The hazards and key recommendations to mitigate the risks surrounding manual sweeping operations in the vegetable oil and animal fat trades, where high cargo temperatures, enclosed space entry, and physically demanding conditions expose crew to significant safety threats.
Vegetable oils and animal fats are characterized by their high viscosity and elevated pour points, making them prone to solidify under ambient conditions. To ensure efficient discharge, the cargo temperature is maintained well above its pour point that can sometimes reach 70°C. Additional measures are also often taken to optimize cargo discharge, such as continuous recirculation of the heated cargo.
To maximize the amount of cargo discharged and minimize the quantity remaining on board (ROB), manual sweeping of the cargo is generally performed during the final stages of the discharge. Sweeping, sometimes also referred to as “squeezing” or “squeegeeing,” involves physically pushing the residue towards the pump suction. The task is labour-intensive, hazardous and can substantially increase crew workload.
Ensuring crew safety during such operations requires a unified and coordinated effort from both charterers and owners/managers (and their crew). The following recommendations, while not exhaustive, are crucial:
Operational planning:
- Early dialogue with commercial counterparts: Initiate early dialogue between the owner/manager and charterer to explore alternative options, including employment of shore-based gangs for sweeping, and incorporate appropriate charterparty clauses to prevent future disputes. Furthermore, the additional time necessary to safely carry out sweeping operations in all cargo tanks should also be considered and incorporated into the overall laytime calculations.
- Local regulations: Obtain information from local agents on any domestic regulations pertaining to working in hot environments.
- Efficient discharge plans: Formulate efficient cargo discharge plans that maximise the utilisation of fixed pumps, stagger man entries into multiple tanks, and allow sufficient additional time for the operation when planning the turnaround.
Developing and implementing procedures:
- Heat management guidelines: Develop heat and fatigue management guidelines, including things such as maximum man-entry time, minimum rest periods between consecutive entries, and how to recognise symptoms of dehydration.
- SDS verification: Verify Safety Data Sheets (SDS) and consult chemical experts when needed to ensure accurate cargo composition and hazard information.
- Toxic gas release: The crew needs to be aware of the toxic gases that a cargo can release when heated, such as carbon monoxide from coconut oil. Also, because of the varying densities of these gases, gas checks must be performed at different levels of the tank with the ventilation turned off. This ensures that the vapour sample is not diluted, giving the crew an accurate reading.
- Simultaneous tank entries: Limit the number of simultaneous tank entries to manage the risk effectively, taking into consideration things such as crew fatigue, rest hours, ventilation equipment and availability of standby responders and equipment for a rescue operation.
- In-house expertise: Maintain a continued emphasis on developing in-house expertise, especially when new personnel are involved.
Personal safety:
- Safe manning levels: Align the minimum safe manning levels with operational demands and IMO guidance.
- Appropriate PPE and detection equipment: Equip the vessel with PPE capable of withstanding cargo characteristics (temperature and chemical composition), and gas meters/chemical detection tubes to detect the full range of gases likely to be present.
- Training: Train personnel in the correct use of detection equipment, recognising heat-related symptoms, rescue from tanks, and providing the necessary first aid.