| 165 / | HD | HEAT EXCHANGE |
| DIG 51 | DD | HAVING EXPANSION AND CONTRACTION RELIEVING OR ABSORBING MEANS {2} |
| DIG 52 | DD | .~ For cylindrical heat exchanger {6} |
| DIG 53 | | .~.~ Flexible or movable header or header element {3} |
| DIG 54 | DD | .~.~.~> Movable header (e.g., floating header, etc.) {1} |
| DIG 57 | DD | .~.~.~> Flexing tubesheet |
| DIG 58 | DD | .~.~.~> Movable tubesheet (e.g., floating tubesheet, etc.) {1} |