Working Principle and Main Structure of Building Materials Combustion Calorific Value Tester

The building materials combustion calorific value tester is a key precision instrument for fire‑safety testing of construction materials. It strictly complies with the national standard GB/T 14402‑2026 and international standard ISO 1716:2018. It is mainly used to accurately determine the gross and net combustion calorific values of various building‑material products, and serves as critical equipment for evaluating fire load and classifying combustion performance grades of building materials. Adopting the oxygen‑bomb calorimetry principle, the instrument delivers accurate and stable test data, and is widely used in quality‑inspection institutions, building‑material manufacturers, scientific research institutes and other organizations.

The instrument operates based on the constant‑volume oxygen‑bomb combustion temperature‑measurement method. During testing, a precisely weighed building‑material specimen is placed inside a sealed oxygen bomb, which is filled with high‑pressure pure oxygen to create conditions for complete combustion. The specimen is ignited by an electric ignition device and fully burns within the leak‑tight closed bomb. The released heat is entirely transferred to the constant‑temperature water in the inner vessel, causing uniform temperature change of the water body. High‑precision sensors collect real‑time water‑temperature rise‑and‑fall data. Combined with pre‑set heat‑capacity parameters, heat‑loss compensation formulas and latent‑heat‑of‑vaporization correction coefficients, the system accurately calculates the combustion calorific value of the specimen and eliminates test errors induced by ambient temperature differences.

The instrument features a modular overall structure, consisting of four major units: oxygen‑bomb combustion system, constant‑temperature water‑supply system, data‑acquisition system and automatic control system. The oxygen bomb is made of high‑strength corrosion‑resistant alloy with pressure‑resistant and explosion‑proof performance to ensure safety under high‑temperature and high‑pressure combustion conditions. The constant‑temperature system is equipped with precise temperature‑control components to stabilize water temperature of inner and outer vessels and resist ambient temperature interference. The intelligent control system realizes automatic ignition, automatic stirring, real‑time data recording and result calculation for fully‑automated operation. Compared with conventional testing equipment, this instrument effectively reduces manual operation errors and offers high test repeatability. It provides accurate and reliable basic data for judging the combustion performance of building materials.

Combustion calorific value testers / calorimeters are developed and supplied by Beijing Xinsheng Zhuorui Technology Co., Ltd.