Conductometer

WLMD ID: alcz
The Conductometer was used to check conductivity of operating room floors, equipment and the shoes of personnel as part of protocols that were followed to prevent the occurrence of electrostatic sparks in operating rooms (ORs). This device was introduced around 1950, at a time when the importance of preventing static spark in ORs was well recognized. A simple static spark could ignite flammable mixtures of oxygen and anesthetics. In order to equalize the electrostatic charge of critical 'objects' in the OR, including equipment, flooring, patient and personnel, all objects needed to conduct an electric current relatively well. Ohmmeters, like the Conductometer, measured the resistance of materials to the flow of an electric current. Objects and materials with too much resistance were not allowed in the OR. This meter was installed in the wall near an entrance to the OR, and was connected to conductive flooring or a metal plate on the floor in front of it. When anesthesiologists or other personnel tested themselves, they touched an elbow to the large metal switch while standing on the conductive flooring or metal plate and read the dial to be sure their shoes were conductive. The dial has a numerically incremented scale as well as color coding for easy reading. Twenty-foot leads with electrodes could be plugged into the meter for periodic testing of flooring and equipment.

Catalog Record: Conductometer

Access Key: alcz
Accession No.: 2009-08-11-1

Title: Conductometer.

Title variation: Not Applicable

Publisher: Boston, Mass. : Conductive Hospital Accessories Corp, [between 1950 and 1970?].

Physical Descript: 1 ohms meter : metals, plastics ; 30 x 20.5 x 9.5 cm.

Subject: Static Electricity – instrumentation.
Subject: Operating Rooms – safety measures.
Subject: Safety – history.
Subject: Explosions – prevention and control.
Subject: Health Facilities – fires and fire prevention.

Note Type: General
Notes: The early year in the date range is based on the year that the manufacturer,
Conductive Hospital Accessories, applied to Trademark the name
“Conductometer”. The end year is an estimate based on the dates of various
publications with references to Conductometer use in operating rooms. The
date range could change if reliable information indicates that it should be
corrected.

Note Type: Citation
Notes: Arrowsmith M. Reflecting on theatre explosion danger. Health Estate. January,
2006;60(1):49-51. https://www.healthestatejournal.com/Print.aspx?Story=767.
Accessed August 3, 2014.

Note Type: Citation
Notes: The Conductometer [advertisement]. Hosp Top. 1952;30(7):63.

Note Type: Citation
Notes: Emerson CI, Jr., designer; Callaghan Hession Corporation, assignee. Combined
meter and switch panel. US Des. patent 183,879. November 11, 1958. https://www
google.com/patents/USD183879. Accessed August 3, 2014.

Note Type: Citation
Notes: Snow JC. Fires and explosions. Anesthesia: In Otolaryngology and
Ophthalmology. Springfield, Illinois: Charles C Thomas; 1972:149.

Note Type: Citation
Notes: Weston Electrical Instrument Corporation. FTL Design History of Technology
website. https://weston.ftldesign.com/. Accessed August 3, 2014.

Note Type: Citation
Notes: Weston: the company and the man. Weston Meter website. https://www.westonmeter
org.uk/thecompany.htm. Accessed August 3, 2014.

Note Type: Physical Description
Notes: One ohmmeter for testing electrical resistance of staff, flooring and
equipment in the operating room; The back of the meter is exposed; At the top
of the front of the meter is the needle-dial face; The curved scale is marked
from 0 to infinity; The scale is also color coded; From 0 to approximately 25
000 the scale is yellow; From 25,000 to 1,000,000 the scale is green; From 1,
000,000 to infinity the scale is red; The following manufacturer markings are
printed below the scale: “[In small letters] WESTON [new line] CONDUCTOMETER
[new line] MODEL UL 90-500 A [new line] PATENT NO. 183879 [new line]
CONDUCTIVE HOSPITAL ACCESSORIES CORP [new line] AFFILIATE OF [new line]
FEDERAL FLOORING CORP [new line] BOSTON 18, MASS.”; Just below the dial face,
on the left is a metal knob marked, “ZERO ADJ.”; To the right of that a metal
plate is affixed to the front of the meter; The plate bears the logo of the
Underwriter’s Laboratories, Inc. Reexamination Service and the following
text: “110 VOLTS 60 CYCLES 0.15 AMPS [new line] USE STANDARD TEST [new
line] PERIODICALLY TO INSURE [new line] CORRECT OPERATIONS”; To the right of
the plate is a small light bulb; Below the zero knob, plate and bulb, is a
black plastic knob marked FUSE; Below the black knob is a port for a long
lead; To the right of the black knob is an ‘elbow switch’ which is marked
“PERSONNEL TEST LEVER”; To the right of the elbow switch is a metal
depressing switch that is marked “PRESS FOR FLOOR TEST”; Below the depressing
switch is a lever with text above and below it; Text above the lever is “STD.
TEST”, and the text below the lever is “ZERO TEST”.

Note Type: Reproduction
Notes: Photographed by Mr. Steve Donisch, February 11, 2014.

Note Type: Acquisition
Notes: Donated to the WLM by Dennis Doblar; Donation facilitated by Amos J. Wright.

Note Type: Historical
Notes: The Conductometer was used to check conductivity of operating room floors,
equipment and the shoes of personnel as part of protocols that were followed
to prevent the occurrence of electrostatic sparks in operating rooms (ORs).

It was introduced at a time when the importance of preventing static
discharge in ORs had become well recognized. A common static spark could
ignite flammable anesthetic gas mixtures, such as oxygen and cyclopropane or
ether. In order to equalize the electrostatic charge of critical objects in
the OR, including equipment, flooring, patients and personnel, the objects
needed to conduct an electric current relatively well. Ohmmeters, like The
Conductometer, measured the resistance of materials to the flow of an
electric current. Objects and materials with too much resistance were not
allowed in the OR.

This meter was installed in the wall near an entrance to the OR, and was
connected to conductive flooring or a metal plate on the floor in front of it
When anesthesiologists or other personnel tested themselves, they touched an
elbow to the large metal switch and read the dial. The dial has a numerically
incremented scale as well as color coding for easy reading. Twenty foot leads
with electrodes could be plugged into the meter for periodic testing of
flooring and equipment.

The Conductometer was made by the Conductive Hospital Accessories Corporation
of Boston using Weston Electrical Instrument Company components. Weston was
well recognized for making quality electrical devices. Conductive Hospital
Accessories Corporation applied to trademark “The Conductometer” in 1950, and
applied for a design patent in 1956. Both were granted.

Note Type: Publication
Notes: Brown TC. Farewell! flammable agents – ether and cyclopropane. Paediatr
Anaesth. 2013;23(2):195-196.

Note Type: Publication
Notes: Franco A, Diz JC, Cortés J, Alvarez J. Fires and explosions with anaesthetics
Br J Anaesth. 1995 Dec;75(6):821-822. https://bja.oxfordjournals.
org/content/75/6/821.long. Accessed August 3, 2014.

Note Type: Publication
Notes: Horton JW, Carter H, Finnegan JB, etc.; Conference Committee on Operating
Room Hazards. Recommended safe practice for the use of combustible
anesthetics in hospital operating rooms. Anesthesiology. September,
1941;2(5):580-586. https://journals.lww.
com/anesthesiology/Citation/1941/09000/RECOMMENDED_SAFE_PRACTICE_FOR_THE_USE_
F.15.aspx. Accessed August 3, 2014.

Note Type: Publication
Notes: MacDonald AG. A short history of fires and explosions caused by anaesthetic
agents. Br J Anaesth. 1994;72(6):710-722.

Note Type: Publication
Notes: National Fire Protection Association Committee on Hospital Operating Rooms.
Recommended safe practice for hospital operating rooms. Boston: NFPA; 1949.
NFPA; no. 56.

Note Type: Exhibition
Notes: Selected for the WLM website.