hangings take 5mins if they fuck up and don't break the next , otherwise the person is left hanging there to suffocate
The "drop" must be based on the prisoner's weight, to deliver 1260 foot_pounds of force to the neck. The noose is then placed snugly around the convict's neck, behind his or her left ear, which will cause the neck to snap. The trap door then opens, and the convict drops. If properly done, death is caused by dislocation of the third and fourth cervical vertebrae, or by asphyxiation
check out
http://www.richard.clark32.btinterne.../hanging2.html
for more info