FORMAL SAFETY ASSESSMENT

PARTS COUNT METHODOLOGY

CONTENTS

FRONT PAGE

CONTENTS

ABBREVIATIONS

1.0 INTRODUCTION

1.1 Purpose

1.2 Scope

1.3 Associated Documents

2.0 SYSTEM BOUNDARIES

2.1 Process System

2.2 Grouping by Category

2.3 Other Hydrocarbon Systems

3.0 ISOLATABLE SECTIONS

3.1 Designation

3.2 Boundary Delineation

4.0 PARTS COUNT METHODOLOGY

4.1 General Approach

4.2 Counting Simplifications

4.3 Marking up P&IDs

5. EQUIPMENT AND PIPING CATEGORIES

6. PARTS COUNT TABULATION

7. REFERENCES
 APPENDIX A EQUIPMENT GROUPS COUNTED

APPENDIX B EXAMPLES OF COUNTING

ABBREVIATIONS

3D Three dimensional

BDV Blowdown Valve

COPI ConocoPhillips Indonesia

ESDV Emergency Shutdown Valve

FERA Fire and Explosion Analysis

HCR Hydrocarbon Release

LPG Liquid Propane Gas

NC Normally Closed

NLL Normal Liquid Level

OIR Offshore Industry Release

OTO Offshore Technology Organisation

PARLOC Pipeline and Riser Loss of Containment

PDMS Process Dimensional Model System

PFD Process Flow Diagram

PSV Pressure Safety Valve

P&ID Piping and Instrumentation Diagram

QRA Quantitative Risk Assessment

SDV Shutdown Valve

SP Sample Point

UK HSE United Kingdom Health & Safety Executive

1.0 INTRODUCTION

Leaks may occur from various process ‘parts’ such as vessels, pipes, valves, flanges
and instruments. It is these leaks that represent the hazardous events that may lead
to escalation and possibly catastrophic consequences. The potential for a leak is
 dependent on the number of parts physically installed in a process such that a leak is
possible. The greater the number of ‘leak sources’, the greater is the chance of there
being a leak. The overall leak frequency potential for a process facility is therefore
the summation of the number of process parts (determined through a parts count)
multiplied by their individual frequency of failure.

Over the many years of offshore operations, incidents relating to loss of hydrocarbon
containment have been recorded and analysed with respect to individual failures of
these process components and as a function of process type/system, fluid type and
the size of leak (hole size). The UK HSE OIR12 Offshore Industry Release is one
such database from which Hydrocarbon Release (HCR) Statistics have generated
generic historical leak frequency per single component, eg a leak frequency per
flange-year or per metre of pipe per year.

This database is continually updated to include all offshore incidents within the UK
waters. As a participant of this venture, ConocoPhillips has membership access to
the information contained in the database. The most recent and complete public
domain document providing this data is the previous HSE OTO 1999 (Ref 1) that
should be used if up to date information is not available. In addition the PARLOC
database (Ref 2) is used instead of HCR for riser and pipeline leaks as it is more
complete. Other references such as the older E&P Forum (Ref 3) may also be
appropriate under certain circumstances.

Risk reduction measures to prevent hazardous events through loss of hydrocarbon

containment therefore focus on the number reduction of parts or a reduction in the
parts leak frequency through welded connections or preventive maintenance.

This document focuses on establishing the parts count for a process facility and
providing statistical data that contributes to the understanding of the overall risk
picture for the facility.

1.1 Purpose

The purpose of this document is to standardise the approach by which a Parts Count
is conducted such that a consistent, acceptably accurate and verifiable count is
achieved, and in so doing potential ‘leak sources’ within a process system are
identified and recorded.

1.2 Scope

This document and its contained methodology shall be applied to all Fire and
Explosion Analyses conducted as part of the Formal Safety Assessment for process
facilities associated with the ConocoPhillips Indonesian Business Unit. The data
represents the input parameters for the determination of the potential hydrocarbon
leak frequency of the process facility.

It does not cover the actual determination of leak frequency which is the subject of
another technical note.

1.3 Associated Documents

Basic spreadsheet for Parts Count

2.0 SYSTEM BOUNDARIES

2.1 Process System

The boundaries of the process system will be the location of the first and last potential
leak source that could impact the facilities, ie first and last isolation valve at the
onshore boundary fence, or the import and export riser valves on an offshore
platform.

Leak sources are identified and recorded through a systematic count of all equipment
and fittings illustrated on the P&IDs and other associated piping
information. Consolidation of this information provides a comprehensive count of the
number of individual components making up the facilities. This, coupled with generic
historical leak frequency data for the components identified, provides the input data
for determining the potential release frequency of a hydrocarbon release event that
may occur within the process.

The parts count will be delineated through a hierarchy of ‘sections’ in order to ensure
that all is counted, easily verified and can be adjusted thereafter should changes
occur to the process and P&ID. Certain grouping of the sections also provides
statistical insight into areas of potential risk.

The hierarchy of sections are:

Isolatable Section – a subdivision of a larger hydrocarbon fluid stream defined by

isolation primarily between in-line emergency shutdown valves (ESDV) or process
shutdown valves (SDV) in the main hydrocarbon process stream and other
hydrocarbon containing utility streams.

Release Section – a specific part within an Isolatable Section relating to a fluid

phase and/or a major item of equipment. This is particularly relevant for an Isolatable
Section that contains vessels with more than one hydrocarbon phase.

Parts Count Section –the smallest part of an Isolatable Section that allows ease of
counting and recording; eg a piping line number or major item of equipment. The
sum of the parts count sections represents the Isolatable Section.

2.2 Grouping by Category

The Parts Count often provides statistical insight into the specific leak potential for a
facility when grouped together under certain categories. The potential for loss of
containment in the facilities may be identified for a particular fluid, process system or
specific location. This may be done within a spreadsheet by providing a designator or
colour for certain rows that are similar.

2.2.1 Grouped by P&ID

The P&ID on which the recorded line numbers reside is often used as an
identification category. Although it serves no statistical purpose, it does provide ease
of identification when referring back to P&IDs for updating the parts count
information.

The P&ID number first associated with the start of the isolatable section shall be used
as the designator. In some drawing schedules, particularly those used by COPI, part
of the P&ID number will also represent the Process System (see below).

2.2.2 Grouped by Contained Fluid Phase

The actual type of fluid phase contained within the process system shall be recorded
against each line number. Specific designators should be used, rather than gas or
liquid, in order to better differentiate between the different fluids types of phase and
hydrocarbon composition, eg well (production) fluids, process gas, sales gas, fuel
gas, condensate, oil, diesel, etc.

Release Cases are defined in part by the fluid phase with some Isolatable Sections
containing more than one hydrocarbon phase. The resulting consequence of a leak
could therefore be different for each phase. It is important to identify the sections
containing well fluids as it is a two phase fluid and is handled differently than single
phase when performing consequence modelling.

2.2.3 Grouped by Process System

A useful grouping is by process system, eg separation, compression as historical

data is often categorised in this way to indicate the higher risk contributors. These
process systems are often identical to the isolatable sections or delineated by a
manifold that represents the start of a new process system. Onshore, it is likely that
an isolatable section will be associated with a process system and a specific location
due to availability of space. However offshore, an isolatable section may cover one
or more process systems and extend over several deck levels. Analysis may show
this is not desirable with respect to large inventory volumes and therefore it is
important to capture this aspect.

The designator for this category may best be a shortened version of the process
system description to immediately highlight the section of the facility.

4. Grouped by Location

The final delineation category for an isolatable section is its physical location, and as
mentioned above, could span several deck levels on a platform. Such information,
together with fatality estimation, may highlight specific locations where the risk is high
and personnel presence should be avoided for continuous periods.

Release Cases are also defined by their location as it is possible for a fluid phase
withn an isolatable Section to extend over more than one deck or vessel. In this case,
the fluid phase will give rise to several Release Cases defined by location.

Care should be taken when applying this category offshore as decks may be either
plated or grated. No separation is assumed in the vertical plane when the deck is
grated.

2.3 Other Hydrocarbon Systems

In addition to the main hydrocarbon process streams, other hydrocarbon systems

may exist and should be included if such fluids give rise to events that have serious
consequences, eg

o Fuel Gas System

o Diesel Fuel System
o Hot Oil System
o Methanol System
o Amine System
o Lubricating Oil System
The decision to include these systems in any Fire and Explosion Risk Analysis (FERA)
or Quantitative Risk Assessment (QRA) depends on whether the inventory
temperature exceeds the flash point of the fluid or whether it is a known airborne toxic
substance.

3.0 ISOLATABLE SECTIONS

3.1 Designation

A discrete reference number shall be provided for each isolatable section in order that
traceability is achieved during subsequent risk analysis and consequence modelling.

The following represents a commonsense approach to designating the isolatable

sections but may not be suitable for all situations and therefore should be used as a
guideline only.

As there will be a number of isolatable sections within any given process facilities,
then an ascending two digit code shall be used, eg 04.

The fluid phase should be identified and shall be represented by a two letter code that
is a short descriptor of the fluid phase, eg PG (process gas). The code used in the
piping specification may be appropriate, or it may be extended if more definition, is
required, eg SG (sales gas).

The location of an isolatable section should be known within the process and
therefore the first P&ID number (or part representation of it), on which the isolatable
section began, shall be used, eg 3126. It may also represent the Process System, eg
26 - Compression. No set number of digits is stipulated here.

As several release cases (potential points of hydrocarbon release) may exist within
an isolatable section, then a further ascending two digit code shall be used, eg 01
etc.

The location of the release case may be useful and this shall be represented by a two
letter code that is a short descriptor of the location, eg MD (Main Deck).

Thereafter additional sub-codes may be used depending on how descriptive the

designation is required to be. For example, if the P&ID code does not contain the
Process System or Process Module, then a two digit code may be used to locate the
isolatable section, eg 26 (optional).

The actual consequence to be modelled as a result of a hydrocarbon release is also

important. This shall be represented by a two letter code that is a short descriptor for
the consequence, eg JF (jet fire).

A discrete designation is therefore established on a hierarchy basis of the form:

[Isolatable Section] – [Release Section] – [Consequence]

For example:

[04 – PG – 3126] – [01MD] – [JF]

Other two letter codes that may be used are:

PF Production Fluid TD Top Deck PF Pool Fire

PG Process Gas MD Main Deck JF Jet Fire

PG Process Liquid CD Cellar Deck FF Flash Fire

GF Fuel Gas SC Sub Cellar Deck GC Gas Cloud

DF Diesel Fuel BL Boat Landing EX Explosion

3.2 Boundary Delineation

As mentioned above, the Isolatable Sections are a subdivision of the larger

hydrocarbon fluid stream and are defined by points of positive isolation using the
following acceptable means:

Emergency Shutdown Valve, ESDV

Process Shutdown Valve, SDV

Blowdown Valve, BDV

Pressure Safety (Relief) Valve, PSV

Manual Valve, Normally Closed, NC (drain valve)

Blind Flanges

Instrument fittings

Other valves such as choke valves, check valves or control valves do not provide
positive isolation as it is not their designated safety function and are therefore not
considered. However, actuated control valves may achieve acceptable isolation
provided they are specified as fail close, fire resistant with gas tight seals and have
additional solenoid valve isolation in the control line.

It is important before commencing a parts count that the number of Isolatable

Sections is approximately known in order to determine the optimum approach to data
recording. Complex facilities may require subdivision of the parts count in order to
address the quantity of information. For a quick appraisal, the Process Flow Diagram
(PFD) may be used to identify isolatable sections as it highlights only the relevant
components such as vessels, ESDVs, SDVs and fluid types. This diagram however
is not of sufficient detail to provide a parts count.

Once the isolatable sections have been identified from the PFDs (or P&IDs), it will be
necessary to conduct a parts count from the P&IDs for each isolatable section. This
will include all in-line equipment and any associated branches for process splits,
PSVs, blowdowns, sampling points, drains and chemical injection.

It is recognised the P&IDs do not necessarily capture all equipment parts, e.g. hook-
up flanges, some instrument connections, but the P&IDs provide sufficient detail for
the purposes of risk modelling.
 In the majority of cases, an isolatable section will consist of major equipment and
several piping runs that represent changes in piping material (spec breaks), inlet and
outlet lines of vessels, and branches for pressure relief valves and blowdown
valves. Each piping line number and major equipment item shall be recorded
separately as a Parts Count Section in order to simplify updating of the Parts Count
should P&IDs be revised.

4. PARTS COUNT METHODOLOGY

4.1 General Approach

The UK HSE database is annually updated and provides leak frequency data for the
list of generic process equipment and piping fixtures as given in Appendix A. This list
represents the groups in which parts are to be counted. In most cases, the equipment
will be pressure vessels, compressors, pumps and heat exchangers and the
interconnecting piping, flanges, valves, and instruments.

All equipment items on the P&IDs shall be counted in accordance with the list in
Appendix A but the grouping with regard to size shall be ignored. Pipelines, risers
and process piping shall be counted in sizes as shown on the P&ID in order that
hydrocarbon inventory may be calculated. This also applies to flanges, valves and pig
launchers/receivers. Where equipment on a P&ID does not correspond to a
particular group, then it should be recorded as an additional group and highlighted for
further review.

It is recommended that the parts count is recorded in a simple spreadsheet format,

with Rows as piping line numbers and major equipment, and Columns as equipment
and piping/fixture sizes. This will then be in the correct layout to continue with the
determination of leak frequency data.

The following approach will be employed to define what shall be counted within an
Isolatable Section:

o Pipelines and risers shall be recorded separately under their own Parts Count
Section and pipeline category.
o Only the downstream isolation valve of an Isolatable Section is counted
rather than counting half a valve at each end of the section
o Each isolation point is inclusive of the upstream flange and valve, but
excludes the downstream flange.
o All internal boundaries such as drain lines, flare lines and blowdown lines are
taken to the first positive pressure isolation.
o Normally Closed valves (e.g. usually marked NC) are assumed to provide
isolation with the valve and upstream flange included in the upstream section;
o Spectacle Blind in closed position, or Spade is assumed to provide isolation.
The count for the upstream section is taken up to and including the flange
connection that contains the spectacle blind or spade, but no further
components downstream;
o If a cap or blind flange is shown against a valve, it is to be assumed that the
valve is in the Normally Closed position, even if no NC is shown;
o Chemical Injection and Inert Gas connections are to be counted for the
hydrocarbon section back to the first Closed valve encountered by
hydrocarbon flowing back into the injection system. Where Special
Connection (SP) injection connections are shown (temporary or manual
injection connection), all valves in the connection are assumed closed.
o Check valves are NOT to be included as isolation boundaries, but are
assumed to function as normal valves.
In counting only the downstream isolation valve of an Isolatable Section ensures that
a whole valve of a single size is counted instead of perhaps two half valves of
dissimilar sizes. The only difference between the two methods is when the process
stream splits into two or more streams when the parts count would be overestimated
by half a valve in each stream. However, the effect on the overall leak frequencies
for each section is considered negligible.

Each equipment item comprises the item of equipment itself, excluding all valves,
piping, flanges, instruments and fittings beyond the first flange.

4.2 Counting Simplifications

There are certain simplifications that are made when dealing with multiple
equipment as follows:

o Only one flowline need be counted for a multi-flowline production system with
other flowlines assumed to be of equivalent lent and parts count. (The total
Parts Count will be calculated based upon the number of flowlines in each
production header).
o Only one process train need be counted with other trains assumed to be of
an equivalent parts count. (The total Parts Count will then be calculated
based upon the number of trains).
o Standby duty equipment shall be treated as if isolated by the first isolation
valves installed in the inlet and the last isolation valve installed in the outlet
line, unless otherwise advised. Equipment shall be counted to ensure 100%
duty, ie 3 x 50% pumps – two operating, one on standby.

In establishing Release Sections, two-phase flowlines, such as those containing well

fluids, will be counted as a separate Release Case from gas and liquid sections. The
boundary for a two-phase section will be the flange that connects the two-phase
flowline to a vessel where separation of the fluid into gas and liquid occurs. The
vessel and other components downstream of that flange shall be classed liquid or gas
and counted as separate Release Sections appropriately. See Figures in Appendix II
for two-phase inlet examples.

4.3 Marking up P&IDs

Each equipment item, valve, flange, piping run and branches, instrument and fittings
on the P&ID shall be marked in highlighter or felt tip pen, once it has been
counted. This will identify those items that have been missed and also assist in the
revision of the parts count at a later stage. The parts count is usually prepared at an
early stage of design and the P&IDs may go through several revisions before being
approved for construction. Although it is likely that the changes will not significantly
affect the final outcome of the analyses, the parts count does require to be accurate
at the end of detailed design and therefore some adjustment will be necessary. The
following method of marking up shall be adopted:

o Equipment Item: The illustrated outline of the equipment on the P&ID shall
be traced with an coloured felt tip pen, preferable Red and the type, as listed
in Appendix A, written either inside the outline or alongside it, eg pressure
vessel, vertical, scrubber. The tag number of the equipment shall be
highlighted in Yellow.
o Isolation Valves shall be highlighted in Pink. Moreover, for automated
shutdown valves, the circular symbol for SDV shall also be shaded in Pink.
 o Boundary Valves (on drain lines, pressure relief, blowdown and pressure
isolation) shall be highlighted in Orange. Moreover, for automated blowdown
valves, the circular symbol for BDV shall also be shaded in Orange.
o Other valves, required to be counted, shall be highlighted in Blue.
o Flanges, required to be counted, shall be highlighted in Green.
o Lines belonging to an isolatable section shall be traced in a Single Colour
and varied for each isolatable section. Care shall be taken not to overlap
other highlighted items.

• Instruments shall be circled in Red felt tip pen.

• Each Release Section shall be clearly marked on the P&ID with a dotted line
in Blue felt tip pen and the section ID annotated.

All marked up P&IDs shall be retained for reference purposes.

5. EQUIPMENT AND PIPING CATEGORIES

The following categories represent the Columns of the spreadsheet. As mentioned

before the actual sizes of the equipment is retained in the Parts Count and not
consolidated as given in the list of Appendix A.

5.1 Pipelines and Risers

Pipelines and risers shall be recorded as separate Parts Count sections from other
process piping and their diameter and length given in metres or kilometres. This will
enable leak frequencies from a pipeline database (PARLOC) to be applied.

Subsea isolation valves or valves relating to any subsea manifold shall be counted
and recorded on the same pipeline number or riser designator.

5.2 Pig Receivers/Launchers

For the purpose of the parts count, differentiation is made between pig launchers and
receivers as the activity is seen to be different. However, unless influenced by
adverse process conditions, a pig receiver/launcher is generally used infrequently,
normally isolated and left de-pressurised. Pig receivers/launchers shall therefore not
be counted unless known to be in regular use (once a month or more frequent).

5.3 Wells

Each well bore represents an isolatable section with length determined by the depth
of the installed downhole safety valve to the surface xmas tree. The completion
string will denote the diameter of the well.

For analysis purposes, it will be assumed that all wells are identical. Care should be
taken to identify dual completion wells as this will increase the number of producing
wells beyond that associated with the well template.

5.4 Wellheads/Xmas trees

A wellhead is defined as the joint between the xmas tree and the well itself.

A xmas tree is a single component comprising a series of manual and remotely

operated flanged valves that secures the well contents under shutdown conditions. It
can be viewed as one manual master valve, one actuated master valve and an
actuated wing valve excluding all piping, valves and instruments branching off
it. However, leak frequency data is available for it as a single component.

The wellhead and xmas tree are counted separately in accordance with their design
pressure.

5.5 Process Piping

Each piping line number will be entered on the parts count worksheet and the
diameter and length of pipe in linear metres recorded. Depending on the level of
design, piping lengths may be approximated from the equipment layouts using the X,
Y, Z, coordinates. Alternatively, the following estimates may be used where drawings
are not available:

Process lines 25m for each line number

Manifolds 12m

Pressure relief 10m

Blowdown 10m

Instruments 1m

However for more accurate work, other sources should be considered:

- blowdown and relief study

- piping isometrics where available

- direct interpolation from a 3D PDMS model from which the isometrics are derived.

All piping and valves of nominal bore 2 inch and over shall be assumed to have
flanged connection. Reference should be made to the schedule for piping less than 2
inch. Flanges, valves and instrument fittings shall be captured in their appropriate
equipment group and recorded against the piping line number.

Pipe fittings such as reducers, tee-pieces etc. are assumed welded and not counted
unless otherwise advised as flanged on the P&ID.

PIPING, STEEL

PIPING, FLEXIBLE

5.6 Flanges

Flange size is associated with the line size or vessel nozzle, are counted separately
with respect to size and recorded against the piping line number. Access entrances
to vessels will be counted as shown on the P&ID, or if not, as one 24 inch flange.
 Parts count is often discussed in the context of flange counting but in actual fact, it is
the counting of ‘leak sources’ that is carried out. In applying flange counting, it is
necessary to exclude flanges that are manufactured as part of other equipment such
as valves and vessels. In most cases, one flange represents one leak source. For
example:

• An orifice plate between two flanges results in two leak sources,

• A flanged valve between two flanges results in two leak sources at the flanges.

However, there are times when this is not so. For example:

• Two mating flanges or a blind flange results in one leak source

• A flange connected to a flanged vessel nozzle results in one leak source.

Therefore care must be taken in defining what flanges are counted and where they
are recorded on the parts count spreadsheet.

5.7 Valves

A valve consists of a valve body, stem and packer, but excludes flanges, controls and
instrumentation. Valves are classified in the HCR database according to:

SIZE : NOMINAL BORE (INCH)

FUNCTION : BLOCK, BLOWDOWN, ESD, CONTROL, RELIEF, CHOKE, CHECK,

BLEED

ACTUATION : MANUAL OR ACTUATED

The number and size of each valve are counted and recorded against the piping line
number. Generally valves with a nominal bore of 2 inch and larger will be flanged
unless otherwise denoted on the piping specification or P&ID as a fully welded
section where the valves are assumed to be flange-less.

As mentioned in an earlier section, isolatable section boundaries are usually identified

by isolation valves. The parts count shall only record one valve, that being the
downstream valve. The flange associated with the downstream section of the valve
shall be counted in the next isolatable section.

One exception exists that requires to be noted. When a valve is connected directly to
a vessel nozzle, the potential ‘leak source’ upstream of the valve shall be recorded as
a flange on the downstream piping line number.

5.8 Vessels

Vessels are classified within the HCR database in accordance with:

ORIENTATION : VERTICAL OR HORIZONTAL

FUNCTION : ADSORBER, KNOCKOUT DRUM, REBOILER, SCRUBBER,

SEPARATOR
STABILISER OR OTHER

The vessel comprises the vessel itself, its nozzles and manways only and all piping,
valves and associated instrumentation shall be counted and recorded separately on
the equipment vessel line number.

Where a vessel contains more than one phase (gas and liquid), the vessel shall, for
the purpose of the parts count, be split in accordance with the associated volume
occupied by each phase. The P&ID may indicate the normal liquid level (NLL) and
this shall be used to determine if the vessel is either 1, ¾, ½, or ¼ full of liquid, which
ever is the nearest. For example, an LPG column that has a nominal 20% liquid level
should be counted as ¼ of a liquid vessel and ¾ of a gaseous vessel.

Where no normal liquid level is given on the P&ID, the vessel shall be assumed to be
half filled with liquid and recorded as ½ a liquid vessel and ½ a gaseous vessel.

The parts count shall roughly differentiate from the P&ID illustration of the vessel
which nozzles and instruments are above (gas) or below (liquid) the normal liquid
level, so that they may be counted and recorded appropriately.

For the sake of the parts count, each phase in the vessel shall be recorded as a ‘line
number’ and the respective nozzles, manways and installed instruments counted as
part of the line number. Although this method is seen to remove one flange count
from each process line, it allows the parts count to accurately represent the vessel
data sheet in terms of nozzles. Because the line numbers are eventually combined,
there is no overall loss of count for the section.

For two-phase lines within a process section (but excluding incoming well-fluid lines),
the parts count shall be divided equally between the downstream liquid and gas
release cases. This is a simplification in making the release analysis manageable,
and is not considered critical to the outcome.

The same approach shall be used for atmospheric storage tanks.

5.9 Pumps

Pumps are classified according to:

PUMPS, CENTRIFUGAL, DOUBLE SEAL PUMPS, RECIPROCATING, DOUBLE

SEAL

PUMPS, CENTRIFUGAL, SINGLE SEAL PUMPS, RECIPROCATING, SINGLE

SEAL

PUMPS SEAL-LESS MAG DRIVE

The type of pump is usually identified from the symbol used on the P&ID but process
assistance will be required to determine the type of seal integrity

The number of pumps to provide 100% duty shall be counted and remaining pumps
assumed isolated as from the last upstream isolation valves installed in the inlet line
and the first downstream isolation valve installed in the outlet line. However, isolation
of standby equipment should be confirmed as this will affect the parts count in this
section by increasing the equipment count and inventory.

5.10 Compressors
Compressors are classified according to:

COMPRESSORS, CENTRIFUGAL

COMPRESSORS, RECIPROCATING

TURBO-EXPANDERS

RE-COMPRESSORS

It is often the case that more than one compression stage is needed to achieve the
desired pressure, and this is done using a single turbine with a common shaft. In
keeping with the compressors being individual and separate on the shaft, each stage
is counted. Therefore a three stage compressor represents a count of
three. However this is not in line with the method used by the UK HSE to collect leak
frequency data which only registers the incidents occurring on a single shaft
regardless of the number of compressors.

5.11 Turbines

Turbines shall be recorded in accordance with the type of fuel used as determined
from the P&ID:

TURBINES, DUAL FUEL

TURBINES, GAS

5.12 Heat Exchangers

A heat exchanger comprises the compartment of the exchanger in which

hydorcarbons are contained, the nozzles and/or the bonnets but excludes all piping,
valves and instrumentation associated with it. Heat exchangers shall be counted only
with respect to their hydrocarbon duty and their containment, either shell or tube side
recorded in accordance with:

HEAT EXCHANGERS, HC IN SHELL

HEAT EXCHANGERS, HC IN TUBE

HEAT EXCHANGERS, PLATE

FEED GAS EXCHANGER

Where both sides of a shell and tube exchanger contain hazardous inventories, one
tube side and one shell side heat exchanger shall be counted. WHAT ABOUT
FLANGED BONNETS

5.13 Fin Fan Cooler

A Fin Fan Cooler is generally a heat exchanger using forced draft air as a cooling
medium. It may be a single unit or multiples arranged in banks. It is likely that only
one cooler will be illustrated on the P&ID but with the actual number either noted or
displayed in the tag number as A/B/C (for 3 units). The parts count shall record the
total number of units.
 5.14 Instrumentation and Small Bore Fittings

Instruments shall be to be counted and recorded individually in the following groups:

• Pressure tapping points

• Differential pressure tapping points (including orifice flow meters)
• Temperature tapping points
• Level tapping points (including sight glasses)
• Flow tapping points
• Sample and other small bore connections (chemical injection, corrosion coupons)

The OIR12 reporting system has stated that an instrument plus up to two valves, four
flanges and small bore piping shall be counted as one instrument. As a simplification
this will be extended to all instruments even if the flange/valve count per instrument
exceeds the criteria specified above. This is considered a reasonable assumption
with minor impact on the overall leak frequency analysis. The exception here is that
the valves, flanges and small bore piping shall be counted as separate items and not
included as part of the instrument.

6.0 PARTS COUNT TABULATION

Once the P&IDs are annotated, the count shall be tabulated in a spreadsheet with the
Parts Count Section as row headings, equipment groups as column headings, and
the count contained within.

An example of the parts count spreadsheet is given in Appendix C although non used
equipment groups have been removed in order to conveniently fit the landscape page.

o To the left of the table are the categories that group the various line numbers.
o To the left of the table are the various line numbers and major equipment
items recorded sequentially as they approximately appear in each isolatable
section.
o At the top of the table is the categories as given in Appendix A, subdivided
into the sizes corresponding to the facilities.
o At the bottom of the table for each equipment and piping group are the total
number of items contained in each equipment and piping group

The spreadsheet may contain all the isolatable sections, or only those isolatable
sections for a particular fluid, or represent only one isolatable section. The amount of
information on each spreadsheet depends on the complexity and extent of the
process. Dividing it into manageable sections may be advantageous but eventually a
single spreadsheet consolidating the data will be required.

The spreadsheet is also used to determine the potential hydrocarbon leak frequency
associated with the design of the process facilities. This is not shown in Appendix C
and will be the subject of another document.

The spreadsheet may also be used to calculate the individual hydrocarbon

inventories associated with each line number and thereby derive a total inventory for
the isolatable section when later combined with equipment volumes.

7.0 REFERENCES
 1. HSE Offshore Hydrocarbon Releases Statistics 1999. UK HSE. OTO 1999
079, Jan 2000

2. PARLOC Pipeline and Riser Loss of Containment, published in 1996, 1998,

2003, 2005.

3. Exploration & Production (E&P) Forum, Quantitative Risk Assessment

Data Directory, Report No. 11.8/250, 1996.

4. DNV Technica, Offshore Reliability Database (OREDA), 2004

APPENDIX A

EQUIPMENT GROUPS COUNTED

WELLHEADS XMAS TREES

PIPELINES, STEEL, D < = 4" RISERS, FLEXIBLE, D < =4"

PIPELINES, STEEL, 4" < D < = 8" RISERS, FLEXIBLE, 4" < D < = 8"

PIPELINES, STEEL, 8" < D < = 12" RISERS, FLEXIBLE, 8" < D < = 12"

PIPELINES, STEEL, 12" < D < = 16" RISERS, FLEXIBLE, 12" < D <= 16

PIPELINES, STEEL, D > 16" RISERS, FLEXIBLE, D > 16"

PIG LAUNCHERS, D < = 8" PIG RECEIVERS, D < = 8"

PIG LAUNCHERS, 8" < D < = 12" PIG RECEIVERS, 8" < D < = 12

PIG LAUNCHERS, 12" < D < =16" PIG RECEIVERS, 12" < D <=16"

PIG LAUNCHERS, D > 16" PIG RECEIVERS, D > 16"

PIPING, STEEL, D < 3" PIPING, FLEXIBLE, D < 3"

PIPING, STEEL, 3" < D < = 11" PIPING, FLEXIBLE, 3" < D < =11"

PIPING, STEEL, D > 11" PIPING, FLEXIBLE, D > 11"

PRESSURE VESSEL, HORIZONTAL, ADSORBER PRESSURE VESSEL, VERTICAL, ADSORBER

PRESSURE VESSEL, HORIZONTAL, K.O. DRUM PRESSURE VESSEL, VERTICAL, K.O.DRUM

PRESSURE VESSEL, HORIZONTAL, REBOILER PRESSURE VESSEL, VERTICAL, REBOILER

PRESSURE VESSEL, HORIZONTAL, SCRUBBER PRESSURE VESSEL,VERTICAL SCRUBBER

PRESSURE VESSEL, HORIZONTAL, SEPARATOR PRESSURE VESSEL, VERTICAL, SEPARATOR

PRESSURE VESSEL, HORIZONTAL, STABILISER PRESSURE VESSEL, VERTICAL, STABILISER

PRESSURE VESSEL, OTHER

HEAT EXCHANGERS, HC IN SHELL FILTERS

HEAT EXCHANGERS, HC IN TUBE FIN FAN COOLERS

HEAT EXCHANGERS, PLATE STATIC MIXER

FEED GAS EXCHANGER STORAGE TANKS

PUMPS, CENTRIFUGAL, DOUBLE SEAL PUMPS, RECIPROCATING, DOUBLE SEAL

PUMPS, CENTRIFUGAL, SINGLE SEAL PUMPS, RECIPROCATING, SINGLE SEAL

PUMPS SEAL-LESS MAG DRIVE

COMPRESSORS, CENTRIFUGAL TURBINES, DUAL FUEL

COMPRESSORS, RECIPROCATING TURBINES, GAS

TURBO-EXPANDERS

RE-COMPRESOR

VALVE ACTUATED, BLOCK, D < = 3" VALVE ACTUATED, BLOWDOWN, D < = 3"

VALVE ACTUATED, BLOCK, 3" < D < = 11" VALVE ACTUATED, BLOWDOWN, 3" < D < = 11"

VALVE ACTUATED, BLOCK, D > 11" VALVE ACTUATED, BLOWDOWN, D > 11"

VALVE ACTUATED, ESDV, D < = 3" VALVE ACTUATED, CONTROL, D < = 3"

VALVE ACTUATED, ESDV, 3" < D < = 11" VALVE ACTUATED, CONTROL, 3" < D < = 11"

VALVE ACTUATED, ESDV, D > 11" VALVE ACTUATED, CONTROL, D > 11"

VALVE ACTUATED, RELIEF, D < = 3" VALVE ACTUATED, CHOKE, D < = 3"

VALVE ACTUATED, RELIEF, 3" < D < = 11" VALVE ACTUATED, CHOKE, 3" < D < = 11"

VALVE ACTUATED, RELIEF, D > 11" VALVE ACTUATED, CHOKE, D > 11"

VALVE ACTUATED, P/L ESDV, D < = 4" VALVE ACTUATED, P/L SSIV ASSEMBLY, D < 4"

VALVE ACTUATED, P/L ESDV, 4" < D < = 8" VALVE ACTUATED, P/L SSIV ASSEMBLY, 4" < D < = 8"

VALVE ACTUATED, P/L ESDV, 8" < D < = 12" VALVE ACTUATED, P/L SSIV ASSEMBLY, 8" < D < = 12"

VALVE ACTUATED, P/L ESDV, 12" < D < = 16" VALVE ACTUATED, P/L SSIV ASSEMBLY, 12" < D < = 16"

VALVE ACTUATED, P/L ESDV, D > 16" VALVE ACTUATED, P/L SSIV ASSEMBLY, D > 16"

VALVE MANUAL, BLOCK, D < = 3" VALVE MANUAL, CHECK, D < = 3"

VALVE MANUAL, BLOCK, 3" < D < = 11" VALVE MANUAL, CHECK, 3" < D < = 11"

VALVE MANUAL, BLOCK, D > 11" VALVE MANUAL, CHECK, D > 11"

VALVE MANUAL, CHOKE, D < = 3" VALVE MANUAL, BLEED

VALVE MANUAL, CHOKE, 3" < D < = 11"

VALVE MANUAL, CHOKE, D > 11"

 FLANGES, D < = 3"

FLANGES, 3" < D < = 11"

FLANGES, D > 11"

INSTRUMENTS

APPENDIX B – EXAMPLES OF COUNTING

SUBSEA 12 14 RISER 12 14 PIPING 2 3 4 8 INSTRUMENT PRESSURE TEMPERATURE FLOW LEVEL HORIZONTAL VESSEL
PIPELINE

BELIDA 32
PIPELINE, km
34KAQ001 BELIDA 100
RISER, m
BELIDA 32 0 100 0 00 00 0 0 0 0
PIPELINE/RISER
KEONG 4
PIPELINE, km
34KAQ004 KEONG 100
RISER, m
KEONG 0 4 0 100 00 00 0 0 0 0
PIPELINE/RISER
12"-PG-D1-34-003
34KPT001 PIG 1
RECEIVER
12"-PG-D1-22-003 1 2
14"-PG-E1-34-002
14"-PG-E1-22-002 1 1
24"-PG-D1-22-005 4
22MBF001 SLUG 2
CATCHER
24"-PG-D1-22-008 2 1
4"-PG-D1-22-018
8"-PG-D1-22-277
24"-PG-D1-22-671
22MPF002 SLUG 2
CATCHER
24"-PG-D1-22-673 1 2
14"-PG-D1-22-676
8"-PG-D1-22-009
20"-PG-D1-22-010 2
to SDV-0051/0052
20"-PG-D1-22-011 2
to SDV-0061/0062
GAS 0 0 0 0 00 00 18 8 0 4
CONDITIONING

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