Gas Detection Tubes Limitations

Limitations: Tubes and pumps are ______-specific

No alarm system, therefore not recommended for ______ monitoring

Dependent upon operator’s interpretation of ______

Application can require longer periods of time in atmospheres for results to ______ (up to several minutes)

Many ______-sensitivities

Range of application is dependent on ______ and temperature

Multi-gas detectors use separate sensors for ______ and combustible atmospheres

Accidental power-off protection: requires the power-off button to be held continuously for at least 3-5 ______

Portable field docking stations are also available for several models to facilitate ______

More accurate than colorimetric tubes - accurate within +/- ______%

Gases recognized are ______-specific

Environmental conditions such as temperature, humidity, dust, dirt, and rough handling all contribute to premature sensor ______

During underground exploration, gas testing should be performed at ______ or where conditions change.

Sampling at the top, middle, and bottom of a space must be done in accordance with ______ specifications.

Sample every 1–2 metres (3–7 ft) due to the weights of gases. Some are lighter than air (methane), some are slightly lighter (carbon monoxide), and some are heavier than air (______).

Bump Testing and Calibration The most important elements of gas detector maintenance are function (“bump”) testing and ______.

Manufacturers recommend that a bump test be performed on every instrument prior to each day’s ______.

Any time an instrument fails to respond properly during a bump test, a full ______ should be completed successfully prior to use.

Colorimetric (Tube-style) indicators measure more than 200 organic and inorganic gases and vapours in the __________

The sealed glass tubes are filled with a granular material coated with a chemical that changes colour when it reacts to a particular gas or __________

Before Use: Refer to manufacturer’s instructions for the particular tube type. Perform a pump leak test. Ensure the direction arrow is oriented toward the __________

Operation: A portable pump draws a known volume of air through a detector tube designed to measure the concentration. The colour Drager (L) and Gastec (R) colorimetric tubes change is then read on a scale printed on the __________

Measurement accuracy, limits of detection, interferences, temperature/humidity, shelf life, time period for which the colour stain is stable after __________

Tube Storage and Shelf Life: Tubes have a shelf life. These expiration dates are printed on the box. Store properly by avoiding excessively low or high temperatures and direct __________

There are four categories of hazardous atmospheres: Toxic, Oxygen deficiency/Asphyxiating gases, Explosive/flammable gases or vapours, and ______

Intrinsic Safety is a design applied to electrical equipment and wiring for hazardous locations based on limiting energy, both electrical and thermal, to a level below that required to ignite a specific hazardous atmospheric mixture. All personal protective equipment must be considered before any and all gas testing. Always check that any monitoring equipment or other electrical devices are ______

It is important to select gas detection equipment that fits the specific needs of the incident. Mine rescue gas detection involves the use of direct-reading instruments (DRI). These instruments provide information at the time of sampling, thus enabling rapid ______

Upon completion of the chapter on Gas Detection Instruments, the trainee shall be able to demonstrate competency in what gases could be encountered during an emergency response, selecting monitoring equipment and methods suitable for the incident, and practical skills for an effective gas detection ______

Rescue teams can determine the gases and vapours present in an atmosphere using a few different methods and tools. Intrinsic Safety is a design applied to electrical equipment and wiring for hazardous locations. The technique is based on limiting energy, both electrical and thermal, to a level below that required to ignite a specific hazardous atmospheric mixture. All personal protective equipment must be considered before any and all gas testing. Always check that any monitoring equipment or other electrical devices are ______

Gas Detection Instruments chapter aims to equip trainees with the ability to select monitoring equipment and methods suitable for the incident, what gases could be encountered during an emergency response, and practical skills for an effective gas detection ______