Underwriters Fire Extinguisher Value Guide

This early 20th-century Underwriters Fire Extinguisher, manufactured by Knight and Thomas Inc. in Boston, represents a pivotal era in American fire safety history. These soda-acid units are highly collectible for their striking polished copper bodies and the 'Underwriters' label, which signifies adherence to safety standards established after the 1894 Chicago World's Fair.

What Is Underwriters Fire Extinguisher Worth?

The typical price range for Underwriters Fire Extinguisher is $150 - $165 based on recent sales. However, values can vary depending on the item's condition, rarity, and other factors such as:

• The condition and luster of the polished copper body, as heavy denting or severe oxidation significantly reduces the $150-$165 market value.
• Completeness of the unit, including the original internal glass acid vial and the external rubber discharge hose.
• Legibility and preservation of the brass instructional plate and the Underwriters Laboratories seal.
• The presence of original mounting brackets or wall hardware which can add a premium to the final sale price.

How to Identify Underwriters Fire Extinguisher?

• Look for the Knight and Thomas Inc. manufacturer stamp specifically noting the Boston, Massachusetts origin.
• Verify the presence of the embossed or riveted brass Underwriters Laboratories certification plate on the front of the copper cylinder.
• Check for the original rubber hose and the heavy brass screw-top cap used to seal the soda-acid internal components.
• Examine the base and handles for authentic wear patterns consistent with 1920-1940 era manufacturing techniques.

History of Underwriters Fire Extinguisher

Manufactured by Knight and Thomas Inc. in Boston, these soda-acid extinguishers were a staple of fire safety from the late 1800s through the mid-20th century. They operated by turning the cylinder upside down, which mixed bicarbonate of soda and sulfuric acid to create pressurized carbon dioxide gas that expelled the water. The 'Underwriters' label indicates it met the safety standards of Underwriters Laboratories, which was founded in 1894 following the World's Fair in Chicago.