What is a B570 Fire Extinguisher?

Last updated: July 7th, 2026

The Amerex B570 is a 30 lb Class D fire extinguisher that uses sodium chloride dry powder to suppress combustible metal fires involving magnesium, sodium, potassium, and sodium-potassium alloys. It is not effective on lithium fires, which require a copper-powder unit like the Amerex C571. Understanding when and how to deploy it correctly is essential for any facility that machines, processes, or stores reactive metals.

When managing fire safety in a high-stakes industrial environment, using the wrong tool isn't just ineffective; it can be catastrophic. Standard commercial fire suppression systems are designed for wood, paper, or electrical fires, but they fail completely when encountering combustible metals. This is where specialized heavy-duty equipment becomes non-negotiable. If your facility processes, machines, or stores reactive metals, you need an exact, purpose-built defense system.

The Amerex B570 fire extinguisher is the definitive answer to severe industrial metal fire hazards. Engineered specifically to tackle Class D thermal emergencies, this industrial fire safety equipment provides heavy-duty security for machine shops, aerospace manufacturing labs, and automotive production floors. Understanding the inner workings, operational capabilities, and technical parameters of the B570 is essential for keeping your facility compliant, safe, and fully prepared for high-temperature incidents.

What is a Class D Fire and How Does the B570 Work?

To understand what the B570 fire extinguisher is, you must first understand the volatile nature of a combustible metal fire. Metals like magnesium, titanium, and zirconium can ignite and burn at extreme temperatures, in some cases exceeding 5,000°F. Alkali metals like sodium and potassium burn at lower temperatures by comparison, but they present their own severe hazard: contact with water or standard fire suppression agents triggers a violent reaction that releases highly explosive hydrogen gas, intensifying the blaze rather than putting it out.

The Amerex 30 lb Class D extinguisher bypasses this danger entirely through a specialized sodium chloride dry powder agent. Often referred to in industrial settings as "Super-D" powder, this extinguishing medium is formulated to smother chemical fires at their core. When the operator applies the dry powder to a burning metal surface, the extreme heat causes the sodium chloride crystals to fuse, cake, and form a dense, continuous, heat-insulating crust over the hazard.

This solid crust acts as a dual-action barrier:

• Oxygen Exclusion: It completely seals the material, preventing ambient air from reaching the underlying burning metal.
• Heat Dissipation: It rapidly conducts and dissipates heat away from the core of the fire, lowering the temperature until the material falls safely below its ignition threshold.

Engineering and Design Features

Every element of the Amerex B570 is engineered to protect the operator while maximizing suppression efficiency. The first thing facility managers notice is the striking yellow paint finish. Unlike common red units, a legitimate Class D fire extinguisher is legally color-coded in a brilliant, corrosion-resistant yellow polyester powder finish to prevent dangerous confusion during an emergency.

Component Breakdown and Visual Layout

Amerex B570 component diagram

• Valve assembly: releases the powder when you squeeze the handle. It's constructed out of metal so it won't corrode or crack over years of storage.
• Pull pin: the oversized loop lets you grab it fast, even with thick gloves on.
• Cylinder body: holds 30 lbs of powder. Formed from a single sheet of drawn steel for extra strength, backed by a 6 year warranty.
• Applicator wand: sprays the powder gently instead of blasting it, so you don't scatter burning metal fragments around the room.
• Detachable nozzle: pops off the wand when you need a tighter, longer-reaching stream instead of a wide spray.

Approved Applications: What Metals Can It Fight?

The Amerex Model B570 is thoroughly tested and certified by standard compliance bodies, carrying comprehensive FM (Factory Mutual) and UL (Underwriters Laboratories) approvals. It is explicitly designed to provide robust combustible metal fire protection against specific industrial hazards.

The unit is rated to control and extinguish the following materials:

• Magnesium: Commonly found in machining chips, turnings, and aerospace alloys.
• Sodium and Potassium Spills: Critical for chemical processing plants and specialized manufacturing zones.
• Sodium-Potassium Alloys (NaK): Highly reactive liquid metals used in engineering heat transfers.
• Specialty Metals: There is data showing the B570 can control and extinguish fires involving titanium, zirconium, uranium, and powdered aluminum.

B570 vs. C571 vs. Standard ABC Dry Chemical

Amerex B570 Specifications and Data Sheet

To assist safety compliance coordinators, safety professors, and procurement teams with building layout planning, the precise technical specifications for the B570 unit are detailed below:

Operation Guidelines and Pro Safety Tips

Successfully managing a metal fire depends entirely on understanding the spatial limitations and operational constraints of your equipment. The B570 operates via a stored pressure design. When the pin is pulled and the lever is compressed, the unit provides a continuous discharge time of roughly 24 seconds. This gives the responder a precise, focused window to blanket the hazard.

When training your team on how to extinguish a metal fire, emphasize the following protocols:

1. Maintain Proper Distance: Begin discharging at the outer limit of the effective range (3 to 6 feet with the soft-flow extension wand attached). This ensures the initial blast of pressure does not disturb the molten metal.
2. Build the Emulsion Layer: Completely cover the burning hazard with a thick, even layer of the sodium chloride powder. Allow the heat to naturally form the oxygen-depleting crust.
3. Isolate and Cool: Once the crust forms, leave the area undisturbed. Do not attempt to poke, move, or break the crust prematurely. Breaking the crust introduces fresh oxygen to the super-heated core, which can trigger an instant, violent re-ignition.
4. Mind the Weight: Because the fully charged cylinder has a substantial shipping weight of 53 lbs, consider pairing the unit with an optional heavy-duty dolly cart (Model 859) to ensure rapid mobility across expansive facility floors.

Watch: How to Use a Class D Fire Extinguisher

The video below demonstrates proper technique for discharging an Amerex Class D extinguisher, including correct standoff distance, powder application, and how to let the extinguishing crust form without disturbing it the same protocols outlined above.

Reviewed by Joseph Hedrick, NFPA-certified fire protection specialist

Related: Class D Extinguishers at Pro Fire and Safety