Frequently Asked Questions
Below you’ll find answers to our most commonly asked questions. If you don’t find the answer you’re looking for, please contact us.
Certifications and Approvals
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Yes. SOR Measurement and Control produces a full line of nuclear-qualified pressure, differential pressure, vacuum, and temperature switches for nuclear power generation and has supplied the nuclear power industry for more than 30 years.
The SOR Measurement and Control nuclear-qualified product line includes the N6 and RT model pressure switches, N6 and RT temperature switches, and nuclear-qualified differential pressure switches (Models 131 and 141).
SOR Controls Group also designs and manufactures custom-engineered nuclear products for specific plant requirements, including replacement products for discontinued lines from other manufacturers.
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Many SOR Measurement and Control pressure switches, differential pressure switches, pressure transmitters, and temperature switches carry ATEX and IECEx approvals for use in Zone 1 and Zone 2 hazardous locations.
ATEX is the European Union directive governing equipment for explosive atmospheres.
IECEx is the International Electrotechnical Commission’s certification scheme for the same purpose, accepted in over 50 countries. Specific approvals vary by product model.
Check individual product data sheets on product pages or contact SOR for certifications on a specific model.
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A Safety Instrumented System (SIS) is a system designed to bring a process to a safe state when predetermined conditions are exceeded. It consists of three functional layers: sensors that detect abnormal process conditions, a logic solver (typically a safety PLC) that processes sensor inputs and makes decisions, and final elements such as valves or shutoffs that act on those decisions.
Pressure switches, differential pressure switches, and transmitters are the sensors in this chain. When a SIS is designed to a specific SIL level, every instrument in the safety loop must be evaluated against the overall SIL target. SOR supplies SIL2-certified pressure and differential pressure switches for use in SIS applications in oil and gas, chemical, and power generation facilities.
Pressure and Vacuum Switches | Differential Pressure Switches
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SIL stands for Safety Integrity Level. A SIL2-rated device has been evaluated and certified under IEC 61508 and IEC 61511 to meet specific reliability and failure-rate requirements for use in Safety Instrumented Systems (SIS).
For a pressure switch or transmitter, SIL2 certification means the device has a documented probability of failure on demand (PFD) that qualifies it for safety instrumented functions requiring a medium-to-high degree of risk reduction. This is relevant in oil and gas, chemical, and power generation plants where process safety systems must meet IEC 61511.
Many SOR Measurement and Control pressure switches and differential pressure switches carry SIL2 certification.
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SOR Controls Group holds a comprehensive set of agency certifications and quality system approvals:
- Quality System: ISO 9001:2015 (Lenexa and Houston facilities).
- Nuclear: 10CFR50 Appendix B, 10CFR21, NQA-1-2015, ANSI N45.2, CSA B51 Part 1. Audited by NUPIC and NIAC. Certified by Tractebel Engineering GDF SUEZ and the Technical Standards and Safety Authority (TSSA).
- Hazardous Location and Safety: ATEX, IECEx, CSA, UL, FM, UKCA, INMETRO, PESO/CCOE, TIIS, KOSHA, SASO, TestSafe/SAA, CE, and SIL2.
General
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SOR Controls Group was founded in 1946 by Roy Dunlap, making 2026 the company’s 80th anniversary. The company began with the invention of the Static “O” Ring pressure switch, developed with University of Kansas physics professor Ben Brown. Over eight decades, SOR expanded from a single pressure switch product into a full-line instrumentation manufacturer with global operations and three active product brands.
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SOR Controls Group is an industrial instrumentation manufacturer headquartered in Lenexa, Kansas. Founded in 1946, SOR designs and manufactures electronic and mechanical instruments for measuring pressure, temperature, level, and flow, and produces grab sampling systems for process industries. SOR operates three active brands: SOR Measurement and Control, SSi Temperature Sensors, and SENSOR Sampling Systems. Products from all three brands serve customers in over 70 countries across industries including oil and gas, power generation, chemical processing, nuclear power, water treatment, and petrochemicals.
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SOR Controls Group serves a broad range of process industries worldwide, including oil and gas (upstream, midstream, and downstream), nuclear power generation, chemical and petrochemical processing, conventional and renewable power generation, water and wastewater treatment, pulp and paper, food and beverage, and marine and offshore applications.
- Nuclear Power Generation
- Oil & Gas
- Power Generation
- Chemical/Petrochemical/Refining
- Water & Wastewater
- And more!
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Yes! We have sales reps and agents both across the United States and internationally.
Products
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Yes. SOR Measurement and Control produces a full line of nuclear-qualified pressure, differential pressure, vacuum, and temperature switches for nuclear power generation and has supplied the nuclear power industry for more than 30 years.
The SOR Measurement and Control nuclear-qualified product line includes the N6 and RT model pressure switches, N6 and RT temperature switches, and nuclear-qualified differential pressure switches (Models 131 and 141).
SOR Controls Group also designs and manufactures custom-engineered nuclear products for specific plant requirements, including replacement products for discontinued lines from other manufacturers.
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A multipoint temperature sensor contains multiple sensing elements at different positions along a single assembly, allowing temperature measurement at several points from a single process connection. Multipoint sensors are used where temperature varies along a column or across a bed, such as in catalytic reactors, distillation columns, storage tanks, heat exchangers, and fired heaters.
SSi Temperature Sensors manufactures both full-size and mini multipoint assemblies for space-constrained applications.
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A thermocouple generates a small voltage signal based on the temperature difference between two dissimilar metal junctions. Thermocouples cover a wider temperature range (up to 2300F or higher depending on type), respond faster to temperature changes, are more rugged, and cost less. They are standard for high-temperature applications in furnaces, boilers, and combustion processes.
An RTD measures temperature by detecting changes in electrical resistance, typically in a platinum element. RTDs provide higher accuracy and better repeatability, making them the preferred choice for precision measurement where tighter tolerances are required. RTDs are generally limited to temperatures below 1200F.
SSi Temperature Sensors manufactures both types.
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SSi Temperature Sensors manufactures a complete line of industrial temperature sensing products:
- Thermocouple elements: Grounded, ungrounded, and exposed junction types in a range of sheath materials and configurations. View Thermocouples
- RTD sensors: 2-wire, 3-wire, and 4-wire Pt100 and Pt1000 resistance temperature detectors. View RTDs
- Thermowells: Threaded, flanged, Van Stone, socket weld, weld-in, and retractable styles. View Thermowells
- Sample probes: For representative gas or liquid sample extraction from process lines. View Probes
- Specialty assemblies: Multipoint temperature sensors, tubeskin thermocouples, surface-mount sensors, and high-temperature assemblies rated above 2000F (1093C). View Specialty Sensors
All SSi products are custom-designed and manufactured to customer specifications.
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A grab sampling system, also called a closed-loop sampling system, is a piping assembly designed to extract a representative sample of a process fluid from a pressurized pipeline or vessel under controlled conditions. The sample is used for quality analysis, process monitoring, or regulatory compliance testing.
SENSOR Sampling Systems designs and manufactures grab sampling systems for oil and gas, petrochemical, refining, chemical, and power generation industries. Applications include pipeline quality monitoring, custody transfer sampling, emissions compliance sampling, and process troubleshooting.
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An engineered bypass chamber is an external chamber connected to a process vessel that houses level instruments such as switches, transmitters, or magnetic level indicators. The chamber is isolated from the vessel using block valves, which allows instruments to be installed, calibrated, or replaced without shutting down the process.
Bypass chambers are used in continuous process operations where taking the vessel offline for instrument maintenance is not acceptable. They are standard in refineries, chemical plants, and power generation facilities. SOR designs and manufactures engineered bypass chambers as complete assemblies with instrument mounting provisions.
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A flushing ring is a fitting installed between a process connection and a pressure instrument that allows the instrument’s sensing element to be cleaned or flushed without removing the instrument from the line. The ring contains one or more ports for injecting a flush fluid.
Flushing rings are used when the process fluid contains solids, slurries, viscous material, or other contaminants that would plug or damage the instrument’s sensing element over time. They are common in wastewater, chemical processing, and pulp and paper applications. SOR offers flushing rings for both pressure and level instrument connections.
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A magnetic level indicator (MLI), also called a magnetic level gauge (MLG) provides continuous visual level indication without requiring electrical power at the measurement point. A magnetic float inside a chamber connected to the process vessel rises and falls with the liquid level, rotating magnetic flags or driving an indicator strip on the outside of the chamber to show current level visually.
MLIs are used in vessels operating under pressure or vacuum, in corrosive or hazardous fluids, or where electronic instruments would require frequent maintenance. They are common in refineries, chemical plants, and power generation facilities. Switches and transmitters can be mounted on the same chamber to add alarm and control functions.
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A level switch provides a discrete on/off signal when liquid reaches a specific point in a vessel. It answers whether liquid is above or below a threshold. Use a level switch for high-level alarms, low-level shutdowns, and pump control where you need to detect a single level condition.
A level transmitter provides a continuous output signal representing actual liquid level at all times. Use a level transmitter when you need to monitor level continuously, trend data, or feed a control system.
SOR Measurement and Control offers both technologies, including magnetostrictive level transmitters for applications requiring high accuracy.
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A flow switch detects whether flow is present or has crossed a threshold, then triggers an on/off signal. Use a flow switch for pump protection, no-flow shutdown, or high-flow alarms where you need a binary indication of flow status.
A flow transmitter provides a continuous signal representing actual flow rate. Use a flow transmitter when you need to measure flow volume, control a process based on flow rate, or log flow data over time.
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A pressure switch provides a discrete on/off electrical signal when process pressure reaches a predefined setpoint. Use a pressure switch when you need to trigger an action at a fixed pressure point, such as activating an alarm, shutting off a pump, or opening a valve.
A pressure transmitter provides a continuous 4-20mA analog output representing the actual pressure value at all times. Use a pressure transmitter when you need continuous monitoring, data logging, process control, or trending over time.
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SOR Controls Group manufactures instrumentation across five measurement categories:
- Pressure: Switches, transmitters, differential pressure switches and transmitters, and flushing rings. View Pressure Products
- Temperature: Switches, thermocouples, RTDs, thermowells, and specialty assemblies. View Temperature Products
- Level: Switches, transmitters (including magnetostrictive), magnetic level indicators, and engineered bypass chambers. View Level Products
- Flow: Switches and transmitters. View Flow Products
- Sampling: Grab sampling systems and probes. View Sampling Systems
SOR also manufactures nuclear-qualified pressure, differential pressure, and temperature switches for nuclear power generation.
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We know that you can’t work with a team you don’t trust. We hold a number of different certifications and emphasize rugged dependability with each of our products, to ensure that your product meets all safety measures and is built to last.
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Absolutely! We offer products that are engineered-to-order and can customize a specific part based on the unique needs of each of our customers.
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SOR Controls Group operates three active brands:
- SOR Measurement and Control: The flagship brand, offering pressure switches, pressure transmitters, differential pressure switches and transmitters, temperature switches, level switches and transmitters, magnetic level indicators, flow switches and transmitters, and nuclear-qualified instrumentation.
- SSi Temperature Sensors: Based in Houston, Texas, SSi manufactures thermocouples, RTD sensors, thermowells, sample probes, and specialty temperature assemblies for oil and gas, petrochemical, chemical, and power generation applications.
- SENSOR Sampling Systems: Also based in Houston, SENSOR designs and manufactures closed-loop grab sampling systems and probes for representative process sample extraction.
Looking for a specific product? Check out our range of: