TC Energy and Waterfall Security relate lessons learned and the experience of deploying unidirectional gateway technology for two kinds of use cases with Enterprise SCADA . In TSA terms, the gateways constitute isolation (III.F.1.d) of IT & OT networks, while still permitting business-critical data to flow from OT to IT networks, with remote access options. We cover architectures, project drivers, timing, redundancy and other aspects, for two different pipeline installations.