Abstract An inexpensive passive heat flux sensor and recording device for measurements in fires or other hot environments comprising a pair of small spring steel strips of different thicknesses, heat treated to maximum hardness. The strips are fastened together back-to-back with asbestos paper insulation between them, or they are mounted side-by-side on a piece of asbestos millboard. After immersion in a fire the two steel pieces are tested for Rockwell C hardness, which is referred to a set of charts prepared with the aid of a computer program. The charts give the average heat flux and the time from beginning of exposure to approximately the maximum temperature of the steel pieces. It is also possible to calculate the approximate flame temperature from the data.
Inventors
👤 W Smith
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-06 18:05
CPC Classifications
G; G01; G01K; G01K17/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
27 words
The device of claim 1 wherein said steel elements consist of flat elements of differing thicknesses disposed on one surface of said fireproof material in side-by-side relationship.
Claim 2
Dependent Claim
15 words
The indicator device of claim 2 wherein the ratio of said thicknesses is approximately 2:1.
Claim 3
Dependent Claim
22 words
The device of claim 1 wherein said elements are of like dimension; and heat sinks of differing thickness attached to respective elements.
Claim 4
Dependent Claim
19 words
The device of claim 1 wherein said elements are separated by fireproof material so that opposite faces are exposed.
Claim 5
Independent Claim
75 words
The method of obtaining heat flux measurements in large fires comprising: placing a plurality of fully hardened high carbon steel elements having equal exposed surfaces and varying thicknesses in a fire; removing the steel elements from the area after the fire and subjecting said elements to a test for hardness on a Rockwell hardness tester using the C scale; and comparing the hardness of the samples to ascertain the effects of the fire on each.