The IGC and IGF codes both require ships to be fitted with Emergency Shut-Down (ESD) systems that can be linked to a compatible shore system. However, neither describes exactly how to fulfil the intention to link ESDs.
SIGTTO and SGMF publish guidelines that detail the various links in use worldwide. This has improved global compatibility, but there are still some grey areas which unfortunately must be addressed on a case by case basis.
The radio based wireless link is the most misunderstood ship-shore link (SSL) technology.
Most traditional office-based jobs can be performed anywhere around the world on devices such as mobile phones thanks to wireless technology. While most people appreciate the benefits, we must take care when looking to change existing systems to wireless media to ensure that we do not create new problems.
SSL-ESD systems are required to transmit an ESD signal without delay*. This is easily achievable using hardwired fiber optic or electrical links. However, for pneumatics and radio-based systems this can be problematic. Radio based systems would have to be configured with minimal latency, yet enhanced availability.
Wireless sensors and communication are well accepted in standard industrial process control. These applications are subject to site-specific radio surveys and have all the required antennae located in appropriate locations.
However, installing these radio systems on floating applications poses several challenges, including:
- Vessel movement during operations
- The potential for numerous other port activities taking place nearby
- Changeable weather conditions
- Differing designs / size / topside construction of vessels using the facility
All these considerations can have an effect on the radio link quality.
LNG & LPG vessels trade worldwide and so any radio solutions will be based around a frequency and bandwidth for the operation to establishing a reliable safety communication link. Any practical solution would have to ensure that these parameters are accepted globally at all ports and be compatible with all country radio frequency licence allocations.
This paper will discuss the various technology solutions available today for radio ESD and communication links. We will carefully consider the functionality offered by each and the operational benefits and issues in providing the safe, reliable and timely activation of a linked ESD system.