HOLDS CLEANING
Preparing cargo holds for loading is a intricate process, demanding expertise due to factors like limited understanding, time constraints, and rigorous survey checks. Stakeholders must adopt a dedicated approach for effective preparation.
FIRST STEP
Dry Cargo Hold Cleaning
Dry cleaning is the initial step in preparing cargo holds before loading. This involves sweeping hold sides, bulkheads, ladders, tank tops, and bilges to remove previous cargo residues. Brushes with long handles aid access, while brooms and shovels collect residues.
Thoroughly covering potential accumulation areas is vital, including hatch undersides, coaming trackways, and drainage channels. Opening hatch covers multiple times dislodges residues and rust. Bilge wells must be cleared too.
Certain cargos require blowing compressed air across holds, from bottom to top.
Residues collected on the tank top are packed into containers for proper disposal. Quality dry cleaning impacts holds' preparation.
C.W.P. Company Limited is a global leader in cargo hold cleaning, boasting extensive experience and skilled professionals.
SECOND STEP
Chemical Application
Chemicals are essential for efficient cargo hold cleaning before loading. Proper selection and application are vital:
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Choose appropriate chemicals for specific contaminants.
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Follow application guidelines and safety measures.
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Prepare hold surfaces for chemical treatment.
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Thoroughly apply chemicals.
Chemical Cleaning Process
Apply chemicals to dry surfaces; seawater reduces effectiveness by 40%. After seawater rinsing, chemicals go on desalinated, dry areas. Rinse with seawater or freshwater.
Prepare by determining freshwater concentration and considering dilution. Severe contamination may need undiluted chemicals. Reapply if necessary.
Cleaning Coal and Coke Residues
Oily residues from coal and coke require strong alkaline chemicals. Emulsion application followed by seawater rinsing, potentially needing multiple applications.
Acid-Based Cleansing
Diluted acid removes residues from cement, clinker, and ores. Apply, rinse, and stubborn residues might need multiple applications or physical removal. Acid reactions change color and release steam.
Safety Precautions
Strict safety measures are essential during chemical application. Special protective equipment safeguards body parts and respiratory tracts.
C.W.P. Company Limited excels in chemical cargo hold cleaning, offering global services.
THIRD STEP
General sea water wash
This method is applied after transporting cargo that doesn't leave residues, such as coal, clinker, and others, in well-maintained cargo holds (free of paint flakes, loose rust, and hardened cargo residues). After thorough dry cleaning and careful chemical application, within an appropriate timeframe, comprehensive marine cleansing becomes a crucial step. Subsequently, the holds require rinsing with fresh water. How is the comprehensive hold washing process carried out?
Following meticulous dry sweeping and chemical application, pressurized seawater is supplied from the main deck fire system through fire hoses using advanced delivery systems like Maxi-Gun or Combi-Jet. The flow of seawater should be directed towards areas in the cargo hold and hatch cover affected by contamination.
Selecting the optimal cargo hold cleaning method depends on various parameters, including understanding the types of previous and subsequent cargoes.
Experts at "C.W.P. Company Limited" will determine the most suitable strategy to meet cleanliness standards. Our skilled Cleaning Team is ready to perform their duties efficiently on vessels worldwide.
FOURTH STEP
HP Machine wash
High-Pressure Machine Wash (HPM Wash) Efficient Cargo Hold and Hatch Cover Cleaning
HPM wash entails thorough cleaning of cargo holds and hatch covers using specialized high-pressure machines with an output pressure of 300 to 500 Bar. Here's a breakdown of the process:
High-pressure hoses connect to the HPM machine, reaching 30 to 80 meters from the machine to the point of use. A turbo-nozzle boosts impact force on heavily contaminated areas. A portable HPM on the tank top or main deck delivers pressurized water through hoses to an easily handled nozzle. This reaches challenging spots using climbing gear.
The cleaner ensures comprehensive coverage, removing residues, paint flakes, and rust scales. Poor prior cleaning or chemicals can lead to residue hardening during wet work.
If remnants or stains persist, re-wash or reapply chemicals and blast with HPM.
After HPM and seawater rinse, fresh water rinse is advised. Check holds later for potential rust and paint scale dislodging. Inspect holds before loading for defects due to passage.
After successful cleaning, hold and hatch covers are finally rinsed with fresh water to remove dried salts. Rinse level depends on upcoming cargo; steel products require thorough rinsing.
C.W.P. Company Limited provides global HPM washing services. Our mobile team ensures high-standard hold cleaning swiftly.
FIFTH STEP
Tank top & Bilges
The final step in preparing cargo holds for the next load involves cleaning tank tops and bilge wells. Utilizing high-pressure machinery is essential, regardless of the previous cargo. Inspection helps decide if a rustibus machine is needed for stubborn rust on the tank top. If high-pressure water washing doesn't remove it, a rustibus machine is recommended.
Sometimes, tank tops are free of cargo and rust, but corrosive dust remains. Applying acid-based chemicals is crucial, but they must be rinsed off within 20 to 30 minutes.
Bilge wells must be thoroughly cleansed and covered with tarpaulins and watering tape to prevent cargo ingress.
After washing, collected water should be removed. Activating the ventilation system aids drying, including bilge wells. Due to likely condensation, pre-surveyor checks are recommended. Ventilation can mitigate this, done by partially opening hatch covers or activating the system.
SIXTH STEP
Cargo holds painting
Cargo Hold Painting: Maintenance and Process
Timely maintenance is key to efficient holds cleaning, reducing the need for touch-ups or full painting, based on desired cleanliness standards. Partial touch-ups prevent metal corrosion, enhance hold condition, and safeguard cargo from potential damage due to peeling paint or rust.
Process of Painting Seagoing Vessel Holds
Thorough surface prep is vital before painting. Use manual or mechanical tools to remove paint, rust, and oil/grease to meet ISO 8501 St2* cleanliness standard. Rinse with fresh water and paint within 2 hours to prevent oxidation.
Apply paint using rollers or sprayers. Prevent leaks by painting small areas with thin layers. Pay attention to corrosion-prone spots. Follow manufacturer's mixing ratios for two-component paint. Curing takes 2-3 days under good ventilation, weather permitting.
Suitable conditions are +4°C air temp and 40-70% humidity. C.W.P. Company Limited excels in hold preparation for surveyor approval. We provide global hold cleaning and painting services with efficiency and cost-effectiveness.
St2 – Thorough manual and mechanical cleaning – Surface must be devoid of visible oil, grease, dirt, loose adhering scale, rust, paint coatings, and foreign substances when viewed without magnifying devices.