Heat Tracing for Loading Arms and Tanker Terminals

Loading arms and tanker connections are the last few metres of a heated line — and the place where heat tracing usually fails first. Movement, weather, tight geometry and short operating windows make this one of the most demanding details in a project.

Why loading areas are difficult

• The arm moves: cable must follow without fatigue.
• Short lengths and small pipe volumes: heat loss dominates and freezing is fast.
• Weather exposure: wind, rain, snow and ice.
• Hazardous areas: vapours at the loading point often need certified equipment.
• Access: maintenance is done in a live terminal, often at night.

Design points

1. Flexible heating for moving parts

Use cable configurations and a fixing method that allows movement: loops, spring or elastic support, and a swivel or loop at the pivot. Rigid fixing will fatigue the cable within a season.

2. Separate the moving section from the fixed line

The fixed line is traced and insulated normally; the arm has its own heating and a junction point designed for movement. Do not run one continuous cable across the pivot without a proper loop.

3. Maintain temperature at the nozzle

The nozzle and the last metre before the tanker connection are critical: they are uninsulated in many designs and lose heat fastest. Insulated covers or short traced sections are often needed.

4. Hazardous area certification

Loading vapour zones are usually classified; cable, terminations, junction boxes and control must be certified for the zone and gas group. Flexible or moving terminations need particular care.

5. Control and alarms

Loading is intermittent: control may be manual for loading windows plus thermostatic protection always on. Alarms to the loading control room are recommended, because a frozen arm stops operations.

Scope checklist for a loading project

Common mistakes

• Continuing the fixed-line cable across the pivot with no loop.
• No insulation or cover on the nozzle and last metre.
• Certified cable but uncertified junction boxes at the arm.
• No alarm, so a failure is found when loading is blocked.
• Fixing designed for a fixed pipe, not for movement.

What to provide for a quotation

• Arm drawings and movement envelope
• Product, maintain temperature and flow
• Area classification drawing
• Fixed line layout and insulation
• Control interface requirements

Topic hub: Heat Tracing by Industry (Applications)