As a core equipment for building safety and industrial testing, the fireproof coating thickness gauge accurately evaluates the coating thickness through non-destructive measurement technology, ensuring that the fireproof performance of substrates such as steel structures and pipelines meets the standards.Based on measurement principles and structural differences, mainstream products in the market can be divided into four types: electromagnetic induction, eddy current, ultrasonic, and composite. Each type of instrument presents significant differences in application scenarios and technical characteristics.

　　1、 Electromagnetic Induction Thickness Gauge: "Standard Selection" for Fire Protection of Steel Structures

The thickness gauge based on electromagnetic induction principle is the mainstream tool for fire detection of steel structures. It excites a magnetic field through an iron-based probe, measures the attenuation degree of the non-magnetic coating on the magnetic field, and then calculates the thickness. This type of instrument generally covers a range of 0-5000 μ m, with an accuracy of ± (3% H+2 μ m), in compliance with the GB/T 4956-2003 standard, and can measure and store 2000 sets of data in a single/continuous manner. Typical applications include the acceptance of fire-resistant coatings for bridges and high-rise building steel structures.

　　2、 Eddy current thickness gauge: the "precise choice" for lightweight substrates

For non-magnetic metal substrates such as aluminum and copper, eddy current thickness gauges generate eddy currents in conductive coatings through high-frequency alternating magnetic fields, and calculate the coating thickness in reverse. This type of instrument typically has a range of 0-1500 μ m and a resolution of 0.1 μ m, and is suitable for detecting fire-resistant coatings on aviation aluminum and copper pipelines.

　　3、 Ultrasonic thickness gauge: the "penetration expert" for complex surfaces

Using the reflection time difference of high-frequency sound waves at the interface between the coating and substrate to calculate thickness is particularly suitable for detecting curved surfaces, irregular structures, and thick coatings. Its range can reach 0-10mm, resolution is 1 μ m, and it can penetrate composite coatings such as enamel and rubber.

　　4、 Composite thickness gauge: a "technology integrator" with full scene coverage

Integrated electromagnetic induction and eddy current dual probes, capable of automatically identifying iron-based/non-ferrous materials and switching measurement modes, with a range extended to 0-9500 μ m. This type of instrument is equipped with Bluetooth transmission and APP analysis functions, supporting real-time data upload and report generation.

The technological evolution of fireproof coating thickness gauges, from electromagnetic induction to composite detection, has always revolved around the three core requirements of "precision, efficiency, and applicability". Whether it is steel structure fire inspection, pipeline anti-corrosion monitoring, or high-precision testing in the aerospace field, selecting the appropriate type and parameters of thickness gauge has become a key link in ensuring engineering safety and quality.