14
Other Maintenance. The time-weighted average (TWA), short-term exposure limit (STEL), and peak
readings can each be "cleared." When any summary reading is cleared, its value is reset to zero and its
time-related setting is also reset to zero.
Note: The peak readings and the data log readings are stored independently of one another; therefore, clearing the peak reading
does not affect the data log. Powering the instrument off or changing its battery does not affect the peak reading. These checks
and balances help promote operator safety and serve to contain the peak readings in a "black-box" manner. In the event of a
gas-related incident, this black-box record can be useful to the safety team or an investigator.
Recommendations
Industrial Scientific Corporation minimum frequency recommendations for each procedure are summarized
in the table below. These recommendations are based on field data, safe work procedures, industry best
practices, and regulatory standards to help ensure worker safety. Industrial Scientific is not responsible for
setting safety practices and policies.
Industrial Scientific also recommends a daily bump test for any instrument that is not operating in
DualSense
®
mode. This includes the Tango
®
TX1 when it is operating with only one working sensor.
When two redundant, working sensors are installed in the Tango TX1, the instrument is operating in
DualSense mode and the probability of sensor failure–compared with a single-sensor instrument–is
diminished regardless of bump test frequency.
When two sensors of the same type are operating in DualSense mode and one sensor needs to be
replaced, replace both sensors at the same time.
The frequency of bump testing for DualSense instruments, between monthly calibrations, is best
determined by a company's safety policies. These policies may be affected by the directives and
recommendations of regulatory groups, environmental and operating conditions, instrument use patterns
and exposure to gas, and other factors.
Table 2.1 Industrial Scientific recommended practices, Tango TX1
Recommended minimum frequency
Before first use and as needed thereafter.
Calibration
a
Before first use and monthly thereafter or in accordance with local or national rules, with the
maximum interval not exceeding 6 months.
Bump test
b and c
Immediately following each calibration.
d
a
Between regular calibration procedures, Industrial Scientific also recommends that calibration be performed following each of these
incidences: the unit falls, is dropped, or experiences another significant impact; is exposed to water; fails a bump test; or has been
repeatedly exposed to an over-range (positive or negative) gas concentration. Calibration is also recommended after the installation of a
new (or replacement) sensor.
b
When only one installed sensor is operational, the instrument is not operating on DualSense® technology, and a daily bump test is
recommended.
c
A bump test must be performed daily for compliance to EN 45544-1. Workplace atmospheres — Electrical apparatus used for the direct
detection and direct concentration measurement of toxic gases and vapors, Part 1: General requirements and test methods.
d
The Tango TX1 self-test is performed automatically during the start-up process. It can be user-initiated from operation mode.
Note: The use of calibration gases not provided by Industrial Scientific may void product warranties and limit potential liability claims.
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