Factories act has the following provision :
32. Floors, stairs and means of access.—In every factory—
(a) all floors, steps, stairs, passages and gangways shall be of sound construction and properly maintained 65 [and shall be kept free from obstructions and substances likely to cause persons to slip], and where it is necessary to ensure safety, steps, stairs, passages and gangways shall be provided with substantial handrails;
(b) there shall, so far as is reasonably practicable, be provided and maintained safe means of access to every place at which any person is at any time required to work.
2[(c) when any person has to work at a height from where he is likely to fall, provision shall be made, so far as is reasonably practicable, by fencing or otherwise, to ensure the safety of the person so working.]
So I think this will confer your case.
While lifeline is not specified as such, it's a good idea to provide it.
More important I think is to know where the lifeline is to be attached. It's meaningless if the worker is not attaching it to a secure place that can take his weight and prevent a fall from the height.