Dear Jagjeetsingh.Aroraunileve,
Factory Act 1948 and the rules thereunder either by Central or by any State to my knowledge nowhere described any structure / shed permanent or temporary.
If the factory inspector finds any structure / shed erected in the factory during his visit to factory or in case of any any accident / incident caused due to such structure / shed erected in the factory, he will not see whether the structure / shed erected is a permanent one or temporary one. If such structure / shed erected in the factory is not in the approved plans then you are in default and liable for action.
Temporary monsoon shed erected at outer wall of the factory is also require a permission from local authority. If factory inspector finds such temporary monsoon shed without permission from local authority, he will not going to spare you. You are not going to spared by the local authority also.
Regards,
Akhil Bhartiya