Transcript LSA/NORM Training and Awareness Pack 1

LSA/NORM
Training and Awareness Pack
1
Why Oilfield Scale Occurs
• Reservoir water is rich in calcium, barium
and strontium ions. Injection water is rich in
sulphate ions. When they mix, precipitation
of calcium, barium and strontium sulphate
occurs.
• Pressure and temperature drops also
promote precipitation.
• This causes a layer of scale to form inside
production tubing and process vessels.
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Why it Becomes LSA
• Reservoir rock contains small amounts of
natural uranium and thorium and daughters.
One daughter, radium, is water soluble dissolves in the reservoir water.
• Radium precipitates with the barium and
calcium ions to make the scale slightly
radioactive.
• This makes the scale a Naturally Occurring
Radioactive Material (NORM) which is of Low
Specific Activity (LSA).
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Where it Appears
• LSA scale appears within the well fluid
handling system Tubing string (especially tailpipe)
Liner, below the packer
Subsurface Safety Valves
Wellheads
Manifolds
Separators
Oil coolers
Produced water pipework
• It can also appear in the service water
system, in pig wax, in storage cells etc.
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How it Gets There
• Incompatible waters mix as they pass through
perforations - this starts scale depositing in the
tailpipe and tubing, then throughout the plant.
• Deposition is heaviest in areas of turbulence bends, valves, restrictions.
• Also where temperature or pressure changes occur chokes, separators, coolers.
• Separator deposits - clays may absorb radionuclides
directly from water.
• Service water systems probably due to concentrating
natural radioactivity from seawater.
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How it Looks
• Pure barium sulphate is hard dense white solid.
Pure LSA scale can be like that (especially in
tubulars).
• More usually thin, eggshell-like, light or dark brown.
• Can be stratified, like rings in a tree trunk.
• Sometimes deep in the surface matrix, so not visible.
• Separator sludges are granular suspensions.
• Pig waxes are black tarry materials, often with
chunks of rust and scale mixed in.
• See Photo.
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An LSA Contaminated Tubular
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Structure of the Atom
• All matter consists of atoms.
• The atom consists of a nucleus, made
up of protons and neutrons, and a cloud
of electrons surrounding the nucleus.
• Each sub-atomic particle has its own
properties in terms of mass and chargeProton
Neutron
Electron
• See picture
Mass = 1
Mass = 1
Mass = 0.0005
Charge = +1
Charge = 0
Charge = -1
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Atomic Structure
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Types of Radiation
• Some atomic structures are unstable
because the ratio of protons to neutrons
in the nucleus is wrong.
• These naturally decay to a stable
configuration by emitting radiation.
• Three types of radiation are emitted Alpha
Beta
Gamma
2p+2n
electron
photon
Mass = 4
Charge = +2
Mass = 0.0005 Charge = -1
Mass = 0
Charge = 0
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Hazards of Each Type
• Alphas - large and highly charged. Easily
stopped and absorbed. Sheet of tissue,
outer skin or centimetres of air will stop them.
• Betas - smaller and less charged, so more
penetrating. Sheet of cardboard, metal foil or
metres of air will stop them.
• Gammas - pure electromagnetic energy.
Very penetrating. Require lead sheet, steel
plate or many metres of air to stop them.
• See penetration picture.
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Penetration of Each Radiation Type
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External and Internal Hazard
• These properties determine effect on health.
• Gammas can penetrate body from outside
and damage deep internal cells. This
penetration makes them an External Hazard.
• Alphas/betas cannot penetrate far from
outside. However if alpha emitting materials
enter the body, particularly the lungs, the size
and charge of the alphas makes them very
damaging to the cells they hit. This alpha
toxicity makes them an Internal Hazard.
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Uranium -238 and Thorium-232 Decay Series
• Two decay series in LSA scale - U-238 and Th-232.
• Uranium-238 emits alphas, betas and gammas to
decay through protoactinium, thorium, radium,
radon, polonium and bismuth to stable lead-206.
• Thorium-232 emits alphas, betas and gammas to
decay through radium, actinium, radon, bismuth,
polonium and thallium to stable lead-208.
• Each decay step takes an approximate length of time
(half life). Because some half lives are long, ratio
alphas/betas/gammas is fairly constant.
• See decay series charts.
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Uranium -238 Decay Series
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Thorium -232 Decay Series
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Hazards of LSA Scale
• Because LSA scale contains so little activity,
the external field is generally low. However
some old tubulars, separators, Wemcos may
give measurable fields.
• Because of the high alpha content, LSA scale
is a significant internal hazard.
• Therefore priority is to stop LSA scale
particles being inhaled or ingested.
• This alpha toxicity also makes safe disposal
important.
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Units of Radiation
• Unit of Activity - Becquerel (Bq)
1 Becquerel = 1 disintegration per second
This is effectively the size of the source, or as Bq/g,
the amount of radioactivity in a substance
• Unit of Absorbed Dose - Gray (Gy)
1 Gray = 1 joule per kilo absorbed
This is the amount of radiation energy absorbed
• Unit of Corrected Absorbed Dose - Sievert (Sv)
1 Sievert = 1 Gray x Quality Factor
This is the “harmfulness” of absorbed radiation
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Legislative Overview
• Two main pieces of legislation.
• Ionising Radiations Regulations - set
standards for protection of workers, by
requiring certain precautions.
• Radioactive Substances Act - set standards
for protection of public and the environment,
by setting conditions for holding, using,
storage and disposal.
• Transport regulations are separate.
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Ionising Radiations Regulations
• Set standards for protection of workers
Risk Assessment
Appointment of Radiation Protection Adviser (RPA)
and Radiation Protection Supervisor (RPS)
Local Rules
Controlled and Supervised Areas
Dose control
Training and awareness
• Regulated by HSE.
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Radioactive Substances Act
• Set standards for protection of public and
environment
Registrations and Authorisations set detailed
conditions
Contaminated equipment to specified locations
Offshore waste to sea only
Ground to below 1mm
Annual total discharge activity limit
Record of all discharges
No transfer between platforms
• Regulated by SEPA.
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Definition of “Radioactive”
• IRR brings a substance into its remit at 100
Bq/g.
• RSA has a Schedule by radioelement - for
radium the level is 0.37 Bq/g.
• The large difference is due to the intent of the
legislation - protection of the public and
bioaccumulation require lower limits.
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Rare Earths Exemption Order
• RSA is supported by Exemption Orders allow some exemptions for certain
radioelements under certain conditions.
• Phosphatic Substances (Rare Earths) EO
can be used for LSA scale.
• Exempts material up to 14.8 Bq/g from RSA.
• User must be able to prove EO applies.
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Radiation Protection Adviser
• Every radiation employer must appoint a
Radiation Protection Adviser (RPA)
Professional radiation specialist
Must be accredited by professional body
Registered with HSE
Must be consulted on radiation protection matters
Carries out annual inspection of each location
Shell RPA - Dr. Brian Heaton
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Radiation Protection Supervisor
• At workplace level, every radiation employer
must appoint Radiation Protection
Supervisor(s) (RPS)
Supervise radiation work directly
Ensure Local Rules are met on the worksite
Shell Expro 2 day course - Level 3
Train meter users and workforce - Level 2M, 2, 1
Appointed in writing - in APR and Local Rules
Shell Competent Person is lead RPS
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Local Rules
• Every radiation employer must make Local
Rules
Detailed and prescriptive rules
Tailored to each location
Written in cooperation with Business Units and RPSs
Checked and approved by RPA
In Document 3133-001
Also contains Source Register and LSA Record of
Work
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Shell Expro LSA Local Rules
• In Document 3133-001
01 - Preparation and Interfacing Prior to Work
08 - Working on LSA Contaminated Equipment
09 - Decontamination on the Installation
10 - Milling on LSA Scale
11 - Handling of LSA Contaminated Tubulars
12 - Handling of LSA Contaminated Well Control Equipment
13 - Handling of LSA Contaminated Pigs and Pig Debris
14 - Entry and Cleaning of LSA Contaminated Vessels
15 - Discharge of LSA Scale to Sea
16 - Dispatch of LSA Contaminated Items Onshore
17 - Instruction to Refurbishment Contractors
18 - Record Keeping, Reporting and Auditing
19 - Radiation Training and Competence
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Controlled and Supervised Areas
• Every radiation employer must set up
Controlled and Supervised Areas.
• Controlled Area
Where it is necessary to restrict significant exposure
Where dose likely to exceed 6 millisievert/y
• Supervised Area
Where risk needs to be kept under review, or
Where dose likely to exceed 1 millisievert/y
• Shell Expro sets up an LSA Supervised Area
around LSA work.
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Dose Controls
• Every radiation employer must limit radiation
exposure ALARP
Engineering controls
Systems of Work
Personal protective equipment
• Dose limits
Workers - 20 millisievert/y
Public/others - 1 millisievert/y
At 6 millisievert/y, workers must be Classified.
• Not really relevant to LSA scale work
(external radiation limitation).
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Philosophy of LSA Management
• Stop inhalation or ingestion of scale particlesStop dust being created
Stop dust becoming airborne
Stop dust from entering the body
Contain scale in one area and minimise contact
• To achieve this we Adhere to Local Rules
Keep scale wet to stop dust rising
Wear personal protective equipment
Set up LSA Supervised Area and restrict contact
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LSA Workflow
• General workflow is as follows Identification of work with LSA potential
Preparation for work with LSA potential
Detection and identification of LSA contamination
Working on LSA contaminated equipment
LSA disposal to sea
LSA contaminated equipment to onshore cleaner
• The rest of this pack will cover each of these
areas in detail.
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Identification of Work with LSA Potential
• Assume all fluid bearing systems are LSA
contaminated until proven clean.
• Use Local Maps to identify areas of known
LSA contamination.
• External monitoring may identify very active
LSA but not reliable.
• Test all systems at first breach, and regularly
as new surfaces are encountered.
• Record zero readings.
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Preparation for Work with LSA Potential
• Local Rule 01 (onshore), 08 (offshore).
• Onshore planning of work - coordination
between Shell and contractor(s).
• LSA Procedures/Local Rules in Workpacks.
• All parties must know/understand Shell and
own Local Rules.
• Equipment - muncher, tape, labels, tags,
polythene, PPE etc.
• Training and awareness. Tool Box Talks etc.
• Permit to Work.
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Detection and Measurement of LSA Scale - 1
• Shell standard LSA meter - Mini 900 with 44A
probe
Scintillation counter - detects high energy betas and
gammas
Readout in counts per second (cps)
Fairly robust probe
Not intrinsically safe
• See Picture.
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Mini 900 with 44A Probe
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Detection and Identification of LSA Scale - 2
• Special meter for confirming external
contamination on tubulars - Mini 900 with
EP15 probe
Geiger tube - detects alphas and low energy betas
Readout in counts per second (cps)
Fragile probe
Not intrinsically safe
Used by some operators and contractors as their
standard LSA meter - Shell prefers 44A probe
• See Picture.
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Mini 900 with EP15 Probe
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Detection and Identification of LSA Scale - 3
• Dosemeter - ICI Gammatrol PRI 90 and 90s
Measures external radiation field at a point
PRI 90 readout is in millirads per hour (mrad/h)
Converts to microsieverts per hour (μSv/h) by
multiplying by 10 (1 mrad = 10 μSv)
PRI 90s readout is in microsieverts per hour (μSv/h)
Both have three ranges - 100, 1000, 10000 μSv/h
Use 100 μSv/h range for LSA scale fields
Intrinsically safe
• See Picture.
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ICI Gammatrol PRI 90
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Selection and Use of Meters
• The Mini 900 with 44A probe is Shell’s
standard meter for LSA identification.
Measuring gammas is more reliable than
alphas/betas in the field situation, as they are not
attenuated by water, mud, wax etc.
• The Mini 900 with EP15 probe can be used
to confirm external contamination on tubing.
• However the Mini 900 with EP15 probe is not
always reliable for LSA identification in the
field situation.
Alphas/betas may be attenuated in dirty material
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Meter Reading to Declare LSA
• Using the Mini 900 with 44A probe, a
reading of 3 cps above background is LSA.
3 cpsabg is the lowest statistically reliable reading
with the meter
Does not convert directly to Bq/g, but 3 cpsabg is in
the range of 0.37 Bq/g (depending on thickness etc)
Note - it is not possible to convert from cpsabg to
Bq/g as you do not know the thickness and thus the
mass of scale that the counts come from.
• We identify contamination, we do not
measure scale activity.
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Use and Care of the Meter
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Local Rule 08.
Turn on, battery check (green), read.
With or without speaker.
Function test - use test source before use.
Probe and meter are matched - do not mix.
Remove cap, replace with thin plastic bag.
Take background, bring to surface, back away - look
for rise and fall.
• Test all new exposed surfaces.
• Calibrate annually - Aberdeen University.
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Work Precautions - LSA Contaminated Equipment
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Local Rule 08.
Record the whole job on Form F/4507 as you go.
Regular monitoring of surfaces.
LSA Supervised Area.
Personal protective equipment.
Personal hygiene - shower after work.
PA announcement before work.
Keep scale wet during work.
Minimise wire brushing, grinding, burning.
If Mini 900/44A >200 cps, check with Gammatrol
PRI 90. If >7.5 μSv/h, contact BU HS&E team.
• Label and tag everything.
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Work Precautions - LSA Supervised Area
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Local Rule 08.
Barriered off and labelled as “LSA Supervised Area”.
Deck lined with polythene to collect any loose scale.
Entry controlled and logged.
PPE donned on entry, removed at exit.
Contamination check on exit.
Minimise entry - need only.
Eyewashes and showers where appropriate.
PA announcement on setup.
All LSA to be contained in the area.
When work completed, area thoroughly cleaned and
monitored.
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Work Precautions - Personal Protective Equipment
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Local Rule 08.
One piece slicker suit or Tyvek disposable suit.
Impermeable gloves.
Impermeable boots.
Facepiece respirator to EN146FFP3 - 3M 8835 or
Moldex 3405.
• Eye protection - safety goggles.
• All PPE to be cleaned after job and monitored as
free from contamination. Must be reused or returned
as normal waste.
• Contaminated PPE cannot be sent to shore.
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Work Precautions - Personal Hygiene
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Local Rule 08.
No eating, drinking, chewing gum, sweets, tobacco.
No application of barrier cream.
All cuts and abrasions effectively dressed.
Wash hands and face before eating, drinking or
smoking.
• Shower after work.
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Work Precautions - Labelling and Tagging
• Local Rule 08.
• Tape and tag immediately after testing.
• Positive reading - yellow/black LSA Contaminated
tape + tag.
• Negative reading - green LSA Externally Clear tape
+ tag.
• Mark tags with cps, Date, Name of Tester, Platform.
• Tubulars - tape ends + 2 tubular tags
• See pictures.
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Labelling and Tagging - LSA Contaminated
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Labelling and Tagging - LSA Externally Clear
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Labelling and Tagging - Tubulars
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Work Precautions - Offshore Decontamination
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Local Rule 09.
Mainly for repair and reinstatement on installation.
Not for tubulars or very large items.
Carried out by experienced contractor cleaning crew.
Extensive decontamination requires dedicated
habitat - preferably purpose-fitted container.
Habitat is an LSA Supervised Area.
Can be used for onshore refurbishment or scrap Clearance Certificate required.
Arisings must be discharged as per Authorisation.
Work must be recorded on Form F/4507.
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Work Precautions - Milling of LSA Scale
• Local Rule 10.
• LSA scale cleanouts in wells - usually coiled tubing.
• Large LSA scale particles caught in junk-sub, small
LSA scale particles entrained in brine.
• Solids in junk-sub must be disposed to sea as per
Authorisation. Sample and mass estimate required.
• Light brine discharged to sea. Sample and mass
estimate of solids required.
• Heavy brine filtered for reuse - precoat filter. Sample
and mass estimate of backwash solids required.
• After work, mud handling equipment and filter
equipment must be decontaminated and tested.
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• Work must be recorded on Form F/4507.
Work Precautions - LSA Contaminated Tubulars
• Local Rule 11.
• Use Mini 900 with 44A probe. Lay down tubular,
insert probe into pin end.
• Test every fifth joint until LSA indicated, then every
joint from then on.
• Mark clean tested joints with green tape + tags.
• Mark contaminated joints with yellow/black tape +
tags. Fit end caps, segregate. Mark slings with tape.
• Tape and tag each joint - not bundle.
• Test for external contamination - Mini 900 with EP15
probe, or wipe test if meter not available.
• Work must be recorded on Form F/4507.
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Work Precautions - LSA Contaminated Pigs
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Local Rule 13.
Only on installations which receive interfield pigs.
Use Mini 900 with 44A probe. Pig and pig wax.
LSA precautions apply for handling and cleaning.
If pig is to be reused directly, visually clean and send
back to launch installation.
Wrap pig in polythene, tape, label as visually but not
radiologically clean.
Send sample(s) of pig wax to UESP to determine if
Rare Earths exemption applies.
If exemption applies, send wax onshore for disposal.
Work must be recorded on Form F/4507.
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Work Precautions - LSA Contaminated Vessels
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Local Rule 14.
Carried out by experienced contractor cleaning crew.
Vessel entry precautions apply.
External radiation check with PRI 90 dosemeter. If
>7.5 microsievert/h - vessel is Controlled Area.
Otherwise LSA Supervised Area.
Prior to entry, flush vessel as much as possible.
Arisings must be discharged as per Authorisation.
Sampling and mass estimate very important as these
discharges are usually large.
Sampling is a Shell Expro responsibility.
Work must be recorded on Form F/4507.
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Discharge of LSA Scale to Sea
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Local Rule 15.
Conditions set by Authorisation, must be strictly met.
All free scale, sludges must be discharged to sea.
Dedicated hose below sea surface.
Ground to below 1 mm (confirm).
Suspend diving.
Authorisations contain discharge limit - 3-10 GBq/y
Must sample discharges and estimate mass.
Samples sent to UESP for radiological analysis.
Tracked in spreadsheet.
• Discharges must be recorded on Form F/4507.
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Sampling of LSA Discharges
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Local Rule 15 Appendix.
Sample grinder output to check particle size.
Sample discharge solids for radiological analysis.
Samples must be representative of total discharge.
Samples about 100 g (50 ml).
For discharges <100 kg, single sample sufficient.
For larger discharges, eg separators, several
samples probably required.
• If scale differs markedly in places, sample each type.
• Samples must be recorded on Form F/4507.
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Dispatch of LSA Contaminated Items Onshore
• Local Rule 16.
• Must be properly sealed, labelled, taped, tagged.
• Proper documentation - manifest “LSA
Contaminated”, Dangerous Goods Declaration.
• Must go to AEAT Dounreay for decontamination.
• LSA1 package, Group 2912.
• Items must be recorded on Form F/4507.
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LSA Record Keeping
• Local Rule 18.
• Complete LSA job recorded on Form F/4507.
• Contains eight boxes A - LSA Job Number
B - Job Details
C - Monitoring Details
D - Sand/Scale Discharged to Sea
E - LSA Scaled Equipment Backloaded
F - Discharge Analysis
G - Comments
H - Supervised Area Log
• All boxes must be completed. Maximum information.
• In addition to contractor records - Shell’s overview.
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LSA Record Keeping - Form F/4507 A-C
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LSA Record Keeping - Form F/4507 D-G
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Inspection and Audit
• Local Rule 18.
• HSE and SEPA have the right to inspect any
authorised premises at any time.
• To confirm terms of IRR, RSA, registrations and
authorisations are being met.
• Sanctions include Warning Letter, Enforcement
Notice, Prosecution (fine, imprisonment).
• SEPA will compare their application/records with
offshore work records to ensure consistency.
• Shell Expro carries out annual audit of each platform
RPA audit of radiation protection arrangements
Record keeping audit
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Training and Awareness
• Local Rule 19.
• Shell Expro has produced a Competence
Matrix
Five levels -
5432(2M 1-
Expert - RPA
Senior Specialist
Shell RPS
Working with LSA hardware
LSA Meter user)
General workforce
• Also approved training for each level.
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Summary
• LSA scale represents two types of risk to Shell Expro
A HS&E risk
A legal, reputation and business risk
• Both are real and important risks and must be taken
seriously.
• We have an LSA management system to protect us described in Local Rules
Understand it
Use it (precisely)
Record everything
• Protect yourself, your colleagues and the Company.
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Keep Us Out of the Headlines!
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The Solid Gold Tubulars Return From Italy
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