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How to prevent reefer cargo deterioration ? Technic of Controlled Atmosphere (C.A.)

A reefer container, also identified as a refrigerated container, is an isolated container provided with a cooling unit. This unit is electrically powered and performs refrigerated transport over longer periods possible. Reefer containers require special care after they are loaded onboard ship. These containers need to be supplied with power, monitored closely for proper function, and repaired as required in malfunctions. The article here is about procedures and guidelines on how to troubleshoot, repair & preserve the cargo, and avoid deterioration.

Controlled Atmosphere (C.A.) cargoes : Controlled atmosphere storage or transportation provides a means of augmenting (but not replacing) refrigeration enhances the shelf life of fresh fruits and vegetables and has been extensively adopted for refrigerated ships.

containerships operational matters
Oil Tanker Safety Guide
The respiration rate of production is closely related to its rate of maturation and subsequent deterioration. Respiration is reduced by holding at an optimum temperature as low as possible without freezing or chilling the produce. It may be reduced further by lowering the oxygen content of the surrounding air. Atmospheres containing below 2% oxygen are found to be most beneficial, though the exact composition of an optimum atmosphere is species and variety dependent. The degree of the benefit obtained from C.A. varies widely between different types of products, and it may be advantageous to use additional controls on carbon dioxide, humidity and ethylene level for some produce.

Low oxygen and high carbon dioxide atmospheres have also been used to slow microbiological deterioration of fresh meat, though this is more often done nowadays using vacuum packaging or similar techniques.

It should be noted that the shelf life of produce, previously subjected to C.A. and then stored in air, has not been fully investigated for many varieties. It should also be noted that while some produce (e.g. apples, bananas) may be transported without C.A. and could therefore possibly be carried without major loss in the event of C.A. failure, much subtropical produce may not survive the length of a sea voyage without C.A.

A common means of providing C.A. in a ship's hold involves using a nitrogen generator that uses a membrane to act rather like a sieve and effectively separates nitrogen and oxygen from the air. A nitrogen-enriched stream (about 98% nitrogen) is injected into the hold space under appropriate controls to maintain the desired atmospheric composition. For the system to be effective, good sealing and good control are needed.

It is essential to understand that C.A. involves flooding hold spaces with an atmosphere that will not support human life. Safety is, therefore, a paramount issue, and control of access to cargo spaces together with warnings and alarms is essential. Specific recommendations are provided by classification societies such as Lloyd's Register of Shipping.

Individual ship owners/operators will provide clear instructions for the procedures to be adopted when loading, carrying, and discharging cargo under C.A. conditions to ensure that ships' staff and stevedores are protected. Such instructions must be followed rigorously.

Similarly, shippers will provide detailed instructions for the carriage of specific cargo, and these instructions must also be strictly followed.

Reefer repair

a) If a temperature controlled unit malfunctions while the vessel is in port, the terminal Operator and the ship Operatorís Agent shall be notified and they will, in turn, be responsible for notifying the Container Operator which is operating the unit in question.

b) While at sea, it shall be the shipís personnelís responsibility to make all necessary repairs possible to any malfunctioning unit to the best of their ability and contact the charterers for advice.

Integral reefer container side air delivery
Integral reefer container side air delivery

c) All repairs performed by the ship shall be documented for each container. The minimum information that must be recorded on is as follows: d) The "Reefer Container Trouble Report" should be sent to the charterer and the Vessel management office.

e) If the ship requires spare parts replenishment, the ship should submit the Reefer Container Trouble Report to charterer and the Vessel management office as soon as possible after the unit is repaired.

Damage and Failure Report for Refrigeration Unit
f) If a malfunctioning unit cannot be repaired onboard, and possible cargo damage is anticipated, it shall be the vesselís responsibility to report the situation to the Container Operator as soon as possible. This report shall include the following information:
g) If, at any time, the ship needs technical assistance addressing refrigeration unit problems, enquiries should be sent to the container operator or charterer.

Caution prior reefer loading

(1) Check and monitor each reefer container as per voyage instruction, which requires following essential check items.

Upon sailing from a loading port, make sure ;
(2) Once any malfunction or troubles are detected, make an immediate report to the concerned parties as per voyage instruction. If they are reefer units, also follow instructions provided .

Reefer Container Shipment

Procedures and guidelines for stowage of reefer containers shall be adhered to. A reefer container list or manifest must accompany every reefer container proposed for shipment. Additionally read our article on:
  1. Reefer cargo Handling In Port
    Reefer containers shall be plugged in and supplied with ships power as soon as practicable after loading. In case it is to be done by shore hands, ships crew shall still closely monitor the operation and confirm that all reefer containers are supplied with power earliest after loading....

  2. Reefer cargo care at sea
    At sea, all reefer containers shall be monitored by checking physically at least twice daily (weather permitting). All monitored data for each reefer container on board shall be entered in a reefer monitoring log and retained for three years. Some reefer containers with special cargo (e.g., VIP cargo) come with instructions for more frequent monitoring and reporting. Such instructions shall be strictly followed. ....

  3. Commodities Shipped In Reefer Containers
    Some cargoes may require controlled humidity (e.g. flower bulbs). In such cases, many refrigeration units are only capable of reducing humidity within the cargo space, and the settings should be applied accordingly. ....

  4. Reefer Cargo Temperature Recording
    A Partlow recorder registers temperature on a pressure-sensitive circular chart over 31 day period. If the voyage transit is expected to exceed 31 days, care must be taken to ensure charts are replaced before expiry. The first chart should be placed underneath the new chart to build up a complete temperature record for the entire voyage up until arrival at the final destination. .....

  5. Reefer Cargo Maintaining Records
    Monitoring the digital & chart temperatures of all reefer containers at least twice a day. Daily reefer container temperature checklists should be maintained, and printouts from monitoring unit should be preserved.....

  6. Reefer Cargo Care During Sea Transit
    Reefer containers usually have their own refrigeration unit, with an air or water-cooled heat exchanger. They have a data logger to record the temperature. The logger may be in the form of a Partlow chart or a digital logger. They usually contain high-value cargo, and any damage to cargo would likely result in substantial claims......

  7. Reefer Cargo Defrosting
    During the operation of a refrigeration unit, a layer of ice will form on the evaporator coils depending on the temperature set, the temperature of the cargo, the amount of fresh air ventilation and the cargo humidity. The unit periodically enters a phase where heat is produced by a series of electrical bars, allowing defrosting to occur. At such times, all fans are turned off automatically to prevent heat from entering the cargo compartment. ....

  8. Basic check item prior stowing Reefer Cargo
    Stowage location of reefers must be checked against vessels reefer receptacle locations. In case reefer containers must be loaded in random locations, it must be confirmed that monitoring and repair will be possible during the voyage, and that vessel has sufficient extension cables for providing power. ....

Container handling additional guideline:

Containership cargo stowage and planning

Stacking Weights Restrictions

Lashing strength calculation

Dangerous goods stowage and segregation

Reefer Container Stowage

Out of Gauge Container Stowage

Special Container Stowage

20 or 40 or 45 feet Compulsory Stowage Locations

Irregular Stowage of Containers

Over-stow of Containers

Hatch Cover Clearance (High cube containers Under Deck )

Other matters regarding cargo stowage as necessary

How to load maximum number 20 feet container on deck ?

What are the extra precaution should be taken prior loading a 45 feet container on deck ?

Container damage in ''2 in 1'' cargo Operation

Modern containership & loading of various container types

How to load containers coming in different forms/sizes

Our additional pages contain somewhat larger lists of resources where you can find useful informations

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Reefer cargo handling Troubleshoot and countermeasures
DG cargo handling Procedures & Guidelines
Safety in engine room Standard procedures
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