Professional tools for Building Management Systems and Extra-Low Voltage design — CCTV storage, fire alarm, UPS sizing, points lists and building automation per NFPA, IEC and BACnet standards.
Calculate NVR hard disk size (TB) from cameras, resolution, FPS, H.264/H.265 & retention days — with bandwidth & HDD suggestions
Size FACP standby batteries (Ah) per NFPA 72 — 24hr + 5min worksheet with device currents, derating & standard battery selection
Size UPS kVA rating & battery bank (Ah, 12V blocks) from load, power factor, growth margin & required backup runtime
Generate DI/DO/AI/AO points count from equipment schedule with DDC controller estimate
Calculate network bandwidth per camera and total NVR/switch load
Speaker quantity from area & SPL requirements with amplifier wattage sizing
Our BMS & ELV calculators help engineers, system integrators and installers design low-voltage building systems quickly and accurately. Extra-Low Voltage (ELV) covers everything below 50V AC — CCTV surveillance, access control, fire alarm, public address, structured cabling and intercom — while the Building Management System (BMS) ties HVAC, lighting and power together through DDC controllers, sensors and open protocols like BACnet and Modbus. These systems now represent a major share of modern building budgets, and getting the calculations right at design stage avoids expensive rework during testing and commissioning.
Size NVR storage in terabytes from camera count, resolution, frame rate and codec. H.265 compression cuts storage roughly 45% versus H.264 — our CCTV Storage Calculator handles all codecs, motion-based recording and gives per-camera GB/day plus total network bandwidth for NVR switch sizing, following IEC 62676 practice.
Fire alarm panels require battery backup sized per NFPA 72 — typically 24 hours standby plus 5–15 minutes of alarm load, with a 20% derating factor. Our upcoming Fire Alarm Battery Calculator automates the standby/alarm current worksheet. Related fire tools are already available in our Fire Fighting category.
ELV head-end equipment — NVRs, servers, DDC panels, access controllers — needs clean uninterrupted power. UPS sizing works from connected load (VA/W), power factor and required runtime to select the kVA rating and battery bank. Until the dedicated tool launches, our Generator Sizing Calculator and Load Current Calculator cover the electrical side.
BMS design starts with the points list — counting DI, DO, AI and AO points per equipment (AHUs, FCUs, chillers, pumps) to size DDC controllers with spare capacity. Standards such as BACnet (ISO 16484-5) and ASHRAE Guideline 13 govern the architecture. The BMS Points List Calculator is coming soon; meanwhile the HVAC tools cover the mechanical equipment these systems control.