p_pr	T_pr	Expression formula
A (2.0, 5.4]	(1.02, 1.2]	$Z = 0.553 p_{p r} T_{p r} - 1.0338 p_{p r} + 2.0943$
	(1.2, 1.5]	$Z = 1.1527 p_{p r} T_{p r} - 1.5183 p_{p r} - 3.3389 T_{p r} + 5.2344$
	(1.5, 3.0]	$Z = 0.0258 p_{p r} T_{p r} - 0.042 p_{p r} + 0.8797 T_{p r} - 0.6195$
B (5.4,30.0)	(1.02, 1.6]	$Z = 0.0202 p_{p r} T_{p r} - 0.0002 p_{p r} + 0.0227 T_{p r} + 0.741$
B (5.4,30.0)	(1.6, 3.0]	$Z = 0.046 p_{p r} T_{p r} - 0.0503 p_{p r} - 0.4054 T_{p r} + 1.5685$