## 1 Introduction
They established a quantitative model using the partial least squares method and compared the effects of various spectral data preprocessing algorithms, such as smoothing and the Savitzky-Golay filter, on the model. The results showed that second-order smoothing preprocessing could enhance the accuracy of the partial least squares model, reducing the root mean square error of the prediction model from 2.36 \(\times\) 10\({}^{9}\) mJ/kg to 2.76 \(\times\) 10\({}^{8}\) mJ/kg. There has been considerable research on the impact of environmental factors on LIBS technology. [PERSON] and colleagues [27] studied the effect of sample temperature on LIBS signals. The experimental results indicated that increasing the sample temperature significantly enhanced the intensity and reproducibility of the LIBS signals. In experiments with artificial samples, raising the sample temperature to 973 K led to a 280% increase  
Figure 1: Fireproof coating application scenarios: (**a**) Valve hall sealing, (**b**) Cable fireproof coating. in signal intensity, a 20% improvement in the signal-to-noise ratio (SNR), and a 260% reduction in the limit of detection (LOD). [PERSON] and colleagues [28] investigated the influence of relative humidity on air plasma, finding that humidity has a significant impact on the emitted spectra. [PERSON], [PERSON] and colleagues [29] examined the LIBS spectra under various atmospheric conditions and discovered that altering pressure and the composition of the background gas can significantly affect the spectral results; lowering the pressure and using argon and helium gases can enhance the spectral intensity, SNR, and resolution. Research on the use of LIBS for detecting coating thickness is relatively rare. [PERSON] and colleagues [30] characterized solid samples with LIBS, investigating the emission characteristics of aluminum (Al) and zinc (Zn) spectral lines in laser-induced plasmas, and exploring the relationships between element concentration and film thickness. [PERSON] and colleagues [31] combined LIBS technology with a laser profile and interface roughness model (LPIR model) to study how the ablation rates of different materials affect the accuracy of thickness measurements of deposited layers. Their results indicated that the thickness correction method they proposed significantly improved the measurement accuracy of multilayer samples. [PERSON] and colleagues [32] introduced a method for the online monitoring of the laser coating removal thickness of double-layer coatings on aluminum alloy plates using a high-frequency nanosecond infrared pulsed laser combined with LIBS technology. Through the standard curve method and principal component analysis-support vector regression (PCA-SVR) algorithm, they achieved high-precision online monitoring. Around the world, many countries are actively researching high-voltage transmission technology, which relies on fireproof coatings to enhance safety. For example, Brazil's Belo Monte Hydroelectric Plant project utilizes \(\pm\)800 kV direct current transmission technology to transport electricity from the northern Amazon region to the southeast. India is implementing multiple ultra-high voltage transmission projects to connect its resource-rich northeastern region with other load centers. In the United States, projects like the Pacific DC Intertie are used to transmit renewable energy from resource-rich areas to load centers. China's ultra-high voltage (UHV) and extra-high voltage (EHV) transmission lines cover extensive areas, including high-altitude regions such as Qinghai and Tibet. The Qinghai-Tibet Grid Interconnection Project was put into operation in 2011; in November 2014, the 500 kV Sichuan-Tibet Interconnection Transmission and Transformation Project was launched; and in December 2020, the ultra-high voltage transmission line known as the \"Sky Road\" connecting Ali and Central Tibet was officially put into operation.