Zhou dynasty school, disperse, fall apart
泮 centers on division and dissolution: things dispersing, falling apart, or being separated. The Zhou dynasty school sense is a specific historical application of a divided or separated space.
泮 combines 氵 (water) with 半, which likely contributes the sound and the idea of division or separation. The exact historical development is uncertain.
Water 氵 beside 半 (half) suggests something being split or dispersed by water, like a substance dissolving and falling apart.
For ハン, imagine a half-dissolved hand (ハン) in water: the hand disperses as it falls apart, and ハン cues the reading.