Heat Tracing Design Review: 12 Checks Before You Order

Most heat tracing problems are decided before the order is placed: the wrong maintain temperature, a cable that cannot reach the far end, a control scheme nobody can maintain. This design review checklist is what a buyer should confirm with the supplier before signing.

1. Design basis is written down

Design minimum ambient, maintain temperature, insulation specification, wind exposure and supply voltage should all be documented — not "as discussed".

2. Heat loss calculation is traceable

Ask for the calculation per line: pipe size, insulation thickness, temperature difference, heat loss per metre, margin and the resulting cable output.

3. Cable output is checked at the design ambient

Self-regulating cable output falls as temperature rises and is higher when cold — confirm the catalogue figure used matches the design ambient, not 10 °C.

4. Circuit lengths are within limits

Each circuit must stay within the maximum length for the cable type, voltage and breaker; check voltage drop at the far end.

5. Protection is sized for the design

Breaker and earth leakage protection sized for the actual current, including low-temperature output and inrush. One RCD per group of circuits, not one for everything.

6. Control philosophy is agreed

Line temperature control, ambient compensation or simple thermostats? Who sets the set points, and how are they documented? Where do alarms go?

7. Hazardous area classification is confirmed

Zone, gas group and temperature class checked against the certified equipment; certificates cover the exact models to be supplied.

8. Termination and accessory scope is clear

Who supplies terminations, junction boxes, glands, fixing and labels? Missing accessories delay installation more often than cable delivery.

9. Installation constraints are known

Access, scaffolding, insulation timing, winter conditions and who installs. A design that ignores access will be installed badly.

10. Testing and documentation are specified

Insulation resistance, continuity, current and functional tests per circuit; test record templates; as-built drawings and circuit schedules.

11. Spares and training are planned

Spare cable, terminations and thermostats on site; training for the maintenance team on fault finding.

12. Deliverables are listed

Drawings, calculations, certificates, test records, manuals and warranty terms — listed in the order, not promised separately.

Review summary table