In-building wireless keeps getting more complicated, and the line between “nice to have” and “required by code” isn’t always obvious. To help, IBWS has published two new 2026 reference guides. The short version: ERCES is usually about code compliance, while Cellular DAS is usually about business value. Many buildings need both.
California ERCES Jurisdiction Guide
ERCES keeps first-responder radios working inside buildings where concrete, Low-E glass, and below-grade levels would otherwise kill the signal. It’s typically mandated by the California Fire Code, NFPA 1225, and the local Authority Having Jurisdiction (AHJ). But the rules aren’t uniform. An approach accepted in one city may not be approved in another.
Our guide maps this across 25 of California’s most active jurisdictions, from Los Angeles and San Diego to Fresno, Riverside, and the Orange County Fire Authority. For each one it identifies the governing document, the codes cited, its status, and practical notes on permitting and testing. Some jurisdictions don’t publish a stand-alone guideline at all, so early AHJ verification is essential.
[→ Download the California ERCES Jurisdiction Guide (PDF)]
Always confirm current requirements with your local AHJ before design.
Cellular DAS Reference Guide
Where ERCES is about compliance, Cellular DAS is about experience and value. There’s generally no code forcing you to install it. Deployment is driven by tenant expectations, guest satisfaction, and operational needs. A hotel with dead zones gets bad reviews; a Class A office without solid coverage loses tenants.
Our guide helps owners and design teams frame that decision early. It covers building types and design drivers, construction materials and signal loss, when DAS makes sense, architecture options (including the Comba platforms IBWS prefers), and 5G considerations.
[→ Download the Cellular DAS Reference Guide (PDF)]
Every building is different. Final design should be confirmed with a benchmarking survey and RF modeling.
One system, or both?
Hospitals, hotels, large multifamily, and Class A offices frequently deploy both. They’re separate systems with different drivers, but when planned together they can share pathways, riser space, and sometimes antennas, which saves cost and coordination.
Whether you need an ERCES compliance path, a Cellular DAS design, or both, IBWS can help with site surveys, predictive modeling, and system design.
Have a project coming up? Contact IBWS to talk it through.