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DNV-OS-F101 Submarine Pipeline Systems
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APPENDIX F
Requirements for Shore Approach
and Onshore Sections
App.F
A. Application
App.F
A 100 Objective
App.F A
101 The objective of this appendix is to provide the complementary
requirements to the onshore part of the submarine pipeline system
compliant with the safety philosophy for the offshore part. This
appendix specifies the requirements for design, construction and
operation of parts of pipeline systems going onshore. This appendix is meant to ease the project execution of submarine
pipeline developments where parts are going onshore.
Guidance note:
A submarine pipeline system is defined to end at weld beyond
the first flange/valve onshore or to the pigging terminal.
This implies that a, sometimes significant, part of the pipeline
system can be located onshore. This part of the pipeline system
may have different legislations, failure modes and failure consequences
compared to the submarine part.
The exact limit of the submarine pipeline system at the onshore end
may differ from this definition herein based on different statutory
regulations which may govern.
Onshore codes may also take precedence of this part due to
legislation aspects. ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F A
102 The appendix also covers requirements to shore approach. App.F
A 200 Scope and limitation
App.F A
201 The limitations found in Sec.1 A300 are
in general also applicable for this Appendix.
App.F A
202 The onshore section is limited by the definition of submarine
pipeline system.
App.F A
203 This appendix does not cover regular onshore pipelines, i.e.
pipelines starting and ending onshore not having any submarine parts.
River crossings or crossing of fresh water lakes are not considered
as submarine sections. Guidance note:
This appendix is not meant to replace current industry practice onshore
codes or any national requirements.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F A
204 Specific requirements for the onshore parts given in this appendix
overrule requirements given elsewhere in the standard.App.F
A 300 Other codes
App.F A
301 This Appendix is fully aligned with the requirements given
in ISO 13623Guidance note:
ISO 13623 requires a specific utilisation for landfall. According to
this code the assessment of risk will constitute selection of safety
class for each specific pipeline and pipeline sections. Normally
the safety class classification for a landfall will give the same
utilisation as required by ISO 13623 however this does not always
need to be the case. This implies that the utilisation in landfall
may differ from the ISO 13623 requirements and care should be taken
when stating compliance with ISO 13623 for a specific pipeline development. ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F A
302 Onshore pipelines are normally regulated by national regulations
and cover a wide range of areas from public safety, traffic and
roads, water ways, environmental impact, etc. Some of these regulations
may be stricter than the requirements given in this code and care
shall be exercised when assuring compliance with different national
regulations.
Fig. 1 Maximum application extent of OS-F101 with Appendix F.
App.F
A 400 Definitions
App.F A
401 Battery limit - the
limit at which the scope of work ends. The battery limit can be
different for designer, installation contractor, verifier and owners.
Normally defined at as 'including' or 'up
to' a certain weld.
App.F A
402 Code break - the exact
point at which the design code changed from submarine to onshore
code. Normally defined at as 'including' or 'up
to' a certain weld. This is often defined at the location
of the first flange or valve onshore. Note that this may differ
based on different statutory regulations.
App.F A
403 First (or last) valve onshore -
valve separating the offshore and onshore pipeline. Often the position
of the battery limit and the code break. Often an emergency shut
down valves (ESDV)
App.F A
404 Isolation joint - a
special component separating (isolating) the offshore cathodic protection
from the onshore cathodic protection system and installed within
the onshore part of the offshore pipeline. It is normally positioned
very close to the landfall as the offshore cathodic protecting system has
limited protection capabilities when the pipeline is not submerged
in water.
App.F A
405 Landfall - where the
pipeline comes on shore. Often defined by a point called LTE; Land
Terminal End.
App.F A
406 Near shore - the transition
from the offshore pipeline to the shore approach area. Often not
well defined, but can be the area in where the pipeline goes from
laying on the sea-bed to being positioned in an open trench to where
it is buried. Sometimes the extent of the areas is defined by the
reach of the installation vessel or trenching equipment, and sometimes
this area is given special attention by the fishing industry.
App.F A
407 Onshore part of offshore pipeline -
the first part of the pipeline on shore. It is distinct as the offshore
design code is still applied, while the pipeline is not offshore.
The length is normally short, up to some kilometres.
App.F A
408 Onshore pipeline -
the pipeline on shore following onshore codes and normally subject
to different authority regulations
App.F A
409 Right-of-way - corridor
of land within which the pipeline operator has the right to conduct
activities in accordance with the agreement with the land owner.
App.F A
410 Shore approach - the
last part of the pipeline before it comes on shore. The need for
burying the pipeline in the shore approach area should be evaluated
and include:| — | environmental loading (breaking
waves, current and tide), |
| — | requirements to a 'clean beach' for
recreation, |
| — | shipping activity or |
| — | protection (reduced access by 3rd parties). |
App.F
B. Safety Philosophy
App.F
B 100 General
App.F B
101 The design philosophy for the shore approach and the onshore
pipeline shall comply with Sec.2. This implies that the consequences
of failure (economical, environmental and human) shall be quantified
by the concept of safety class. The safety class is normally determined
by fluid category, location class and phase (construction, operation)
of the pipeline.
App.F B
102 The presence of people and facilities necessitates a further
refinement of the location classes used offshore. In highly populated
areas the consequences may be more severe than for offshore, requiring
a higher safety class, Very High.
These complementary
issues are described in this sub-section.Guidance note:
It should be noted that ISO 13623 contain even more stringent utilisation
requirements than safety class Very High. However, as this code
is meant to only cover onshore parts of an offshore pipeline system
it is not foreseen that such a line will be located in areas with
even higher population densities. ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F
B 200 Safety philosophy
App.F B
201 The safety philosophy outlined in Sec.2 B is applicable for
shore approach and onshore sections.Guidance note:
In particular is it important to perform a systematic review
of all hazards to identify consequences as third party presence
is more significant onshore. ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F B
202 The quality assurance outlined in Sec.2 B is applicable for
shore approach and onshore sections.
App.F B
203 The health, safety and environmental aspects outlined in Sec.2
B is applicable for shore approach and onshore sections also.App.F
B 300 Quantification of consequence
App.F B
301 Fluids shall be categorised in line with Sec.2 of this standard.
App.F B
302 A location class shall be determined for each part of the pipeline
as shown in Table F-1.App.F B
| Table F-1 Location
Classes Onshore |
| Location Class | Description 1
(Equivalent to Location class
1 as defined in Sec.2) | Locations subject to infrequent human
activity with no permanent human habitation. Location Class 1 is
intended to reflect inaccessible areas such as deserts and tundra
regions | | 2 | Locations with a population density of
less than 50 persons per square kilometre. Location Class 2 is intended
to reflect such areas as wasteland, grazing land, farmland and other
sparsely populated areas | 3
(Equivalent to Location class
2 as defined in Section 2) | Locations with a population density of
50 persons or more but less than 250 persons per square kilometre,
with multiple dwelling units, with hotels or office buildings where
no more than 50 persons may gather regularly and with occasional
industrial buildings. Locations Class 3 is intended to reflect areas
where the population density is intermediate between location Class
2 and Location Class 4, such as fringe areas around cities and towns,
and ranches and country estates. | | 4 | Locations with a population density of
250 persons or more per square kilometre, except where a Location
Class 5 prevails. A Locations Class 4 is intended to reflect areas
such as suburban housing developments, residential areas, industrial
areas and other populated areas not meeting Location Class 5. | | 5 | Location with areas where multi-storey
buildings (four or more floors above ground level) are prevalent
and where traffic is heavy or dense and where there may be numerous
other utilities underground. | |
App.F B
303 The population density in Table F-1, expressed as the number
of persons per square kilometre, shall be determined by laying out
zones along the pipeline route, with the pipeline in the centreline
of this zone having a width of:| — | 400 m for category D fluids,
and |
| — | to be determined for category E fluid pipelines, but
not less than 400 m. The determination shall include the possibility
of very low temperature during a leakage of high pressure pipelines,
giving high density gas that may "float" significant
distance prior to ignition. |
App.F B
304 Half the zone width shall not be less than the effective distance
of fluid release.
App.F B
305 The length of the zones shall be 1.5 km and located at any
location along the pipeline. The length of the random sections may
be reduced where physical barriers or other factors exist, which
will limit the extension of the more densely populated area to a
distance less than 1.5 km.
App.F B
306 The possible increase in population density and level of human
activity from planned future developments shall be determined and
accounted for when determining population density.
App.F B
307 Additional considerations shall be given to the possible consequences
of a failure near a concentration of people such as found in a church,
school, multiple-dwelling unit, hospital, or recreational area of
an organised character in location classes 2 and 3.
App.F B
308 Pipeline design according to this standard is based on potential
failure consequence and is quantified by the concept of safety class.
These may vary for different phases and locations and are defined
in Table F-2.App.F B
| Table F-2 Definition
of safety classes |
| Safety Class | Description | Low | Where failure implies low risk of human injury
and minor environmental and economic consequences | | Medium | Where failure implies risk of human injury, significant
environmental pollution or very high economic or political consequences | | High | Where failure during operating conditions implies
high risk of human injury, significant environmental pollution or
very high economic or political consequences | | Very High | Where failure during operating conditions implies
very high risk of human injury. | |
App.F B
309 The acceptable failure probability of safety class Very High
is one order of magnitude lower than for safety class High as given
in Sec.2 of this standard.
App.F B
310 The safety class determined by the crossing shall apply from:| — | for road crossings |
| — | the road right-of-way boundary |
| — | if this boundary has not been defined, to 10 m from
the edge of the hard surface of major roads and 5 m for minor roads |
| — | for railways |
| — | 5 m beyond the railway boundary or |
| — | if this boundary has not been defined, to 10 m from
the rail. |
App.F B
311 The safety class can often be determined based on the location
class and fluid category. Typical selection of safety class is given
in Table F-3.App.F B
| Table F-3 Classification
of safety classes |
| Phase | Fluid Category | Location
Class | 1 | 2 | 3 | 4 | 52 | Temporary1 | All | Low | - | | Operating Onshore | A,C | Low | Medium | - | | B | Medium | Medium | High | Very High | - | | D,E | Medium | Medium | High | Very High | - | | |
- Installation until commissioning
(temporary) will normally be classified as safety Class low. During
temporary conditions after commissioning of the pipeline, special
considerations shall be made to the consequences of failure, i.e.
giving a higher safety class than Low.
- This code is not applicable for areas in location Class
5.
App.F
C. Design Premise
App.F
C 100 General
App.F C
101 The basis for design premises for the shore approach shall
be as given in Sec.3. Special attention shall be given to aspects
related to installation, on-bottom stability, fatigue due to direct
wave loading and 3rd party activities. Statutory requirements apply.
App.F C
102 The shore approach should be constructed by either | — | a tunnel, |
| — | horizontal directional drilled (HDD) guide tube, |
| — | cofferdam, |
| — | trench, |
| — | dredging, or |
| — | combinations of the above. |
App.F
C 200 Routing
App.F C
201 The requirements in Sec.3 C apply to the shore approach section.
Additional requirements are given below.
App.F C
202 The routing shall be selected and prepared so that risk of fire,
explosions and un-intended occurrences is at an acceptable level.
Spacing between pipelines, associated equipment, harbours, ship
traffic and buildings shall be evaluated by risk assessments considering
the service of the pipeline.Guidance note:
The preferred means of routing for shore approach pipeline
will be to bury them. Examples of additional protective means are Concrete
coating or cover, additional steel wall thickness, deeper trenching,
additional marking and means to minimize the possibility for impacts
from ship traffic and vehicles.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F C
203 Special focus shall be on:| — | safety of public |
| — | protection of environment |
| — | 3rd party activities |
| — | access |
| — | other property and facilities. |
App.F C
204 Pipeline conveying category B, C, D and E fluids should avoid
built-up areas or areas with frequent human activity.
App.F C
205 In absence of public safety statutory requirements, a safety
evaluation shall be performed in accordance with the general requirements
for:| — | Pipeline conveying category
D fluids in locations where multi-storey buildings are prevalent,
where traffic is heavy or dense, and where there may be numerous
other utilities underground |
| — | Pipelines conveying category E fluids. |
App.F C
206 An Environmental Impact Assessment (EIA) shall be performed.
The EIA shall consider as a minimum:| — | temporary works during construction
and operation (e.g. repair, modifications etc.) |
| — | the long-term presence of the pipeline |
| — | leakage. |
App.F C
207 The route shall permit the required access and working width
for the construction and operation (including any replacement),
of the pipeline. The availability of utilities necessary for construction
and operation should also be reviewed.
App.F C
208 The route shall be tidy and free from flammable materials on
and in the vicinity of the pipeline system. A safety area along the
pipeline shall be defined which may restrict public access and activities.
The extent of the area shall be established based on risk analyses
and shown on the plan for the pipeline system.
App.F C
209 Facilities along the pipeline route should be identified and
their impact evaluated in consultation with the operator of these
facilities. Facilities should not be allowed closer than 4 m from
the pipeline.
App.F C
210 A wider restriction zone compared to public access may apply
to future development (buildings etc.).App.F
C 300 Environmental data
App.F C
301 Environmental data shall be collected as described in Sec.3.
Long term shore profile shall be considered. Special attention shall
be given to tidal variations. App.F
C 400 Survey
App.F C
401 Route and soil surveys shall be carried out to identify and
locate with sufficient accuracy the relevant geographical, geological,
geotechnical, corrosive, topographical and environmental features,
and other facilities such as other pipelines, cables and obstructions,
which may impact the pipeline route selection. The surveys shall
be continuous, and the accuracy and tolerance should be selected
with regard to the adjoining land and offshore surveys.
App.F C
402 Inshore survey coverage should be continuous and in agreement
within specified tolerances and accuracies of both adjoining land
and offshore route surveys.App.F
C 500 Marking
App.F C
501 The pipeline system shall be marked in such a way that its
location in the terrain is clearly visible. Provisions shall be made
to restrict public access to pipelines that are not buried.
App.F C
502 Warning signs shall be placed within visible distance and
at each side of crossings with rivers, roads and rail ways giving
information on:| — | content |
| — | owner |
| — | phone number to nearest manned station which may be alerted
in the event of fault on the pipeline. |
App.F
D. Design
App.F
D 100 General
App.F D
101 The pigging requirements in Sec.5
B114 and B115 applies to the pipeline system.App.F
D 200 System design
App.F D
201 Any electrical equipment within the location class areas shall
comply with the location class requirements.
App.F D
202 The need for lightening rod and means to avoid build up of
static electricity shall be considered.
App.F D
203 Branch connections for pipelines on land shall be supported by
consolidated backfill or provided with adequate flexibility.
App.F D
204 Braces and damping devices required to prevent vibration of piping
shall be attached to the pipe by full encirclement members.
App.F D
205 Structural items should not be welded directly to pressure
containing parts or linepipe due to the increased local stress on
the linepipe. External supports, attachments etc. shall be welded
to a doubler plate or ring. The double plate or ring shall be designed
with sufficient thickness to avoid stresses on the linepipe. In
case structural items are integrated in the pipeline, e.g. pipe
in pipe bulkheads, and are welded directly to the linepipe, detailed
stress analyses are required in order to document sufficiently low
stress to ensure resistance against fatigue, fracture and yielding. App.F
D 300 Design loads
App.F D
301 The loads shall be established as described in Sec.4. Special
attention shall be given calculations of loads from 3rd party activities
such as traffic (potential cyclic loading) and other construction
work.
App.F D
302 The loads shall be classified into functional, environmental,
interference or accidental loads as per Sec.4 of this standard with
the additional requirements below.
App.F D
303 Traffic axle loads and frequency shall be established in consultation
with the appropriate authorities or other relevant sources and with
recognition of existing and forecast residential, commercial and
industrial developments.App.F
D 400 Design criteria
App.F D
401 The design should comply with the requirements in Sec.5. Special
attention shall be given to statutory requirements.
App.F D
402 For safety class Very High the safety class factors in Table
F-4 apply.App.F D
| Table F-4 Partial
safety class resistance factor for safety class Very High |
| Limit state | gSC | Pressure containment | 1.593 | | Other limit states | 1.5 | |
App.F D
403 Buried pipelines on land should be installed with a cover depth
not less than shown in Table F-5. App.F D
| Table F-5 Minimum
cover depth for buried pipelines on land (alternative, preferred
formulation to the table above) |
| Safety Class 3) | Cover depth [m] 1) 2) 4) 5) 6) 7) |
| Trench blasted in rock | Other |
| Low | 0.5 | 0.8 |
| Medium | 0.8 |
| High | 1.2 |
| Very High | 1.2 |
- Cover depth shall be measured
from the lowest possible ground surface level to the top of the
pipe, including coatings and attachments.
- Special consideration for cover may be required in areas
with frost heave.
- River crossings, road crossings and railway crossing
shall in this context be classified as safety class High.
- Cover shall not be less than the depth of normal cultivation +0.3
m.
- For river crossings; to be measured from the lowest
anticipated bed.
- For roads and railway crossings; to be measured from
the bottom of the drain ditches
- The top of pipe shall be at least 0.15 m below the surface
of the rock.
App.F D
404 The effect of cover depth shall be considered in the expansion
evaluations.
App.F D
405 If the pipeline is not laid at a frost free depth, the mass below
the pipe's centre line must be frost proof.
App.F D
406 Pipelines may be installed with less cover depth than indicated
in Table F-5, provided a similar level of protection is provided
by alternative methods. The design of alternative protection methods
should take into account:| — | any hindrance caused to other
users of the area |
| — | soil stability and settlement |
| — | pipe stability cathodic protection |
| — | pipeline expansion |
| — | access for maintenance. |
App.F D
407 Pipelines running parallel to a road or railway should be routed
outside the corresponding right-of-way.
App.F D
408 The vertical separation between the top of the pipe and the
top of the rail should be a minimum of 1.4 m for open-cut crossings
and 1.8 m for bored or tunnelled crossings.
App.F D
409 Protection requirements for pipeline crossings of canals, rivers
and lakes should be designed in consultation with local water and
waterways authorities.
App.F D
410 Crossings of flood defences can require additional design
measures for prevention of flooding and limiting the possible consequences.
App.F D
411 Crossing pipelines and cables should be kept separated by
a minimum vertical distance of 0.3 m.
App.F D
412 Pipeline bridges may be considered when buried crossings are
not practicable. Pipe bridges shall be designed in accordance with
structural design standards, with sufficient clearance to avoid
possible damage from the movement of traffic, and with access for
maintenance. Interference between the cathodic protection of the
pipelines and the supporting bridge structure shall be considered.
App.F D
413 Provisions shall be made to restrict public access to pipe bridges.
App.F D
414 If other criteria are used, the nominal failure probabilities
shall be demonstrated to be as specified in Sec.2.App.F
E. Construction
App.F
E 100 General
App.F E
101 The same requirements as for the Offshore part of the pipeline
system shall be applied to the onshore part, if applicable. Where
this is not applicable, the requirements of ISO 13623 should
be complied with.Guidance note:
This is applicable for e.g. welding and NDT in Appendixes
C, D and E---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
App.F
E 200 Linepipe
App.F E
201 The manufacture of linepipe should comply with the requirements
in Sec.6.App.F
E 300 Components and assemblies
App.F E
301 The requirements to components and structural items as well
as assemblies should comply with Sec.7. App.F
E 400 Corrosion protection & coatings
App.F E
401 The corrosion protection shall comply with Sec.8.
App.F E
402 All metal pipelines should be provided with an external coating
and, for buried or submerged sections, cathodic protection. Corrosion
protection should normally be provided by impressed current.
App.F E
403 The design of the impressed current protection system shall
strive for a uniform current distribution along the pipelines and
shall define the permanent location for the measurement of the protection
potentials.
App.F E
404 Protected pipelines should be electrically isolated from other
structures, such as compressor stations and terminals, by suitable
in-line isolation components.
App.F E
405 Isolation joints should be provided with protective devices
to prevent damage from lightning or high-voltage earth current where
possible. Low-resistance grounding to other buried metallic structures
shall be avoided. Electrical continuity shall be provided across
components, other than couplings/flanges, which would otherwise
increase the longitudinal resistance of the pipeline. Spark gaps
shall be installed between protected pipelines and lightning protection
systems.
App.F E
406 Test points for the routine monitoring and testing of the cathodic
protection should be installed at the following locations:| — | crossings with DC tractions
systems |
| — | road, rail and river crossings and large embankments |
| — | sections installed in sleeve pipes or casings |
| — | isolated couplings |
| — | where the pipeline runs parallel to high-voltage cables |
| — | sheet piles |
| — | crossings with other major metallic structures with,
or without, cathodic protection. |
App.F E
407 The primary corrosion control for internal corrosion is identical
with the submarine part, see Sec.8.App.F
F. Operation
App.F
F 100 General
App.F F
101 The requirements to safe and reliable operation of the pipeline
systems and the pipeline integrity management (PIM) as described
in Sec.10 apply.
App.F F
102 The whole route shall regularly be checked for:| — | any required re-classification
of location class due to changes in premises like populations etc. |
| — | new facilities |
| — | new intruders or changed configurations that may cause increase
risk of threats. |
App.F
G. Documentation
App.F
G 100 General
App.F G
101 In addition to the requirements in Sec.11, the following apply:| — | crossing locations related to
lakes, straits, rivers, streams, transport communication arteries
and similar |
| — | maps necessary to evaluate the proposed route classification |
| — | relevant drawings on bridges etc. |
| — | maps with any crossing services (cables, sewage etc.). |
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