Alan Rhodes
Head of Diving (Training Department)
KBA Training Centre Pte Ltd (KBAT)

Inland / inshore divers using surface supplied diving equipment, comprising of a minimum of an air supply line, a safety line & hard-wire communications will be using either a Band Mask or Helmet.

A Band Mask exposes the main part of the head to the surrounding water, with the face seal providing an air space for breathing through the regulator and vision through the face plate. A helmet totally encloses the diver's head, so affording hard hat protection from dropped objects and keeping the diver's head dry.

The main air supply arrives at the diver’s hat via his umbilical and passes through a block on the side of the helmet, (unsurprisingly called a 'side block'). From here via a tube to what is called the second stage regulator (the umbilical supplied air already having been regulated at the surface). This second stage regulator is designed to be supplied with 10 bar of pressure. This is the pressure at which the qualified hat technician sets up the regulator when doing checks, servicing or maintenance. The diaphragm in the second stage regulator senses the ambient pressure (i.e. the pressure at the water depth the diver is working) and ensures that the second stage regulator supplies air to the diver with a set pressure of 10bar. The side block has two valves, one for clearing the faceplate of condensation to improve the diver's view or as back up if there is a complete failure of the second stage regulator. The second valve allows activation of the diver's emergency bailout bottle supply carried on his back, also if there is a main air supply failure on his umbilical supply.

The hat itself is the last link in the divers air supply, and is safety critical equipment. As such, it must only be maintained by suitably qualified & competent trained personnel. Whilst around the world there are several commercial diving helmet manufacturers, the most common of these used in both onshore & offshore commercial diving would be those of Kirby Morgan Dive Systems International (KMDSI), more commonly referred to as a 'Kirby' or 'Kirby Morgan'.

There are two levels of competency for KMDSI helmets, Operator User and Basic Repair Technician.

The KMDSI Helmet and Band Mask Operator/User Course is intended to instruct personnel in the manufacturer's recommended maintenance and set-up procedures, as well as basic inspection and adjustment procedures. The operator course is not intended to be a repair technician course and does not qualify person(s) to perform repairs or overhauls. The course is intended to teach divers, tenders, and diving supervisors how to make pre-dive assessments as to the condition and serviceability of KMDSI helmets and band masks based on pre-dive visual inspection and functional tests using the applicable KMDSI checklists and Operations and Maintenance Manuals. The course certificate is valid for two years initially and three years upon re-certification.

Above: The KMDSI Basic Technician Course. (pic: KBA Training Centre Pte Ltd)

The KMDSI Basic Technician Course is intended to instruct technicians and users of KMDSI helmets and band masks how to perform routine and corrective maintenance procedures and equipment overhauls. The course covers demand regulator and side block overhauls, as well as all recommended owner level repairs, including face port insert testing. On this course technicians are taught how to strip down helmets and mask to the bare shell and reassemble, test & certify.

Helmet maintenance is not about how fast somebody can strip down & assemble, which is the goal in for example the army infantry man disassembling & reassembling a rifle, in which case the fastest is best. On the helmet & band mask courses, emphasis is put on identifying each individual part and when & why we need to replace it. In this way, a greater appreciation of the workings of the helmet become ingrained in the technician, resulting ultimately in a safer diving operation.

For more information on Helmet & Mask maintenance, please visit our Kirby Morgan DSI Courses page.