A potential significant risk when using closed diving bells is that the diving bell and its divers cannot be recovered, either because the main lift wire, secondary lift wire(s) and main umbilical are severed, or because the bell is trapped.
Such an incident is referred to as a ‘lost bell’ if supplies of breathing gas or heating from the surface are lost.
It is recognised that a lost diving bell incident is a rare occurrence, but one which is life-threatening for the divers. Previous lost bell incidents have proved fatal.
The main aims of IMCA D 077 are to describe:
The importance of emergency preparedness for a lost bell incident;
Means of preventing lost bell diving incidents; and
Means of mitigating the harmful effects of lost diving bell incidents should they occur.
IMCA D 077 collates material previously contained in several AODC and IMCA documents to provide updated guidance on the prevention and mitigation of lost bell diving incidents, superseding previously published guidance contained in the following documents which have now been withdrawn:
AODC 009 – Emergency Isolation of Gas Circuits in The Event of a Ruptured Bell Umbilical;
AODC 012 – Bell Emergency Location Equipment Trials;
AODC 019 – Emergency Procedures – Provisions to be Included for Diving Bell Recovery;
AODC 061 – Bell Ballast Release Systems and Buoyant Ascent in Offshore Diving Operations.
IMCA Diving Manager Bryan McGlinchy said:
“The publication of IMCA D 077 pulls together the Association’s key advice on lost bell emergencies into a single document, making appropriate guidance on this important and complex topic even more accessible for IMCA Members and other stakeholders.
“Following the up-to-date guidance should prevent lost bell emergencies from happening. Even so, divers and those managing diving operations should not be complacent. The information and guidance set out in IMCA D 077 will help them prepare for, and deal effectively with, a lost bell emergency.”