storage temperatures in the range of 1000 to 1300C are particularly troublesome, and therefore not be allowed to cycle above and below the boiling point of water.

Clear Heating Instructions must be obtained from Charterer and Master and followed accordingly.

SPECIAL PROTECTIVE CLOTHING

These cargoes are loaded, carried and discharged at very high temperatures – normally in the region of 10 to 1700 Centigrade. At these temperatures bitumen fumes are generated. Both the high temperature of the cargo and the fumes present hazards to personnel. Operators may be exposed to these hazards due to splashing of hot cargo or uncontrolled venting of fumes.

Due to high cargo temperatures involved, the manifold watchkeeper and the persons involved in connecting / disconnecting of the cargo and vapour manifolds must be provided with special personal protective clothing (PPE), to safe guard against burns and/or bitumen fume vapours as follows:

· Full length thick coveralls.

· Safety goggles.

· Safety helmet with full-face visor and neck cover flap.

· Long sleeve insulated gloves.

· Long ankle safety shoes.

· Safety gas masks – to be ready for use in case of accidental vapour release.

Note: the coverall sleeves and leggings must be worn over the gloves and shoes.

LOADING / UNLOADING

Bitumen ships are provided with loading lines which are insulated / lagged, and in some cases fitted with a tracing line to ensure that bitumen does not solidify when passing through it. The ship’s lines are connected to the shore lines by specially lagged hoses capable of standing the temperatures at which the bitumen is loaded. In case ship’s hoses are required to be used for cargo operations, ensure that Letter of Indemnity (LOI) has been obtained from the terminal for use of ship’s cargo hoses prior use.

When everything is ready to load, the shore line together with the ship’s line are blown through with compressed air. The reason for this is to test that the line is clear and not blocked by solidified bitumen from some previous operation. In addition, should either the ship’s or the shore’s pumping system contain water, it will be blown into the ship’s tanks where it will be observed from the deck, loading operations can then be held up till the tank is dry and any defects remedied. If the air reaches the tank without displacing anything, loading operations can be commenced as the line can be assumed to be clear. After the cargo has been loaded, both the ship’s and shore lines are cleared with air. This can be a long drawn out operation if a long length of shore line is involved. Master to ensure that MSDS is provided by shipper for the cargo.

LOADING AND UNLOADING PLANNING

The Chief Officer shall draw up loading and unloading plans, taking following matters into consideration:

a) Information on loading and discharge ports.

b) Terminal regulations at loading and discharge ports.

c) Zones and seasonal areas to be navigated.

d) Narrow channel restrictions.

e) Hull strength.

f) Cargo properties and temperature.

g) Nominated loading quantity, final stopping ullage.

h) Loading and discharging rates.

i) Cargo lines to be used for loading and discharging, vent lines,ballast lines, and their capacities.

j) Layout of cargo tanks and ballast tanks and their capacities.

k) Vessel’s Trim and List during cargo handling operations.

l) SF & BM calculations for various stages of cargo operations.

m) Assignment of crew members to posts and safety measures.

n) Regular use of all cargo pumps – Vessel shall plan discharging sequence in such a way that each cargo pump is put to use during the cargo operation.

• There shall never be a case where a particular cargo pump is kept idle and not used regularly for a specific cargo to be discharged. Not using a pump may cause significant settling and solidification of cargo in pump cavities & pipelines around the pump rendering it un-usable.
• When carrying out flushing of cargo tanks and lines, same principle shall be applied. All cargo pumps fitted on board shall be used during flushing so that all pumps, their cavities, adjoining lines & columns get flushed with flushing medium and old cargo deposits are reduced to minimum.
• When in use, a cargo pump should be used for a minimum of one hour. When performing flushing each tank shall be flushed for at least one hour. For example if a vessel is fitted with two pumps and twelve set of tanks, total flushing duration shall be for twelve hours and each pump will be used for six hours.

EXCHANGE OF INFORMATION BEFORE PORT ARRIVAL

The master shall confirm before port arrival that necessary information has been exchanged between ship and shore concerning terminal regulations and cargo handling operations.

PREPARATORY OPERATIONS BEFORE CARGO WORK

The Chief Officer shall make necessary preparations and inspections before port arrival and cargo handling operations. The ship-shore safety checklist and all other company forms and checklists currently in use for conventional tankers must be utilized prior to and during operations. Ship or cargo specific items may be added to the checklists are necessary and must be included in the Chief Officer’s cargo operation instructions.

Prior arrival port, visually check all manifold lines for any remnants of cargo by opening the respective manifolds.

PRE-MEETING TO DISCUSS CARGO HANDLING OPERATIONS

The Chief Officer shall discuss the following matters with the terminal prior to cargo handling operations:

a) Inspect the cargo tanks prior loading for any damage to insulation.

b) Ship / Shore safety checklist should be complied with.

Pre-Transfer meeting should cover the following points:

a) Maximum permissible loading/discharging rate, maximum pressure.

b) Check whether cargo work is stopped by an order from the shore or from the ship and the quantity of cargo to be received after giving a stop order.

c) Matters concerning measurement of cargo quantities, taking samples, taking temperatures and thieving.

d) Matters concerning cargo (temperature, specific gravity, water content).

e) Confirm nominated grades and corresponding tanks with the terminal.

f) Agree on the sequence of loading and the minimum number of cargo tanks to be kept open for each grade.

g) Matters concerning the supply of bunkers, water, ship’s stores and provisions.

h) Matters concerning ballasting and de-ballasting.

i) Possibility of returning vapor to the shore terminal.

j) Blow through procedures prior loading, at any stoppage of operations and on completion of discharge.

k) Check for any terminal requirement and restriction for that particular port.

Any changes to cargo plan should be clearly notified to the duty officers to avoid any misunderstandings or miscommunications. All OOWs should familiarise with the contents of the pre-transfer meeting prior taking over watch.

MANIFOLD

a) Check the shore hose/ loading arm for any visible blockage.

b) Once manifold is connected, carry out a leak test.

c) Once confirmed there is no leak, install the splash guard on manifold and release the air as agreed with terminal.

d) Cordon off the manifold area prior commencement of heated cargo with effective means or warning rope (e.g., tiger rope, warning tape, etc). This shall indicate clearly the restricted area, as shown below. Heightened level of alertness and caution must be exercised when entering and operating in this area.

FLUSHING OF CARGO TANKS WITH FUEL OIL FOR GRADE CHANGE

Vessels generally engaged in Bitumen trade, generally load following three types of grades:

1. Liquid Pitch
2. Bitumen/ Asphalt Grades
3. Non-heated cargoes

The Officer in charge shall always bear in mind the challenges faced in grade changes when going from HOT to COLD and COLD to HOT. The term HOT refers to as a cargo with higher carriage temperature than the previous or next cargo and the term COLD refers to as a cargo with lesser (or NO) carriage temperature than the previous or next cargo.

In assessing these two factors there are two main risks to understand and mitigate, which are as follows:

1. HOT to COLD – Clogging due to HOT cargo getting coagulated below its softening and melting point.
2. COLD to HOT – Flammability, if the COLD cargo has LOW boiling and flash point.

Handling of cargo, and pumps will be basis above and other properties of cargo to ensure safe operations.

Following is the Company’s recommended procedure for such cases, however, it does not relieve Master from performing his own assessment to perform the operation safely and with optimum efficiency.

FLUSHING WITH MEDIUM:

If the vessel is instructed to load liquid pitch after carrying bitumen, flushing is required to be done by a medium (HFO). Detailed procedure is provided below.

Flushing by medium will also be required when loading Bitumen or liquid pitch after vessel has carried a non-heated cargo of low boiling point. The process of flushing in this case will remain same as for Bitumen to Pitch Change over procedures.

When HFO is transferred from bunker tanks an entry for same shall be recorded in ORB Part 1 & 2, and the code used for transfer shall be for internal transfer. It should not be recorded as loading operation under CODE A.

Flushing Procedures for Change of Grade from Bitumen to Pitch and from Low Boiling Point Cargo to High-Temperature Cargo:

Ventilation and cooldown (24-48hrs)

To reduce the temperature of lines, tanks and pumps before introducing cleaning medium, the temperature needs to be lowered. This can be started as discharge is completed.

Reduce temperature set-point on Tanks, lines and pumps depending on cleaning medium
HFO Temp: 130o to 140º C.

Ventilation of tanks – To increase cooldown of tanks, the access hatch can be opened while the vessel is at open sea. Further, ventilation of void spaces should be started.
Without ventilators running – temperature decrease is expected at 1 degree per hour.
With ventilators running – temperature decrease 1.5 to 2 degrees per hour.

If sea spray or rain is encountered, hatches must be closed to prevent any water going into the tanks.

Flushing medium

HFO is to be transferred from a Bunker tank or taken from a barge or shore. Vessel should be aware of the flash point of the fuel oil. The temperature of the thermal heating oil shall never be put more than 10 deg C below the flash point of the fuel oil. Normally the lowest flash point of heavy fuel oil is around 120 deg. C, therefore, the temperature of thermal oil shall be set at maximum 110 deg. C.

The Softening Point (SP) of Bitumen as mentioned in the Material Safety Data Sheet (MSDS) is to be noted. Normally, SP of Bitumen is 45~52 deg C. As a rule of thumb, the Melting Point (MP) of Bitumen or Pitch is generally 15~20 deg C over the SP. In order for previous product to be cleaned in fluid pumpable condition, the tank temperature should be maintained at least 20 deg C more than its melting point (i.e., 35~40 deg C over the SP).

The amount of cleaning media (Fuel oil) to be used shall be calculated so that minimum 2 tanks are filled to a level where they can be recirculated at the same time. This will of course vary from vessel to vessel but a minimum of20 cub. m. of Fuel oil per tank shall be used in order to make sure that the remaining blend will be pumpable without having to apply excessive heat. Charterer’’s permission must be sought to determine no. of tanks to be cleaned simultaneously to optimise the cleaning time.

The flexible hoses used during transfer must be approved for oil transfer and pressure tested at least annually in accordance with OCIMF recommendations. Hoses should be inspected each time prior use.
Ventilation must be stopped, and all tanks must be closed prior commencement of transfer. Record of transfer shall be recorded in ORB Part 1 & 2.

The amount of cleaning media (Fuel oil) to be used shall be calculated so that minimum 2 tanks are filled to a level where they can be recirculated at the same time. This will of course vary from vessel to vessel but a minimum of20 cub. m. of Fuel oil per tank shall be used in order to make sure that the remaining blend will be pumpable without having to apply excessive heat. Charterer’s permission must be sought to determine no. of tanks to be cleaned simultaneously to optimize the cleaning time.

The flexible hoses used during transfer must be approved for oil transfer and pressure tested at least annually in accordance with OCIMF recommendations. Hoses should be inspected each time prior use.

Ventilation must be stopped, and all tanks must be closed prior commencement of transfer. Record of transfer shall be recorded in ORB Part 1 & 2.

Introducing cleaning medium in the first tank (1 hour) When loading the tanks with fuel oil through the vessel’s manifold, the last manifold used for discharge shall be used. Similarly, when discharging the residual cleaning oil after the cleaning is done, it shall be carried out using the same manifold through which vessel intends to load the pitch. This is to ensure that no remains of the cleaning oil are left in the ship’s lines. Loading must be done through the bottom lines, it’s imperative that drop lines are not used at this point as free flow in/ to the tank must be ensured. This will also flush out any free water in a safe direction.

Flushing with HFO:
a. Cargo Pump seals to be preheated.
b. SFO (Seal Flush Oil) systems to be heated to about 190 C Temperature.
c. SHU (Separate Heating Unit) System is started to bring temperature to approx. 70o~80o C, temperature to be decided depending on HFO flash point temperature. Temperature to be checked from the HFO analysis report.
d. Commence turning of pump at very slow speed to ensure any solidified bitumen has melted.
e. During circulation of HFO ensure following –

• SFO 150Deg C Temperature is maintained.
• SHU temperature is maintained approx. 70~90Deg C (Self-ignition temperature to be checked from the HFO analysis report).

Introducing the cleaning medium in the first tank is a high-risk operation, as:
a. The medium could contain free water and if the temperature is above 100Deg C, this can create steam that can cause pressure build-up in the pumping system. Observe pressure increase and reduction in boil off from P/V valves until transfer to next tank.
b. The Medium is handled above flashpoint and will create a potentially flammable atmosphere in the tank and the system must be kept closed at all times.
c. Maintain temperature of all parts of the system minimum 10 degrees below boiling point of the cleaning medium.
d. Flush all parts of pumps and lines (except drop lines that have contained other cargo than pitch at this point to avoid clogging). The pump shall run on the medium for at least one hour. e. For vessels fitted with IG systems, tank atmosphere shall always be kept inerted. For non IGS ships, the tank atmosphere shall be measured frequently and should not be allowed to cross the 100% LEL.If it is observed to be increasing, the tank shall be ventilated further to keep the atmosphere lean.

First and second bottom flush cycle (2 to 4 hours per cycle)
a. At all times use the bottom lines.
b. Pump the cargo from tank to tank have the medium in each tank for approximate 30 minutes.
c. Should any tank be blocked, carefully use the cargo pump to push. Check that overpressure valve is adjusted to around max 12 Bars.

Last flushing cycle (2 to 4 hours)
a. At this point the droplines should be used circulating the cargo for 30 minutes in each tank, this will flush the forward part of the tank as well.
b. Should any dropline be blocked carefully use the cargo pump to push the lines to maximum 12 bars.

Stripping (1 hour)
a. Strip all tanks 2 times ensuring that maximum amount of residues is recovered.
b. If sufficient time is available, strip all tanks in calm condition/ port before discharge.
c. Maintain temperature at minimum 10 degrees below boiling point of cleaning medium.

Discharging the cleaning medium
a. Check maximum allowable temperature for discharge with receivers.
b. Conduct risk assessment before the operation.
c. Take sample of cleaning medium.
d. The optimal trim and list in order to have suction at all times during the operation shall be maintained. Once the residual cleaning oil is discharged to barge or ashore, the lines shall be blown to shore in order to minimize any ROB of cleaning oil.

Loading Pitch
a. Load first foot through bottom lines in all tanks to ensure free passage.
b. Flush cleaning medium from pumps into tanks.
c. Prior to arrival load port, the cargo tanks and cargo lines shall be heated to terminal’’s requirements. In the absence of any instructions from terminal, the tanks & lines to be maintained at minimum 50 deg. C below the loading temperature. In such cases, loading should be commenced gradually and loading rate to be increased as the temperature of tank rises to prevent any thermal shock.

FLUSHING WITHOUT MEDIUM:

When vessel has discharged Pitch and is instructed to load either Bitumen (which has a lower carriage temperature) or a non-heated cargo, flushing must be carried out by the cargo itself well in advance of arrival at discharge port.

Pitch to Bitumen (Recirculation)
a. Complete the Pitch discharge operation.
b. Stop the cargo pumps.
c. Heating NOT to be stopped for SFO & SHU and both SFO & SHU temperatures should be maintained same as the cargo of Pitch which was discharged.
d. Reduce the Cargo tank temperature as required to load Bitumen.
e. Load the cargo of Bitumen.
f. After departure load port, both cargo pumps are to be turned slowly by hand.
g. Carry out recirculation of cargo as per the guidance provided below. Reduce the temperature to the loading temperature only after the recirculation.

Bitumen to Crude Oil / HFO (Recirculation)
a. Complete the Bitumen discharge operation.
b. Stop the cargo pumps.
c. Heating NOT to be stopped for SFO. SHU temperature to be maintained 10 degrees below the flash point of the cargo to be loaded.
d. Reduce the Cargo tank temperature as required to load the cargo.
e. Load the cargo of Crude Oil / HFO.
f. After departure load port, both the cargo pumps are to be turned slowly by hand.
g. Carry out recirculation of cargo as per below guidance. Then, reduce the temperature of SFO to 120 Deg C and SHU temperature is to be maintained at 10 degrees below the flash point of cargo to be loaded.

Recirculation Process

When cargo is recirculated, each cargo pump must be run for at least 1 hour from cargo tank to cargo tank to ensure that the previous cargo residue does not remain in associated suction lines of pumps.

Cargo tank to cargo tank recirculation must also be carried out for at least 1 hour via cargo pump. Cargo must be re-circulated through the cargo tank line from each cargo tank to the cargo pumps, to confirm that all lines are free of any obstruction/ previous cargo residues. The process of re-circulation must be carried out in a manner, such that all cargo tanks are also recirculated.
Each cargo pump – For at least 1 Hour.
Each cargo tank – For at least 1 Hour.

It is important to note that pre-loading checks must be thoroughly carried out prior loading a less heated or non-heated cargo. Following must be diligently followed:

1. Previous cargo must be stripped and discharged to maximum possible extent.
2. Effective draining of bottom lines of any minor residue to be carried out to avoid settling and solidifying of cargo.
3. Mud box strainers to be cleaned post discharge.
4. A spare set of strainers to be kept ready.
5. While the draining process is followed, all efforts and precautions to be taken to ensure previous high heat cargo has been removed as much as possible from lines, columns and pumps.

Well before arrival at the discharge port, following checks must be performed:

1. Cargo pumps must be tried out by hand to see turning freely prior setting up the system to perform a pre-discharging circulation from tank to tank for all pumps fitted on board.
2. This circulation must be carried out for at least 1.5 hours.
3. All suctions valves must be opened and checked that the valves are not stuck.
4. Verify that cargo pumps are taking positive suction from each tank and that there is no clogging.

CARGO PUMP OPERATION

When cargo pumps are being operated, a record of following should be maintained:

1. Loading cargo
2. Discharging cargo
3. Flushing carried out with a medium such as HFO
4. Circulation carried out
5. Pre-arrival discharge port tests and checks
6. Any other reason due to which pumps are operated

Below is a typical cleaning cycle for 1 tank pair, where each set of tanks is recirculated twice:

BITUMEN VESSELS – OPERATION OF FUME SCRUBBER

Fume scrubber is a filtration system that utilizes wash oil to remove gas pollutants and odours from exhaust streams emanating from positive pressure created during loading of liquid pitch. The scrubber is designed to filter volatile organic compounds, inorganic compounds, Hydrogen Sulphide, Ammonia, Mercaptan, other carcinogenic & main pollutants, and various odours.

SPECIFICATION AND CONSTRUCTION DETAILS OF A FUME SCRUBBER

Specifications:
Capacity approx. 2,000 m3/hr vapor of Pitch cargo
Wash oil pump capacity: 20 m3/hr
Delivery height 30 mtrs
Tank capacity: 1400 litres

Construction: The system consists of following sub-parts –

• Two towers
• One wash oil tank
• Connecting windpipe
• Oil sprinkling system
• Filtering system
• The left tower containing two tiers of activated carbon adsorption and a layer of liquid filler
• The right tower is fitted with a wash oil sprinkler which cools down and absorbs particles from pitch vapours
• A submerged pneumatic pump which sprays oil for filtering.Cargo vapours go through spraying wash oil inside the right tower for further absorbing/filtering.

Operation of Fume Scrubber Pump:

Initially, the vapour inlet tower contains granules which must be cleaned along with its support plate.

Ensure that the vapour outlet (Scrubber Tower) mouth is fitted with a wire mesh to prevent carryover of Wash Oil with the outgoing vapours. Absence of this wire mesh will cause the droplets of Wash Oil to fall on deck presenting risk to crew health and housekeeping on deck due to its corrosive nature.

Ensure all the connections are made as shown in the below photograph, including placing a drum for air outlet to contain traces of Wash Oil.

• Air inlet pressure should be at least 6 to 7 Bars.
• One end of the flexible cargo hose is to be connected to the scrubber tower and the other end to the vapour line. Ensure that the vapour manifold valve is kept open.

• Ensure that the cargo venting system is lined up to a common outlet.
• Once all the above checks have been carried out, the air can be started in a controlled manner to make a final check on the integrity of the complete system.
• Ensure that the system is started prior commencement of loading.

OPERATION PROCEDURES

• In case a new pump is used, remove the paint of pump prior installation. Otherwise, the paint of the pump will peel off resulting in clogging of impellor due to the corrosive nature of the Wash Oil being used.
• Ensure that the connections are set as shown in the below diagram.
• Wash Oil level should be maintained at least 75% of the tank to ensure complete immersion of the Fume Scrubber submersible pump.
• There should not be any sludge at the bottom of the tank.
• All concerned should be briefed about the operation and PPE level is to be maintained as per company’s guidelines.
• Regular checks should be carried out during the entire loading operation to check for proper operation of the pump and integrity of the system.
• Connect vapour suction to the inlet tower flange.
• Connect compressed air to pump.
• Open wash oil discharging valve.
• Open inlet compressed air valve to start the pump.

SAFETY GEAR AND PRECAUTIONS

1. Wear safety gear including the following when handling Wash Oil:
   • Full Face shield
   • Face mask
   • Apron
   • Long gauntlets or insulated chemical resistant gloves
   • Full body cover (boiler suit)

2. Exposure to fumes from hot liquid may cause irritation to skin, eyes, nose, throat.
3. Inhalation of vapours may cause headaches, dizziness, irregular breathing and confusion.
4. Avoid skin and eye contact from fumes or liquid product. Splashes of hot liquid will cause burns, fume contact with skin may cause photosensitivity of skin areas and sunburn of subsequent exposure to UV alpha rays. Eye contact with fume and liquid may cause severe irritation and discomfort.
5. Avoid ingestion (swallowing) of the product. Long term exposure to liquid may cause problems with lungs.
6. Acute over-exposure to fumes may cause headaches, drowsiness and dizziness. Chronic over-exposure to higher vapour concentration may cause irregular breathing, collapse and coma.
7. In case a ship staff comes in contact with Wash Oil, obtain medical advice and follow first aid procedures as per below:
   • Eyes – Hold eyes open and flush immediately with water for at least 15 minutes.
   • Skin – Wash affected areas with warm soapy water & wash cloth and apply broad spectrum UV resistant cream to affected areas.
   • Keep out of warm area and keep person in fresh air.
   • If not breathing, apply mouth to mouth resuscitation.
   • Keep patient in comfortable environment.
   • If product is swallowed, give milk or vegetable oil.
   • Do not induce vomiting

• Special precautions in handling wash oil:
  • Use sound containers to prevent leakage and spillage of product.
  • Avoid naked flames, welding sparks and other possible sources of ignition near product. Prevent breathing vapour or fumes from product.
  • Avoid wearing contaminated clothing. Wash contaminated clothing before reuse.
  • Follow guidance as per MSDS.

BITUMEN TO NON HEATED CARGO

Change of Grade from Bitumen to Non Heated Cargo (Crude / Fuel Oil)

Concerns:

a) Change of grade from a highly viscous cargo like Bitumen to a non-heated cargo presents significant risks of clogged cargo lines.

b) This matter of line clogging is further aggravated due to separate cargo lines being used for loading and discharging. Loading is done through drop lines while for discharging, bottom lines & pump room lines are used. The chance of clogging is more in the discharge line from where last cargo was discharged. If the previous cargo was Bitumen, improper stripping will lead to clogged suction and pump room lines. Loading of next non-heated cargo will happen without issue but when discharging, these clogged suction & pump room lines may cause considerable delays.

c) Since the flash point of the non-heated Crude/ Fuel Oil is considerably lower than the flash point of the Bitumen cargoes, application of heat through thermal oil will pose fire hazard.

Precautions:

a) Before grade change to non-heated cargoes, line blowing and draining should be thoroughly carried out at the discharge port.

b) Further flushing of bitumen tanks/ lines with Fuel Oil should be done effectively to ensure that all lines and pumping system are well drained, and lines are clear of all bitumen.

c) During bulk loading of non-heated cargo, checks on the bottom lines and pumping system should be done by running cargo to the tanks through the suction lines and pumproom instead of drop lines. This can be accomplished by using the cargo pump bypass line and running the cargo through pumproom to the cargo tank. Whilst doing this, pump room should be inspected more frequently, and remote gas reading should be monitored to get alert on early indications of any leakage.

Tank Preparation:

From Bitumen to non-heated cargo:

1. – Vessel should not normally load Vacuum Gas oil Light (Light clean / Heavy)
2. – The vessel should ensure that tanks, lines and pumps are well stripped and drained prior loading Fuel Oil (Low Sulphur, High Sulphur), and Crude Oil.

From non-heated to Bitumen:

1. If previous cargo is Vacuum gas oil, Fuel Oil, the vessel should ensure that tanks, lines and pumps are well stripped and drained prior loading Bitumen.
2. If previous cargo is Crude Oil, the vessel should ensure following precautions prior loading Bitumen:

If cargo to load has a pour point greater than sea or air temperature or has a viscosity greater than 3,000centistokes at 104 0 F, either:

– Bottom flush with terminal-supplied cutter stock or

– Thoroughly machine wash all tanks and thoroughly flush all load/ discharge lines and pumps.

PRECAUTIONS WHILE CARRYING OUT RECIRCULATION OF CRUDE OIL AFTER CARRIAGE OF BITUMEN / PITCH CARGO

The crude oil does not normally require heating when carried on board tankers dedicated to carry Bitumen/ Pitch cargo. However, the remnants of the previous cargo i.e. Bitumen/Pitch will be present in the cargo pumping system posing a potential blockage at the time of discharging the current crude oil cargo in tanks.

For this purpose, it is important that cargo is recirculated in the lines and pumps to clear the previous cargo residues. However, prior doing so, pumps and lines need to be heated using thermal oil on vessels which are fitted with SFO (Seal Flushing Oil)/ SHU (Seal Heating Unit) for the cargo pumps. The pumps and lines must be pre-heated between 130-140 degrees C by running hot thermal oil for recirculation of the cargo pumps. This re-circulation will be done for almost 2hours and then the heating to be stopped while keeping the re-circulation on so that the temperature slowly cools down and in the process all the Bitumen remnant gets removed.

During discharge, heating of the SFO unit is restarted to achieve a temperature of 100 degrees C.Once the discharge operation is established, heating of the SFO system must be stopped.

Below procedure is to be followed:

• Start the thermal oil heating.
• This oil will be circulated in the lines on deck and in the pump room.
• Ensure that all the sensors and indication gauges are working properly
• Keep the SFO and SHU for the pump heated to 130 ~ 140 degrees C
• Start the pump with suction valve closed and the start cargo in recirculation mode from pump to pump via recirculation line.
• After some time, when recirculation is established stop the SHU heating and start putting the cargo in tank and open the suction from tank.
• Keep a close eye on the suction pressure and do not let it fall below – 0.5 bar.
• Clean strainer if required.
• After two hours of operation like this, close the SFO heating. The SFO temp will come down slowly.
• After a couple of hours, when it is established that the line is full of crude oil, stop the recirculation.
• Drain the lines and inspect the strainer. Any residue must be cleared.
• At the discharge port, prior starting the discharge, again heat the SFO to 100 degrees C and (SHU not to be heated) and once the discharge operation is established, shut the heating of SFO.
• Check the flash point of the particular cargo carried and seek office guidance, if required.

TANK PRE-HEATING

When the tanks are empty and dry, the thermal oil should be turned on the heating coils, while the tank lids are still open. This has the effect of drying out the metal surfaces of the tank and any atmospheric moisture in the tanks. After one hour the tank’s lids should be lowered secured and the temperature of the tank brought up in the range of 1000C to 1200C. Due to the fact that bitumen is loaded at high temperatures the tanks must be completely free from water, as even small pools of water cause the bitumen to froth.

Advance Information must be obtained from the loading port about the tank preheating requirements. With proper consideration of the time taken to heat the ship’s tanks to the required temperature, the pre-heating operations must be started.

The cargo tanks must be pre heated to minimum 1000C to about 1200C. This will take around 18-24 hrs. Also, cargo lines must be preheated prior to loading to melt away any cargo that may still be present in the pipelines.

Prior test opening and operating the cargo valves, the lines must be heated. If solidified Asphalt is present in the line adjacent to the valves, the valves spindles can break. Therefore, in order to exert minimum force on the valve it is necessary that the cargo in the pipeline is melted.

The heating should be gradual to keep thermal stresses to minimum.

LOADING

Loading should be planned such that there are no stoppages required for change of tanks. The loading rate should be controlled to avoid pressure surges in the piping.

When changing over tanks, valves to the next tank are to be opened first & only when it is ascertained that cargo is being received in it, the previous tank valves shall be closed. The line up must be verified physically prior changing over cargo tanks. Manifold pressures to be monitored closely during changeover of tanks.

Open loading is considered safe and is acceptable in most of the ports as long precautions are taken to avoid direct inhalation of any fumes that may emanate from the cargo. However prior sailing, the vessel must ensure that all tank openings are fully shut. Any water Ingress in the COT will have serious consequences.

The venting system on Bitumen carriers are usually of free flow design and P/V valves or secondary venting arrangements may not necessarily be fitted. A common venting system with all tank vent lines connected to single vent riser is an acceptable arrangement for Bitumen carriers. The common vent riser will be equipped with a flame arrestor at the outlet and is usually fitted with a block valve to isolate the venting system should the need arise.

It should be noted that keeping the venting valve open will not significantly lower the cargo temperatures; hence this valve should be left open even during passages unless rough weather poses the danger of water entering the tanks. As a general procedure, the vent head (usually cowl or mushroom) should be opened up frequently to check for residue build up at least during the first few voyages. Whatever be the case, it is definitely a safer option to allow the tanks to breathe instead of risking structural damage.

Upon Completion of cargo operation ensure to blow the lines, at least 4-5 times, from crossover connection at manifold, from port and starboard manifold.

As far as possible the cargo in the tanks should be loaded full or kept empty. This is necessary for stability and also to avoid sloshing and damage to insulation.

Tank RADAR gauge ullages should be manually cross-checked while topping up the Tanks at ullages lower than 3 mtrs.

It is imperative that cargo temperature is monitored during loading and the minimum cargo temperature should be as stipulated in Charter Party, if cargo temp is less than as defined in Charter Party, the Owners and Charterer’s must be notified, LOP Issued to terminal, all delays to terminal account to raise the temp and V/L will be on demurrage (time will not be counted as lay time)

COMPATIBILITY GUIDE FOR LOADING ASPHALT PRODUCTS

DURING VOYAGE

During carriage the cargo temperatures must not be allowed to drop below 1400C or other special instructions of the shippers or charterers.

Prior arrival discharge port (18 hrs), heat lines, pumps and operate valve to ensure proper functioning.

COP must be manually turned after heating, prior arrival discharge port.

Since the ship has insulated tanks, it is expected that on short passage bitumen ship the temperature of the cargo will remain as close to loaded temperature as possible, so that full advantage can be obtained from the high temperature of the cargo when the vessel discharges. On long ocean hauls, this procedure however would be a very costly one, and the object then is to combine economy in heating with a nicely judged reduction in the temperature of the cargo. The cargo must not be allowed to cool sufficiently then the vessel will be unable to bring the temperature up in the time allotted for this operation, or the pumps may be unable to handle it. On the other hand, any economy which may have been achieved by reducing the amount of heating in the early stages of the voyage may be more than offset by the efforts required to heat the cargo up to a pumpable temperature in the later stages of the voyage. Experience and sound knowledge of the capabilities of the particular vessel are desirable of personnel working on bitumen carriers.

MINIMIZING OXIDATION AND VOLATILE LOSS

These factors are related to the surface to volume ratio of the bitumen or to the exposed surface to volume ratio of the tank. The taller the tank, the lower the ratio for a given radius. Vertical tanks, therefore, provide better resistance to oxidation and volatiles loss. Similarly, in case only a small amount of cargo is left in the tank, oxidation and volatile losses will be very high. When circulating, the bitumen should re-enter the tank below the level of the product in the tank to prevent excessive exposure to air. Circulation should be intermittent when bitumen is stored for an extended period.

HOMOGENEITY

Circulation via a pump is the best method of ensuring homogeneity throughout the tank. When heated, bitumen produces convection currents that are helpful in mixing the product. Circulation should begin as soon as the bitumen is fluid enough to pump.

DISCHARGING

Initially upon starting the discharge, cargo may be circulated through manifold cross over and drop lines just to ensure that the lines are clear.

The discharge pressure on the pump & piping system may rise very fast if there is any blockage in the line.

Due to high viscosity Cargo will continue to flow to the suctions even after emptying the tanks.Therefore one tank may have to be stripped many times.

On completion of discharge the COP should be run dry at low rpm to clear the cargo from pumps and vertical lines in pump room. And all lines should be thoroughly blown from port, starboard and manifold crossover.

Bitumen tanks are provided with only main suction lines connected to main pump. There is no dedicated stripper suction or stripper pump provided. The gear pumps are very efficient and capable of stripping the tanks. A stern trim of 2 metres or more would be ideal for tank stripping. Line blowing with air after discharge will ensure all lines discharge (to shore) and suction (back to the tank) are clear of product.

The discharge of bitumen presents no difficulty while the vessel is discharging the bulk of her cargo, provided the cargo is sufficiently viscous to be pumpable. However, when draining cargo tanks, trouble may be experienced as a result of air leaking into the system through suctions in tanks already empty. This trouble is generally due to the fact that the valve in question is clogged with bitumen and no longer tight. Because of this it is best to shorten the suction lines wherever possible by closing master valves between tanks which are already empty and those still containing cargo. Bitumen in the pumps which has been allowed to cool could affect the efficiency of the suction and delivery valves but, as a general rule the heat from successive cargoes is sufficient to clear residue and keep the pump working efficiently.

Bitumen is non-crystalline in character and provided the temperature is sufficiently high it will pump readily enough, though the tank walls and bottom together with any other cooling surfaces may be left with a solid film or layer of bitumen which will vary in thickness according to the temperature. If the vessel is engaged permanently in the bitumen trade this residue will not matter, provided that suctions, strums and essential valves are not clogged or jammed by this bitumen residue.

After the first discharge, the vessel will be left with a coat of bitumen on all surfaces of the cargo tanks; this will be a permanent feature for the ship’s life. It is prudent to rework the ship’s constant after every discharge for the first three months of service of a new vessel. After two or three operations the constant it will remain more or less around the same figure and outturn figures will start tallying.

LINE BLOWING

Line blowing is a very critical operation on a bitumen tanker due to the nature of cargo being carried out onboard. Due to requirements to maintain high load/ discharge temperature, effective line blowing must be done after every cargo operation to clear the cargo lines of the remaining bitumen, before it solidifies and blocks the cargo lines. Line blowing must be immediately carried out in case of any unforeseen or planned stoppages.

Compressed air for line blowing can be provided by some terminals, however ship’s compressed Air Tank may be used, where the shore facility for line blowing is not available. The air blown will push the cargo in the lines into the cargo tank and the air will then vent out through the free flow venting line. Once the blowing is completed, the cargo line must be checked by tapping the line to ensure effective draining.

There can be serious consequences, in case of change of grade where any previous cargo with lower flash point if not effectively drained remains in lines/ pumps comes in direct contact with pumps or lines at a much higher temperature.

In general, after loading/ discharging operation is completed, compressed air will be used to blow the line contents either ashore or in the ship’s nominated cargo tanks for this purpose.

During the ship-shore safety meeting, following must be discussed and agreed with the terminal and recorded in Ship / Shore Safety Checklist.:

-Quantity of shoreline content that is expected to be blown into the cargo tank

-Nominated tanks for receiving the line content, sufficient ullage space must be ensured to accommodate the line content (shore as well as the ship) into the nominated cargo tank.

-Maximum air pressure, which must be less that the safe working pressure of the cargo lines.

Following risk factors should be considered during line blowing operations:

1. Danger if over-pressurization of the tanks
2. Risk of hot cargo coming in contact with the personnel in the vicinity.
3. Previous cargo remnant with lower flash point coming in contact with lines and pumps at higher temperature.

To prevent over-pressurization of tanks, it must be ensured that the vent line is not clogged and maintained free of blockage at all times.

For safe operation, strict adherence to the following procedure must be ensured.

1. Personnel involved in the operation must don proper PPE.
2. Minimum 3 personnel are required for this operation:
   a. One-person manning/ operating the manifold valve
   b. One-person manning/ operating the drop valve of the nominated tank
   c. Chief Officer – supervising the operation on deck
3. All openings to the cargo tanks, like ullage ports, manholes, sounding pipes etc. must be securely SHUT.
4. All cargo tanks must be isolated, and their inlet valves SHUT
5. Venting should be carried out only through the free flow venting line.
6. To prevent back flow of the cargo into the air hose, always pressurize the air hose prior opening drain on the cargo line. Similarly for disconnection, the cargo side of the valve should be closed prior shutting off air into the hose. The pressure from the air hose must be bled off into the cargo line in short bursts.
7. Shore hose must be blanked before lowering to the terminal.

In order to ensure that Cargo with lower flash point is not coming in contact with lines and pumps at higher temperature, pumps, lines (Loading & Discharge) must be well drained. Dead ends and strainer must be opened and cleaned after completion of line blowing. Cargo must be loaded / discharged once confirmed that all lines are clear of previous cargo.

SAFETY CONSIDERATIONS ONBOARD

The following hazards threaten safety:

· High temperatures

· Creation of flammable or explosive atmospheres

· Presence of toxic materials

HIGH TEMPERATURES

Burns – Contact with bitumen or pipes carrying it at these temperatures can cause serious burns. All piping vessels and equipment should be suitably insulated or lagged to minimize this risk. In the event of an accident that results in skin contact, NO ATTEMPT SHOULD BE MADE TO REMOVE THE BITUMEN. Medical attention should be sought immediately.

Contact With Water – Contact with water at high temperatures causes rapid expansion of the water and foaming of the bitumen. This leads to explosive boil over. Water is lighter than bitumen so water contamination in a tank will move to the top.

Water finding gel should be used on cool tanks before they are heated to check for the presence of water. If water is present, the cooled bitumen should be heated through the range 92°C to 125°C at a rate of not more than 10°C to 15°C per hour. The addition of 0.1 percent of a silicone antifoaming agent is helpful in preventing foaming and boil over.

· Ensure that pipes are clear of water before using them to pump bitumen into the tank ensure that there is no water in any diluents or additives added to the bitumen.

· Proper personal protective equipment should be used when working in areas of pipes or vessels carrying high temperature bitumen material. Such equipment should be labelled appropriately.

CREATION OF FLAMMABLE OR EXPLOSIVE ATMOSPHERES

Bitumen’s normally have flash points greater than 250°C. This means that explosion potential is limited. However, flammable atmospheres may develop in confined storage if:

a) Contamination is present from light ends, cutter, or fluxes. The temperature of the tank is allowed to rise above the flash point.

b) Vapours become trapped in carbonaceous deposits or in insulation areas that are disturbed.

c) Cracked bitumen vapours become trapped and build up over time.

Sources of ignition include:

a) sparks from electrical equipment.

b) auto-ignition.

c) hydraulic oil (leaking from hydraulic lines or valves) falling on thermal oil heating lines which are at high temperatures.

Auto-ignition can occur in bitumen fume/ air mixtures at temperatures greater than 230°C.

Pyrophore formation occurs when iron and hydrogen sulphide gases evolved from the bitumen at high temperature produce iron sulphide. This sulphide is reduced to sulphur or may react spontaneously with oxygen in the air auto-ignite.

The formation of coke insulates temperature sensors and may lead to overheating.

Static electricity– Bitumen and products containing bitumen do not build a static charge. However, the bitumen will carry charges during handling from one piece of equipment to another. It is important that equipment such as pumps, tank walls, and pipes are grounded.

Measures that may be taken onboard during transportation to avoid potential hazards are:

1) Ensure accurate temperature measurement.

2) Use oil with high flash point for heating.

3) Maintain a non-flammable atmosphere in the vapour space.

4) Use a tank level control system.

5) Control pyrophoric deposits and reactions by:

a) Avoiding drafts of fresh air in the tank vapour space (this can create a sudden increase in oxidation rates.
b) Avoiding steep changes in temperature at surfaces; do not insulate the roof!

c) Cleaning the inside of the tank at regular intervals to prevent deposits from breaking off and exposing new surfaces; this may cause ignition.

6) Clean coke out regularly and avoid buildup by ensuring that overheating does not occur.

7) Inspect all equipment regularly using a work permit system. Ensure that only trained personnel are used.

PRESENCE OF TOXIC MATERIALS

Fumes can occur when bitumen is heated. These contain particulate bitumen, hydrocarbon vapor, and hydrogen sulfide. Of these, the only significant material for safety consideration inside the tanks is hydrogen sulphide (rotten egg gas). Vapour spaces in tanks can build up lethal levels (< 200 ppm) of this highly toxic gas.

Safe practices and tank entry procedures should be followed, including use of correct breathing apparatus.

CLEARANCE OF BLOCKAGES

Blockages occur in bitumen distribution and delivery systems despite careful precautions to avoid them. They can be cleared by solvent soaking (filling the line or valve or pump with kerosene or diesel and allowing it to soak).

Correct heating and temperature control of the bitumen are major considerations in bitumen storage and handling. Correct design of facilities is required to ensure economical and practical storage and handling. Transportation by the vessel is as important as storage and handling in the refinery or depot.

CARGO SPILL CONTROL AND CONTAINMENT

Owning to its very high temperature, any spilled cargo must be prevented from coming in contact with water. Contact with water may cause violent splashing & formation of steam. Spilled cargo must be contained with absorbent at its edges and allowed to cool and coagulate. Then it must be scooped with shovels and arranged for disposal as solid garbage.

PHYSICAL AND CHEMICAL PROPERTIES OF BITUMEN

Combustible : No

Flammable : No

Explosive : No

Pyrophoric : No

Reactivity : No

Boiling Point deg C : >5350

Specific Gravity at 600F : 1.021

Melting Point : Not defined – depends on grade

Soluble : Insoluble in water

Appearance temperature : Black viscous semi solid at ambient

Flash Point : 3240C

Flammability Limits : N.A.

Extinguishing media : CO2 and Dry Chemical

Pour Point : 300 -1000C

HEALTH AND SAFETY INFORMATION

Carcinogen : No

Corrosive : No

Irritant : Yes

Toxic : Yes, imitating to eyes & respiratory systems

INHALATION

Asphalt fumes may cause moderate imitation to respiratory system. At low concentrations of sulphide has an odour of rotten eggs. It causes eye and respiratory irritations at concentrations of 10 – 50 PPM.

High concentrations of 500 -1000 PPM hydrogen sulphide acts as poison causing unconsciousness and death by respiratory paralysis.

SPECIAL EFFECTS

Acute hazards are recognized at the elevated temperatures of use. Severe burns to the skin and eyes can occur with contact. Eye and skin protection should be used when there is a splash potential.

Hot fumes provide discomfort and irritation upon breathing. Caution: H2S – Since sulphur components in hot asphalt may form hydrogen sulphide gas, precautions should be taken.

FIRE EXTINGUISHING MEDIA

Suitable: CO2 and Dry Chemical

Not Suitable: Water or foam may cause frothing

1. SPECIAL FIRE FIGHTING PROCEDURE

Wear self contained breathing apparatus when in confined area. Avoid inhalation of fumes. Water or foam may cause frothing.

ACCIDENT RELEASE MEASURES

Goggles or face shield, rubber boots and rubber gloves, avoid direct skin contact. Discard contaminated clothing, including shoes and skin. Wash thoroughly with soap and water after handling. All safety gear must be resistant to chemicals and hot asphalt.