1.1.1 The requirements of this chapter apply to all pressure vessels for human
occupancy including but not limited to submersibles, diving bells, hyperbaric
chambers for life boats, diving systems, deck decompression chambers and non
conventional vessels as such Diving Suits. Attention should also be given to any
relevant Statutory Regulations of the country in which the unit is to be operated.
1.1.2 The pressure chambers are to be designed, manufactured and tested in
accordance with the requirements of these Rules and any applicable National or
International pressure vessel Standards/Regulations taking into consideration the
additional loads specified in this Rule.
1.1.3 All penetrations on the pressure boundaries are to be attached to the
shell by full penetration welds, irrespective of the diameter of the penetration,
unless otherwise approved by LR. All joints of the pressure chambers/pressure
boundaries are also to be of full penetration type.
1.1.4 It should be noted that a reinforcing pad on the penetration opening is
not permitted. The preferred method of compensation for Penetration opening in the
shell is:
- Increased shell plate thickness locally or
- Increased branch thickness or
- A combination of (a) and (b).
1.1.5 Intermediate heads for the pressure chambers should be designed and
attached using the adopted national or internal pressure vessel design code. In the
case where the intermediate heads’ attachment are not covered by the adopted code,
the heads shall be attached based on the guidance given is ASME PVHO-1.The basic
allowable stress will be as per the adopted Design Code/Standard factored by the
reduction factors given in ASME PVHO-1 Para 1-7.1.
1.1.6 All diving bells and compression chambers/PVHOs are to be fitted in a
prominent position with a permanently mounted name plate containing at least the
following details:
- Name of manufacturer
- Serial number and year of manufacture
- Maximum permissible working pressure or operating depth
- Test pressure
- Capacity (in litres) (of each chamber compartment)
- Maximum permissible number of divers
- Date of test and test stamp.
- LR Rules for Submersibles and the Adopted Design Code/Standard
and year of the Rule/Code/Standards.
1.1.7 All other pressure vessels and gas bottles are to be prominently and
permanently marked with the following details:
- Name of manufacturer
- Serial number and year of manufacture
- Capacity (in litres)
- Test pressure (bar)
- Empty weight (of gas bottles)
- Date of test and test stamp.
1.1.8 Permanently installed gas bottles, gas containers and gas piping systems
are, in addition, to be marked with a permanent colour code in accordance with Table 1.1.1 Marking of gas system and with the chemical symbol
designating the type of gas concerned. The marking of gas bottles must be visible
from the valve side.
Table 1.1.1 Marking of gas system
| Type of
gas
|
Chemical symbol
|
Valve End Colour
code
|
| Oxygen
|
O2
|
White
|
| Nitrogen
|
N2
|
Black
|
| Air
|
-
|
White and Black
|
| Helium
|
He
|
Brown
|
| Oxygen/Helium-Gas
mixture
|
O2/He
|
White and Brown
|
| Note:
|
Extract from BS1319:1976 and IMO resolution A536 "Code of Safety
for diving systems"
|
1.1.9 Piping, control surfaces, etc., external to the hull of the submersible will also
need protection. Protective items should be so arranged that they can be secured in
position when required.
1.1.10 An appropriate FMECA (Failure Mode Effect and Criticality Analysis)
which includes a safety hazards analysis, shall be carried out by the manufacturer
in accordance with IEC 60812 or IMCA D-039. For diving systems an analysis
concerning the function and availability of the diving system after occurrence of a
single failure is to be submitted for LR review.