You may need to provide a fuller description of the project, as that will point towards the most applicable standard. In my view, if the retractable handrail is a permanent fitment but can be retracted when required, then BS EN 13374 would not be the most relevant as that covers handrails that are temporary i.e. only fitted for a short period of time. BS EN 14122 applies to access to and around machinery BS 6180 applies to barriers in buildings generally