SynC™

SynC · Editorial revision

Analytical Instrumentation

Revision8
EditedOct 19, 2026
StatusCurrent
Contents

View changes in this revision   Revision history

Current revision. This is editorial revision 8, the current text of this standard. Read it on the standard's page.

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)
Remake batch 25 and its neighbor re-points, batch 24 where missing, and the adopted-electrical-code parameter: brought in line with the authoring repository

1 Scope

NOTE This standard governs online, continuous-reading analyzers that measure the chemistry and quality of a liquid process stream and deliver that measurement to the control system: the sensor or measuring cell, the analyzer or transmitter, the sample conditioning and sample delivery that feed a flow-through sensor, the reagents and reagent handling of a wet-chemistry analyzer, the automatic cleaning and temperature compensation, and the analog and digital outputs. (1.1)
NOTE The boundary of work under this standard runs from the sample tap or the insertion point in the process, through the sample line and its conditioning, the sensor, and the analyzer or transmitter, to the output terminals of the transmitter; the field wiring, the controller input, and the final element lie beyond it. (1.2)
NOTE An online analyzer runs unattended between service visits in the live process, with its fouling, bubbles, temperature swings, and chemical attack, and produces a signal the control system acts on continuously; a laboratory instrument measures a prepared sample under an analyst's hand. The provisions of this standard that have no counterpart in a laboratory method, sample conditioning, automatic cleaning, fault signaling, and verification against the laboratory reference, exist because of that difference. (1.3)
NOTE Where an analyzer reading is reported to a primacy agency or a permitting authority under a drinking-water or discharge permit, the analyzer serves a compliance-reporting function, and the method requirements of the applicable regulation apply to it in addition to the requirements of this standard. (1.4)
NOTE The following are governed elsewhere and are outside this standard: (1.5)
  • pressure, level, temperature, and flow measurement, governed by Pressure InstrumentationPressure InstrumentationResolves to the current adopted revision.sync/pressure-instrumentation, Level SensorsLevel MeasurementResolves to the current adopted revision.sync/level-sensors, Temperature InstrumentationTemperature InstrumentationResolves to the current adopted revision.sync/temperature-instrumentation, and Flow MeasurementFlow MeasurementResolves to the current adopted revision.sync/flow-measurement
  • the shared field transmitter platform, loop architecture, and instrument tagging conventions, governed by Process InstrumentationProcess InstrumentationResolves to the current adopted revision.sync/process-instrumentation
  • ambient gas detection that protects the occupants of a space, governed by Gas Detection SystemsGas Detection SystemsResolves to the current adopted revision.sync/gas-detection-systems
  • the control valves and actuators an analyzer drives, governed by Control Valves And ActuatorsControl Valves and ActuatorsResolves to the current adopted revision.sync/control-valves-and-actuators
  • the controller, the supervisory system, and the network, governed by Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers, SCADA And HMI SystemsSCADA and HMI SystemsResolves to the current adopted revision.sync/scada-and-hmi-systems, and Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks
  • loop checks, tuning, and acceptance testing of the assembled control system, governed by Control Systems IntegrationControl Systems Integration and TestingResolves to the current adopted revision.sync/control-systems-integration
  • signal wiring and raceway, governed by Instrumentation And Control CableInstrumentation and Control CableResolves to the current adopted revision.sync/instrumentation-and-control-cable and Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit
  • gas-phase process analyzers and continuous emissions monitoring systems, laboratory bench instruments, portable meters, and chemical metering pumps, which no article of this standard addresses
1.6 The parameters measured, the number of analyzers of each, and the location of each sample tap and sensor shall be as indicated on the instrument index and the process and instrumentation diagrams.
1.7 The analyzers that serve a compliance-reporting function shall be those identified on the instrument index.
1.8 Analyzers and their sensors shall be listed by a Nationally Recognized Testing Laboratory to UL 61010-1 or to the product standard applicable to the equipment.
1.9 Analyzer installation, wiring, and grounding shall comply with NFPA 70.
1.10 The Contractor shall coordinate each analyzer's signals, diagnostics, and alarm points with the controller under Programmable Logic ControllersProgrammable Logic ControllersResolves to the current adopted revision.sync/programmable-logic-controllers and the supervisory system under SCADA And HMI SystemsSCADA and HMI SystemsResolves to the current adopted revision.sync/scada-and-hmi-systems, and the loop check and acceptance of each analyzer with Control Systems IntegrationControl Systems Integration and TestingResolves to the current adopted revision.sync/control-systems-integration.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
2.3 Where an analyzer serves a compliance-reporting function, the method approved under the applicable regulation at the time of reporting shall govern over a general process-measurement method.
Standard Title
USEPA Method 180.1 Determination of Turbidity by Nephelometry
USEPA Method 334.0 Determination of Residual Chlorine in Drinking Water Using an On-line Chlorine Analyzer
USEPA Method 415.3 Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water
40 CFR Part 141 National Primary Drinking Water Regulations
40 CFR Part 136 Guidelines Establishing Test Procedures for the Analysis of Pollutants
ISO 7027-1 Water Quality: Determination of Turbidity, Part 1: Quantitative Methods
ISO 17289 Water Quality: Determination of Dissolved Oxygen: Optical Sensor Method
ASTM D1293 Standard Test Methods for pH of Water
ASTM D6569 Standard Test Method for On-Line Measurement of pH
ASTM D1498 Standard Test Method for Oxidation-Reduction Potential of Water
ASTM D888 Standard Test Methods for Dissolved Oxygen in Water
ASTM D1125 Standard Test Methods for Electrical Conductivity and Resistivity of Water
ASTM D5391 Standard Test Method for Electrical Conductivity and Resistivity of a Flowing High Purity Water Sample
ASTM D5173 Standard Test Method for On-Line Monitoring of Carbon Compounds in Water by Chemical Oxidation, by UV Light Oxidation, by Both, or by High Temperature Combustion Followed by Gas Phase NDIR or by Electrolytic Conductivity
ASTM D6855 Standard Test Method for Determination of Turbidity Below 5 NTU in Static Mode
ASTM D7315 Standard Test Method for Determination of Turbidity Above 1 Turbidity Unit (TU) in Static Mode
Standard Methods for the Examination of Water and Wastewater 2130 Turbidity, 2510 Conductivity, 2540 Solids, 4500-Cl Chlorine (Residual), 4500-H+ pH Value, 4500-NH3 Nitrogen (Ammonia), 4500-NO3 Nitrogen (Nitrate), 4500-O Oxygen (Dissolved), 4500-O3 Ozone (Residual), 5310 Total Organic Carbon
NSF/ANSI/CAN 61 Drinking Water System Components: Health Effects
NSF/ANSI/CAN 372 Drinking Water System Components: Lead Content
ANSI/ISA-5.1 Instrumentation Symbols and Identification
ANSI/ISA-5.4 Instrument Loop Diagrams
ANSI/ISA-50.00.01 Compatibility of Analog Signals for Electronic Industrial Process Instruments
ANSI/ISA-62382 Automation Systems in the Process Industry: Electrical and Instrumentation Loop Check
NAMUR NE43 Standardization of the Signal Level for the Failure Information of Digital Transmitters
NAMUR NE107 Self-Monitoring and Diagnosis of Field Devices
HART Communication Protocol Specification FieldComm Group Highway Addressable Remote Transducer Protocol
NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)
UL 50E Enclosures for Electrical Equipment, Environmental Considerations
UL 61010-1 Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use, Part 1: General Requirements
UL 121201 Nonincendive Electrical Equipment for Use in Class I and II, Division 2 and Class III, Divisions 1 and 2 Hazardous (Classified) Locations
UL 913 Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations
UL 1203 Explosion-Proof and Dust-Ignition-Proof Electrical Equipment for Use in Hazardous (Classified) Locations
NFPA 70 National Electrical Code
NFPA 497 Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
ANSI/ISEA Z358.1 Emergency Eyewash and Shower Equipment
ISO 9001 Quality Management Systems: Requirements

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for review before analyzers are procured:
  • product data for each analyzer, identifying the measured parameter, the measurement principle, the measuring range, the resolution, the accuracy, the repeatability, the response time, the sample flow and pressure the sensor requires, and the wetted materials
  • the governing method for each parameter and, for each analyzer identified as serving a compliance-reporting function, documentation that the analyzer type is approved for online use under that method
  • sensor data: body and cable rating, pressure and temperature limits, fouling and cleaning provisions, and the mounting hardware
  • the sample system design for each flow-through analyzer: the tap, the sample line material and size, the conditioning components, the sample flow rate, the transport lag, and the sample panel arrangement drawing
  • reagent data for each wet-chemistry analyzer: the reagent identity, the safety data sheet, the consumption rate, the container size, the replacement interval, and the shelf life
  • the calibration and verification method for each parameter, the reference standards or the grab-sample reference method, the manufacturer's recommended interval, and the acceptance criterion
  • the temperature compensation method and the reference temperature for each temperature-dependent parameter
  • the output data: analog output, fault signal levels, the digital protocol, and the list of measured values, diagnostics, and alarms available on each output
  • power requirements, enclosure rating, and the hazardous-location listing where the analyzer is installed in a classified location
  • the instrument index entries and loop diagrams for each analyzer per ANSI/ISA-5.1 and ANSI/ISA-5.4, coordinated with Control Systems IntegrationControl Systems Integration and TestingResolves to the current adopted revision.sync/control-systems-integration
  • mounting and installation details, including the service clearance and the washdown orientation of the enclosure and its entries
Action Submittal Packagecheckbox
☑ Analyzer product data
☑ Governing method and compliance approval documentation
☑ Sensor data and mounting hardware
☑ Sample system design and panel arrangement
☑ Reagent data and safety data sheets
☑ Calibration and verification method
☑ Temperature compensation method
☑ Output, fault signal, and digital protocol data
☑ Power, enclosure, and hazardous-location data
☑ Instrument index entries and loop diagrams
☑ Mounting and installation details
3.1.2 Analyzers shall not be procured until the action submittals for them have been reviewed and returned.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following with or before the action submittals:
  • the manufacturer's experience record for analyzers of each type furnished
  • the location and the response time of the factory-authorized service organization that will support the analyzers
  • the manufacturer's written confirmation of the availability period for replacement sensors, reagents, and parts
  • the startup and verification plan, identifying the reference standards, the grab-sample reference method, the party performing the laboratory analysis, and the acceptance criterion for each analyzer
Informational Submittal Packagecheckbox
☑ Manufacturer experience record
☑ Factory-authorized service organization
☑ Parts and consumables availability confirmation
☑ Startup and verification plan

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the analyzers are accepted:
  • operation and maintenance manuals for each analyzer, with the manufacturer's installation, calibration, operation, cleaning, and maintenance instructions
  • the as-calibrated record for each analyzer: the initial calibration values, the reference standards used with lot and expiration, and the startup verification result against the reference method
  • factory calibration certificates where furnished
  • the reagent inventory and the documented replacement interval and consumption rate for each wet-chemistry analyzer
  • the recommended calibration, verification, cleaning, and consumable replacement schedule for each analyzer
  • the loop check and fault-signal verification records
  • the spare parts list with manufacturer part numbers
  • warranty documentation, including the published sensor warranty for each sensor type
  • a signed receipt from the Owner for the spare parts delivered
Closeout Submittal Packagecheckbox
☑ Operation and maintenance manuals
☑ As-calibrated record and startup verification result
☑ Factory calibration certificates
☑ Reagent inventory and replacement interval
☑ Calibration, cleaning, and consumable schedule
☑ Loop check and fault-signal verification records
☑ Spare parts list
☑ Warranty documentation
☑ Spare parts receipt

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 Each analyzer shall be the product of a manufacturer that has produced online analyzers of that type for not less than the period indicated in the datasheet.
Manufacturer Experience with the Analyzer Typerange
Not less than
years
351015
4.1.2 Replacement sensors, reagents, consumables, and factory service for each analyzer model shall remain available for not less than ten years from the date of substantial completion.
4.1.3 The manufacturer shall operate a quality management system certified to ISO 9001.
NOTE Experience with one analyzer type does not transfer to another: a maker with decades of turbidimeters is new to ammonia analyzers the year it introduces one, so the datasheet period is met per analyzer type. Projects weigh the newness of a measurement technology against what it offers, which is why the field asserts no norm. (4.1.4)

4.2 Method Conformance

4.2.1 Each analyzer shall measure its parameter by the method identified for that parameter in this standard.
4.2.2 Each analyzer identified as serving a compliance-reporting function shall be of a type approved for online use under the method the applicable regulation names for that parameter, and the approval shall be documented in the action submittal.
NOTE Under the federal drinking-water regulations at 40 CFR 141, online turbidity is reported by USEPA Method 180.1 or by an alternate test method the USEPA has approved for that use, and online chlorine residual by USEPA Method 334.0; under the wastewater test procedures at 40 CFR 136, the approved methods are those the part lists for each parameter. A state primacy agency can approve additional methods or restrict the federal list, and the method that governs a given analyzer is the one the agency accepts for that permit. (4.2.3)

4.3 Drinking-Water Contact Materials

4.3.1 Whether the wetted components of analyzers in contact with potable water are required to be certified to NSF/ANSI/CAN 61 shall be as indicated in the datasheet.
NSF/ANSI/CAN 61 Certification of Wetted Componentsradio
○ Required
○ Not required
4.3.2 Where certification is required, the wetted parts of each sensor, flow cell, and sample line in contact with water that is or will become potable shall be certified to NSF/ANSI/CAN 61, and components in that contact shall comply with the lead-content limits of NSF/ANSI/CAN 372.
NOTE A sample drawn to a flow cell and sent to drain never returns to the potable stream, and some agencies exempt it on that basis, while an insertion sensor in a finished-water pipe is in continuous contact; the requirement follows the agency's reading of the contact, which is why the field is undefaulted. (4.3.3)

4.4 Factory Calibration

4.4.1 Each analyzer shall be calibrated and tested at the factory before shipment, with the calibration traceable to recognized reference standards.
4.4.2 Each sensor that stores its calibration data in the sensor shall be shipped with that data loaded, so that a replacement sensor restores its calibration when it is connected.

5 Environmental and Service Conditions

5.1 Process Conditions at the Sample Point

5.1.1 Each analyzer and sensor shall be rated for the pressure, temperature, and chemistry of the process stream at its sample tap or insertion point, which shall be as indicated on the process data of the instrument index.
5.1.2 The wetted materials of each sensor shall be compatible with the process chemistry, including any disinfectant residual, acid, caustic, solvent, or oxidant present in the stream.

5.2 Enclosure Rating

5.2.1 The enclosure type rating of analyzers and transmitters shall be as indicated in the datasheet.
Analyzer and Transmitter Enclosure Type Ratingselect
Type 1
Type 12
Type 3R
Type 4
Type 4X
5.2.3 Analyzers and transmitters installed outdoors shall be rated Type 4X and shall be furnished with a sunshade or a weather hood over the display and the sample panel.
5.2.4 Analyzers and transmitters installed in a corrosive atmosphere, including a chlorine or ammonia storage room, a headworks, or a digester area, shall have a nonmetallic or stainless-steel enclosure rated Type 4X.
NOTE Type 1 and Type 12 enclosures suit a conditioned instrument room where no hose is used and no corrosive vapor is present; Type 3R sheds rain and is not sealed against a hose stream or a corrosive vapor; Type 4 and Type 4X are gasketed against hose-directed water, and the X adds corrosion resistance of the enclosure material itself. Analyzer transmitters are built to Type 4X almost without exception, and they sit in galleries, chemical rooms, and basins far more often than in instrument rooms, which is the norm the default records. (5.2.5)

5.3 Hazardous Locations

5.3.1 The hazardous-location protection method of analyzers and sensors installed in a classified location shall be as indicated in the datasheet, and the classification of each location shall be as indicated on the hazardous area classification drawings.
Hazardous-Location Protection Methodselect
General-purpose for an unclassified location
Nonincendive, Class I Division 2
Intrinsically safe, Class I Division 1
Explosionproof, Class I Division 1
Increased safety or flameproof, Class I Zone 1
5.3.2 The listing of the analyzer, the sensor, the sensor cable, and any sample pump shall cover the class, division or zone, group, and temperature code of the location.
5.3.3 Where intrinsic safety is selected, the barrier or isolator shall be furnished with the analyzer and installed in accordance with the control drawing the manufacturer publishes for the combination.

5.4 Ambient Temperature Rating

5.4.1 The minimum ambient operating temperature rating of analyzers and transmitters mounted outdoors or in an unconditioned space shall be as indicated in the datasheet.
Lowest Ambient Operating Temperature Ratingrange
Not more than
°C
-40-30-20-105
Derived — Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum where the analyzer is outdoors, or the lowest temperature of the unconditioned space where it is inside one (by default)
5.4.2 The maximum ambient operating temperature rating of analyzers and transmitters mounted outdoors or in an unconditioned space shall be as indicated in the datasheet.
Highest Ambient Operating Temperature Ratingrange
Not less than
°C
4045505560
Derived — Site Ambient Temperature MaximumSite Ambient Temperature MaximumParameterEach project supplies its own value.site-ambient-temperature-maximum plus the solar gain on an outdoor enclosure, or the highest temperature of the unconditioned space where the analyzer is inside one (by default)
5.4.3 Where the published rating of the analyzer does not reach the derived value, the analyzer shall be furnished in a heated or cooled enclosure that holds it within its rating.
NOTE A wet-chemistry analyzer carries a narrower ambient rating than an electrochemical sensor, because its reagents and its optical bench set the limit, and an analyzer in direct sun reaches an internal temperature well above the air around it; an analyzer inside a conditioned room is rated for the room and carries no requirement under this article. (5.4.4)

5.5 Freeze Protection

5.5.1 Where Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum is below 0°C, each outdoor sample line, flow cell, sample pump, and reagent supply shall be protected from freezing by the method indicated in the datasheet.
Freeze Protection of Outdoor Sample Systemsselect
Heated and insulated analyzer enclosure
Heat-traced and insulated sample line with a heated enclosure
Continuous flow with a self-draining sample line on loss of flow
Not required
NOTE A heated enclosure protects the analyzer and the flow cell and not the sample line that feeds it; heat trace protects the line as well and costs a circuit and a controller; a self-draining line relies on flow and empties when flow stops, which leaves the analyzer without a sample until flow returns. Where the whole sample system is indoors, the field records that protection is not required. (5.5.2)

6 Measured Parameters

6.1 Parameter Selection

6.1.1 The parameter articles of this standard that apply to the project shall be those selected in the datasheet.
Measured Parameters Providedcheckbox
☐ pH
☐ ORP
☐ Turbidity
☐ Chlorine residual
☐ Dissolved oxygen
☐ Conductivity
☐ Ammonia
☐ Nitrate
☐ Total organic carbon
☐ UV absorbance at 254 nm
☐ Suspended solids
☐ Sludge blanket level
☐ Streaming current
☐ Dissolved ozone
NOTE Each measured parameter is a distinct analyzer with its own sensor technology, calibration regime, and consumables, and the article for each parameter carries the technology decision for that parameter alone, because a technology that suits one parameter has no bearing on another. (6.1.2)

6.2 Sensor Signal Interface

6.2.1 The interface between each sensor and its transmitter shall be as indicated in the datasheet.
Sensor Signal Interfaceradio
● Digital sensor with calibration data stored in the sensor
○ Analog sensor with the preamplifier at the sensor
6.2.2 Where a digital sensor is selected, the transmitter shall accept any sensor of the same family without reconfiguration and shall report the sensor serial number and the date of its last calibration to the control system.
NOTE A digital sensor carries its calibration in the sensor head, so that a fouled sensor is exchanged for one calibrated in the shop and the exchange takes minutes at the process, and its cable carries a digital signal immune to the moisture and noise that corrupt a high-impedance pH signal; an analog sensor costs less, is the only form some specialty sensors take, and ties the calibration to the transmitter it is connected to. Digital sensors are the standard offering of the major analyzer lines for the parameters in this standard, which is the norm the default records. (6.2.3)

6.3 pH

6.3.1 pH shall be measured electrometrically with a measuring electrode and a reference electrode in accordance with ASTM D6569 for the online measurement and ASTM D1293 for the reference measurement.
6.3.2 The pH measuring electrode shall be as indicated in the datasheet.
pH Measuring Electroderadio
● Glass electrode
○ Non-glass solid-state electrode
6.3.3 The pH reference system shall be as indicated in the datasheet.
pH Reference Systemselect
Sealed gel-filled single-junction reference
Sealed gel-filled double-junction reference
Differential reference with a replaceable salt bridge
Flowing liquid-junction reference with an electrolyte reservoir
6.3.4 pH calibration shall use not fewer than two certified buffer points that bracket the operating range of the stream.
NOTE The glass electrode is unaffected by color, turbidity, and most oxidants and reductants and is what nearly every online pH sensor uses, which the default records; the solid-state electrode cannot break and suits a food process or a location where glass is prohibited, at the cost of a higher drift. The reference junction is where a pH sensor fails: a sealed single junction is the lowest cost and is poisoned fastest by sulfide, ammonia, or heavy metals; a double junction places a second electrolyte between the process and the reference and extends its life in a fouling stream; a differential sensor replaces the junction with a salt bridge the operator renews, which suits a wastewater stream that poisons sealed references within months; a flowing junction holds the highest accuracy in a clean industrial process and needs its reservoir refilled. (6.3.5)

6.4 ORP

6.4.1 Oxidation-reduction potential shall be measured with a noble-metal measuring electrode against a reference electrode in accordance with ASTM D1498 and reported in millivolts.
6.4.2 The ORP measuring electrode metal shall be as indicated in the datasheet.
ORP Measuring Electrode Metalradio
● Platinum
○ Gold
6.4.3 The reference system of ORP sensors shall be the system selected for pH sensors in the datasheet.
NOTE ORP reads the net oxidizing or reducing state of the stream rather than the concentration of any one species, which makes it the control variable for a dechlorination endpoint, a chromium reduction, or a cyanide oxidation, and a poor stand-in for a residual measurement where the residual itself is reportable. Platinum is the electrode of nearly every ORP sensor sold, which the default records; gold is used where the stream attacks platinum or where a cyanide oxidation needs the response gold gives in that chemistry. (6.4.4)

6.5 Turbidity

6.5.1 Turbidity shall be measured by nephelometry, the detection of light scattered by suspended particles, and reported in the units the governing method defines.
6.5.2 The turbidity measurement method shall be as indicated in the datasheet.
Turbidity Measurement Methodselect
USEPA Method 180.1 white-light nephelometric
USEPA-approved alternate test method with an LED source
ISO 7027 near-infrared nephelometric
Backscatter nephelometric
6.5.3 The upper range value of each turbidimeter shall be as indicated in the datasheet.
Turbidimeter Upper Range Valuerange
NTU
1101001000400010000
6.5.4 Turbidimeters that serve a drinking-water compliance-reporting function on filter effluent shall resolve 0.001 NTU.
6.5.5 The calibration standard for turbidimeters shall be as indicated in the datasheet.
Turbidimeter Calibration Standardradio
○ Formazin prepared from reagent
○ Stabilized formazin suspension
○ Polymer microsphere secondary standard
6.5.6 Each turbidimeter calibration shall be verified between calibrations with a secondary standard or a sealed check standard at the interval the governing method requires.
6.5.7 Each flow-through turbidimeter shall be furnished with a bubble trap or a flow cell that vents entrained air before the measuring volume.
NOTE A white-light tungsten source under USEPA Method 180.1 is the method the federal drinking-water rule names, and it reads color in the sample as turbidity; an approved alternate method with an LED source holds the same standing for compliance reporting where the USEPA has approved it and the primacy agency accepts it, with a source that lasts for years; the ISO 7027 near-infrared source is unaffected by color, is the method of most process turbidimeters and of compliance reporting outside the United States, and is not accepted for federal drinking-water compliance reporting. The two sources read differently on the same sample, so the method is chosen once per stream and the laboratory reference matches it. Backscatter optics read into a stream too dense for a 90° detector and suit a raw sludge or a high-solids raw water. (6.5.8)
NOTE A low upper range gives resolution on a filter effluent and saturates on a raw water; a high upper range reads a raw water and cannot resolve a tenth of an NTU. Formazin made from reagent is the primary standard every method defines and is prepared fresh; a stabilized formazin suspension holds its assigned value for its shelf life; a polymer microsphere standard is a secondary standard assigned against formazin for one instrument design and is not transferable to another. (6.5.9)

6.6 Chlorine Residual

6.6.1 Chlorine residual shall be measured in accordance with USEPA Method 334.0 where the analyzer serves a drinking-water compliance-reporting function, and otherwise in accordance with Standard Methods 4500-Cl for the species measured.
6.6.2 The chlorine species each analyzer measures shall be as indicated in the datasheet.
Chlorine Species Measuredcheckbox
☐ Free chlorine
☐ Total chlorine
☐ Monochloramine
6.6.3 The chlorine measurement technology shall be as indicated in the datasheet.
Chlorine Measurement Technologyselect
Amperometric membrane-covered sensor
Amperometric bare-electrode sensor with reagent addition
DPD colorimetric wet-chemistry analyzer
6.6.4 The upper range value of each chlorine analyzer shall be as indicated in the datasheet.
Chlorine Analyzer Upper Range Valuerange
mg/L
0.51251020
6.6.5 Amperometric chlorine sensors shall be furnished with the pH compensation and the sample flow regulation the sensor requires, and the sample pH range within which the sensor holds its stated accuracy shall be stated in the submittal.
6.6.6 Each chlorine analyzer serving a compliance-reporting function shall be verified against the grab-sample reference method and shall meet the acceptance criterion of USEPA Method 334.0 at startup and at the interval the method requires.
NOTE A membrane-covered amperometric sensor consumes no reagent and reads continuously, needs a steady sample flow and a sample pH within its compensation range, and reads free chlorine or total chlorine according to the membrane and electrolyte fitted; a bare-electrode amperometric sensor adds a buffer reagent to hold the sample pH and holds its accuracy across a wider pH range at the cost of that reagent; a DPD colorimetric analyzer performs the laboratory reference reaction on a timed cycle, matches the laboratory result most directly, consumes two reagents, generates a reagent waste stream, and reads at intervals of a minute or more rather than continuously. The upper range value sets the resolution: a distribution residual below 2 mg/L is resolved on a 0 to 5 mg/L range and lost on a 0 to 20 mg/L range, while a contact basin dosed at 10 mg/L saturates the lower range. (6.6.7)

6.7 Dissolved Oxygen

6.7.1 Dissolved oxygen shall be measured by an optical luminescence sensor in accordance with ASTM D888 Test Method C and ISO 17289, or by an electrochemical membrane sensor in accordance with ASTM D888 Test Method B.
6.7.2 The dissolved oxygen sensor technology shall be as indicated in the datasheet.
Dissolved Oxygen Sensor Technologyselect
Optical luminescence sensor
Electrochemical galvanic membrane sensor
Electrochemical polarographic membrane sensor
6.7.3 The upper range value of each dissolved oxygen analyzer shall be as indicated in the datasheet.
Dissolved Oxygen Upper Range Valuerange
mg/L
0.020.22204060
6.7.4 The saturation value used for air calibration of dissolved oxygen sensors shall be corrected for the barometric pressure at AltitudeAltitudeParameterEach project supplies its own value.altitude and for the salinity of the stream.
NOTE An optical sensor has no membrane to replace and no electrolyte to refill, does not consume oxygen at its face and so needs no flow across it, and holds calibration for months, which is why it is the sensor of nearly every aeration basin installed today and the norm the default records; a galvanic membrane sensor needs no warm-up and no polarizing voltage and suits a low-cost or intermittent application; a polarographic membrane sensor reaches the trace range of a boiler feedwater or a deaerator outlet that an optical sensor cannot resolve, at the cost of a membrane, an electrolyte, and a flow requirement. A 0 to 20 mg/L range spans an aeration basin and a surface water and is the range of nearly every treatment-plant sensor; the trace ranges serve power and high-purity water, and the 40 and 60 mg/L ranges serve a pure-oxygen activated-sludge process or an ozonation side stream. (6.7.5)

6.8 Conductivity

6.8.1 Conductivity shall be measured in accordance with ASTM D1125 and Standard Methods 2510 B and reported in µS/cm or mS/cm, and the measurement of a flowing high-purity water shall comply with ASTM D5391.
6.8.2 The conductivity cell type shall be as indicated in the datasheet.
Conductivity Cell Typeselect
Contacting two-electrode cell
Contacting four-electrode cell
Toroidal inductive sensor
6.8.3 The upper range value of each conductivity analyzer shall be as indicated in the datasheet.
Conductivity Upper Range Valuerange
µS/cm
2202002000200002000002000000
6.8.4 The cell constant of each contacting conductivity cell shall be as indicated in the datasheet.
Conductivity Cell Constantrange
1/cm
0.010.050.10.5110
Derived — the selected conductivity upper range value (by default)
6.8.5 The temperature compensation algorithm of each conductivity analyzer shall be as indicated in the datasheet.
Conductivity Temperature Compensation Algorithmselect
Linear coefficient
Natural water nonlinear
Ultrapure water
6.8.6 Where linear compensation is selected, the coefficient shall be adjustable at the transmitter and shall be set for the stream at startup.
6.8.7 The cell constant shall be entered or verified at each conductivity calibration.
NOTE A two-electrode contacting cell gives the highest resolution at low conductivity and polarizes as the conductivity rises; a four-electrode cell drives current through one pair and senses with another, which removes the polarization error and extends a contacting cell to several hundred mS/cm; a toroidal sensor couples through the liquid with no exposed electrode, cannot foul or polarize, and loses resolution below a few hundred µS/cm. The cell constant follows from the range, a low constant for the low ranges and a high constant for the high ranges, and the manufacturer resolves it from the range selected, which is why the field is derived. Linear compensation at about 2 percent per degree fits most natural and process waters and is the norm the default records; the natural-water curve fits a low-conductivity surface water across a wide temperature span; ultrapure compensation accounts for the conductivity of water itself and is what a condensate, a deionized water, or an RO permeate requires. (6.8.8)

6.9 Ammonia

6.9.1 Ammonia nitrogen shall be measured in accordance with Standard Methods 4500-NH3 by the technology indicated in the datasheet.
Ammonia Measurement Technologyselect
Ammonium ion-selective electrode with potassium compensation
Gas-sensing ammonia electrode after sample pH elevation
Colorimetric wet-chemistry analyzer
6.9.2 The upper range value of each ammonia analyzer shall be as indicated in the datasheet.
Ammonia Analyzer Upper Range Valuerange
mg/L as N
1520501001000
NOTE An ion-selective electrode reads ammonium in the basin directly, needs no reagent and no sample system, and drifts with potassium and with the condition of its membrane, which its compensation electrode and its calibration interval address; a gas-sensing electrode raises the sample pH with reagent to convert ammonium to ammonia gas and reads it through a membrane, which removes the ionic interference at the cost of a reagent and a sample system; a colorimetric analyzer performs the laboratory reaction on a timed cycle, matches the reference result most directly, and reads at intervals rather than continuously, with two or three reagents to maintain. An aeration control loop lives with the electrode's drift for the sake of its continuous reading, and an effluent limit report wants the colorimetric result. (6.9.3)

6.10 Nitrate

6.10.1 Nitrate nitrogen shall be measured in accordance with Standard Methods 4500-NO3 by the technology indicated in the datasheet.
Nitrate Measurement Technologyselect
Nitrate ion-selective electrode with chloride compensation
Ultraviolet absorption optical sensor
Colorimetric wet-chemistry analyzer
6.10.2 The upper range value of each nitrate analyzer shall be as indicated in the datasheet.
Nitrate Analyzer Upper Range Valuerange
mg/L as N
2520501001000
NOTE A nitrate ion-selective electrode is the lowest-cost sensor and suffers chloride and bicarbonate interference that its compensation electrode corrects only within limits; an ultraviolet absorption sensor reads the nitrate absorbance directly with no reagent and no membrane, holds calibration for months, and is confounded by organic matter and turbidity in a raw wastewater unless its optics compensate for them; a colorimetric analyzer reduces nitrate and reads the colored product on a timed cycle, matches the reference method most directly, and carries the reagents and the cycle time of any wet-chemistry analyzer. A denitrification control loop in a clarified mixed liquor suits the optical sensor, and a raw influent with high organics pushes toward the colorimetric analyzer. (6.10.3)

6.11 Organic Carbon and UV Absorbance

6.11.1 Total organic carbon shall be measured by oxidation of the organic carbon in the sample and detection of the carbon dioxide produced, in accordance with ASTM D5173 and Standard Methods 5310, by the technology indicated in the datasheet.
Total Organic Carbon Measurement Technologyselect
UV-persulfate oxidation with NDIR detection
UV-persulfate oxidation with membrane conductometric detection
High-temperature combustion with NDIR detection
6.11.2 The upper range value of each total organic carbon analyzer shall be as indicated in the datasheet.
Total Organic Carbon Upper Range Valuerange
mg/L
0.5152050100100010000
6.11.3 Ultraviolet absorbance at 254 nm shall be measured by a reagentless optical sensor with a stated path length, reported in absorbance units per centimeter, with compensation for turbidity by a reference wavelength or by filtration of the sample.
NOTE UV-persulfate oxidation with NDIR detection handles the full range from a drinking water to an industrial effluent and consumes a persulfate reagent and an acid; the membrane conductometric detector reaches the trace range of a pharmaceutical or power water and loses accuracy in a sample with high salts or high chloride; high-temperature combustion oxidizes particulate and refractory organics that persulfate leaves behind, which matters in a wastewater, and carries a furnace and a carrier gas. UV absorbance at 254 nm is a surrogate for the aromatic organics that form disinfection byproducts and is read continuously by a sensor with no consumables; where USEPA Method 415.3 is the basis of a treatment-technique requirement, the laboratory TOC and the online surrogate are correlated for the source water rather than treated as the same measurement. (6.11.4)

6.12 Suspended Solids and Sludge Blanket

6.12.1 Suspended solids concentration shall be measured by the principle indicated in the datasheet and verified against the gravimetric method of Standard Methods 2540 D.
Suspended Solids Measurement Principleselect
Near-infrared scattered-light optical sensor
Near-infrared absorption optical sensor
Microwave total solids sensor
6.12.2 The upper range value of each suspended solids analyzer shall be as indicated in the datasheet.
Suspended Solids Upper Range Valuerange
mg/L
1000500030000100000300000500000
6.12.3 Sludge blanket level shall be detected by the method indicated in the datasheet.
Sludge Blanket Detection Methodselect
Ultrasonic profiling sensor
Optical sensor lowered through the clarifier on a motorized cable
Optical sensors fixed at set depths
6.12.4 Each suspended solids sensor installed in mixed liquor or sludge shall be furnished with automatic cleaning under the Automatic Sensor Cleaning article of this standard.
NOTE A scattered-light sensor reads a mixed liquor or a return sludge across a wide range with a response that depends on the floc size, which is why it is calibrated against a grab sample from the stream it serves; an absorption sensor reads a lower solids range with less sensitivity to floc structure; a microwave sensor reads a thickened or dewatered sludge in the percent-solids range that no optical sensor penetrates. An ultrasonic profiler reads the full depth of a clarifier from the surface and returns both the blanket and the fluff layer above it; a lowered optical sensor reads the interface directly at the cost of a moving mechanism in the clarifier; fixed optical sensors answer only whether the blanket has reached each depth they occupy. (6.12.5)

6.13 Streaming Current

6.13.1 Streaming current shall be measured by a streaming current monitor fed by a continuous sample of the coagulated water, reported in streaming current units relative to a zero the operator sets.
6.13.2 The coagulant control function of the streaming current monitor shall be as indicated in the datasheet.
Streaming Current Monitor Control Functionradio
○ Monitor output to the plant control system
○ Integral controller output to the coagulant feed
6.13.3 The streaming current monitor shall draw its sample downstream of the point at which the coagulant is completely mixed and shall be furnished with a sample pump and a sample line sized for the velocity its sensor requires.
NOTE A streaming current monitor reads the net surface charge of the particles after coagulant addition rather than any concentration, and its reading is relative: the operator sets the zero at a dose that produces the clarified water the plant wants, and the control holds that charge as the raw water changes. An integral controller closes the dose loop in the monitor itself with its own tuning, which suits a plant whose control system does not host the loop; a monitor-only output lets the plant controller host the loop beside the turbidity, flow, and UV absorbance signals it also reads, which is where a feed-forward and feedback strategy is built. (6.13.4)

6.14 Dissolved Ozone

6.14.1 Dissolved ozone residual shall be measured in accordance with Standard Methods 4500-O3 by the technology indicated in the datasheet.
Dissolved Ozone Measurement Technologyradio
● Amperometric membrane-covered sensor
○ Indigo colorimetric wet-chemistry analyzer
6.14.2 The upper range value of each dissolved ozone analyzer shall be as indicated in the datasheet.
Dissolved Ozone Upper Range Valuerange
mg/L
0.52520
NOTE An amperometric membrane sensor reads dissolved ozone continuously with no reagent and is what nearly every ozone contactor residual loop uses, which the default records; the indigo colorimetric analyzer is the reference chemistry run online, matches the laboratory result most directly, and consumes an indigo reagent that is itself light-sensitive. Ozone residuals in a contactor run below 2 mg/L in nearly every case, and the higher ranges serve an ozone generator side stream or an industrial oxidation process. (6.14.3)

7 Sensor Installation and Sample Systems

7.1 Sensor Mounting Arrangements

7.1.1 The sensor mounting arrangements used on the project shall be those selected in the datasheet, and each sensor shall be mounted by the arrangement indicated for it on the instrument index.
Sensor Mounting Arrangements Usedcheckbox
☐ Insertion through a retractable or ball-valve fitting in a pressurized pipe
☐ Submersion in an open basin or channel on a rail, float, or handrail mount
☐ Flow-through cell on a sample panel fed from a sample tap
7.1.2 Insertion sensors in a pressurized pipe shall be mounted in a retractable fitting or behind an isolation valve, so that the sensor is withdrawn for cleaning and calibration without depressurizing the pipe.
7.1.3 Submersion sensors shall be mounted so that the sensor is raised to the walkway for service without entering the basin and without a lifting device beyond the mount itself.
7.1.4 Submersion mounts in a basin with aeration or mixing shall hold the sensor at the depth and the orientation the manufacturer requires and shall restrain the cable against the turbulence.
7.1.5 Flow-through sensors shall be mounted in the flow cell the manufacturer furnishes for the sensor, with the center of the cell between 900 mm and 1500 mm above the standing surface.
NOTE An insertion sensor sits in the pipe with the fastest response and no sample lag, is exposed to the full process pressure and fouling, and needs a retractable fitting if the pipe cannot be taken down for service; a submersion sensor is the only arrangement an open basin offers and relies on its mount for every service visit; a flow-through cell isolates the sensor from the process pressure and debris, allows the sample to be deaerated and its flow regulated, and brings the sensor to a convenient height, at the cost of a sample line with its lag and its own maintenance. Turbidimeters and wet-chemistry analyzers are flow-through by construction, dissolved oxygen in a basin is submersion by necessity, and pH, ORP, and conductivity are the sensors for which the choice is open. (7.1.6)

7.2 Sample Tap and Sample Line

7.2.1 The sample tap for each flow-through analyzer shall draw from a well-mixed, representative portion of the stream, downstream of any chemical injection point by the distance required for complete mixing, and clear of dead legs, air pockets, and the pipe invert.
7.2.2 The process tap, root valve, and tap fitting for each sample line shall comply with Instrument Installation And TubingInstrument Installation and Impulse TubingResolves to the current adopted revision.sync/instrument-installation-and-tubing.
7.2.3 The sample line material shall be as indicated in the datasheet.
Sample Line Materialselect
PVC Schedule 80 pipe
CPVC Schedule 80 pipe
Opaque polyethylene tubing
PFA or PTFE tubing
Type 316 stainless steel tubing
7.2.4 Sample lines shall be opaque, or shall be jacketed, to exclude light from the sample.
7.2.5 The sample transport lag from the tap to the sensor at the design sample flow shall not exceed the time indicated in the datasheet.
Sample Transport Lagrange
Not more than
s
103060120300600
7.2.6 Sample lines shall be sized for a velocity that keeps solids in suspension at the design sample flow and shall run continuously rising or continuously falling with no pocket where air or solids collect.
7.2.7 Each sample line shall be furnished with an isolation valve at the tap and a means of flushing the line without disconnecting it.
NOTE PVC and CPVC pipe are the lowest-cost lines and the ones most plants already stock, with CPVC carrying a hot sample that softens PVC; polyethylene tubing bends around obstructions without fittings and is the line of most short runs; PFA and PTFE tubing resist every chemistry a treatment plant handles and are chosen for a strong oxidant, a solvent, or a trace organic measurement where plastic leaches into the sample; stainless steel tubing carries a hot or pressurized industrial sample and is attacked by a chloride-bearing or chlorinated stream. Lag is the sample volume divided by the flow, so a long line is shortened by a smaller bore or a faster bleed at the panel, and a control loop fed by an analyzer sees the lag as dead time it has to be tuned around. (7.2.8)

7.3 Sample Conditioning

7.3.1 Each flow-through analyzer shall be furnished with the sample conditioning components indicated in the datasheet, delivering a sample at the flow, pressure, and condition the sensor requires.
Sample Conditioning Componentscheckbox
☑ Isolation valve at the sample tap
☐ Strainer or self-cleaning filter
☑ Pressure regulator or constant-head overflow device
☑ Sample flow indicator with flow-control valve
☐ Bubble trap or deaeration chamber
☑ Low-sample-flow switch wired to the transmitter
☐ Sample pump
☑ Grab-sample valve at the flow cell
☐ Sample cooler
7.3.2 Where a sample pump is selected, it shall be rated for the sample chemistry and for continuous duty, and it shall be protected against running dry.
7.3.3 The low-sample-flow switch shall be wired to the transmitter so that loss of sample flow is reported to the control system as a status distinct from the measured value.
7.3.4 Spent sample and reagent waste shall discharge through an air gap to a drain or to the return point indicated on the process and instrumentation diagrams.
NOTE A sensor in a stagnant or empty flow cell reports a plausible value that is not a measurement, which is what the low-flow switch exists to expose; a constant-head overflow holds the flow steady against a varying tap pressure with no moving part and spills the excess to drain, while a regulator holds it with a diaphragm and spills nothing; a strainer protects a narrow flow cell from the debris that would block it and is itself the component that blocks most often; a bubble trap removes the air that reads as turbidity and as a chlorine error; a cooler brings a hot industrial sample within the sensor's rating. (7.3.5)

7.4 Sample Panel

7.4.1 Where two or more flow-through analyzers share a location, their flow cells, conditioning components, valves, and transmitters shall be mounted on a common sample panel arranged for operation and service from the front.
7.4.2 The sample panel material shall be as indicated in the datasheet.
Sample Panel Materialselect
Fiberglass-reinforced polyester
Polypropylene or PVC sheet
Type 304 stainless steel
Type 316 stainless steel
Painted carbon steel
7.4.3 Sample panel tubing, valves, and fittings shall be of a material compatible with the sample chemistry, and each panel-mounted component shall be labeled with the tag of the analyzer it serves.
7.4.4 Sample panels shall be furnished with a drip tray or a drained sump that collects spilled sample and reagent and discharges it to the drain.

7.5 Reagent Handling

7.5.1 Each wet-chemistry analyzer shall be furnished with reagent containers sized for not less than the replacement interval indicated in the datasheet at the analyzer's design cycle rate.
Reagent Replacement Intervalrange
Not less than
days
14306090180
7.5.2 Reagent containers shall be housed within the analyzer enclosure or in a ventilated reagent cabinet beneath it, shall be replaced without tools, and shall be identified by reagent name and expiration date.
7.5.3 Where a reagent is classified as hazardous in its safety data sheet, an emergency eyewash complying with ANSI/ISEA Z358.1 shall be located within the travel distance that standard permits from the reagent handling point.
NOTE A 30-day reagent interval is the design basis of most colorimetric chlorine analyzers; a longer interval needs a larger reagent volume that may not keep within its shelf life, and an analyzer that cycles faster for a control loop consumes its reagent sooner. A reagent-free sensor carries none of this, which is the operating-cost argument that decides many technology selections above. (7.5.4)

7.6 Automatic Sensor Cleaning

7.6.1 The automatic cleaning method furnished for sensors that require it shall be as indicated in the datasheet.
Automatic Sensor Cleaning Methodselect
Compressed-air blast at the sensor face
Mechanical wiper
Ultrasonic cleaning
Chemical cleaning spray
None
7.6.2 Sensors submerged in mixed liquor, raw wastewater, primary effluent, or sludge shall be furnished with automatic cleaning.
7.6.3 The cleaning interval and duration shall be adjustable at the transmitter, and the transmitter shall hold the output at its last value during a cleaning cycle.
7.6.4 Where compressed-air cleaning is selected, the air source shall be as indicated on the process and instrumentation diagrams, and plant instrument air supplied to it shall comply with Compressed Air SystemsCompressed Air SystemsResolves to the current adopted revision.sync/compressed-air-systems.
NOTE An air blast strips biological growth from an optical face and needs a dry air supply and a solenoid; a wiper clears a flat optical window and wears against grit; ultrasonic cleaning shakes deposits off an electrode with no moving part and no air and does little against a slime that has matured; a chemical spray dissolves a mineral scale or a grease film that none of the others remove and consumes a cleaning solution. A sensor in a clean filtered water needs none of them, which is why the field offers that answer. (7.6.5)

8 Transmitter and Signal Output

8.1 Transmitter Configuration

8.1.1 Each transmitter shall provide the local indication indicated in the datasheet.
Transmitter Local Indicationradio
● Local display and keypad at the transmitter
○ Blind transmitter configured over the digital interface
8.1.2 The number of sensors served by each transmitter shall be as indicated in the datasheet.
Sensors per Transmitterradio
○ One sensor per transmitter
○ Multi-channel transmitter serving the sensors at one location
8.1.3 Transmitters shall display the measured value, the compensating temperature, the sensor diagnostics, and the calibration status, and shall retain a log of calibrations with date and values.
8.1.4 Transmitter housings shall be polycarbonate, fiberglass-reinforced polyester, or stainless steel, with a clear window over the display.
NOTE A local display is where an operator calibrates and reads the sensor at the process, and nearly every analyzer transmitter is furnished with one, which the default records; a blind transmitter saves cost where every sensor is calibrated from a handheld or over the network. A multi-channel transmitter serves two or more sensors on one panel with one display and one set of outputs, which costs less per sensor and places every sensor on the panel behind one failure. (8.1.5)

8.2 Transmitter Power

8.2.1 The power source for each transmitter and analyzer shall be as indicated in the datasheet.
Transmitter Power Sourceselect
AC branch circuit at 120 VAC
AC branch circuit at 240 VAC
DC control power at 24 VDC
Two-wire loop power from the controller input
8.2.2 Transmitters and analyzers shall be powered from the backed-up control power source that serves the controller receiving their signal.
NOTE A wet-chemistry analyzer, a turbidimeter, and any transmitter driving relays and a heated enclosure draw more than a loop can supply and are powered from a branch circuit, and 120 VAC is the circuit a treatment plant runs to every instrument location, which the default records; a 24 VDC supply from the control panel removes the AC wiring from the field and suits a panel-mounted transmitter; a two-wire loop-powered transmitter is the lowest-cost pH or conductivity installation and offers no relays, no display backlight, and no sensor cleaning. (8.2.3)

8.3 Analog Output

8.3.1 Each transmitter shall provide an isolated 4 to 20 mA analog output for each measured value, conforming to ANSI/ISA-50.00.01, and the output of each analyzer shall be scaled to the span indicated on the instrument index.
8.3.2 Whether HART communication is provided on the analog output shall be as indicated in the datasheet.
HART on the Analog Outputradio
○ Required
○ Not required
8.3.3 The number of relay outputs furnished on each transmitter shall be as indicated in the datasheet.
Transmitter Relay Outputsrange
relays
24
NOTE HART carries the sensor diagnostics and the secondary values over the analog pair without a network, and it is read only where the controller input or an asset management system is HART-capable; relays at the transmitter drive a local alarm, a cleaning solenoid, or a sample pump without a controller output. (8.3.4)

8.4 Fault Signaling

8.4.1 The analog output shall signal a detected analyzer or sensor fault in accordance with NAMUR NE43 in the direction indicated in the datasheet.
NAMUR NE43 Fault Signal Directionradio
○ Downscale to 3.6 mA or below
○ Upscale to 21 mA or above
8.4.2 A measurement outside the measuring range shall be distinguishable at the controller from an instrument fault, and a cleaning cycle and a calibration in progress shall each be reported as a status distinct from the measured value.
8.4.3 Where a digital interface is furnished, the diagnostic status of each analyzer shall be classified in accordance with NAMUR NE107.
NOTE A turbidimeter whose lamp has failed reads zero, which is also what clean water reads, and a fault signal is what separates the two at the controller. A downscale fault reads as a low value and trips the low alarm a loop already carries; an upscale fault reads as a high value and trips the high alarm; the direction is chosen so that the fault state lands on the alarm the loop needs to see, a high alarm for a chlorine residual whose loss is the hazard and a low alarm for a turbidity whose rise is the hazard. (8.4.4)

8.5 Digital Communication

8.5.1 Whether each transmitter is furnished with a digital network interface shall be as indicated in the datasheet.
Digital Network Interfaceradio
○ Required
○ Not required
8.5.2 Where a digital network interface is required, its protocol shall be as indicated in the datasheet.
Digital Network Protocolselect
Modbus RTU over RS-485
Modbus TCP
EtherNet/IP
PROFIBUS DP
PROFINET
FOUNDATION Fieldbus H1
Derived — the control protocol selected for the device-level segment under the process control networks standard (by default)
8.5.3 The digital interface shall expose the measured value, the compensating temperature, the sensor diagnostics, the calibration status, and the sample-flow status as readable points, and the network connection shall comply with Process Control NetworksProcess Control NetworksResolves to the current adopted revision.sync/process-control-networks.
NOTE The protocol follows the network rather than the analyzer: a transmitter on a segment that speaks one protocol speaks that protocol or sits behind a gateway, so the field is derived from the network standard's selection. (8.5.4)

8.6 Tagging and Loop Identification

8.6.1 Each analyzer, sensor, sample panel, and signal shall be tagged in accordance with ANSI/ISA-5.1 and the instrument index, matching the loop diagrams and the point list of SCADA And HMI SystemsSCADA and HMI SystemsResolves to the current adopted revision.sync/scada-and-hmi-systems.
8.6.2 Nameplates and labels shall comply with Equipment LabelingElectrical Equipment LabelsResolves to the current adopted revision.sync/equipment-labeling.

9 Calibration and Verification

9.1 Temperature Compensation

9.1.1 Each analyzer whose reading is temperature-dependent shall include automatic temperature compensation from a temperature element integral to the sensor, referenced to 25°C unless the governing method states another reference temperature.
NOTE Conductivity shifts on the order of 2 percent per degree Celsius, the pH electrode slope changes with temperature, and the solubility of oxygen falls as water warms, so an uncompensated reading of any of them is a different number at every hour of the day and is not reportable. (9.1.2)

9.2 Calibration Method by Parameter

9.2.1 Each analyzer shall be calibrated at startup by the method this standard identifies for its parameter: certified buffers for pH, a certified reference solution for ORP and conductivity, the formazin-based or assigned secondary standard selected for turbidity, water-saturated air or a zero standard for dissolved oxygen, a certified standard solution for ammonia and nitrate, a certified organic carbon standard for total organic carbon, a gravimetric grab sample for suspended solids, and the grab-sample reference method for chlorine and dissolved ozone.
9.2.2 Calibration standards and buffers shall be certified, within their shelf life, and traceable to a recognized reference, and the lot and expiration of each shall be recorded with the calibration.
9.2.3 Each analyzer shall be verified against its laboratory reference method at startup by a grab sample drawn at the sensor or at the grab-sample valve and analyzed by the party identified in the startup and verification plan, and the result shall be within the manufacturer's stated accuracy for the analyzer or the acceptance criterion of the governing method, whichever is tighter.
9.2.4 A grab sample drawn for verification shall be analyzed within the holding time the reference method allows.
NOTE Calibrating a stable sensor more often than its drift warrants introduces the error of each calibration standard in turn, and calibrating it less often lets a fouled sensor drift out of its accuracy unnoticed; the interval is set from the drift observed between verifications, which is why the manufacturer's interval is a starting point and the record of verifications is what adjusts it. (9.2.6)

9.3 Compliance Reporting Records

9.3.1 Each calibration and verification of an analyzer serving a compliance-reporting function shall be documented with the reference value, the analyzer value, the standard lot, the date, and the name of the person performing it, in a record the Owner retains for the period the regulation requires.

10 Installation

10.1 Sensor Location

10.1.1 Sensors shall be located in a representative, well-mixed portion of the stream, away from a chemical injection point by the distance required for complete mixing, and clear of dead legs, air pockets, stratified flow, and surface foam.
NOTE A chlorine or pH sensor placed too near a feed point reads the unmixed chemical rather than the process, and a dissolved oxygen sensor placed over a diffuser grid reads the bubble plume rather than the basin; the location on the drawings is the one the process design selected for mixing, and a field relocation for convenience of access changes the measurement. (10.1.2)

10.2 Service Access

10.2.1 Each analyzer and sensor shall be installed so that the sensor is cleaned, calibrated, and replaced from a floor, platform, or walkway without a ladder, without entering a basin, and without removing adjacent equipment.
10.2.2 The clear working space in front of each transmitter and sample panel shall be not less than 900 mm deep across the full width of the panel.
10.2.3 Transmitter displays shall be mounted with the center of the display between 1200 mm and 1700 mm above the standing surface.
10.2.4 Analyzers and sensors in washdown areas shall have their cable entries and fittings oriented downward and sealed so that washdown water sheds from them.

10.3 Sensor Wiring

10.3.1 Sensor cable shall be the manufacturer's cable for the sensor, run from the sensor to the transmitter without a field splice except at a junction box the manufacturer furnishes for the purpose, and not longer than the manufacturer's published limit for the sensor type.
10.3.2 Sensor and analog signal cable shall be run in raceway separate from power conductors under Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit, shielded where the manufacturer requires, with the shield grounded at the transmitter end only; the cable from the analyzer to the control system is under Instrumentation And Control CableInstrumentation and Control CableResolves to the current adopted revision.sync/instrumentation-and-control-cable.
NOTE An analog pH or ORP signal is a high-impedance millivolt signal that moisture in a connection shorts and a nearby power conductor swamps, which is why its cable, its length, and its single junction are the manufacturer's and not the installer's choice; a digital sensor cable carries none of that sensitivity and still carries the length limit of its driver. (10.3.3)

11 Testing and Commissioning

11.1 Startup Verification

11.1.1 Each analyzer shall pass the startup verifications indicated in the datasheet before it is accepted.
Startup Verifications Requiredcheckbox
☑ Loop check from the sensor to the operator interface
☑ Fault signal level verified at the controller
☑ Calibration against the reference standard with as-left values recorded
☑ Verification against the laboratory reference method by grab sample
☑ Sample flow and low-sample-flow switch verified
☑ Temperature compensation verified
☐ Automatic cleaning cycle and output hold verified
☐ Digital interface points verified at the controller
11.1.2 The loop check of each analyzer shall be performed under Control Systems IntegrationControl Systems Integration and TestingResolves to the current adopted revision.sync/control-systems-integration, and the analyzer calibration shall be performed with it by the party that standard assigns.
11.1.3 An analyzer that fails a startup verification shall be corrected and re-verified at the Contractor's expense, including the cost of any repeated laboratory analysis.
11.1.4 The verification of an analyzer serving a compliance-reporting function shall be witnessed by the Owner's operator who will perform the ongoing verifications.

11.2 Demonstration and Training

11.2.1 The Contractor shall demonstrate to the Owner's operations staff, hands-on at the installed analyzer, the routine calibration, verification, sensor cleaning, reagent replacement, and consumable replacement of each analyzer type.
11.2.2 The demonstration duration for each analyzer type shall be not less than the time indicated in the datasheet.
Demonstration Duration per Analyzer Typerange
Not less than
hours
1248
NOTE Training on the supervisory display of analyzer data is provided under SCADA And HMI SystemsSCADA and HMI SystemsResolves to the current adopted revision.sync/scada-and-hmi-systems, and training on the control narratives under Control Systems IntegrationControl Systems Integration and TestingResolves to the current adopted revision.sync/control-systems-integration; the demonstration under this standard is limited to the analyzer itself. (11.2.3)

12 Delivery, Storage, and Handling

12.1 Analyzers, sensors, reagents, and reference standards shall be delivered in the manufacturer's packaging and stored within the storage temperature range published for each item, protected from freezing and from direct sun.
12.2 pH, ORP, and ion-selective sensors shall be stored with their junctions and membranes wetted in the manufacturer's storage solution until installed.
12.3 Reagents and reference standards shall not be installed past their expiration date, and a reagent whose shelf life expires before the scheduled startup shall be replaced by the Contractor at no cost to the Owner.
12.4 The optical windows of turbidimeters, dissolved oxygen sensors, and ultraviolet sensors shall remain capped until the sensor is installed.
NOTE A sensor allowed to dry out is not restored by rewetting: the reference junction crystallizes and the glass membrane loses its hydrated layer, and the sensor reads slowly and drifts for the rest of its life. (12.5)

13 Warranty

13.1 The manufacturer shall warrant each analyzer and transmitter against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.
Analyzer and Transmitter Warranty Periodrange
Not less than
years
1235
13.2 Sensors and measuring cells shall be warranted for the period the manufacturer publishes for that sensor type, and the published sensor warranty shall be stated in the submittal.
13.3 A warranted repair or replacement shall itself be warranted for a full new term equal to the original period measured from the completion of the repair, or for the remainder of the original period, whichever ends later.
NOTE Consumables, including buffers, reagents, electrolyte, membranes, lamps, and reference standards, are not warranted against consumption in normal service, and a sensor that reaches the end of its published service life is not a warranted defect. (13.4)
NOTE Analyzer manufacturers publish a one-year warranty on the transmitter and the analyzer body almost without exception, with longer terms purchased as an extension, which is the norm the default records; the sensor itself carries a shorter or a prorated term because a pH bulb, a chlorine membrane, and an optical cap wear out in service. (13.5)

14 Spare Parts

14.1 The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the analyzers are accepted and shall obtain a signed receipt for them.
Spare Parts to Be Furnishedcheckbox
☑ One spare sensor of each type installed
☑ One set of membranes, electrolyte, and O-rings for each electrochemical sensor type
☑ One replacement reagent set for each wet-chemistry analyzer
☑ Calibration buffers and reference standards for one year of calibrations
☐ One spare flow cell of each type installed
☐ One spare sample pump of each type installed
☐ One spare transmitter of each model installed
☐ One spare lamp or optical source of each type installed
14.2 Spare sensors shall be the same model as the installed sensors, shall be delivered in the manufacturer's storage packaging, and shall be labeled with the parameter and the tags of the installed sensors they replace.