Operation Theatre & ICU Temperature and Humidity Monitoring

There is no single number that every hospital must follow. The figures below are commonly cited guidance drawn from NABH hospital standards, ASHRAE Standard 170 (ventilation of health care facilities) and Ministry of Health and Family Welfare (MoHFW) planning guidance. They are not law, and your own infection-control committee, HVAC designer and surgical teams set the final limits for each room.

People often ask why ICU temperature is low or why an operation theatre feels cold. Cooler, drier air slows the growth of bacteria and fungi, keeps gowned surgeons comfortable under bright lights, and offsets the heat from anaesthesia machines, monitors and imaging equipment. Humidity is held below about 60 % because damp air supports microbial growth and can compromise sterile wraps, and above about 40 % in most specifications to reduce static and dry airways.

The patient is protected separately with warming blankets and fluid warmers, which is why the room itself can stay cool. The risk is not the target range but drift: an AHU trip, a stuck humidifier or a chiller fault moves both values within an hour, and nobody in a busy theatre is watching a wall thermometer.

An OT temperature and humidity monitoring system replaces the wall hygrometer and paper chart with a logger that reads both values continuously and sends them to a cloud dashboard. Ideabytes built-in sensor loggers (IBI-WTH50, IBI-ETH50, IBI-MTH50) measure 0 °C to +50 °C at ±0.5 °C and 0–100 % RH at ±2 % RH, with 0.1 resolution on both. Readings are sent every 15 minutes by default, and the interval is configurable if your SOP asks for more frequent readings.

Each unit has an OLED display so staff can read the current values at the door, an IP64 enclosure, up to 20 hours of battery backup during a power failure, and 90 days of internal storage at 15-minute sampling, so a network outage does not leave a gap in the record.

Placement matters as much as the logger. Mount it at about working height on a wall away from supply diffusers, return grilles, the door and heat sources such as anaesthesia workstations or warming cabinets, so it reads the air around the patient rather than a draught. In large theatres or ICUs with several bays, one logger per zone shows whether the far end of the room holds the same band. Where a reading is needed inside the AHU or a pass box, use a probe model and keep the logger outside the sterile area.

The three built-in models differ only in how they connect. Ethernet (IBI-ETH50, IBI-ETH120) suits new blocks where a LAN point is already in every OT and the IT team prefers wired devices. Wi-Fi (IBI-WTH50, IBI-WTH120) suits hospitals with good 2.4 GHz coverage and a quick IT approval process.

4G (IBI-MTH50) uses a built-in M2M SIM with 2G fallback, so it needs no hospital network, credentials or firewall changes, which often shortens approval from months to days. For a whole building with many rooms and other parameters, the IBI-WC-X (Wi-Fi) and IBI-MC-X (4G) customised room parameter systems bring several sensors into one project; sensors and accessories for these are specified per site.

NABH standards expect hospitals to maintain a safe environment in critical areas and to show evidence that it is monitored. In practice assessors typically ask to see the temperature and humidity record for a sample of OTs and ICUs, the last deviation, who was informed and what corrective action was taken. They also check that the measuring instrument is calibrated.

Ideabytes is not an accreditation body, and a logger alone does not make an OT compliant. What it gives your quality team is a continuous, time-stamped record with an audit trail, alarm logs, trend graphs and CAPA notes, exported as 21 CFR Part 11 compliant PDF reports, with NABL-traceable calibration certificates available on request.

Each logger raises live alerts and app push notifications, with SMS as an option, when temperature or humidity crosses its limit, when the power fails or when the device goes offline. Set separate limits for each room so a NICU and an orthopaedic theatre are judged against their own bands, and add a short delay so a door opened for a trolley does not trigger an alarm.