Ptil logo 2018 svart mobile ptil-logo-english-new

§ 90 Positioning

When carrying out maritime operations, the responsible party shall implement necessary measures so that those who participate in the operations, are not injured, and so that the likelihood of hazard and accident situations is reduced.
Requirements shall be set for maintaining the position of vessels and facilities when conducting such operations, and criteria shall be set for start-up and interruption.
Section last changed: 01 January 2018

In order to fulfil the requirement relating to marine operations as mentioned in the first subsection, Table 1 Equipment Class should be used for vessels and facilities with dynamic positioning, with the following addition:
in the event of dynamic positioning near other floating facilities or vessels, consideration should be given, inter alia, to
  1. mutual movement and different movement patterns,
  2. the effect of current and noise from propellers,
  3. interference with other or joint transponders
  4. varying shadow effect for antennas connected to the dynamic positioning system.
For calculation of anchoring systems, see also Section 25.

Table 1 Equipment Class
For a description of the equipment classes in this table, see IMO/MSC Circular 1580, Chapter 2, Equipment Classes.

ACTIVITY

 

 

a) Manned underwater operations

where loss of position entails a high risk for divers or diver platforms

3

b) Other manned underwater operations

where loss of position entails risk for divers or diver platforms

2

c) Support vessels for manned underwater operations conducted from work boats

where loss of position for the support vessel has direct consequences for the work boat

2

d) Drilling and well activities

where well control is ensured by a facility with dynamic positioning

3

e) Facilities that produce or store hydrocarbons

3

f) Flotels with gangway connected

Two reference systems may be accepted for arrival and departure

3

g) Vessels with offshore gangway connected to simpler facilities

2

h) Activities carried out by lifting vessels or pipe-laying vessels in the vicinity of the facility (here permanently placed and mobile/floating)

It may be acceptable for only two out of three reference systems to be operational upon arrival and departure

3

i) Other activities within the safety zone, where the vessel represents a risk to the facility

The requirement applies if the vessel exceeds the vessel size the facility is designed for with regard to withstanding a collision.

Two reference systems may be accepted for arrival and departure

2

j 1) Tank vessel loading from facilities handling hydrocarbons

j 2) Tank vessel loading from subsea loading and off-loading installations

where the tank vessel is not moored or anchored to these installations

j 3) Tank vessel loading from subsea loading and off-loading installations

where the tank vessel is moored or anchored to these installations

2

2

 

1* or 2*

k) Loading operations from buoys

1

l) Other well activities

The requirement applies to well maintenance facilities if well control is handled by another facility

2

m) Shallow drilling

if encountering hydrocarbons is not expected

1

*Class 1 if the distance between associated facility(-ies) and tank vessel is 2.5 km or more, Class 2 if not.

Notes to the table
  1. For dynamic positioning, consideration should be given to the reference systems' limitations as regards reliability, availability and quality.
  2. High risk as mentioned in this table litera a, means the cases when the diver does not have an unrestricted return to the diving bell, or where loss of the vessel's position can lead to loss of or damage to the diving bell, and possibly the associated bottom weight.
  3. The requirement relating to Equipment Class 3 for drilling and well activities as mentioned in this table litera d, does not apply to shallow drilling and core drilling. For shallow drilling, however, other requirements in the table may be relevant, such as the requirement relating to Equipment Class 2 for other activities within the safety zone without risk to health, environment and safety. Well activities that require Equipment Class 3, include well intervention, such as wireline operations. Other well activities as mentioned in this table litera l, with requirements for Equipment Class 2, where the production facility has well control equipment, may be well stimulations and unmanned underwater operations, including the use of remote-controlled subsea vessels or subsea tools.
  4. The recommendation for Equipment Class 2 for tank vessels as mentioned in this table, is conditional upon the preparation of a positioning capacity plot for the dynamic positioning system.


In order to maintain the position as mentioned in the second subsection, floating production, storage and offloading facilities (FPSOs) and floating storage units (FSUs) that offload to tank vessels, should be equipped with directional control. For information, see also Section 63 of the Facilities Regulations.
Floating production and storage facilities should at all times know their own position and direction and the position and direction of nearby facilities and larger vessels, cf. Section 31.
In loading operations where no hawser is being used, the tank vessel should be able to stop the loading automatically if the limits for distance and direction are exceeded, at the same time as emergency shutdown valves are being closed on the facility and on the vessel, cf. Section 33 of the Facilities Regulations.
For vessels anchored within the safety zone which are larger than the facility has been designed to withstand collision with, the anchoring should fulfil Sections 6 through 17 of the Norwegian Maritime Authority’s Regulations relating to positioning and anchoring systems on mobile facilities (in Norwegian only) (the Anchoring Regulations 09), and should conform with Section 16 of the Norwegian Maritime Authority’s Regulations for mobile facilities with technical production installations and equipment (in Norwegian only) if they lie adjacent to the facility.