The ERCES Process

Where each phase lands in a construction schedule

The five phases above are usually described in isolation, which hides the part that actually costs projects money: when each one has to happen. The sequence below is the common pattern — your Authority Having Jurisdiction (AHJ) sets the real requirements, so confirm the specifics early.

• Before the design is locked — the initial RF survey. Whether your building needs an ERCES at all is a measurement, not an assumption, and the answer shapes pathways, riser space and electrical provisions. Running it late is the single most expensive ordering mistake, because the remedies become construction changes.
• During design coordination — system design, which has to reconcile with the fire alarm scope, the electrical drawings and any survivability requirement your AHJ assigns.
• With the trades, not after them — installation. Cable pathways compete for the same shafts as everything else, and the antenna layout depends on partitions being where the drawings say.
• Before occupancy — commissioning and AHJ acceptance. Many jurisdictions tie ERCES approval to the certificate of occupancy, which puts this phase directly on the critical path to opening the building.
• Every year after that — the annual test cycle, which begins once the system is accepted, not when the building is finished.

Retrofits invert most of this. There is no design phase to align with, so the survey and the remediation plan happen together, and the constraint becomes working around an occupied building rather than around a schedule.

Two things worth settling before you start: which standard actually governs your building (it depends on the code edition your jurisdiction adopted), and what drives the cost, since the survey result is the biggest single variable.