General design principles establish the foundation for effective and coordinated building system design. This section introduces three essential aspects: a structured framework and management approach, strict adherence to applicable codes and standards, and the production of accurate technical documentation. These principles ensure that design activities are aligned with project scope, schedule, and regulatory requirements. International standards such as IEC, NEC, BS, ASHRAE, and IBC guide safe and compliant system development. Clear documentation—drawings, specifications, calculations, and BOQs—translates design intent into actionable outputs. Together, these elements support quality, coordination, and successful multidisciplinary integration across all design phases.

Designing building systems is a structured, interdisciplinary process that integrates architectural, structural, mechanical, and electrical designs through coordinated phases. Each discipline contributes inputs and receives outputs in a sequenced manner, ensuring alignment and traceability throughout the project lifecycle. This process is governed by the PMBOK® Guide’s knowledge areas, with Project Management Plans (PMPs) such as integration, scope, schedule, cost, quality, risk, and stakeholder management providing the management framework.

The coordination pathways illustrated in the design model establish how inputs flow from one discipline to another, promoting consistency, reducing errors, and facilitating phase approvals. At the end of each phase, gateway reviews validate the completeness and compliance of deliverables before transitioning to the next stage. These systematic reviews and handoffs ensure that each design phase supports the overall project objectives, meets stakeholder requirements, and maintains alignment with regulatory and quality standards.

Figure 1. Flow Diagram of Design Process