Tekanan panas merupakan salah satu faktor bahaya fisik di lingkungan kerja yang dapat menyebabkan berbagai gangguan kesehatan akibat panas. Oleh karena itu, diperlukan penilaian tekanan panas yang umumnya menggunakan indeks Wet-Bulb Globe Temperature (WBGT). Namun, penggunaan alat ukur WBGT standar masih memiliki beberapa keterbatasan. Sebagai alternatif, telah dikembangkan alat real-time monitoring tekanan panas berbasis low-cost sensor yang terintegrasi dengan sistem Internet of Things (IoT). Namun, validitas hasil pengukuran alat tersebut masih belum diketahui secara komprehensif. Penelitian ini bertujuan untuk mengetahui dan menganalisis validitas alat real-time monitoring tekanan panas berbasis low-cost sensor terhadap alat ukur WBGT standar pada area indoor dan outdoor. Penelitian menggunakan desain studi komparasi (method comparison study) dengan pendekatan kuantitatif. Analisis validitas dilakukan melalui perbandingan hasil pengukuran alat real-time monitoring berbasis low-cost sensor dan alat ukur WBGT standar berdasarkan kriteria presisi, bias, linearitas, dan error pada parameter suhu kering, suhu basah alami, suhu radian, kelembapan relatif, dan nilai WBGT. Hasil penelitian menunjukkan bahwa suhu kering memiliki validitas yang baik pada pengukuran indoor dan outdoor. Suhu basah alami dan suhu radian menunjukkan validitas yang baik pada pengukuran indoor, namun mengalami penurunan validitas pada pengukuran outdoor. Kelembapan relatif menunjukkan presisi dan linearitas yang baik, namun validitasnya belum optimal karena nilai bias dan error yang relatif tinggi. Nilai WBGT menunjukkan validitas yang sangat baik pada pengukuran indoor, namun masih memerlukan peningkatan akurasi pada pengukuran outdoor. Secara kesuluruhan, validitas alat real-time monitoring tekanan panas berbasis low-cost sensor lebih baik pada pengukuran indoor dibandingkan outdoor. Alat yang dikembangkan ini berpotensi digunakan sebagai sistem pemantauan tekanan panas secara real-time, terutama pada lingkungan indoor, dengan tetap memerlukan penyempurnaan alat untuk meningkatkan validitas pengukuran outdoor.

Heat stress is one of the physical hazards in the workplace that may cause various heat-related health effects. Therefore, heat stress assessment is required, which commonly assessed using Wet-Bulb Globe Temperature (WBGT) index. However, the use of standard WBGT instruments still has several limitations. As an alternative, a low-cost sensor-based real-time heat stress monitoring device integrated with an Internet of Things (IoT) system has been developed. However, the validity of its measurement results has not yet comprehensively known. This study aimed to determine and analyze the validity of a low-cost sensor-based real-time heat stress monitoring device against a standard WBGT instrument in indoor and outdoor environments. This study employed a quantitative method comparison design. Validity analysis was assessed by comparing measurements obtained from the low-cost sensor-based real-time monitoring device and the standard WBGT instrument based on precision, bias, linearity, and error for dry-bulb temperature, natural wet-bulb temperature, globe temperature, relative humidity, and the WBGT value. The results showed that dry-bulb temperature demonstrated good validity in both indoor and outdoor measurements. Natural wet-bulb temperature and globe temperature showed good validity in indoor measurements but experienced a decrease in validity during outdoor measurements. Relative humidity demonstrated good precision and linearity, but its validity was not optimal due to relatively high bias and error values. The WBGT value showed excellent validity in indoor measurements, but still required improved accuracy in outdoor environments. Overall, the validity of the low-cost sensor-based real-time heat stress monitoring device was better in indoor than outdoor environments. The developed device has the potential to be used as a real-time heat stress monitoring system, particularly in indoor settings, although further improvements are needed to enhance the validity of outdoor measurements.