Q&A

Why is magnesium alloy chips selected as the target metal for Class D metal fire extinguishing?

1. It is the most common metal fire hazard on Earth.

- Magnesium is a lightweight metal widely used in industrial settings and is one of the metals most frequently involved in metal fires. Chips, powder, and flakes, particularly during cutting and machining, pose a high risk of ignition.

2. Its combustion characteristics are consistent with typical metal fire reference materials.

- Magnesium exhibits distinct metal fire characteristics, making it an ideal test reference material.

- It has a low ignition temperature and very high combustion heat. It reacts with water to produce hydrogen, and the metal oxidation reaction proceeds rapidly and autocatalytically.

3. Reasons for Using Alloy Chips

- Realistically reflects real-world fire conditions in industrial settings.

- The chip shape exhibits high combustion diffusion, making it ideal for assessing fire extinguishing performance.

- Ensures combustion stability (the ability to reproduce the same combustion conditions even after repeated tests increases the reliability of the testing process.

4. International standards (UL/FM/ISO) also standardize the use of magnesium chips.

How can I find out the legal basis for the definition and installation standards for Class D metal fires?

The definition of Class D metal fires is found in the "Fire Safety Technical Standards for Fire Extinguishing Devices and Automatic Fire Extinguishing Systems (NFTC 101)."

1.7.1.11 "Metal fire (Class D fire)" refers to fires occurring in combustible metals such as magnesium alloys. The appropriate fire extinguisher for metal fires is indicated by the letter "D." <Newly established on July 25, 2024>

2.1 Installation Standards

Table 2.1.1.3, 7. In locations where magnesium alloy chips are stored or handled, at least one Class D fire extinguisher for metal fires must be installed within 20 meters of the metal material.

Where are the main demand sources for Class D metal fire extinguishers?

Class D metal fire extinguishers are found almost exclusively in workplaces that handle combustible metals (magnesium, titanium, sodium, potassium, lithium, aluminum powder, etc.).

Let's break it down a bit.

1. Metal Processing and Manufacturing Plants

Magnesium/Aluminum/Titanium Processing Plants

Factories that cut, grind, turn, and drill magnesium/aluminum/titanium.

Processes that generate a lot of dust (chips, scrap, powder).

Examples:

Magnesium alloy parts factories

Factories that process lightweight automotive components, bicycle frames, laptop housings, and electronic case cases.

Metal powder manufacturing and handling companies

Companies that produce metal powder and supply it to 3D printer powders, additives, explosives raw materials, and special materials. Powders like Ti, Al, Mg, Zr, and Li are difficult to extinguish with standard fire extinguishers once ignited, creating a high demand for Class D fire extinguishers. 2. Battery/Energy-Related Businesses

Lithium Primary/Secondary Battery Manufacturing Plants

Manufacturing plants for lithium-based materials, including lithium, lithium alloys, electrode materials (powder), and slurries.

Demand for Class D fire extinguishers is higher in processes handling electrode materials/powder, research facilities, and pilot lines than in battery assembly lines.

Battery Recycling/Shredding/Sorting Companies

Processes that shred, disassemble, and sort waste batteries.

The fine metal powder and residual lithium generated during the shredding/crushing process create demand for Class D or lithium-specific fire extinguishers. 3. Aviation, Defense, Space, and Advanced Materials Sectors

Aircraft and Space Parts Processing Companies

Factories that process aircraft titanium and magnesium alloy parts

Manufacturing/repairing companies for aircraft structural materials, engine components, satellites, and rocket components

Defense and Weapon Systems Factories

Factory processing defense components using aluminum, magnesium, and titanium

Research and testing buildings using special alloys and metal powders

Military standards and guidelines may require Class D equipment in these areas, and project-level requirements may arise.

4. Chemistry, Research Institutes, and Testing Institutes

University/Corporate Research Institutes

Laboratory facilities that use sodium, potassium, lithium, magnesium, aluminum powders, etc. in solvents, dry reactions, catalysts, and testing.

Especially laboratories for organometallics, battery materials, catalysts, and powder metallurgy.

National/Private Testing and Certification Bodies

Places that conduct combustible metal, battery, and material testing (combustion and safety testing).

Class D fire extinguishers are often required near test equipment and in fire risk assessment areas. 5. Casting, Melting, and Heat Treatment Processes

Magnesium/Aluminum Foundries, Alloy Manufacturing Plants

Due to the risk of metal fires caused by molten metal splashing, splattering, and oxidation reactions at high temperatures, Class D fire extinguishers or special extinguishing agents are required.

6. Special Industries/Others

Fireworks/Sparkle Production, Special Effects Companies

Places that handle metal powder-based fireworks, sparklers, etc. for performances and filming.

While not particularly large in scale, these businesses are sometimes classified as Class D due to strict safety regulations.

Drone/RC/Model Workshops (Metal Processing + Lithium Battery Manufacturing)

Small businesses that process magnesium and aluminum parts for drones and model parts, as well as conduct lithium battery charge/discharge testing, are also potential customers.

(While small in scale, this niche market can be targeted by emphasizing "safety compliance")

What is the operating principle of a Class D metal fire extinguisher?

It operates on the following principles: 

1. It coats the metal surface with a patented special powder to block oxygen,

2. It rapidly reduces the temperature of the metal fire, halting its continuation,

3. It forms a film over the flame to prevent re-ignition.

What are the characteristics of a Class D metal fire?

Class D metal fires are characterized by:

1. The metal itself combusts, generating flames and high temperatures of several thousand degrees Celsius.

2. An explosive reaction occurs when reacting with water or carbon dioxide.

3. Metal dust is dispersed widely, rapidly spreading the fire.

These are the characteristics of a Class D metal fire.

What is a Class D metal fire extinguisher?

Class D metal fire extinguishers are specialized fire extinguishers designed to extinguish fires (Class D fires) involving the combustion of metals such as magnesium (Mg), aluminum (Al), lithium (Li), sodium (Na), potassium (K), and titanium (Ti). These fires cannot be extinguished with standard fire extinguishers (e.g., ABC powder, CO₂, or foam), and can actually cause explosion and spread of the fire, making the use of a dedicated fire extinguisher essential.