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Guide to the Drager Gas Pump - How to Select & Use Gas Detector Tubes InspectAPedia®  -     Recommendations for gas measurement instruments, gas detector tubes, Draeger & Gastec, Komyo How gas detection tubes work How to select & use gas detection tubes Guide to Use of a Drager pump or Sensidyne pump and colorimetric gas detection tubes

This document discusses the Draeger or Drager gas testing pump and gas detection tubes as tools and methods used to test for the level of toxic and other gases in buildings and in outdoors.

In related documents we give references and explanation regarding toxicity of several of the most common indoor gases, based on literature search and obtained from the U.S. government and expert sources.

This text may assist readers in understanding these topics. However it should by no means be considered exhaustive. Seek prompt advice from your doctor or health/safety experts if you have any reason to be concerned about exposure to toxic gases. © Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

© Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

An Example of Use of a Drager pump and Drager Colorimetric Gas Detection Tube (to measure the level of CO₂)

Shown at the top of this page is is our Draeger bellows-type gas sampling pump. This instrument accepts a remarkably wide range of colorimetric gas detection tubes offered by Drager, and includes a counter to count pump strokes. As we explained at the beginning of this article, there is a variety of gas detection pumps available for use with gas detection tubes such as we describe just below, including easy to use, accurate, and quality instruments from Gastec, Sensidyne, as well as Drager and other manufacturers.

The photo below shows a Drager colorimetric gas detection tube (also called a "color detector tube") used to test levels of a very wide range of specific gases in air. In an indoor air test (in our laboratory) this particular detector was not being used to measure oxygen, but rather carbon dioxide.

As the blue-stained portion of the tube shows, this tube detected that the CO₂ level was about 600ppm which is typical of indoor air and is an acceptable and safe level.

Colorimetric gas detection tubes and how they work

Colorimetric gas detection tubes such as those sold by Drager (or Draeger), Gastec, (two that we use predominantly) and by Kitagawa, and pumps from Drager, Gastec, Komyo Rikagaku Kitagawa, and RAE all work on a similar principle: a measured volume of gas (or air) is drawn through a tube which contains chemicals which change in color in response to the presence of a specific target gas (or range of gases) present in the sample.

By knowing the volume of gas or air sampled, the amount of color change read on a linear scale on the colorimetric gas detection tube can be translated into a very accurate measurement of level of gas present, described in percentage of the total air or in parts per million (PPM).

Well it's almost that simple but as we mention in more detail below, you may need to make adjustments for temperature and you may need to watch out for the presence of other gases or chemicals which can interfere with gas detector tube operation.

How a Colorimetric gas detector tube is used

Colorimetric gas detection tubes are sold and distributed in the U.S., Latin America, Asia, and Europe primarily by

• Drager (or in some spellings and literature, Draeger),
• Gastec (two that we use predominantly)
• Kitagawa.
• Komyo
• Rikagaku
• RAE
• Sensidyne

To select the appropriate gas detection tube you need to know what gas or gases is/are to be detected, and at what probable concentrations the gas may be present, or at what level of exposure the test is to be conducted.

NIOSH and other agencies publish specific test parameters that industrial hygienists use for industrial testing for the presence of gases in buildings or outdoors.

Check with the gas tube supplier: A building inspector, IAQ inspector, hygienist, building authority, or fire department who have the appropriate training and experience to perform these tests but who are uncertain about which detector tube to purchase should take advantage of the expert chemists and hygienists employed by the gas detector tube companies by calling for advice. Using a color-changing gas detector tube (colorimetric) is simple: the tube and the instruction sheet are removed from the package.

Read the gas sampling tube instructions: The gas sampling tube instruction sheet may give various numbers of pump strokes or test air volume to be sampled depending on the level of detection needed. (More pump strokes = more air = a more sensitive test.) The ends of the glass tube are broken off using a special cutter provided by the manufacturer of the tube.

Connect the gas sampling tube to the gas pump: The "outlet" end of the detector tube is inserted into the gas collecting pump. The "inlet" end of the tube is exposed to the air to be tested, and the pump is operated for the required number of strokes before looking for a color change on the tube's gas concentration scale. The documentation with each gas detection tube will describe the chemistry of the tube, its accuracy, its calibration, and the color change for which the user is to check.

Effects of temperature on gas level readings

The chemistry and thus the sensitivity and ultimate gas concentration reading shown by a colorimetric gas detection tube may be affected by temperature, it is important to read the temperature data in the gas detection tube specification sheet included with the particular gas detection tube being used. A Gastec gas sampling pump is available which includes a "thermal ring" which can provide this important data at the time that a measurement is obtained.

Effects of other chemicals and gases on gas level readings

The gas detection tube instructions may also list other gases which, if present, can affect the accuracy of the test. The gas sampling tubes shown here were used to test for the presence of perchlorethylene and show what the tubes look like before and after the sealed end is snapped off.

The chemistry and thus the sensitivity and ultimate gas concentration reading shown by a colorimetric gas detection tube may therefore be affected by other gases or chemicals present in the location being measured.

For this reason it is also important to read the characteristics of the gas detector tube being used, and if there is risk of interference from other gases or chemicals it may be necessary to amend the test procedure, perhaps also including tests for the presence or level of these confounding gases. However while it may be a real problem in gas measurements in industrial environments, in residential settings we have rarely encountered this issue.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

CARBON MONOXIDE - CO
CARBON DIOXIDE - CO₂
OXYGEN - O₂
GAS MEASUREMENT TOOLS
  Use of a Drager pump
  How Colorimetric gas detection tubes work
  Using the TIF 8800 Gas Detector
  Using the TIF 5000 Gas Detector
  Warnings re instruments for detection of gases
  Warning: choose the right tube for gas detection

• Jennifer Moore, Sales Administrator, Nextteq, LLC, Tampa FL, www.nextteq.com 813-249-5888. Nextteq is the master Distributor for Gastec in the United States. According to the company's website, Gastec Gas Sampling Pumps are the industry’s first and only pumps to provide on-the-spot measurement of ambient temperature. [Private email, JM to DF 5/23/08]
• "Choosing and Using a Carbon Monoxide CO Monitor," Dan Friedman, The ASHI Technical Journal, Vol. 2 No. 1, July1991
• "Heat Exchanger Testing, Who's Right?" Dan Friedman, The ASHI Technical Journal, Vol. 2 No. 1, July1991
• "Case History: LP Gas Leak - Using the TIF 8800," Dan Friedman, The ASHI Technical Journal, Vol. 2 No. 1, July1991
• Chimneys, Flues, Woodstoves & Fireplaces: Safety Concerns, safe and proper venting of combustion gases, carbon monoxide hazards

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
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More Information on Building Diagnostic Inspections and Repairs

Toxic Gas Exposure Hazards and Test Protocols including links to our toxic gas exposure screening and gas testing protocols.

Gases: Toxic gases, indoor exposure levels, testing, identification

• A Toxic Gas Testing Plan: A Gas Sampling Plan for Residential and Commercial Buildings lists some of the toxic indoor gases for which we test, depending on the building complaint and building conditions
• Gas Exposure Hazard Levels: for Toxic Gas Exposure to Ammonia, Arsine, Arsenic, Bromine, Carbon Dioxide, Carbon Monoxide, Hydride, Ozone - allowable exposure levels and hazard levels
• Carbon Dioxide Gas Toxicity hazard level, poisoning symptoms, & testing
• Carbon Monoxide Gas Toxicity hazard levels, poisoning symptoms, & testing
• Formaldehyde: US EPA. UFFI (Urea Formaldehyde Foam Insulation) was previously considered a hazard (formaldehyde outgassing). Subsequent research virtually closed concern regarding this material; however formaldehyde appears to remain a health concern for sensitive individuals.
• Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
• Sampling for gases in air such as VOC's, MVOC's, toxic chemicals, and combustion products.
  Unfortunately no single test or tool can detect all possible building contaminants. We use methods and equipment which can test for common contaminants. If the identity of a specific contaminant is known in advance we can also test for a very large number of specific contaminant gases in buildings.
  We use gas sampling equipment provided by the two most reliable companies in the world, Draeger-Safety's detector-tubes and Drager accuro bellows pump, the Gastec cylinder pump and detector-tube system produced by Gastec. We also have used gas detection tubes by Gastec previously marketed for use with Sensidyne pumps but Sensidyne pumps now use Kitagawa gas detection tubes. We also use Sensidyne's Gilian air pump. For broad screening for combustibles and a number of other toxic gases and for leak tracing we also use Amprobe's Tif8850 and 8800, and the TIF 5000 automatic halogen leak detector (for air conditioning and cooling system refrigerant leak detection). All of these instruments, their applications, and sensitivities (minimum detectable limits) for specific gases are described in our Gas Sampling Plan online document.
• Radon Gas U.S. EPA Radon level maps

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