Pipe organ wind pressures are on the order of 0.10 psi (0.69 kPa).
0.10 psi above would register as 2.75 inches of water (70 mmAq)
An Italian organ from the Renaissance period may be on only 2.2 inches (56 mm),[58] while (in the extreme) solo stops in some large 20th-century organs may require up to 50 inches (1,300 mm). In isolated, extreme cases, some stops have been voiced on 100 inches (2,500 mm).[59]