8.5 Heater tube length and tube supports
The procedure used is again similar to that already described for HP heaters. However, for LP heaters, this usually only involves consideration of a condensing section.
If integral drain coolers were to be used, the procedure would be the same as that used for HP heater drains coolers. An average U-tube length between tubeplates on an LP heater for a modern 660 MW unit is about 18 m, giving an average tube bundle length of 9 m.