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Gas detection indoors: how to use sampling pumps: 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 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

An Example of Use of a Draeger pump and Dräger 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.

Warning: About Selecting the Proper Dräger (or other brand) Gas Detection Tube

Gas Detection Tube and Gas Pump Must be Compatible

Colorimeteric gas detection tubes produced by different manufacturers are not necessarily interchangeable among gas detection pumps. Be sure that the gas detection tube you are using is one recommended for use with your gas detection pump - check both the gas detection pump manufacturer's instructions and the gas detection tube manufacturer's specifications.

For example, as we were informed in May 2008 by Nextteq Gastec^TM detection tube distributor in the U.S., Gastec tubes that are currently available are not intended for use on the Sensidyne^TM gas detection pump.

At one point in time, Sensidyne had the contract for Gastec tubes and lost it due to rebranding.  The tubes they sell now are Kitagawa tubes, not Gastec.  We don't want to confuse anyone out there that they can use a Gastec tube with the Sensidyne pump.  The Gastec tubes are not calibrated to work with a Sensidyne pump and therefore, the reading could be incorrect and prove fatal in some cases.

Gas Detection Tube Must Be Properly Sensitive to the Anticipated Concentration of Gases Being Investigated

Be sure to select gas detection tubes designed to detect the proper gases being screened in a building, and also to select the gas detector tube which is calibrated to detect gases at the proper level of concern. The detection of many gases is supported at varying levels of sensitivity.

Selecting a gas detection tube which is not sensitive enough may result in failing to detect the presence of the target gas. Selection of a gas detection tube which is too sensitive may result in inability to accurately detect the actual level of gas which is present since the tube will become saturated before the actual gas level has been recorded.

Questions & Answers regarding this article

Questions & answers about how to use gas sampling pumps to test for and measure the level of toxic or other gas contaminants in buildings.

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
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• Additional technical contributors & reference sources for this article are listed below.

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
  GAUGE, REFRIGERATION PRESSURE TEST
  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
• Dräger MSDS for Dräger CH25301 Air Current Tubes, Page 1 of 2.
  Dräger MSDS for Dräger CH25301 Air Current Tubes, Page 2 of 2.
  Watch out: the Dräger air current tube or "smoke tube" # CH16631 produces a sulfuric acid gas sulfuric acid H₂SO₄ /SO₃ that is dangerous to life and is highly corrosive. Take a look at our copy of the Dräger MSDS for their CH25301 Air Current Tubes. We stored this MSDS in the box with the rubber bulb and tube cutter provided by Dräger. These air current monitoring tubes are provided with rubber caps so that the tube can be "stopped" or shut down when not in use. But the sulfuric acid was so corrosive that it not only caused the rubbger caps to disintegrate, it actually "burned" or oxidized our copy of the MSDS paper form!

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

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
• Air Pollution Toxicology: APTI Course SI:300, Introduction to Air Pollution Toxicology, US EPA Air Pollution Training Institute, Environmental Research Center, Research Triangle Park, NC 27711, Sept. 1993, web search 08/28/2010, original source: http://yosemite.epa.gov/

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
• CCSP, 2008: Analyses of the effects of global change on human health and welfare and human systems. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. [Gamble, J.L. (ed.), K.L. Ebi, F.G. Sussman, T.J. Wilbanks, (Authors)]. U.S. Environmental Protection Agency, Washington, DC, USA. Web search 08/28/2010, original source: http://nepis.epa.gov/
• 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
• Health Effects of Carbon Dioxide - see "National Advisory Committee for Acute Exposure Guideline Levels (AEGLs) for Hazardous Substances; Proposed AEGL Values, Federal Register Document", http://www.epa.gov/EPA-TOX/2002/February/Day-15/t3774.htm note that these are proposed guidelines
• Carbon Dioxide CO2: Geologic Sequestration Health Effects: "Vulnerability Evaluation Framework
  for Geologic Sequestration of Carbon Dioxide", US EPA, EPA430-R-08-009, July 2008, web search August 2010,original source: http://www.epa.gov/climatechange/emissions/downloads/VEF-Technical_Document_072408.pdf
• Carbon Dioxide CO₂: Geologic Sequestration, U.S EPA, web search 08/28/2010, original source:
  http://www.epa.gov/climatechange/emissions/co2_gs_tech.html
  • GTSP, 2006: Carbon Dioxide Capture and Geologic Storage: A Core Element of a A Global
    Energy Technology Strategy to Address Climate Change (PDF, 37 pp., 6.05 MB, About PDF).
    April 2006, JJ Dooley et al. Global Energy Technology Strategy Program (GSTP)
  • IPCC, 2005: Special Report on Carbon Dioxide Capture and Storage, Special Report of the
    Intergovernmental Panel on Climate Change [Metz, Bert, Davidson, Ogunlade,
    de Coninck, Heleen, Loos, Manuela, and Meyer, Leo (Eds.)]. Cambridge University Press, The
    Edinburgh Building Shaftesbury Road, Cambridge CB2 2RU England
    
• Carbon Monoxide Gas Toxicity hazard levels, poisoning symptoms, & testing
• Fluorine, Its Compounds, and Air Pollution,: a Bibliography with Abstracts, US Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, December 1976. Web search 08/28/2010, original source: http://nepis.epa.gov.
  NOTE: because the EPA's original source of this document in PDF format is damaged we have created a text image file, converted to a new PDF for readability.
• 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.
• Greenhouse Gas Overview: Carbon Dioxide: U.S. EPA, web search 08/28/2010, original source:
  http://www.epa.gov/climatechange/emissions/co2.html
• Nitrogen Oxides: Air Quality Criteria for Oxides of Nitrogen, Vol III of III, US EPA, EPA600/8-91/049cF, August 1993, web search 08/28/2010, original source: http://nepis.epa.gov [Large PDF 25MB]
  Key chapters in this document evaluate the latest scientific data on (a) health effects of NOx measured ill laboratory animals and exposed human populatIOns and (b) effects of NOx on agricultural crops, forests, and ecosystems, as well as (c) NOx effects on visibility and nonbiological materials. Other chapters describe the nature, sources, distribution, measurement, and concentratiOns of NOx m the environment These chapters were prepared and peer reviwed by experts from various state and Federal government offices, academia, and private industry for use by EPA to support decision makIng regarding potentIal risks to public health and the enVIronment Although the document IS not intended to be an exhaustIve literature reVIew, It IS intended to cover all the pertinent literature through early 1993
• 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 or Sensidyne, and 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. All of these instruments, their applications, and sensitivities (minimum detectable limits) for specific gases are described in our Gas Sampling Plan online document.
• Sulfur dioxide & other Oxides: Air Quality Criteria for Particulate Matter and Sulfur Oxides, Vol. III, US EPA, Environmental Criteria and Assessment Office, Research Triangle Park NC 27711, Dec. 1982, EPA-600/8/2-029c. Web search 08/26/2010, original source: http://nepis.epa.gov [large PDF]
• Radon Gas U.S. EPA Radon level maps, web search 2005, original source: http://www.epa.gov/iaq/radon/zonemap/zmapp33.htm
• "Table Z-1 Limits for Air Contaminants, 1910.1000 Table Z-1" OSHA standard for air contaminant limits (http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9992) - includes for CO2, Carbon dioxide.........| CAS No. 124-38-9 | 5000 ppm | 9000 mg/m3 limits for carbon dioxide as an air contaminant.
• GASES, EXPOSURE, TESTING Toxic Gas Exposure Hazards and Test Protocols including links to our toxic gas exposure screening and gas testing protocols.
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