How to test the calorific value of building materials?

What is the concept of calorific value? The calorific value of building materials is a crucial parameter characterizing their potential fire hazard and is essential basic data for calculating the heat released during combustion and fire load. Beijing Xinsheng Zhuorui Technology Co., Ltd. has developed and produced an oxygen bomb calorific value tester to test the calorific value of several commonly used building materials and compare and analyze the test data. The results show that the calorific values ​​of different building materials vary greatly, and even among the same type of building material, there can be significant differences due to variations in their composition. This aims to provide a reference for the application of building materials in fire protection design codes.

A Burning heat value tester for building materials and products is an instrument used to measure the calorific value of building materials and products. This instrument is widely used in the building materials industry, fire protection field, and building materials quality supervision departments.

The flame retardancy rating of building materials is crucial for ensuring the safety of buildings and their users. The determination of calorific value, as specified in GB/T 14402-2007 and ISO 1716-2010 standards, is a key step in assessing flame retardancy rating. Therefore, a calorific value tester that meets the standard requirements and has excellent performance is essential.

The QINSUN calorific value analyzer boasts several innovative designs and efficient functions, making it a powerful tool for assessing the flame retardancy rating of building materials. Firstly, its 360-degree water-covered inner cylinder completely solves the long-term instability problem of traditional calorimeters, ensuring the accuracy and reliability of test results. Secondly, the standard measurement method takes less than 9 minutes, doubling the efficiency of traditional calorimeters, significantly improving testing and work efficiency.

Notably, the analyzer is equipped with an automatic oxygen filling function and a safety protection device. It automatically controls the oxygen filling pressure, automatically releasing gas to return to a safe pressure if it exceeds the safe range, ensuring operator safety. Furthermore, an independent cooling water station and a high-precision temperature control device ensure precise temperature control, effectively avoiding the influence of external environmental factors on test results.

Additionally, this calorific value analyzer for building materials and products uses laser ignition technology, eliminating the need for ignition wires or cotton threads, making operation more convenient and stabilizing the ignition success rate, thus improving measurement accuracy. Its automatic oxygen filling timing and automatic stop functions make operation more intelligent, reducing the burden on operators.

Significance

As everyone knows, the calorific value of building materials is a crucial parameter characterizing their potential fire hazard. It is essential foundational data for calculating the heat released during combustion and the fire load. Calorific value is a natural property of a material, independent of its dimensions and usage. It can be used to evaluate the potential fire load of building materials and is one of the testing methods for evaluating combustion performance classification.

Industry Application Background of Calorific Value Analysis:

Calorific value, also known as heat output, refers to the heat released when a unit mass (solid or liquid) or unit volume (gas) of fuel is completely burned and the combustion products are cooled to their pre-combustion temperature (generally ambient temperature). It is an important indicator of fuel quality.

Gas fuel is mainly used for combustion heating; therefore, its calorific value is a crucial parameter in gas engineering. Calorific value of gas is frequently measured during gas production, supply, and application. Examples include coke oven gas and blast furnace gas produced in the natural gas industry, various kilns in the steel and metallurgical industries, water gas and semi-water gas in the coal chemical industry, and biogas and biomass fermentation by-product gas produced in fermentation and brewing industries.

Natural gas is a general term for a mixture of hydrocarbons and a small amount of non-hydrocarbon gases. The composition and calorific value of natural gas vary depending on the gas source, and even the same volume of natural gas will produce different amounts of energy when burned.

Test Results and Comparative Analysis:

For homogeneous products, three tests should be conducted. If the dispersion of individual values ​​is consistent, the test is valid, and the calorific value of the product is the average of these three test results. If the test results do not meet the validity requirements, two additional samples need to be tested. Among these five test results, the maximum and minimum values ​​are removed, and the average of the remaining three values ​​is taken. If the validity of the test results does not meet the above requirements, the sample should be remade and the test repeated. If the grading test requires testing the calorific value of the following 26 building materials, random samples of each building material should be tested, and each sample should be tested 3-5 times; the test results will vary.

Phenolic resins and wood fibers have very high calorific values, both exceeding 10 MJ/kg, posing a significant fire hazard. Building fire protection design and usage departments should pay close attention to this. This is because the high organic content of phenolic resins and wood fibers makes them inherently flammable. These materials are typically not used alone in building structures but often appear in the form of composite materials. The calorific value of phenolic composite materials (such as phenolic aluminum foil sandwich panels and phenolic fiber products) depends on the content of each component, especially the phenolic content; the higher the phenolic content, the higher the calorific value. Glass wool, sprayed wool, and adhesives all contain organic glue, and therefore also have high calorific values; the higher the glue content in these materials, the higher the calorific value. Therefore, when fire protection is required, the adhesive content should be controlled to meet standard calorific value requirements. Materials such as calcium silicate boards, gypsum boards, perlite, and rock wool boards typically have calorific values ​​below 2 MJ/kg. These materials are all inorganic products, and due to the endothermic reaction during combustion, their calorific values ​​are usually low, sometimes even negative. These materials can be used as fireproof materials; for example, rock wool boards and mineral wool boards can be used as ceiling materials, with sound insulation and heat insulation functions; perlite products are widely used in the production of fire doors.

What are the standards for determining the calorific value of building materials and products?

Standards for determining the calorific value of building materials and products: The series of calorific value testing instruments for building materials and products developed and manufactured by QINSUN are applicable to the testing of the calorific value of building materials in a constant heat capacity oxygen bomb calorific value tester. The standards for determining the calorific value of building materials and products conform to GB8624/GB/T14402-2007 and ISO1716:2002 test standards.

Maintenance and care

Maintenance and upkeep of the building materials calorific value tester are crucial for ensuring its normal operation and extending its service life. Here are some important maintenance and upkeep measures:

Regularly check the oxygen bomb: After each experiment, clean all parts of the oxygen bomb and rinse them thoroughly with distilled water. If the oxygen bomb leaks, replace it with a spare sealing ring.

Hydraulic pressure test: Regularly perform a hydraulic pressure test on the oxygen bomb to ensure its safety and reliability during its service life.

Clean the outer water cylinder: When not conducting continuous tests, drain the water from the cylinder to keep the interior clean.

Regularly clean the instrument casing and circuitry:** Prevent dust from corroding mechanical and electronic parts or causing poor contact.

Regularly replace consumable parts: Replace consumable parts such as the combustion chamber and Pitot tube promptly.

By following these maintenance and upkeep measures, the service life of building material calorific value testers can be effectively extended, ensuring accurate measurement results during testing.

The determination of the calorific value of building materials and products is of great significance in the field of building safety. From clarifying the concept of calorific value and understanding the industry application background, to mastering the measurement standards and knowing how to compare and analyze test results, every step lays a solid foundation for ensuring the safety of buildings and their users. Proper maintenance and upkeep of building material calorific value testers are crucial to ensuring accurate and reliable testing and the long-term stable operation of the instruments. Only by fully emphasizing these aspects can we better utilize the calorific value parameter to provide a scientific basis for building fire protection design and material selection, promoting the steady development of the construction industry on a safe track.