Buyer guide
Heat Traced Tubing
Heat traced tubing is a factory-assembled bundle in which one or more process tubes run alongside a heat source — an electric heating cable or a steam tracer tube — inside thermal insulation and a protective outer jacket. It keeps the fluid at a controlled temperature so samples do not condense, freeze or change composition between the process tap and the analyser or instrument.
The three types of heat traced and insulated tubing
Electrical heat traced tubing (EHTL)
A resistance heating cable runs parallel to the process tube and replaces the heat the line loses to the surroundings. Choose it when you need controlled temperatures, there is no convenient steam supply, or the run is long.
- Constant-wattage, self-regulating or power-limiting heating cables
- Power-limiting circuits up to 450 m
- Heating cables certified for hazardous areas (IECEx, ATEX, IEC)
Steam heat traced tubing (SHTL)
A copper or stainless-steel steam tracer tube runs alongside the process tube inside the insulation. Choose it where plant steam is available and you want heating without an electrical supply in the field.
- Heavy (tracer in direct contact) and light (separated) configurations
- Maintains process temperatures over 204°C in the heavy configuration
- Condensate is removed at intervals set by the bundle design
Pre-insulated tubing (PIT)
The process tube is insulated and jacketed in the factory, with no tracer. Choose it for small steam, condensate, liquid and gas lines where you only need to limit heat loss, as a cheaper alternative to field insulation.
- Supplied in long coils or straight lengths
- Fibre-glass insulation, or aerogel above 400°C
- Removes field insulation and weatherproofing work
Heating cable types for electrical tracing
The heating cable sets the temperature an electrical bundle can hold and how long a circuit can be. Values are for Techwin Traceline bundles.
| Cable | Maintain | Max exposure | Notes |
|---|---|---|---|
| Constant wattage (CWC) | Up to 200°C | Up to 260°C | Fixed output per metre, cut to zone length, no inrush current at start-up |
| Self-regulating — low temperature | About 40°C | — | Output falls as the tube warms; cut to any length; self-limiting against overheating |
| Self-regulating — medium temperature | About 110°C | — | Common for analyser sample lines and freeze protection |
| Self-regulating — high temperature | 120–150°C | — | Higher maintain temperatures with the self-limiting feature |
| Power limiting (PLC) | By design | — | Longest circuits — up to 450 m |
How a bundle is built
- 1
Process tube
SS 316 seamless or welded, copper, PTFE, FEP or PFA; 1/8″–3/4″ or 6–12 mm OD
- 2
Heat source
An electric heating cable (EHTL) or a steam tracer tube (SHTL); none for pre-insulated tubing
- 3
Heat-reflective foil
An aluminised foil wrap that reflects radiant heat back to the tube
- 4
Thermal insulation
Non-hygroscopic fibre glass for most duties; aerogel above 400°C, rated beyond 1200°F (649°C)
- 5
Outer jacket
FR-PVC (UV-resistant, −40°C to 105°C), TPE, TPU or PA, chosen for the site environment
How to select heat traced tubing
- Maintain temperature — the lowest temperature the fluid must stay above (to avoid condensation, freezing or wax).
- Maximum exposure temperature — the highest temperature the bundle will see, for example during steam-out.
- Available utilities — a reliable power supply favours electric tracing; available plant steam favours steam tracing.
- Hazardous-area classification — the cable type and its temperature class must suit the zone and gas group.
- Run length — longer runs may need power-limiting cable or more than one circuit.
- Number, size and material of process tubes — set by the analyser or instrument and the fluid.
- Environment — UV, chemicals, abrasion and temperature range decide the outer jacket.
Where heat traced tubing is used
The most demanding use is carrying samples to analysers — see analyzer sample lines.
- Analyser sample lines: process analysers, continuous emissions monitoring (CEMS) and gas chromatographs
- Instrument impulse lines to flow, pressure and level transmitters
- Freeze protection of water and small process lines
- Viscosity maintenance for light oil, paraffin and temperature-sensitive chemicals
- Lead lines to steam and condensate manifolds, condensate drain lines
- Oil-burner supply and return lines, LPG supply manifolds
Frequently asked questions
What is heat traced tubing?
Heat traced tubing is a factory-assembled bundle in which one or more process tubes run alongside a heat source — an electric heating cable or a steam tracer tube — inside thermal insulation and a protective outer jacket. It keeps the fluid in the tube at a controlled temperature so samples do not condense, freeze or change composition before they reach the analyser or instrument.
What is the difference between electrical and steam traced tubing?
Electrical traced tubing uses a resistance heating cable and gives controllable temperatures wherever power is available, including long runs. Steam traced tubing uses a copper or stainless-steel tracer fed with plant steam, needs no electrical supply in the field, and suits sites with steam already available.
What temperature can heat traced tubing maintain?
It depends on the heat source. In Techwin bundles, constant-wattage cable maintains up to 200°C with exposure up to 260°C, and self-regulating cables cover about 40°C, about 110°C and 120–150°C ranges. Steam traced bundles in the heavy configuration maintain process temperatures over 204°C while the outer jacket stays below 60°C for personnel protection.
Can heat traced tubing be used in hazardous areas?
Yes, when the heating cable is certified for the area. The heating cables used in Techwin electrical traced tubing carry IECEx, ATEX and IEC hazardous-area certification, and the cable type is chosen so its temperature class suits the zone.
How long can a heat traced tubing circuit be?
Circuit length depends on the cable type and power output. Power-limiting cable gives the longest circuits — up to 450 m in Techwin bundles — while constant-wattage and self-regulating cables are used on shorter runs. The circuit is engineered for each bundle during factory assembly.
When should I use pre-insulated tubing instead of traced tubing?
Use pre-insulated tubing when the line only needs to lose less heat — for example small steam, condensate, liquid or gas lines — and no active heating is required. Use traced tubing when the fluid must be held above a set temperature regardless of the weather.
Specify a bundle for your project
Send the maintain temperature, run length, tube size and area classification, and our engineers will propose a bundle.
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