Doheny Memorial Library, Los Angeles, CA 90089-0189 Public Domain. Release under the CC BY Attribution license--http://creativecommons.org/licenses/by/3.0/--Credit both “University of Southern California. Libraries” and “California Historical Society” as the source. Digitally reproduced by the USC Digital Library; From the California Historical Society Collection at the University of Southern California Send requests to address or e-mail given USC Libraries Special Collections specol@usc.edu
Description
Photograph of a Department of Public Works Sewer Maintenance Division van, ca.1935. At center, a small van with the Department of Public Works seal on its side is pictured, stripes along the bottom half of the chassis. To the right, a second automobile can be seen parked along the curb, behind which a building and trees can be seen. Additional information: This photograph features a "route truck" used by the Public Works Department Sewer Maintenance Division for testing and reporting explosive gas conditions in sewers. The truck carried a two-person crew consisting of a driver and a tester. The truck also carried a combustible gas testing device powered by a 6 volt battery and actuated by a vacuum from the truck engine. This device could detect gasoline vapor, natural gas and combustibility. The crew could test from 300 to 500 manholes daily. The testing device used a long copper tube (probe) that was inserted through the pick hole of a manhole cover to "sniff" for explosive gases. Tests were made by driving up to a manhole and simply inserting the probe to draw a sample of the manhole atmosphere. If explosive conditions were detected, they were immediately reported for remediation.
Type
image
Format
1 photograph : photoprint, b&w 13 x 18 cm. photographic prints photographs
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