In contrast to office and building IT, industrial control systems are partially dependent on a completely uninterrupted flow of information. This applies in particular to all real-time data streams. Even very short interruptions in the availability of data (which can be tolerated in office and building IT) can be critical in an ICS. In addition, dependencies of networks, services, or IT systems can create vulnerabilities. This is often overlooked in planning when an organisation's OT and office and building IT communicate with each other.

If dependencies between OT and office and building IT are not taken into account and resulting vulnerabilities are not closed, security incidents can quickly spread to all the OT in place.

If central components and services of office and building IT are used for remote maintenance of OT (administration across multiple areas), there may also be coordination errors between the office and building IT and the OT. As a result, the correction of critical errors in the ICS of the OT can be delayed. One example would involve a central VPN gateway for remote access that is provided by an organisational unit outside the OT and not operated in an appropriately coordinated manner, which results in it not available quickly enough when needed. This can prolong plant downtime considerably.