In addition to the odadmin's answer following are the skin temperature requirements:
- Seawater side skin temperature shall be kept below 60°C to avoid scale deposition on the heat exchanger wall.
- The hydrocarbon side skin temperature shall be kept above the hydrate formation temperature or wax appearance point or below any temperature that will cause other fouling (e.g. coking,).
- Skin temperature for coolant with anti-freeze (e.g. glycol mixtures) shall be kept below the decomposition temperature of the anti-freeze.
For exceptions to above requirements refer NORSOK Standard P-100.