412 ITU‐T's Technical Reports and Specifications Figure 20 – Utility Shafts in the T‐30 Prefabricated Hotel [Source: BROAD Sustainable Building Co. Ltd., b‐16] [b‐16] provides useful guidance on best practice for the ICT within a building such as a hotel. A sensor network is provided to each room for environmental control. This is shown below. Environmental sensors include: Indoor temperature sensor Indoor humidity sensor Formaldehyde sensor [b‐17] (for sick building sickness sufferers, for whom the World Health Organization has set a 30 min exposure limit of 0.08 ppm) CO2 sensor Particulate Matter Sensor (Acceptable indoor air quality is an occupant need and should be sensed and controlled for. Particulate matter sensors measure the particulate concentration, which, at high levels, correlates to health problems [b‐18]) Indoor infrared sensor (for room occupancy) Water leakage sensor Air flow sensor