INSTRUMENTATION / DOC. NO.: SP-**-00-01
Rev. 0
Page 1 of 13
Date
SIGMATECH
CO., LTD
SPECIFICATION
FOR
GENERAL INSTRUMENTATION
DOC. NO.: SP-I-00-01
CLIENT: S-COMPANY
PROJECT: S-PROJECT
PROJECT NO.: 01001
0 / Aug. 15, 2001 / ISSUED FOR APPROVAL
REV. NO / DATE / DESCRIPTION / PREPARED BY / REVIEWED BY / APPROVED BY
SIGMATECH CO., LTD.
CONTENTS
SECTION TITLE PAGE
1.0 GENERAL…………………………………………………………………….….………… 3
1.1 Scope………………………………………………………………………….….………… 3
1.2 Codes, and Industry Standards…………………………………………….….………… 3
1.3 Symbol Definitions………………………………………………………….…….……….. 5
2.0 DESIGN AND MATERIALS…………………………………………………………….…. 5
2.1 General…………………………………………………………….……….….……….…… 5
2.2 Temperature Instruments………………………………………………………….….…… 5
2.3 Pressure Instruments………………………………………………………………….…... 6
2.4 Flow Instruments…………………………………………….……………………………... 6
2.5 Level Instruments…………………………………………….…………………………….. 7
2.6 Scales and Charts…………………………………………….……….…………………… 8
2.7 Controllers……………………………………………………….……….…………………. 8
2.8 Control Valves and Positioners………………………………….……….……………….. 8
2.9 DCS System……………………………………………………….……………………….. 9
2.10 Transmission Systems…………………………………………………………………… 10
2.11 Instrument Air Supply…………………………………………………………………….. 10
2.12 Instrument Connections………………………………………………………………….. 10
2.13 Instrument Piping…………………………………………………………………………. 11
2.14 Instrument Wiring…………………………………………………………………………. 11
2.15 Instrument Panels………………………………………………………………………… 12
2.16 Location and Mounting of Instruments…………………………………………………. 13
2.17 Instrument Protection…………………………………………………………………….. 13
1.0 GENERAL
1.1 Scope
1.1.1 This specification together with the documents specified in Article 1.2, embodies the
general requirements for the instrumentation to be furnished. This specification outlines
SIGMATECH Co. general practices. This specification can not cover all possible
instrument applications. In general instrument applications are in accordance with API
550, Manual on Installation of Refinery Instruments.
1.1.2 The electrical area hazardous classifications shall be specified in the Electrical Design
Specification, according to electrical area classification.
1.1.3 Relief valves are not part of this specification.
1.2 Codes, and Industry Standards
The documents referenced herein shall be as follows :
NUMBER / TITLEANSI MC96.1 / Temperature Measurement Thermocouples
ANSI / ASME B16.5 / Pipe Flanges and Flanged Fittings NPS ½ Through NPS 24
ANSI / ASME B16.34 / Valves Flanged, Threaded, and Welding End
ASME B1.20.1 / Pipe Threads, General Purpose (Inch)
ASME B16.10 / Face-to-Face and End-to-End Dimensions of Valves
ASME B16.11 / Forged Steel Fittings, Socket-Welding and Threaded
ASME B16.20 / Metallic Gaskets for Pipe Flanges Ring Joint, Spiral Wound and Jacketed
ASME B16.36 / Orifice Flanges
ASME B31.1 / Power Piping
ASME B31.3 / Process Piping
ASME BPVC / ASME Boiler and Pressure Vessel Code
ASME PTC 19.3 / Performance Test Code – Temperature Measurement
ASTM A269 / Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service
ISO 5167 Part 1 / Measurement of fluid flow by means of pressure differential devices – Part 1: Orifice plates, nozzles and Venturi tubes inserted in circular cross-section conduits running full.
APIRP500 / Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2
API RP 520 Part I / Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries (ANSI/API Std 520-1992) Part I, "Sizing and Selection"
API RP 520 Part II / Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries, Part II, "Installation"
API RP 526 / Flanged Steel Pressure Relief Valves
API RP 551 / Process Measurement Instrumentation
API RP 552 / Transmission Systems
ISA RP3.2 / Orifice Plates
ISA S5.1 / Instrumentation Symbols and Identification
ISA S5.2 / Binary Logic Diagrams for Process Operations
ANSI / ISA S18.1 / Annunciator Sequences and Specifications
ANSI / ISA S75.01 / Flow Equations for Sizing Control Valves
LK Spink / Principles and Practice of Flow Meter Engineering
IEC 60079 (All Parts) / Electrical apparatus for explosive gas atmospheres
IEC 60529 / Classification of Degrees of Protection Provided by Enclosures
IEC 61000-4-3 / Electromagnetic compatibility (EMC) - Part 4: Testing and measurement techniques – Section 3: Radiated, radio-frequency, electromagnetic field immunity test
IEC 60584-1 / Thermocouples Part 1 : Reference Tables
IEC 60584-2 / Thermocouples Part 2 : Tolerances
IEC 60654-1 / Operating conditions for industrial-process measurement and control equipment Part 1 : Temperature, humidity and barometric pressure
IEC 60654-2 / Operating conditions for industrial-process measurement and control equipment Part 2 : Power
IEC 60654-3 / Operating conditions for industrial-process measurement and control equipment Part 3 : Mechanical influences
IEC 60654-4 / Operating conditions for industrial-process measurement and control equipment Part 4 : Corrosive and erosive influences
IEC 60751 / Industrial Platinum resistance thermometer sensors
IEC 60534 / Industrial-process control valves
NEMA 250 / Enclosures for Electrical Equipment (1000 Volts Maximum)
NACE Std
MR-01-75 / Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment.
NFPA 70 / US National Electrical Code (N.E.C)
NFPA 70E / Standard for Electrical Safety Requirements for Employee Workplaces
NFPA 496 / Standard for Purged and Pressurized Enclosures for Electrical Equipment
NFPA 499 / Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
1.3 Symbol Definition
1.3.1 "NPS" symbols used in this specification indicate nominal pipe size.
1.3.2 "NPS" denotes a standard tapered pipe thread.
2.0 DESIGN AND MATERIALS
2.1 General
2.1.1 The extent of instrumentation will be shown on the Piping and Instrumentation Diagrams. The
symbolism used shall be that of ISA S5.1 and S5.3 with some modifications. The P & ID will
contain a legend defining the project specific representation. Symbolism shall be complete
for devices located in the field but will besimplified for devices located in the control room.
2.1.2 Instrument transmission systems shall be electronic for control room signals.
2.1.3 Control room instrumentation will be primarily a distributed control system (DCS).
2.1.4 In general, local control loops shall consist of a separate pneumatic transmitter andreceiver
type controller. Exceptions are displacer type level controllers and pressure controllers,
which may be the direct connected type.
2.1.5 Devices (such as solenoid valves, relays, etc.) which operate under emergency conditions or
which automatically correct process abnormalities shall be isolated from the normal control
and alarm systems. These devices shall generally be energized during normal process
operation and de-energized to trip. Other modes of trip shall be considered where required
for safety reasons. The de-energized (safe) condition of such devices, is in general, the
condition that removes energy from the process.
2.1.6 Instrumentation furnished as a regular part of proprietary or standardized equipmentshall
conform to the applicable code requirements ,if any, and be in accordance with the
equipment manufacturer's standards for the design conditions.
2.1.7 Loop numbering will be done using a parallel numbering system with the first letter of the
process measurement being a part of the tag number. For example, FT 5201 would be the
tag number for a flow transmitter. Similarly, LG-5201 would be the tag number for a gauge
glass. All components in a loop will have the same first identification letter and the same tag
number. This identification may be followed by a suffix letter in some instances.
2.2 Temperature Instruments
2.2.1 Resistance or thermocouple type sensors shall be used as far as possible. Pneumatic
temperature transmitters shall be minimized. When used they should be of the filled
thermal system type for operating temperatures of -45.6 to 427℃. The capillary tube
length shall not exceed 8 meters and will be 316 stainless steel armoured, plastic
sheathed and flexible.
2.2.2 In each process area, the preference is to use only one type of temperature sensor.
This will normally be either Type K thermocouples or 100 ohm (at 0℃in accordance with
DIN 43760 resistance temperature detector).
No thermocouple or RTD may be connected simultaneously to more than one instrument,
otherwise duplex sensors shall be used.
2.2.3 Thermocouples shall be of the metallic sheathed type. Sheathing shall be AISI (American
Iron and Steel Institute) Type 316 stainless steel. Superior grades of materials may be used
as required by the service conditions. For temperatures above 600℃"Inconel" sheathing
will be used.
2.2.4 For applications requiring temperature to current converters, these converters will be located
at the field sensor.
2.2.5 Indicating thermometers shall be bi-metallic, having 100mm (4 in.) minimum nominal
diameter dials. Filled thermal systems shall be used where required.
2.2.6 Thermowell material shall be AISI Type 316 stainless steel. Superior grades of materials
shall be used as required by the service conditions.
2.2.7 For general process service, thermowells shall have ANSI 1" flange connection to the
process equipment. Thermowell installation type according to Industry Standards shall be
as follows:
For cryogenic services - socket welded process connection
For general process services - flanged process connection
For temperatures above 232℃ - flanged process connection
For pressures above 25 kg/cm2(g) - flanged process connection
2.2.8 Thermocouple and RTD heads shall be NEMA 4 and 7 or equal type with cable entry and
shall be installed in such a way that entry does not admit water.
2.3 Pressure Gauges
2.3.1 Indicating pressure gauges normally shall be of the Bourdon type with 100 mm (4 in.)
minimum nominal diameter dials. Dials of smaller sizes may be used in pneumatic instrument
circuits and for auxiliary services on mechanical equipment. Damping devices shall be
provided in gauge piping subjected to pulsating pressures.
2.3.2 Direct connected indicating pressure gauges shall be furnished with stainless steel tubes and
socket. They shall be of solid front construction with blow-out back cases. When required by
the service conditions, superior tube materials or diaphragm seal devices may be used.
Bronze tubes may be furnished for gauges used as pneumatic receiver gauges or for gauges
with diaphragm seals.
2.3.3 Direct connected indicating pressure gauges shall be provided for and in view of blind type
instruments such as pressure controllers, pressure transmitters, pressure switches, back
pressure valves, pressure reducing valves, and pressure balance type valves.
2.4 Flow Instruments
2.4.1 Flow measuring instruments shall be of the differential pressure type employing square
edged concentric orifice plates with flange taps. The orifice plates shall have a maximum
(beta ratio) orifice bore to inside pipe diameter ratio of 0.65 and a minimum of 0.2. It should
be noted that 0.75 can be considered for special applications. Orifice plates shall be AISI
type 316 stainless steel minimum. Orifice plate thickness shall be in accordance with ISA
RP3.2.
2.4.2 Instruments installed for local flow indication only, shall consist of pneumatic force balance
transmitters with dial type receiver gauges. In clean service direct-connected aneroid types
may be used.
2.4.3 Variable area meters, integral orifice differential pressure transmitters, or specially calibrated
orifice and piping assemblies may be used in piping NPS 1½or smaller. Variable area
meters, wedge flow meters, and electromagnetic flowmeters may also be used for severely
corrosive, high viscosity, and slurry services.
2.4.4 Venturi tubes, low loss tubes, or flow nozzles may be used where high pressure recovery is
necessary.
2.4.5 Other flow devices may be used as warranted by specific service conditions such as
properties of the fluid and metering accuracy required.
2.4.6 Orifice bore calculations will be made by the vendor of the flow primary element or the vendor
of the flow meter.
2.5 Level Instruments
2.5.1 In general, the primary elements of level control and transmitting instrument loops shall be of
the external chamber displacer type for ranges up to and including 1524 mm(60 inches).
Differential pressure and other types may be used as required, such as high pressure
generators and at temperatures below 50℃. Delta P-type instruments shall be mounted at or
below the lower tap except for liquids which boil at ambient temperature and normal pressure
in which case they shall be mounted above the upper tap and with heating to ensure
vaporization in the liquid leg.
2.5.2 Gauge glass columns shall consist of one or more gauge glass sections with the necessary
valves to permit cleaning of the gauge glass. Gauge glass columns shall not exceed 1828
mm (6'-0") and shall be installed with minimum NPS 1/2 drain valves.
2.5.3 Gauge glass columns in steam service above 21 kg/cm2(g), caustic and other services which
may etch the inner surface of the gauge glass shall be provided with protective shields.
Gauge glass columns shall be provided with non-frosting blocks for operating temperatures
of 0℃and below.
2.5.4 Through vision type gauge glasses (double glass) shall be used for services in which a level
may not be readily distinguishable, such as interface services ; propane and lighter oils;
where protective shields are required; and for fluids of high viscosity or high solid content.
Reflex type gauge glasses shall be used for all other services. In general, illuminators shall
be furnished for through vision types on interface services only.
2.5.5 Displacement type level instruments shall be provided with cooling or warming extensions to
protect the instrument cases when required.
2.5.6 Drain valves and plugged vents for externally mounted level instruments shall be provided.
2.6 Scales and Charts
2.6.1 Units of measurement shall be as follows :
a. Temperature - degrees Centigrade
b. Pressure - kg/cm2(a)
c. Differential pressure - kg/cm2, or mm of water (20℃)
d. Vacuum - mm of mercury or mm of water
e. Flow - kg/hr, Nm3/hr, m3/hr or MT/hr
f. Liquid level - percent
g. Density - kg/m3
2.6.2 Scales on indicating and recording instruments and charts for conventional (large case)
recorders shall be direct reading, except that scales for variable head flow meters may be 0-
10 square root.
2.6.3 For miniature recorder strip charts, direct reading scales shall be furnished for each pen and
the charts shall be as follows :
a. 0-10 square root for variable head flow.
b. 0-100 linear for temperature, pressure, level and linear flow signals.
c. Duplex, 0-10 square root/0-100 linear for multi-pen units recording both square root and
linear variables.
2.6.4 For miniature instruments, strip charts shall be approximately 100 mm (4 in.) wide. For
conventional (large case) instruments, circular charts shall not be less than 300 mm (12 in.)
nominal diameter and strip charts shall be nominally 250 mm wide; however, 150 mm (6 in.)
nominal strip charts may be used in special situations.
2.6.5 Chart drives for instruments shall be operated by electric motors ; where possible.
2.6.6 Each recording instrument shall be provided with enough charts for a minimum of 1 year.
2.7 Controllers
2.7.1 In general, controllers shall be provided with adjustable proportional and reset actions. Other
control actions shall be used as required.
2.7.2 All panel mounted controllers shall be provided with the facility for bumpless transfer between
automatic and manual control.
2.8 Control Valves and Positioners
2.8.1 Control valves shall be sized for the available pressure drop at normal fluid flow rate and also
to permit at least 125% of the normal flow at that pressure drop. The minimum valve body
size shall be NPS 1 for pipe lines which are NPS 1 and larger and shall be line size for pipe
lines smaller than NPS 1.
2.8.2 The use of block and bypass valves or handwheels with control valves shall be in accordance
with the proper specification.
2.8.3 Pilot-operated regulating valves and self-operated regulating valves shall be used only for
auxiliary services or other services in which precise control is not required.
2.8.4 Control valve bodies shall be of materials conforming to the specification for the pipe line in
which they are installed. Carbon steel shall be used as a minimum. The trim shall be as a
minimum, stainless steel.
2.8.5 Control valve end connections for steel globe valves in sizes NPS 6 and smaller shall be
flanged with a minimum rating of Class 300. The body material, pressure rating, and type of
end connection for control valves shall conform to the specification of the pipe lines in which
they are installed.
2.8.6 Control valves shall be provided with air cooled bonnets, bonnet extensions, or special
packing for high temperature service (above 205℃), and bonnet extensions for low
temperature service (below 0℃).
2.8.7 Control valves in throttling services shall be provided with valve positioners for the services
and under the conditions listed below : (pneumatic or electro-pneumatic positioners may be
used)
a. For all temperature control services except when the valve operator is directly connected
to filled thermal systems.
b. For analyzer control services, pH control services and other services with long time
constants.
c. On valves for split-range operation.
d. Where the control air loading pressure to actuator is other than approximately 0.2 to 1.0
kg/cm2(g).
e. For valve sizes NPS 4 and larger.
f. For valves having a high pressure drop at throttling of 7.0 kg/cm2 or more.
g. Where suspended solids may accumulate or viscous services may occur.
h. On butterfly valves and on 3-way valves.
i. For valves operating at temperatures below 0℃or above 205℃.
j. Where vaporization is likely to occur across the ports, greater than 10% of weight at inlet
fluid.
2.8.8 Balanced type valves shall be used in general service. Rotary type valves are preferred
in large sizes and single port top guided valves are preferred in small sizes.
2.9 Distributed Control System(DCS)
2.9.1 The DCS system will normally be the complete operator interface. All normal operating
control functions including discrete control will be implemented in the DCS.
2.9.2 Alarm functions willnormally be implemented in the DCS alarm systems and included in the
DCS alarm summary.
2.9.3 Recording functions will be implemented in the DCS trend systems :either historical or real
time or combinations. Highway recording of selected signals onto a strip chart may also be
used to a limited extent. Logging may supplement these functions.
2.9.4 Safety system functions both analog and discrete will normally be implemented in devices
(programmable controllers, dedicated control units) that are separate from the normal control
devices.
2.9.5 The detail specification for DCS will be specified on the DCS Material Requisition
2.10 Transmission Systems
2.10.1 Analog signals to and from the control room will in general be 4 to 20 mA. ISA S50.1
definitions are used. Specialized electronics and control signals may be used where
appropriate.
2.10.2 Discrete signals will use dry (voltage free) contacts for input. Contact interrogation signals
will normally be low level : less than 24 V DC and at less than 10 mA. Output signals, for
solenoid valves will be nominal 24 V DC.
2.11 Instrument Air Supply
2.11.1 In general, local pneumatic control systems shall be designed for an air supply pressure of
1.4 kg/cm2(g) and a transmitted air pressure range of 0.2 to 1.0 kg/cm2((g). Individual
instrument air isolating valve will be provided for each instrument or loop.