Specific details for both vertical and horizontal quads are given. All diving bells should be equipped with through-water communications to permit voice communications to and from the diving supervisor. This guidance details a practical method of testing through-water communications on the surface prior to the start of diving operations before each bell run. The use of scaffolding on offshore installations presents an inherent danger of falling debris. Many divers have reported scaffolding poles lodged spear-like in the seabed around offshore installations.
Poles can also glide through water for a considerable distance before reaching the seabed.
This guidance makes two recommendations to help establish a safe horizontal separation between divers and scaffolding activities. It is recognised that there are increasing demands on the diving industry to perform tasks on or close to pipelines. These tasks include pressure testing, damage inspection, span rectification and handling of protection mattresses. This guidance sets out good working practices and aims to help both operators and contractors reduce the risks to divers executing such tasks. This publication has recently been revised to reflect the guidance given in IMCA D 019 - Guidance on diving operations in support of intervention on wellheads and subsea facilities.