CONTENTS
1 Scope ……………………………………………………….
2 References ……………………………………………………….
3 Terminology & Glossary …………………………..
4 Development of P&ID …………………………..
4.1 General Consideration …………………………..
4.2 Lay-out Format ……………………………………………………….
4.3 Symbols ……………………………………………………….
4.4 Lines ……………………………………………………….
4.5 Text ……………………………………………………….
4.6 Equipment ……………………………………………………….
4.7 Equipment Details …………………………..
4.8 Equipment Data ……………………………………………………….
4.9 Piping ……………………………………………………….
4.10 Valve Symbols ……………………………………………………….
4.11 Piping Specialty Items …………………………..
4.12 Piping Fittings ……………………………………………………….
4.13 Off-Page Connectors and Tie-In Symbol
4.14 Drain Connectors ……………………………………………………….
5 Instrumentation & Controls …………………………..
5.1 Symbols ……………………………………………………….
5.2 Measurements ……………………………………………………….
5.3 Valves……………………………………………………….
5.4 Safety / Relief Devices …………………………..
5.5 Equipment Start/Stops …………………………..
5.6 Interlocks & Alarms …………………………..
5.7 DCS Points ……………………………………………………….
6 Notes ……………………………………………………….
1 Scope
1.1 This standard provides minimum Process information required for the
development and presentation of Piping and Instrument Diagram.
1.2 This standard covers the generation of new P&IDs and does not apply to the
revision of existing P&IDs.
1.3 It also applies to P&IDs provided by packaged equipment vendors.
2 References
Reference is made in this standard to the following documents. The latest issues,
amendments, and supplements to these documents shall apply unless otherwise
indicated.
SABIC Engineering Standards (SES)
D03-D03 – Instrument Numbering System
D04-G05 – Guidelines for Instrument and Control Drawings Preparation
D04-G02 – Drafting Guidelines for Piping & Instrument Diagram Preparation (for
drafting information)
American National Standards Institute (ANSI)
ANSI/FCI 70-2
American Society of Mechanical Engineers (ASME)
ASME Boiler and Pressure Vessel Code Section VIII – Pressure Vessels
International Society of Automation (ISA)
ISA S5.1 Instrumentation Symbols and Identification (R1992)
ISA S5.2 Binary Logic Diagrams for Process Operations (R1981)
IEC
IEC-61511 Functional safety � Safety instrumented systems for the process industry
sector
IEC-61508 Functional safety of electrical/electronic/programmable electronic safety-
related systems
Tubular Exchanger Manufacturers Association (TEMA)
3 Terminology & Glossary
A piping and instrument diagram (P&ID) is a detailed graphical representation of a
process including the hardware and software necessary to design, construct and operate
the facility and serves as the basic document of a project to show the scope of work, and
provide the detailed plant design definition. These diagrams include all mechanical
equipment, including columns, vessels, pumps compressors, piping valves of all types,
exchangers, furnaces, motors, turbines, engines, all instrumentation, storage tanks,
product handling and loading arrangements, special mechanical equipment and utilities
with corresponding data required for the mechanical design of a particular unit. Common
synonyms for P&IDs include EFDs (Engineering Flow Diagrams) and MFDs (Mechanical
Flow Diagrams).
For the purpose of understanding this standard, the following definitions apply:
Accessible. A term applied to a device or function that can be used or be seen by an
operator for the purpose of performing control actions (e.g., set point changes, automanual
transfer
or
on-off
actions)
(Reference
ISA
S5.1.)
Automated Valve. Any valve with a locally or remotely controlled actuator. Examples are
throttling control valves and on/off block valves. Actuators are typically air-operated
(diaphragm or piston), electric or hydraulic, some with spring return function. Manually
operated valves are sometimes also tagged as automated valves such as when a manual
valve is fitted with position switches.
Auxiliary P&ID. P&ID used to show details in order to unclutter other P&IDs (e.g., lube oil
system, sample systems, instrument details)
Distributed Control System (DCS). The Distributed Control System is the control
equipment and system that is installed to regulate normal production functions. The DCS
is required to operate the process and consist of Controllers, Human Machine Interfaces
and printers. Examples of control functions included in the DCS are regulatory controls,
cascade control, override control, ratio controls and pump start/stop co (Also known as
Basic Regulatory Controls).
Bubble. The circular symbol used to denote and identify the purpose of an instrument or
function. It usually contains a tag number. Synonym for balloon. (Reference ISA S5.1.)
Design Pressure. The pressure used in the design of a vessel component together with
the coincident design metal temperature for the purpose of determining the minimum
permissible thickness or physical characteristics of the different zones of the vessel
(Reference ASME Boiler Pressure Vessel Code Section VIII, Division 1, Appendix 3.)
Equipment Trim. Items attached to equipment as an integral component, identified as
part of the equipment that is exposed to the process and whose function is local to the
equipment it serves. Examples are vent and drain valves, instrument bridles, blind
flanges, plugs or other miscellaneous items associated with a piece of equipment.
Fail Closed (FC). The characteristic of an automated valve that results in the valve
closing as a result of specific malfunctions, including loss of signal or motive power
(Reference ISA S5.1.)
Fail Indeterminate (FI). The characteristic of an automated valve that results in the valve
moving to an unknown position as a result of specific malfunctions, including loss of
signal or motive power. Some automated valves will not stay at the last position upon
failure and will instead move with the process differential pressure. Additional equipment
may be needed to meet the definition of FC, FO or FL. (Reference ISA S5.1.)
Fail Locked (FL) Last Position. The characteristic of an automated valve that results in
the valve remaining in the last (locked) position as a result of specific malfunctions,
including loss of signal or motive power. Automated valves may fail indeterminate without
additional equipment. (Reference ISA S5.1.)
Fail Open (FO). The characteristic of an automated valve that results in the valve
opening as a result of specific malfunctions, including loss of signal or motive power
(Reference ISA S5.1.)
Hand Switch (HS). Any operator manipulated discrete control device, including hardwired
panel switches and software points
Higher Level Control System (HLCS)/ Advanced Process Control (APC). The Higher
Level Control System/APC provides sophistication above that of the DCS. The
HLCS/APC is not necessary to operate the process. HLCS/APC functions are typically
based in process computers or higher level DCS hardware that interacts with the process by manipulating set points in the DCS. Examples of control functions in the HLCS/APC
are statistical process control and model predictive control.
Interlock. A system that, in response to a predetermined condition, initiates a predefined
action. Typically comprised of binary (on – off) signals and logic used for process control,
sequencing or protective interruption of normal process control functions. Protective
interlocks are typically further defined as being either safety related or commercial (asset
or production protection) related.
Isolation Valve. A Valve used as primary block valve to isolate process equipment for
de-pressuring, purging or de-inventorying.
Line Class. A section of the Piping Material Specifications, which provides a listing of
piping components for specific design conditions
Logic solver. The control equipment that performs the logic function. It can be either
hardwired (e.g., relays) or Programmable Electronic Systems (e.g., DCS or PLC based,
including dual or triple redundant microprocessors).
Packaged Equipment. One or more pieces of equipment furnished by a vendor with
supportive devices and components to perform a specific operation as a unit
Programmable Electronic System (PES). Logic performed by programmable or
configurable devices (Reference IEC-61511.)
Root valve. The first valve or valves between the process and an auxiliary device (e.g.,
an instrument) that contacts the process and is used to isolate the device from the
process. This is typically a line class valve used for shut-off and isolation. It is also
commonly referred to as the primary block valve.
Safety Integrity Level (SIL). SILs are defined in terms of Probability of Failure on
Demand (PFD). (Reference IEC-61511.)
Safety Instrumented Systems (SIS). Systems composed of sensors, logic solvers and
final control elements for the purpose of taking the process to a safe state when
predetermined conditions are violated. Other terms commonly used include Emergency
Shutdown System (ESD, ESS), Safety Shutdown System (SSD) and Safety Interlock
System. (Reference IEC-61511.)
Skirt. A cylindrical supporting structure, welded to the bottom of a vertical vessel and
extended to the base support
Tagged. For the purposes of labeling instrumentation and control components, a
hardware device or a software point.
Tight Shut-off (TSO). Leakage Class defined by ANSI Class V or VI per ANSI/FCI 70-2
for control valve.
UPS. Uninterrupted Power Supply
4 Development of P&ID
4.1 General Consideration
4.1.1 This Guideline utilizes the concepts of typical details with implied
components in the P&IDs.
4.2 Lay-out Format
4.2.1 Layout each P&ID to avoid clutter and allow future modifications. Show
no more than three pieces of major equipment per P&ID.
4.2.2 Show primary flow on each P&ID from left to right. Show flow through
equipment relative to actual arrangement (e.g., cooling water supply in
bottom of exchanger tube bundle and cooling water return out top).
4.2.3 Show service description, connector number, P&ID number and
origin/destination for (1) off-plot connectors and (2) Primary / Secondary
and Instrument Signal connectors.
a. Show origin/destination as an equipment number, line number, or
loop number.
b. Show service description as name of fluid or line description for
piping off-page connector.
c. Show service description as a line function or equipment to be
controlled for instrument off page connector.
d. Show service description and origin/destination text starting at
left side of off-page connector symbol on the left side of the
drawing. Show service description and origin/destination text
starting at right side of the off page connector for lines on the
right side of the drawing.
4.2.4 Show equipment arrangement relative to its elevation to grade.
4.2.5 Show pump and compressor driver piping, instrumentation and auxiliaries
on a separate auxiliary P&ID.
4.2.6 Use typical details when they eliminate clutter without detracting from
clarity. Show these details on the P&ID, on an auxiliary P&ID, or on a
cover sheet.
4.2.7 Where lines cross battery limit/plot limit boundaries it is the intention that
the same line data identification continues until its destination point.
Therefore, line data identification in one unit shall indicate lines from
other units as the origin line data identification. Provision on P&IDs and
line lists should be made for this
4.3 Symbols
4.3.1 Show a connection to an equipment nozzle when the connection is
welded.
4.3.2 Show normally closed manual valves using a darkened solid symbol.
When darkened in valves cannot be used because of symbol type (e.g.
butterfly valve), use the abbreviation for Normally Closed (NC) directly
below the valve in a horizontal line or to the right of the valve in a vertical
line.
4.3.3 Show on-off valves in normal operating position.
4.3.4 Do not show control valves or relief valves normally closed.
4.4 Lines
4.4.1 Show flow arrows at corners and intersecting lines, where there is a
change in direction of majority of flow.
4.4.2 Break vertical primary process lines when crossing horizontal primary
process lines.
a. Break secondary and utility lines for primary process lines.
b. Break vertical secondary and utility lines for horizontal secondary
and utility lines.
c. Break instrument lines for all process and utility lines.
d. For utility collection/distribution P&IDs, break entering and exiting
lines around pipe rack lines.
4.5 Text
4.5.1 Show line numbers at entering off-page connectors top/left justified.
Show line numbers at exiting off-page connectors top/right justified.
a. Show equipment number, title and data once for identical
equipment with the same number, title and service.
4.5.2 Show control valve failure action abbreviation directly below control
valve.
4.5.3 Show control valve size between the actuator and valve body symbol if
the valve is not line size or easily inferred from adjoining pipe, reducers
or equipment.
4.5.4 Show control valve seat leakage criteria (TSO) between the actuator and
valve body symbol.
4.5.5 Show the device size and set pressure for PSV’s, PSE’s, and PCV’s
close to the identification bubble.
4.6 Equipment
All the equipment shall be shown with simple outline representation. Exercise
discretion so that equipment symbols do not dominate the drawing, but draw the
symbols large enough for clear understanding. Do not draw equipment to scale.
Show equipment relative to one another both in size and general orientation.
4.6.1 Show nozzles on equipment, including spares, as single lines. Show
manways as double lines. Label process and utility nozzles with nozzle
ID. Show nozzle sizes unless the size is implied by piping connections.
4.6.2 Show equipment not specifically identified in this Guideline with an
equipment symbol that is a reasonable representation of the equipment
as it will exist in the field.
4.6.3 Show Equipment Item Number and Title/Service as a minimum.
Reference Section 4.8 for a complete list of equipment data for all
equipment addressed in this Guideline. For equipment not covered in this
guideline, show equipment data as necessary.
4.6.4 Show internals for equipment as dashed lines. Omit details of internals
that have no significant bearing on the piping design and layout or
equipment operation.
4.6.5 Show the bottom tangent line elevation for vertical vessels, columns,
reactors, and inside bottom elevation for horizontal vessels. The
elevation shall be the height from grade. Also specify equipment
elevations necessary to specify process requirements for associated
equipment location or orientation relative to one another.
4.6.6 Show associated trim (e.g., vent and drain valves, instrument bridles) for
equipment.
4.6.7 Show auxiliary system requirements for individual pieces of equipment
(lube oil systems, seal flush systems, turbine gland leak-off piping,
sample systems) on auxiliary P&IDs.
4.6.8 Show jacketing and tracing requirements for equipment.
4.6.9 Show the type of insulation for equipment as part of the equipment data.
Show insulation thickness.
4.6.10 Means of purging process equipment with inert gas shall be shown on
the P&ID. In toxic and/or flammable service, inert purge (nitrogen) will not
be directly connected to the process.
4.6.11 For Tower, Vessel and Pumps handling hydrocarbons, steam out
connections will be shown on the P&ID with a block valve and blind, will
be defined as SO.
4.6.12 Steam traps and ancillaries for condensate removal will be shown on the
P&ID with the exception of line traps.
4.6.13 All vents necessary to permit depressuring, draining and venting of
equipment will be shown on the P&ID.
4.6.14 Tower and vessel drain connection will be shown on the P&ID on the
bottom-outlet Line upstream of the first block valve. When the bottom
outlet line extends into the vessel, the drain will be directly on the vessel.
4.6.15 All drains for control valve stations will be shown on the P&ID.
4.7 Equipment Details
4.7.1 Show the compressor symbol for each stage of multistage compressors.
Multi-staged compressors may be shown on multiple P&IDs.
4.7.2 Show drivers with driven equipment using the symbols for motors, diesel
engines and turbines. Equipment numbers for drivers are normally not
required since equipment data for the drivers is shown as an integral part
of the associated driven component. Show equipment number for driver if
it drives more than one piece of equipment or if the driver number is
different from the equipment it drives. The base symbol for the pneumatic
driver is the same as the electric driver. Show air inlet and discharge
nozzles for the pneumatic driver.
4.7.3 The term heat exchanger includes unfired heat exchangers, coolers,
condensers, reboilers, vaporizers and heating coils. Show shell and tube
exchangers following the TEMA convention for the type utilized in the
process. Orient exchanger nozzles to indicate the flow path through the
exchanger. Show the total duties for multiple exchangers utilized in series
or parallel configurations for common service.
4.7.4 Air-cooled exchangers are generally of two basic types, forced draft
and induced draft. Each type may have recirculation, multiple bundles,
multiple fans, variable (automatic or manual) fan pitch, variable louvers or
steam coils. Symbols may be modified to represent the type of air-cooled
exchanger used.
4.7.5 For fired heater, show the radiant coils and convection coils to
distinguish between the respective sections.
4.7.6 For pump, do not show base plates unless panned and drained. Show
drains and lines to oil and/or water sumps. Show vendor supplied
instrumentation or controls.
4.7.7 The term packaged equipment includes units such as air driers,
refrigeration systems, etc. Packaged equipment can be shown
generically as a ’black box’ until vendor drawing/information becomes
available. Assign Equipment/Item Numbers to individual equipment in
the package.
4.7.8 Show vessel as representative of actual vessel shape and orientation.
Show man ways, hand holes and skirts. Show other equipment supports
only if needed.
4.7.9 Tray numbers will be indicated on the P&ID for key trays. The trays will
be numbered from bottom to top with the bottom tray (not reboiler) being
numbered one. Other details to be indicated include distributors, vortex
breakers, demister pads, packing, spray nozzles, baffles and relative
positions of inlet and outlet connections and man ways. The term agitator
applies to mechanical mixers and aerators.
4.7.10 Show the blower symbol as centrifugal or positive displacement as
required.
4.7.11 Show tank as representative of actual tank shape and orientation.
4.8 Equipment Data
This section lists the data to be shown on the P&ID for types of equipment. Show
this information on the P&ID in relation to the appropriate equipment symbol.
Show units of measure as per SES for equipment data as required. Equipment
not listed should be described as appropriate to convey important data.
4.8.1 Compressors
a. Equipment Number
b. Service
c. Type
d. Capacity
e. Suction/Disch. Pressure or D/P
f. Number of Stages
g. Power Requirements
h. Materials of Construction
4.8.2 Agitators, Mixers
a. Equipment Number
b. Service
c. Power Requirements
d. Materials of Construction
4.8.3 Fired Heaters
a. Equipment Number
b. Service
c. Type
d. Heat Duty
e. Materials of Construction
4.8.4 Heat Exchangers
a. Equipment Number
b. Service
c. Type
d. Heat Duty
e. Surface Area
f. Shell Design Pressure and Temperatug. Tube Design Pressure and Temperatuh. Materials of Construction (Shell/Tubesi. Trim (Shell/Tubes)
j. Insulation (type/thickness)
4.8.5 Pumps
a. Equipment Number
b. Service
c. Type
d. Capacity
e. Suction/Disch. Pressure or D/P
f. Materials of Construction
4.8.6 Vessels
a. Equipment Number
b. Service
c. Dimensions
d. Design Pressure and Temperature
e. Materials of Construction
f. Trim
g. Insulation (type/thickness)
4.8.7 Driers
a. Equipment Number
b. Service
c. Type
d. Dimension (Vessel/Desiccants and Type)
e. Design Pressure and Temperature
f. Materials of Construction
g. Trim
h. Insulation (type/thickness)
4.8.8 Filters
a. Equipment Number
b. Service
c. Type
d. Capacity & P
e. Design Pressure and Temperature
f. Materials of Construction
4.8.9 Tanks
a. Equipment Number
b. Service
c. Capacity
d. Dimensions
e. Materials of Construction
4.8.10 Package Units
a. Equipment Number
b. Service
c. Duty
4.8.11 Blowers
a) Equipment Number
b) Service
c) Capacity
d) Suction/Disch. Pressure or D/P
e) Power Requirements
f) Material of Construction
4.9 Piping
4.9.1 The line data identification is available in SABIC EDDMS Seed file of
SPPID shall be used.
4.9.2 Show insulation code changes using the point of change symbol.
4.9.3 Show special layout requirements (e.g., No Pockets) with a note.
4.9.4 Show piping line symbols for primary, secondary, utility, jacketed or
double containment, and future lines
4.9.5 Show piping for above ground (AG) and underground (UG) lines in the
P&ID. Use an AG/UG line break and a piping line class break to
distinguish between above ground and underground lines.
4.9.6 Show jacketing and tracing requirements for piping.
4.9.7 Piping to pump out or pressurize heavy liquid hydrocarbons from process
equipment to appropriate waste, storage or flare will be shown on the
P&ID. Double block and bleed valves will be shown where appropriate.
4.9.8 Water boots and steam traps to protect steam lines and headers to
turbine drivers will be shown on the P&ID.
4.9.9 Process vents on piping will be shown on the P&ID, with the exception of
hydrostatic test vents.
4.9.10 Process piping low point drains and valves to be shown on P&IDs, with
the exception of hydrostatic low point drains.
4.9.11 Battery limits block valves and line blind with drain valve will be shown on
the P&ID
4.10 Valve Symbols
4.10.1 Show all valve symbols as full size. Do not show reduced size valve
symbols for drain and vent valving.
4.10.2 Do not show valve size unless the size can not be clearly identified from
the P&ID.
4.10.3 Use the listed valve symbols for defining control valve body types. If the
control valve body type is unknown, use a gate valve as the generic
symbol.
4.10.4 Do not show root valves where these installation details can be
adequately defined on a P&ID cover sheet detail.
4.10.5 Do not show valve tag (commodity) numbers. Use an abbreviation or a
commodity reference to distinguish between two types of a similar valve
where necessary.
4.10.6 Use a note or symbology to specify a valve’s required
installation/orientation when necessary (e.g., valves with a vented
ball/disc).
4.10.7 Do not indicate valve end connections. The exceptions are a blinded,
capped or plugged valve and any design where this requirement is
critical.
4.10.8 Show integral bypass (warm-up/pressurization) valve where applicable.
4.10.9 Utility header block valves will be shown on the utility distribution P&ID
and not on the process P&ID. Valves shown on process P&ID’s are
located at the process end.
4.10.10 Process piping low point drains and valves to be shown on P&ID’s.
4.11 Piping Specialty Items
4.11.1 Piping specialty items are items typically not specified in piping material
specifications.
4.11.2 Additional piping specialty symbols may be added as required.
4.11.3 Assign a tag number to each piping specialty item.
4.11.4 Process Steam traps for condensate removal will be shown on the P&ID
with the exception of pipe line traps. A strainer and block valves will beprovided at steam traps.
4.11.5 Sample connections will be shown on the P&ID.
4.11.6 Utility hose stations will be shown.
4.12 Piping Fittings
4.12.1 Additional piping fitting symbols may be added as required.
4.12.2 Show all reducers on the P&ID. Do not show reducer size if it can be
clearly identified from the P&ID.
4.12.3 Show weld connections when appropriate (e.g., at vessel nozzles).
4.12.4 Requirements of isolation blinds will be reflected on the P&ID considering
the nature of service, maintenance and decommissioning requirements,
etc.
4.13 Off-Page Connectors and Tie-In Symbol
4.13.1 Use the off-page utility connector for lines which enter/exit a P&ID from autility distribution type P&ID. A service description and equipment numberreference are not required for utilities.
4.13.2 Use the primary/secondary line off-page connector for utility lines whenthese lines are the primary system represented on the P&ID. Utilityprimary systems include utility headers and non-distribution type utilitylines (e.g., raw water treatment lines).
4.13.3 Use the off-plot connector for lines that cross unit or battery limits.
4.13.4 Designate Tie-Ins as ‘T-XXXX’ where T indicates a Tie-In and XXXX is a
four digit sequence number.
4.14 Drain Connectors
4.14.1 Show the closed and open drain connectors.
4.14.2 The drain connector consists of a destination line service code and a
reference P&ID number.
5 Instrumentation & Controls
5.1 Symbols
5.1.1 Identify all measurement types by ISA symbol. If necessary, add a
descriptive text label (e.g., analysis components like H2, CH4
or uniqueflow measurement devices like ’Mass’).
5.1.2 Interlock symbology is depicted as follows:
a. For discrete, hardware-based interlocks, use the conventional
diamond symbol per SES D04-G05, ISA S5.1 and S5.2.
b. For PLC-based interlocks, use the diamond-in-a-box symbol per
SES D04-G05, ISA S5.1 & S5.2.
c. For DCS-based interlocks, use the DCS symbol (bubble-in-abox).
For PLCs integral to the DCS, use the PLC symbol
(diamond-in-a-box).
5.1.3 Use directional arrows on instrumentation signal lines only when the
function is not obvious (e.g., cascades, selectors, interlocks).
5.1.4 Instrument Function Symbols are used to clarify the function of certain
tagged instrument bubbles. The symbol is placed outside the bubble at
the upper right.
5.1.5 Use the off-page connector to depict continuation of instrumentation
signals from one P&ID to another.
5.1.6 Do not show any individual instrument bubble more than once, unless
needed to clarify operation of the loop. If an instrument bubble must be
shown more than once, then the succeeding occurrences are shown as
dotted. An example is turbine controls shown on a different sheet than
the turbine.
5.1.7 Show device location and accessibility. Use an instrument bubble with
horizontal double dashed lines to show instrumentation in normally
inaccessible auxiliary locations.
5.1.8 Use FO, per ISA S5.1, to tag all restriction orifices. Do not use RO for
restriction orifice. The same symbol (not tag) is used for a measuring flow
element (FE) orifice and a restriction orifice (FO).
5.2 Measurements
5.2.1 Show all transmitters to avoid misinterpretations of physical and wiring
connections between the transmitter and other devices or systems.
5.2.2 Do not show root valves (process connections) for instruments except for
special non-standard requirements. These are generally shown on the
instrument details sheets. If the instrument is mounted on a vessel or a
piece of equipment, then isolation valves shall be utilized. Use typical
details to identify the valve type, size, rating and materials of
construction, per the applicable piping line class.
5.2.3 When instrument leads or analyzer lines are piping (e.g., level bridles),
then the piping and related components are shown per Piping. Where
instrument leads are tubing, only the tubing is shown but tubing valves,
connections and fittings are not shown. Show both leads for differential
pressure type measurements. Use a single line, representing two leads,
to simplify the drawing where intent is clear (e.g., only a single line is
typically shown for flange tap orifice meters).
5.2.4 Show dip tubes, bubblers and stilling wells for both process and
instrumentation. Add notes for relevant specifications, materials,
dimensions, weep holes, spray heads, etc. as required.
5.2.5 Show flow meters with the appropriate symbol. If no unique symbol exists
or if a device type is unknown, then use a generic symbol and provide a
text label to identify the measurement type. Show all flow elements with a
tagged bubble (FE). Provide a tag bubble for all in-line flow meters. Show
the size of all in-line devices if not line sized or otherwise implied.
5.2.6 Do not show flow meter accuracy. Use of a note to indicate special meter
requirements is optional.
5.2.7 If used, flow conditioning devices (e.g., straightening vanes) are labeled
with an instrumentation tagged bubble (e.g., ’FX-…’) associated with the
flow measurement loop.
5.2.8 Do not show ISO-9000 or other quality designations.
5.2.9 Show a tagged bubble for all thermowells. If a bare element is necessary
(no thermowell), then a note or text label (e.g. BARE) must be added.
Text is placed outside the symbol in the lower right.
5.2.10 Show all thermal or temperature measuring elements (TE) with a tagged
bubble. Use a text label outside of the bubble to identify element type
other than thermocouple (e.g., ’RTD’;)
5.2.11 Show process connection purge and blowback requirements for all
measuring devices requiring it. Include purge media and pressure. Show
detailed hardware associated with purge/blowback (e.g., rotameters) on
installation details, auxiliary P&IDs, or cover sheets.
5.2.12 Air supplies to individual devices are not generally shown. Show air
supplies to solenoids or other special applications as needed to clarify
valve porting or operation (e.g., trip solenoids or pneumatic hand
switches).
5.2.13 Do not show air or inert gas purges on enclosures. Air or inert gas purges
will be shown on instrument installation details.
5.2.14 Show analyzer sample points and return lines and connections. Label
analyzer piping. Label analyzer tubing with size and the applicable
Instrument Piping and Tubing System Specification. Show sample
system hardware on analyzer or other auxiliary drawings.
5.2.15 Show a single stream analyzer on the same P&ID as its sample point.
a. Show multi-stream analyzers only once with off-page connectors
from/to the multiple sample points/returns. Show sample
connections that supply/return samples to/from multiple
analyzers only once, with continuations to/from other analyzers.
b. Show measured components at the upper left of each analyzer
or sample point bubble as required.
5.2.16 Show winterization and heat tracing requirements for analyzers and
instrumentation. Place the insulation type code at the lower left of the
bubble.
5.2.17 If an indicator is integral to a transmitter, then use a single bubble and tag
(e.g.LIT). If separate devices are used for the transmitter and the
indicator (e.g., a remotely located indicator), then show separate bubbles
and tags (e.g., LT and LI).
5.2.18 Level gauges and type will be shown on the P&ID using project approvedP&ID symbology as per SES-D04-G05. Gauge with illuminators to be
indicated on the P&ID.
5.2.19 Do not show the distance between level connections. Level connectionelevations will be shown on the vessel drawings.
5.2.20 Product and feed stock meter for third parties will be shown as custodtransfer meter.
5.3 Valves
5.3.1 Show valves per drawing. The symbols for automated valve bodies and
for manual valves are identical. Use the appropriate actuator symbols(e.g., diaphragm and piston) to distinguish automated valves frommanual valves.
5.3.2 Show automated valve fail actions with text (FC/FO/FL/FI) per ISA S5.1. a. For multi-port automated valves, use FL and FI where
appropriate. Do not use FO and FC. Use arrows to show faiposition flow paths. Note that multiple arrows may be required.
b. Valves that have different fail actions for loss of signal and for
loss of motive power require an explanatory note.
5.3.3 Show valve body sizes for all automated valves if not line sized orotherwise implied.
5.3.4 Do not show automated valve specifications or commodity codes.
5.3.5 For automated valves, identify tight shut-off requirements by using the
abbreviation ’TSO.’
5.3.6 Show valve identifying tags with bubbles for all automated valves and
relief valves.
5.3.7 Show the ranges (e.g., 0-50%, 50-100%) for split range control valves
The preferred labeling is controller percentage output since it applies to
both pneumatic and electronic systems. A graph showing signal vs valveopening shall be shown in the notes for all split control valves.
5.3.8 Do not show valve positioners unless necessary to clarify loop operation.When shown, valve positioners are normally included with the automated
valve symbol and are not tagged.
5.3.9 Show all pneumatic converters (I/Ps) with a tagged bubble.
5.3.10 Show all solenoids that actuate final control elements.
5.3.11 Show solenoid valve fail actions using a directional arrow indicating the
open flow path when de-energized. Note that a 4-way solenoid valverequires two directional arrows to adequately define the flow paths. Show
resets (manual or remote) if included with the solenoid valve.
5.3.12 Identify limit switches on automated valves with a bubble and tag. Theopen or closed tag should be depicted with ZSO or ZSC. Show separatetagged bubbles when both limit switches are provided. Limit switches ondiverter valves should be tagged as ZST and ZSD for the `Through’ and
`Divert’ positions.
5.3.13 Do not show automated valve auxiliaries (e.g., volume tanks, nitrogen
back-up bottles). Typical valve auxiliary details will be shown on an
instrument installation detail or vendor drawing. Use a note to identify the
need for valve travel stops.
5.3.14 Show set points on process regulators.
5.3.15 Block valves for field instruments shall not be shown in the P&ID.
However, P&ID legend sheets will detail piping and block valves along
with instrument symbols. Instrument hook up drawings shall reflect the
actual installation.
5.4 Safety / Relief Devices
5.4.1 Show and tag relief devices and conservation vents.
Use optional explanatory text as needed for clarification of the type and
function of the device (e.g., ’Emergency Relief,’ ’Conservation Vent’,
’Explosion Panel’) located next to the tag.
5.4.2 Show relief device set pressures.
5.4.3 Show the relief device size:
a. PSVs – inlet size and outlet size
b. Rupture discs – disc diameter
c. Conservation vents – inlet nozzle size if there is not a pipe away
or tail piece, otherwise show inlet size and outlet size
d. Explosion panels – surface area or dimensions.
5.4.4 Show the orifice size letter designation for relief valves between the inlet
and outlet sizes (e.g., 3K4). Do not show the relief device sizing basis or
flow capacity.
5.4.5 Do not show the materials of construction for relief devices.
5.4.6 As a rule, PSV block valves are to be shown as CSO or LO.
5.5 Equipment Start/Stops
5.5.1 Do not show the local start/stop hand switch for motors without remote
controls.
Show local (field) hand switches (bubble and tag) that:
a. Are part of an operator control panel
b. Interface with other systems (e.g., interlocks)
c. Otherwise need explanation
5.5.2 Show all control room (DCS or panel board) hand switches with the
appropriate bubble symbol and tag.
5.5.3 Label all hand switch positions or functions. Locate the labels outside the
bubble symbol, on the upper right, using the standard text abbreviations.
All others must be spelled out.
5.5.4 Clearly show all required feedback signals or functions (e.g., valve
positions, run lights). Hardwired signals are normally shown using
standard instrument line symbols. Soft-linked feedback functions can be
shown outside the display bubble at the upper left.
5.6 Interlocks & Alarms
Interlocks are shown only symbolically on the P&ID. Functional definition is
shown on auxiliary documents (e.g., binary logic diagrams, descriptive
narratives). Interlocks are designed for a variety of functions from simple process
sequences to complex safety shutdown systems. A Variety of hardware such as
DCS, PLC, relays, redundant, SIS, etc. is utilized for its implementations. Alarms
are similarly designed in a variety of ways. Alarms come from hardware, over
serial links, from DCS software and they are shown on a variety of facility
documents, including P&IDs, alarm summaries, logic and loop diagrams and
operating procedures. Because of this variety, along with individual Owner
interpretations of the requirements of OSHA 1910.119 and IEC-61508/IEC61511,
many
documentation
aspects
of
interlock
and
alarm
system
design
will
be
defined
by
the
Owner.
5.6.1 Show logic functions or interlocks with the proper symbols. Do not show
binary logic gates, input/output tables or descriptive narratives.
5.6.2 All logic function and interlock symbols contain an identification that
provides reference to a unique logic diagram, narrative, truth table or
program. The format of the reference is to be determined by the Owner.
Descriptive text or a note reference may be placed outside the symbol.
5.6.3 Do not show the type of logic solver hardware or level of redundancy
except through the normal use of ISA symbols and the input and output
signals.
5.6.4 Do not show classifications or Safety Integrity Levels (SIL) for interlocks.
5.6.5 Show all operator initiated interlock trip and reset hand switches.
5.6.6 If used, show all bypass hand switches for interlocks. This includes all
individual initiator and system bypass switches. Unnecessary clutter can
be avoided by use of a table or reference note if large numbers of
bypasses are necessary.
5.6.7 Show all hardwired alarms.
5.6.8 Show all alarms that require engineering or other review and approval
based on safety or operability.
5.6.9 Show hardware-based diagnostic alarms. Show software-based
diagnostic alarms only if safety or operationally related (e.g., defined in
safety reviews). Measurement out-of-range alarms are an example of
software diagnostic alarms not generally shown.
5.6.10 Show required alarms with tag and level (e.g., PAH), but do not show
alarm trip points or settings.
a. For alarms based on analog measurements, the functional tag
(e.g., PI) is shown inside the bubble and the alarm levels are
shown outside the bubble. High alarms (e.g., H, HH) are placed
at the upper right outside the bubble, while low alarms (e.g., L,
LL) are placed at the lower right outside the bubble. The alarm
modifier (A) is not shown.
b. For discrete alarm points (on/off signals), the complete functional
tag and alarm level (e.g., PAH) is shown inside the bubble.
5.6.11 Standard ISA S5.1 abbreviations are used for both trip and alarm
functions (e.g.,LSHH and LAHH).
5.6.12 All interlocks shall be tagged in the format given in SES D03-D03
5.7 DCS Points
Show a DCS point if Operations manipulates the process with it or receives
information from it or the point is essential to understanding the functional
operation of the process controls. It is not necessary to show every point
configured in a DCS. It is not necessary to include implied functions (e.g., I for
indicate, R for recorder) in every DCS point tag. Application of these criteria to
specific systems will determine which DCS points to show. DCS points not shown
may be displayed on special purpose auxiliary drawings.
5.7.1 Show DCS points that indicate measured process values. Include both
analog and digital values obtained from hardwired inputs or via software
links. Examples include flows, temperatures and pressure compositions
from analyzers and valve open/closed status.
5.7.2 Do not show DCS points that exist solely to transmit input signals from
field hardware to other DCS points. For example, do not show a flow
indicator point if the value is represented by a flow controller point on the
P&ID.
5.7.3 Show DCS points that manipulate analog or digital output hardware
devices. Examples include flow, temperature and pressure controllers,
hand switches and logic points.
5.7.4 Do not show DCS points that exist solely to transmit control signals from
other DCS points to field hardware. Examples include analog and digital
output points.
5.7.5 Show DCS points that Operations employs to manipulate the process via
the DCS. Examples include regulatory controllers and pump start/stop
switches.
5.7.6 Show DCS points that provide Operations an interface to manipulate the
process through a software link to other systems. Examples include
points that interface with controllers in the linked system and SIS reset
hand switches.
5.7.7 Show DCS points that are essential to understanding the operation of the
process controls. Examples include selectors in override controls or
enthalpy calculators in heat duty controls.
5.7.8 Show DCS points that are required for regulatory compliance and
mechanical integrity needs. Examples might include rolling averages for
emissions monitoring or compressor runtimes.
5.7.9 Show DCS points that are necessary to understand the functional
operation of process control schemes. Do not show points needed only
for implementation (e.g., points that provide bumpless transfer,
initialization, some logic functions).
6 Notes
5.7.10 Do not show Higher Level Control Systems. For example, do not show
model predictive multivariable control systems.
5.7.11 Do not add symbols to indicate that a DCS point is being manipulated by
a Higher Level Control System/APC. A note should be used to reference
HLCS/APC details.
5.7.12 Do not show DCS points that exist solely to facilitate information transfer
via a software link.
5.7.13 Do not show DCS points that are used solely to log, journal or time stamp
events.
5.7.14 Show non-process indicators and alarms such as those located in the
rack rooms and Motor Control Center on auxiliary P&ID’s. Examples are
loss of power supply or UPS power, loss of cabinet fans and smoke
alarms.
Show general design notes (applicable to all P&IDs) on the piping and/or instrument
related cover (or symbol) sheets.
Show specific design notes on the applicable P&ID.
Notes shall contain a table for Instrument symbol and equipment symbols and that are
used on P&ID and actual configuration. This helps to keep P&IDs less clustered.