LSI LASTEM has developed three solutions for monitoring heat stress indices and alerting to protect the health and safety of workers and exposed persons. The ISTSA2100 station is designed for fi xed outdoor monitoring, while the transportable ISTSA1100 station is suitable for medium and long-term monitoring in both indoor and outdoor environments. Both systems include sensors for measuring air temperature, relative humidity, radiant temperature and wet temperature, as well as an Alpha-Log data logger and specifi c mounting accessories. The data logger directly calculates thermal stress indices and remotely transmits the measurements and calculations, generating alarms via SMS, e-mail and activating local alert systems based on set thresholds. The ISTSA1200 station is designed for portable monitoring in both indoor and outdoor environments and, in addition to the sensors  of the other two stations, measures  solar radiation and wind speed, with these sensors it calculates the UTCI index.