Unmarked pipes represent a hazard.
Marking them with tapes will identify and display their contents.
Such identification is covered by BS 1710. The Health & Safety (Safety Signs and Signals) Regulations place great emphasis on the labelling of pipework.
The Regulations state that pipeline marking tapes and labels are required for use at points where employees are likely to be exposed to the contents of the pipework, for example; sampling or filling points, drain valves and flanging joints.,BS 1710: 1984 Identification of Pipelines and Services and BS 4800 provide guidance on the use of different colours and safety signs to identify the contents of pipework and its associated risks.