Surgical suite monitoring with setback ventilation

Reduce OR energy consumption by 36.7% while maintaining continuous NF S90-351 and ISO 14644 compliance through real-time occupancy and particle monitoring.

The context

ORs run at full power 24/7 — even when empty

Operating rooms require 15 to 20 air changes per hour to maintain ISO 14644 classification during procedures. Most facilities run this rate around the clock, even though ORs are occupied less than 40% of the time. The result: HVAC represents up to 60% of a hospital's energy budget.

Setback ventilation can save up to 36.7% of energy (~41,600 kWh/year), but operators fear contamination events. Without real-time particle monitoring and automated recovery guarantees, facility managers default to running everything at maximum — the safe but expensive choice.

36.7%

Measured energy reduction on deployed sites through occupancy-driven setback ventilation

65% of the time

On standby — out of 168 weekly hours, an operating room is unoccupied for 110 hours

10 months

Typical payback period, driven by HVAC energy savings

The challenge

Energy waste, fragile compliance and fragmented visibility

Energy waste and the compliance dilemma

Over a 168-hour week, an operating room is on standby for 110 hours — 65% of the time. Setback ventilation (reducing air changes during inactivity) can save up to 36.7% of energy (~41,600 kWh/year), but operators fear contamination events.

Without real-time particle monitoring and automated recovery guarantees, facility managers default to running everything at maximum — the safe but expensive choice.

Fragmented visibility and audit readiness

Particle counts, differential pressure, temperature, humidity, door status and OR scheduling live in separate systems. No correlation means no confidence. Engineers cannot prove that setback ventilation is safe, and compliance officers cannot sign off on what they cannot see.

ISO 14644-3 requires documented evidence of classification maintenance. Manual spot checks are insufficient for continuous compliance. Regulators increasingly expect automated, timestamped records — not monthly spreadsheets filled in by hand.

How TERA 360 works

From raw data to automated decisions

TERA 360 connects to your existing infrastructure, correlates multiple data streams, and enables safe setback ventilation with guaranteed recovery.

Connect

SafyrOPC (optical particle counter), BLE DeltaP sensors, T/RH probes, door contacts and occupancy sensors connected to the Gateway Pure™. BMS integration via Modbus for ventilation control.

Correlate

The platform cross-references particle counts with occupancy state, door openings, DeltaP trends and scheduled procedures. A state machine determines the current OR mode: active procedure, preparation, recovery, standby or deep setback.

Act

Based on the determined state, TERA 360 sends commands to the BMS to adjust air change rates, including supervised standby mode per NF S90-351 v2013. Before any procedure, the system verifies ISO classification is met and provides a green-light signal to staff. If recovery is incomplete, the procedure start is flagged.

Sensors & systems

What gets measured

Particle counters

SafyrOPC — wireless optical particle counter (LoRa). Channels >0.3 um and >0.5 um. Flow rate 2.83 l/min (0.1 CFM). ISO 21501-4 certified. Battery life 12h to 168h. Smooth cleanroom-compatible surface.

DeltaP sensors

Differential pressure transmitters across the OR envelope. Monitoring the positive pressure cascade from OR to corridor to ensure containment integrity.

T/H probes

Temperature and relative humidity monitoring for patient comfort and staff working conditions. Logged alongside particle data for correlation analysis.

Occupancy & BMS

Door contacts, PIR sensors and BMS integration via Modbus. OR scheduling system integration for predictive mode switching.

TERA 360 operating room monitoring dashboard with ISO status and ventilation modes

Dashboards & alerts

What operators see and do

Unified view of all operating rooms with color-coded ISO classification status, particle levels, DeltaP, temperature and current mode.

Real-time OR status board — Each tile shows current particle levels, DeltaP, temperature, mode (active/standby/recovery) and time to the next scheduled procedure. Facility managers see at a glance which ORs are compliant and which need attention.
Escalation & notifications — Three-tier alert system: (1) advisory when particle counts trend upward, (2) warning when approaching ISO thresholds, (3) critical alarm when classification is lost. Notifications via SMS, email or direct BMS integration. Each alert includes root cause context — door left open, filter degradation, HVAC fault.
Energy analytics — Per-OR energy consumption tracked against occupancy hours. Setback savings quantified daily, weekly and monthly. Comparison between ORs identifies optimization opportunities. Data feeds into hospital energy management reporting and ESG disclosures.
Compliance reports — Automated ISO 14644-3 classification reports with continuous monitoring data. Excursion logs with timestamps, duration and root cause. Audit-ready PDF export with data integrity signatures. Monthly trend reports showing classification maintenance percentage.

Benefits

Compliance, safety and efficiency — simultaneously

-36.7%

Measured energy reduction on deployed sites. Setback ventilation activates only when real-time data confirms the OR is unoccupied and no procedure is imminent. Recovery is verified before any return to active use.

0 contamination

Across all deployed sites, zero contamination events attributed to setback ventilation. The state machine ensures classification is verified before any procedure begins.

Concrete results

Particle monitoring runs 24/7 with sub-minute resolution. Every data point is timestamped, stored and available for audit. ISO 14644-3 classification status is always known — never assumed.

Typical payback period of 10 months, driven by HVAC energy savings. Additional ROI from reduced manual compliance workload and extended filter life due to lower average airflow.