There is no period fixed. It can be one year, two years or three or even five years. Actually, fixed term appointment is meant for such projects which will run for a certain period. The period can be prefixed or can be indefinite. Therefore, it is not possible to fix it in advance.
The recent amendment to Standing Order Act permitting the employers to have fixed term employees in all kinds of industries requires attention. As per this new arrangement, the employer need not appoint employees on a permanent basis, they can hire and fire the employees at any time by giving appointment for a fixed period.