Dear Zafar Equbal,
30 meter is a good height to observe safety instructions precisely.
I have given below a brief account.
Persons should wear helmet with chin strap.
Safety belt and safety shoes are a must.
The scaffolding must be tested and certified to carry people load and material load.
Persons who work should not have problems like BP or vertigo.
You should further refer to specific standards for the purpose.
V.Raghunathan