What Thermocoax does

Thermocoax (THERMOCOAX SAS) is a French engineering and manufacturing company founded in 1957 and headquartered in Caligny, Normandy, that specializes in extreme-environment thermal measurement and heating products built on proprietary mineral-insulated (MI) cable technology. Its product platform combines conductors, compacted mineral insulation powder, and a metal protective sheath to produce sheathed thermocouples, heating elements, thermal chucks, gas-line heating jackets, catalyst-bed heaters, and signal-transmission cable assemblies qualified for nuclear reactors, aircraft and helicopter engines, satellites and spacecraft propulsion, semiconductor wafer-processing tools, and industrial high-temperature processes. The company's in-house capabilities span design, qualification, in-house COFRAC-certified calibration (No. 2-1384, -40°C to 1500°C), and high-volume manufacturing across five global production sites, with documented flight and plant heritage including 15,000+ space devices on GEO platforms, 300,000+ thermocouples in heavy-duty gas and steam turbines, and 1.2 million cumulative operating hours on long-life turbine thermocouples.

Thermocoax generates revenue primarily through engineered-to-order sales of custom thermal products and solutions, with secondary aftermarket and spare-parts recurring revenue tied to long-lifecycle installed bases in nuclear, aerospace, and semiconductor fabs. Sales are executed via direct enterprise field-sales engineers who co-design with OEM and end-user engineering teams, with no published price list and pricing set by material, complexity, qualification, and volume. Distribution covers more than 50 countries from facilities in France, the United States, Germany, Japan, and China, supported by vertical-specific microsites (Nuclear, Aeronautic, Space, Power Generation, Semiconductor, Analysis, Industries) and the ISOPAD sub-brand for silicone heating jackets and the PEMAC sub-brand for industrial transmission cables. The company's qualification stack includes HAF 604 (China nuclear), ASME BPVC Section IX, 1E/K1 LOCA qualification, IEEE-383, ISO 19443, IEC 60584, COFRAC, and standards aligned with Rolls-Royce, Airbus, ITER, MOOG, Bombardier, Eutelsat, and other tier-one OEMs in safety-critical industries.

Since May 2019, Thermocoax has operated as a wholly-owned subsidiary of Spirax-Sarco Engineering plc (LSE: SPX, FTSE 100), integrated within the group's Electrical Thermal Solutions (ETS) business segment alongside Chromalox, and is led by Managing Director Maxime Ziemniak. In November 2021 the company consolidated its French operations onto a single 12,000 m² "Thermocoax One" site at Caligny with 3,500 m² reserved for expansion, and continues to extend its product platform into adjacent applications including cryogenic environments, pharmaceutical aseptic filling, and heavy-fuel storage heating.

Name

Thermocoax

Legal name

THERMOCOAX SAS

Website

https://thermocoax.com

Company type

Private

Founded year

1957

Operating status

Operating

Headcount range

251–500 employees

Short description

Thermocoax is a French manufacturer of custom mineral-insulated cable-based thermocouples, heating elements, and thermal subsystems for extreme-environment applications, serving OEMs and operators in nuclear, aerospace, space, semiconductor, and power-generation markets across more than 50 countries, and operating as a wholly-owned subsidiary of Spirax-Sarco Engineering plc.

Ownership category

akta.pro rank

Product category

Industrial Thermal Products & Instrumentation

NAICS

Heating Equipment (except Warm Air Furnaces) Manufacturing (333414), Industrial Process Furnace and Oven Manufacturing (333994)

SIC

Air-Cond & Warm Air Heatg Equip & Comm & Indl Refrig Equip (3585), Heating Equip, Except Elec & Warm Air; & Plumbing Fixtures (3430), Industrial Process Furnaces & Ovens (3567)

akta.pro primary industry

Thermal Management Components (Heat sinks, TIMs, fans/blowers, thermal pads) (IMAGAJAL)

akta.pro secondary industries

Aerospace Thermal Management, Insulation & Fire Protection Materials (IMABANAE), Heat Exchangers, Coils & Hydronic HVAC Components (IMADANAF)

Keywords

• Mineral insulated cables
• Sheathed thermocouples
• Industrial heating elements
• Thermal sensing solutions
• Custom thermal products

Headquarters

HQ city

Suresnes

HQ country

France

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Supply Chain, Operations, Technology or R&D, Infrastructure, Marketing or Sales

Revenue model

1. Custom Thermal Products and Solutions: Designs, qualifies, and manufactures custom thermal products including thermocouples, heating elements, cabling systems, and sensors for extreme environment applications. Revenue generated through direct sales of engineered-to-order products and systems to industrial customers.
2. Aftermarket and Spare Parts: Replacement heating elements, thermocouples, and spare parts for installed systems, particularly in semiconductor, aerospace, and nuclear sectors.

Pricing tiers

Go-to-market motion2 records

Distribution channels1 record

Marketing channels4 records

Core offering

Thermocoax designs, qualifies, and manufactures custom-engineered thermal products based on proprietary mineral insulated (MI) cable technology. Its portfolio includes sheathed thermocouples, heating elements, sensors, and cabling systems built to withstand extreme environments (up to 1600°C, high vacuum, radiation, corrosion) for nuclear, aerospace, space, semiconductor, power generation, and industrial customers.

Product overview

Thermocoax is a manufacturer of engineered thermal products and solutions, primarily based on proprietary mineral insulated cable technology. The core product portfolio includes sheathed thermocouples, heating elements, and specialized heating systems. The company operates through specialized divisions serving Nuclear, Aeronautic, Space, Power Generation, Semiconductor, Analysis, and Industrial markets. Key product lines include: sheathed thermocouples for extreme environments; heating elements and cables; ISOPAD branded heating jackets for industrial applications; thermal chucks for semiconductor manufacturing; H2O2 sterilization units; and space propulsion heating systems including catalyst bed heaters and pre-heating rings. The ISOPAD sub-brand provides silicone heating jackets and drum heaters. All products leverage THERMOCOAX's in-house mineral insulated cable technology, manufactured in French facilities certified for COFRAC calibration.

Differentiator

Problem solved

Functional benefit

Brands

• ISOPAD: Brand for silicone heating jackets, gas line heating solutions, and drum heating jackets, primarily serving semiconductor and industrial applications.
• PEMAC

Products and services

• Sheathed Thermocouples Mineral insulated thermocouples for temperature measurement in extreme environments including nuclear reactors and spacecraft engines. Flexible design with bending radius equal to three times outer diameter, high insulation resistance, and resistance to corrosive media.
• Heating Elements Customized heating elements and heating cables based on mineral insulated cable technology for industrial applications. Includes radiative heaters, heating plates, cartridge heaters, and multi-zone rod heaters.
• Mineral Insulated Cables Proprietary mineral insulated cables with highly compacted powder insulation and metal sheath protection. Available in diameters from 0.5mm to 6mm, operating temperatures up to 2300°C, serving as the foundation technology for all THERMOCOAX products.
• H2O2 Sterilization Units Custom designed aseptisation ovens for dry sterilization processes using hydrogen peroxide vapor. Features one or two heating zones, operational power 3-6 kW, temperature range up to 500°C, designed for corrosive media environments and aseptic filling machines.
• ISOPAD Heating Jackets Silicone rubber seamlessly-molded heating jackets for gas line heating, drum heating, and industrial heating applications. Features IP68 standard, temperature range up to 200°C, FDA-approved ultra-low emission materials.
• Gas Line Heating Jackets High purity gas line heaters for semiconductor deposition processes. Silicone rubber seamlessly-molded design, thermal gas flow uniformity ±5°C, temperature range 68°F to 275°F, IP68 standard.
• Thermal Chucks and Pedestals Custom thermal chucks and pedestal heaters for semiconductor ALD, CVD, PVD processes. Up to 7 heating zones, diameters up to 450mm, maximum temperatures up to 900°C, designed for ultra-high vacuum and corrosive environments.
• Flange Immersion Heaters High-efficiency immersion heaters for liquid fuel and heavy fuel storage. Features DN100 & DN200 flanges, mineral insulated heating cable with 316L stainless steel sheath, multi-layer design for natural fluid circulation.
• Ampoule and Canister Heaters Heating solutions for solid and liquid precursor management in semiconductor deposition processes. Integrated with transfer line heating jackets for ALD, CVD, PVD processes.
• Thin-Film Deposition Heating Systems Heating systems for thin-film PV cells manufacturing including cylindrical radiative heaters, heating vaporizers, radiative heating plates, and heating chucks. Maximum temperature up to 1000°C for PVD, CVD, PeCVD processes.
• Catalyst Bed Heaters Heating systems for spacecraft chemical propulsion. Coiled mineral insulated cable design with 1mm diameter, max exposed temperature up to 1600°C, for green propulsion thrusters 1-400N.
• Pre-Heating Rings for Hall-Effect Thrusters 28-watt heating rings for Hall-effect electrical propulsion thrusters. Uses mineral-insulated cable with redundancy options, installed and brazed in metallic rings for spacecraft attitude and orbit control. First application on EUTELSAT 172B satellite.
• Signal Transmission Solutions Inconel 625 signal transmission cables for high-pressure applications. Multi-conductor solutions up to 8 conductors, operating up to 300 bars pressure, suitable for subsea equipment including pumping systems and valves.
• SAT & TUS Thermocouples Thermocouples for System Accuracy Tests (SAT) and Temperature Uniformity Surveys (TUS) in heat treatment. Types R/S/B/J/T/E/K/N/C conforming to ASM 2750E and CQI-9 standards, COFRAC calibrated.
• Core Sensors In-core sensors for nuclear reactor temperature measurement at fuel outlet and reactor core radial distribution. Designed to prevent nucleate boiling and withstand extreme nuclear environments.
• Long-Life Gas Turbine Thermocouples Next-generation thermocouples with 24,000 operation hours capability, featuring patent-protected vibration absorber technology for heavy duty gas turbines. Demonstrated in 446MW machines with 1.2 million cumulated hours.
• In-Core Water Level Detector (RPVL) Reactor Pressure Vessel Level detector for Gen 3 nuclear reactors. Developed and qualified based on THERMOCOAX mineral cable technology for normal and abnormal condition monitoring.
• Magnetic Diagnostics Flux Loop Cable Assemblies Mineral insulated cable assemblies for ITER fusion reactor magnetic diagnostics. Installed in ITER vacuum vessel for plasma performance monitoring.
• COFRAC Certified Calibration Services Internal calibration laboratory certified by COFRAC (No. 2-1384) offering fixed points calibration and comparison calibration from -40°C to 1500°C, with international recognition for temperature calibration.

Quantifiable outcome

• Long-life thermocouples last 7 times longer than standard thermocouples, saving at least 150,000 euros in thermocouple costs for every 20,000 hours of operation by eliminating unexpected maintenance downtime
• +2 more outcomes

Named customers8 records

Segments6 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Scale indicators8 records

Recent moves8 records

Expansion highlights5 records

Direct peers

• Chromalox: Sister company under Spirax Group's Electric Thermal Solutions segment and the most direct comparable to Thermocoax. Manufactures industrial electric heating elements, temperature sensors, and thermal systems for similar process industries, with overlapping customers in oil & gas, power, and chemicals.
• Minco: Designs and manufactures heaters, sensors, and integrated thermal solutions for medical, aerospace, defense, and industrial markets. Comparable as a custom-engineered thermal components supplier to OEM customers.
• Watlow: Direct competitor in custom-engineered industrial heaters, thermocouples, and temperature control solutions. Serves semiconductor, aerospace, and process-industry OEMs with comparable specification-driven, application-engineered products.
• Durex Industries: U.S.-based manufacturer of custom electric heating elements, sensors, and temperature assemblies for industrial, medical, and semiconductor OEM customers. Competes with Thermocoax on engineered-to-order heating solutions for demanding applications.
• Tempil (LA-CO Industries): Specialist in temperature measurement and indication products including thermocouples and temperature-indicating devices. Adjacent peer in industrial temperature sensing and calibration.
• Heraeus Electro-Nite: Specialist in immersion sensors, thermocouples, and measurement solutions for molten metals and high-temperature industrial processes. Comparable in niche temperature-sensing applications for foundries, steel, and similar extreme environments.
• Tutco (Sundyne): Manufacturer of electric heating elements and assemblies for industrial, medical, semiconductor, and aerospace applications. Overlaps with Thermocoax on engineered heating solutions for OEM and process-industry customers.
• Backer Marathon: Custom manufacturer of heating elements, thermocouples, and temperature assemblies serving industrial, rail, defense, and semiconductor customers. Closely comparable in engineered thermal component manufacturing for OEM clients.

Emerging players

• MI Cable Company: Specialist manufacturer of mineral insulated cable, the same core technology platform as Thermocoax. A close technology peer serving industrial heating and sensing customers, though at smaller scale and with less vertical-specific productization.
• Temp-Pro: Niche U.S. manufacturer of high-purity thermocouples and temperature assemblies, primarily serving semiconductor OEMs. Directly comparable to Thermocoax's semiconductor thermal chucks and gas-line heating business.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/thermocoax

Compliance12 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

Subsidiaries6 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Thermocoax