– Frequently asked questions

Land-based fish farming

What must be certified in terms of land-based fish farming in Norway?

The regulation for land-based fish farms demands that pipes, tubes and tanks need to be certified. This means that components belonging to new facilities must be certified, and newly bought components in old facilities must be certified. This by an accredited company like Aquastructures AS.

What is a state analysis in terms of land-based fish farms?

A state analysis is a part of the technical escape report which must be delivered to the Directorate of Fisheries and forms the basis of the license of use. Aquastructures has contributed with the Directorate of fisheries in the work around the guide towards issuing state analysis. The land-based fish farm is divided into departments, based on for example area or type of component, and each department will get its own state level, based on the state of the components in the department. The lowest state level will form the basis of the structure total state level and will again form the basis of the lifetime of the license.

Do old land-based fish farms need product certificate?

Only new components such as pipes, tubes and tanks that are installed on the structure built before 01.01.2018 must be product certified. Structures built after 01.01.2018 must have product certified components.

What must a technical escape report contain?

The technical escape report shall form the basis of the license. The license is given by the Directorate of Fisheries. The report should contain the following:

  •  A state analysis of the structure
  • A sketch of the sewerage- and the delivery system.
  • Risk assessment for operation and the delivery of fish.
  • Geotechnical review
  • Maintenance plan.


Mooring analysis

What is an accredited mooring analysis in accordance with the Norwegian standard?

In Norway, all mooring analysis related to aquaculture must be in accordance with the Norwegian Standard, NS 9415. The standard sets the requirements for the dimensioning of the mooring system in terms of Ultimate limit states, Accidental limit states, Fatigue limit states, safety factors etc. Aquastructures is accredited by the Norwegian government to perform mooring analysis, for the aquaculture industry, in accordance with the NYTEK-regulations.

What is meant by an anchor holding power?

An anchor holding power is the resistant of the anchor to prevent drift. The holding power is dependent on the type of anchor, topography and the type of seabed. The holding power of the anchor must always be larger than the dimensional force in the anchor line.

What is pre-tension?

Pre-tension is the force in the mooring line in static condition, i.e. without the influence of waves and current.

What is a grid?

The grid is a part of the mooring system. With a grid the floating collars can be at a safe distance from each other, and still be connected to the same system.

What is a bridle?

The intention of a bridle is to connect the floating collar to the grid.

What is a local analysis?

A local analysis provides an accurate view of the stresses around structural connections, hubs hinges etc. Appropriate design of local details is crucial to prevent failures based on high stresses or fatigue.




How to get product certification?

Contact Aquastructures. We are happy to assist you.

What is a product certificate?

A product certificate is a proof that the producer can deliver a product within the aquaculture, and that this product is in accordance with the NYTEK-regulations, and the Norwegian standard NS 9415.

What is a risk analysis?

A risk analysis consists of three steps: 1) Identify potential events, 2) determine possible consequences and belonging probabilities of these potential events and 3) determine which risks that need to be handled and in which priority.

What is a mooring report?

A mooring report shall give a detailed description of the mounted mooring system. The mooring report must describe on component level what the mooring system consist of, the coordinates of the bottom mooring points, deviations from the mooring analysis, documentation of the holding power of the bottom mooring points, time for mounting the structure and a map of the mooring system.


What is extra equipment?

Extra equipment is a fixed or movable equipment, which is not a main component, that can lead to escape of fish.



Hva er et ekstrautstyr?

Ekstrautstyr er påmontert eller flyttbart utstyr, som ikke er en hovedkomponent, som kan føre til rømning dersom de brukes feil.


Site survey

What is a site survey?

In site survey design, wind, wave height and current velocity is calculated. In addition, conditions like icing, mapping of seabed and tidal level are documented. The findings from a site survey are summarized in a site survey report. The report forms the basis for mooring analysis, which in turn determines the design of the fish farm.

What is a significant wave height, Hs?

The significant wave height is defined as the mean-value of the 1/3 highest waves measured at the site.

What is wave height?

Wave height is the vertical distance between the wave crest and the wave trough.

What is maximum wave height, Hmax?

Maximum wave height is the highest wave registered within a period of three hours. From NS 9415 this is defined as: Hmax = 1.9 x Hs.





What is stability calculation?

Stability calculations deals with how a floating object behaves in waves and still water, both in intact and damage condition. The stability calculations focus on the centre of gravity, centre of buoyancy and the metacentre of the object. The stability calculations are done for different load conditions.




What does the Norwegian Standard say about stability calculations?

The Norwegian standard claims that stability calculations need to be performed for all barges. Both for intact condition and damage condition. There are specific demands for what to be calculated, and what minimum criteria that needs to be fulfilled.




When do one need to perform new stability calculations?

New stability calculations need do be performed when there are significant changes on the barge that can influence the behaviour of the barge in water. For example, new equipment with significant weight or changed load conditions.




What is the freeboard dimensional water-line?

The freeboard dimensional water-line is the barge allowed freeboard and is determined by the stability of the barge, and the strength of the hull. This limit must be marked on the hull of the barge with a white line. Loading beyond this mark may lead to instability and in worst-case capsizing.




Do not hesitate to contact us:

Aquastructures AS
Email: mail@aquastructures.no
Phone: +47 73 83 17 47
Adr: Kjøpmannsgata 21, 7013 Trondheim