Gas Detection and Respiratory Protection Solutions for Landfill Gases

from the Instrumentation Group at Cross

Draeger-Tubes

Quick, Easy, and Comprehensive Chemical Measurement

Though methane and carbon dioxide are generated in the largest quantities, many other substances can be found in landfill gas.  Hydrogen sulfide (H₂S), a very toxic substance, is also a by-product of decaying organic material.  Various fuels, oils, paints, solvents and other hydrocarbons may end up in the landfill.  Even at these much smaller quantities, these compounds are toxic.  Many of these chemicals give little or no warning through a sense of smell.

The Draeger-Tube system is the most form of gas and vapor measurement in the world.  The system is easy to use, produces quick results, and offers the most comprehensive (over 500) choice of hazards detected.

The Draeger-Tube system consists of glass vials filled with chemical reagents.  The hand operated accuor bellows pump pulls a calibrated amount of air through the tube.  Should the targeted gas or vapor be present, the reagent inside the Tube changes color.  A longer the length of color change is produced when more of the targeted chemical is present.  A scale printed on the tube indicates the amount of gas or vapor present.  

Landfill Gas: Carbon Dioxide

Measuring toxic gases generated in a landfill

Large quantities (35-50 %Vol.) of carbon dioxide (CO₂) are produced in by decomposition of organic materials in a landfill. CO₂  poses two safety concerns.  First it will displace the available oxygen (O₂) for proper respiration.  However, it is also a toxic gas, able to cause sudden and serious effects like dizziness, impaired judgment, or even unconsciousness from a relatively short exposure to levels found in a landfill.

The Draeger X-am 7000 Monitor can be equipped with and Infrared (IR) sensor for measuring 0-5.0 %Vol. and/or 0-100 %Vol. of CO₂ allowing it to measure in both the toxicity range and higher levels experienced in landfill operation.  The X-am 7000 Monitor can also be equipped with Methane, O₂, H₂S and CO sensor making it ideal for use in many landfill gas measurement applications.

The versatile monitor can also be equipped with a Photo-Ionization Detector (PID) which can detect and measure toxic amounts of fuels, solvents, paints and other chemicals that mistakenly find their way into a landfill.  All measurements made by the X-am 7000 can be recorded on an internal datalogger for documentation purposes.

Landfill Gas: Methane

Monitor for Safety and Process Applications

The anaerobic decomposition of organic materials in a land fill produces large quantities (55-65 %Vol.) of methane (CH₄) in a low oxygen background.  Additionally, relatively large quantities of gases like carbon dioxide (35-50 %Vol.) and hydrogen sulfide (1000 ppm) may also be present.  This poses problems for conventional gas detectors.  The catalytic oxidation sensors used in most combustible gas detectors requires oxygen to measure methane.  Additionally these higher quantities of H₂S will cause these catalytic methane sensors to lose sensitivity over time.  Most gas detectors are also limited to a measuring range of only 0-100 %LEL (0-5 %Vol.) of methane. 

The Draeger X-am 7000 Monitor can be equipped with an Infrared (IR) based sensor for measuring 0-100 %LEL and 0-100 %Vol. of methane.  Unlike conventional catalytic combustible gas detectors, the IR sensor does not need oxygen to operate and is completely unaffected by sulfur bearing compounds.  The X-am 7000 is ideally suited for making both safety and process style measurements.

The X-am 7000 is completely dust-proof and waterproof (IP-67), even submersion in water does not bother the electronics or sensors.  The integral rubber boot allows this monitor allows this monitor to withstand the most challenging industrial conditions.  The integral rubber boot allows this monitor to withstand the most challenging industrial conditions.  The internal pump can draw a sample from up to 150 ft (45m) away, strong enough to measure deep inside any vent hole or well.  The standard NiMH battery pack will last well in excess of 10 hours continuous usage.

Industrial Grade SCBA

For Maximum Protection

High levels of carbon dioxide and other toxic chemicals can be encountered in a municipal landfill.  There is also the distinct possibility for low oxygen environments.  Both oxygen deficiency and high levels of carbon dioxide and other toxic gases require the highest level of respiratory protection equipment.  The Draeger ProAir Evolution SCBA provides the protection needed in these demanding environments.  This is because our industrial system uses the same high-performance and pneumatic system as our fire fighting unit and is backed with a life time warranty.

The NIOSH certified ProAir Evolution uses an ergonomic and light weight carbon fiber back plate and fully adjustable harness system, providing the user with exceptional safety, maneuverability, and comfort.  Our one-size-fits-all Panorama Nova mask provides a safe and reliable seal to all users.  Lightweight aluminum and carbon fiber air cylinders with durations of 30, 45 and 60 minutes are available.  Compressed airline connections and other accessories are available.

Filtering Respirators

Protection and Comfort

The new Draeger X-Plore Series masks set a new benchmark in fit and comfort in respiratory protection.  The innovative X-guided strap system secures the mask evenly over the face providing an excellent fit while remaining very comfortable.  Three sizes (S, M, L) of masks and a flexible nose seal ensure a proper fit for every type of face.  The X-plore comes in limited use (3300) and re-usable (3500) half-mask styles.  The full face (5500) mask provides a higher level protection when needed.  To meet a wide range of industrial applications, Draeger offers a full line of NIOSH approved cartridges and filters with their exclusive two-point bayonet connector.

Draeger X-Plore 5500 Twin Filter Respirator

With an exclusive multi-layer filtering design, the Piccola provides the best particulate filtration efficiency with the lowest breathing resistance in a disposable filtering face mask.  Draeger’s patented SynSafe material uses both mechanical and electrostatic filtration principles for the ultimate filtering efficiency.  It is extremely lightweight and comfortable to wear with a soft humidity resistant inner lining.  The foldable mask designs allows for easy storage in your pocket and repeated use through the workday.  The X-plore 1300 masks are available in a NIOSH approved N95 and R95 types, with or without exhalation valves. 

For assistance with Draeger Safety selections, contact the experts at BuyDraegerSafety.com

866.905.9793

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Introduction to Gas Measuring with Draeger Gas Detection Instruments

From Dan Hines / Instrumentation Group at Cross

Gas measurement serves as a technical aid and an assessment of the concentration is only possible with a gas measurement device. To determine the hazard potential of a gas it is necessary to measure its concentration and to consider the duration of exposure and other parameters such as the type of work being performed.

Natural, ambient air is chemically a gas mixture that consists of 78 % nitrogen, 21 % oxygen 0.03% carbon dioxide as well as argon, helium and other rare gases in trace concentrations. In addition there is water vapor, e. g. humidity. If the concentrations of the components change, or a foreign gas is added, we no longer have natural air. When these changes occur, the potential for adverse health effects exist.

The spectrum of other so-called air components can be extremely broad. It can range from
the pleasant fragrance of a good perfume to the over powering stench of hydrogen sulfide.
Likewise, the hazard of each “air pollutant” varies considerably. The type of substance, its
concentration and duration of occurrence, as well as probable synergistic effects with certain gas compounds must all be considered. In addition, there are many air pollutants which cannot be perceived by human senses because they are colorless and odorless (e. g. carbon monoxide).

If the composition of the natural air changes in any way, it should be tested, to determine
the substance which caused this change. Even substances with distinctive odors cannot be reliably assessed with the aid of the olfactory nerve in the nose. The olfactory nerve can become desensitized after a certain period of time or repeated exposure, making it impossible to smell even immediately dangerous concentrations. After a few hours we do not even perceive the pleasant fragrance of our own perfume and high concentrations of hydrogen sulfide escape from the sense of smell even after a very short while.

Subjectively, one persons sense of smell may be more sensitive to certain air pollutants
than others. In many cases substances are noticed in very low concentrations which, even after a long-term exposure do not necessarily cause adverse health effects. In general the sense of smell is sufficient in determining the presence of air pollutants, but the need exists for an objective gas analysis method. Gas measurement serves as a technical aid and an assessment of the concentration is only possible with a gas measurement device. To determine the hazard potential of a gas it is necessary to measure its concentration and to consider the duration of exposure and other parameters such as the type of work being
performed.

An important prerequisite to determining the potential of any gaseous air pollutants is the
determination of the concentration with a suitable gas measurement device. The kind of
device to be used depends on which gases have to be measured and how often. Much to
the dismay of both the user and the manufacturer, there is no universal instrument which
measures all gases or vapors. The variety of substances is too wide for a single technique
to measure all possible air pollutants. The more chemically complex a substance is, the more complex the gas measurement technique.

It may be that more than one measurement device or measurement method may be
employed, each based on different operational principles. The instrumentation industry
offers various devices for this purpose which can be used, individually or in combination on
the measurement task:

- flame ionization detectors
- photo ionization detectors
- gas chromatographs
- infrared spectrometers
- UV-VIS photometers
- warning devices for explosion hazards
- Draeger Tubes
- Draeger Chip-Measurement-System
- laboratory analysis in conjunction with sampling tubes or gas wash bottles (impinger)
- mass spectrometers
- substance selective instruments with e. g. electrochemical sensors

The choice of which monitor or measurement method to use depends upon the objective.
The user must evaluate the situation and determine which substances to measure, how often, etc. Each of the above mentioned devices and methods have advantages and limitations. There is no universal monitor for all possible scenarios. For the selection of a suitable measuring device and to support the user in solving measurement problems, Drager Safety AG & Co. KGaA offers competent know-how and technical assistance. The customer / employer should carefully train the user / employee on the use of their measurement device. Any use of the measurement device without receiving prior comprehensive training can be permitted by the customer / employer to the user / employees, at the customer / employees own risk.

Photo and flame ionization detectors are distinguished by short response periods but they do not offer substance selectivity. Gas chromatographs, infrared and UV-VIS photometers are very versatile but on the other hand they are comparatively expensive and require a specialist to calibrate the devices and interpret the readings correctly. Warning devices for explosion hazards like the Drager X-am 5000 are equipped with catalytical sensors to determine explosion levels of combustible gases and vapors. They are not designed to measure lower concentrations and thus are not suitable for this task.

Draeger-Tubes with direct reading colorimetric indication have many applications. Approximately 500 different substances can be measured with Draeger-Tubes. Limited selectivity and the fact that Draeger-Tubes are usually capable of only being used a once may present a disadvantage. If repeated measurements of the same substance are to be performed daily, a measurement device like the Draeger Pac 7000 CO with its electrochemical sensor for the measurement of carbon monoxide is more economic than Draeger-Tubes.

When complex mixtures (e. g. solvent mixtures), are present, usually only a laboratory analysis will suffice. The prerequisite is that the contaminated air is trapped in a sorbent sampling tube like silica gel or activated charcoal.

After collecting the sample, analysis is performed in the laboratory with gas chromatographic methods, or sometimes by the combination of gas chromatography / mass spectroscopy. Laboratory procedures of this kind offer particularly high selectivity, but the analysis devices are very expensive, requiring high maintenance costs and operation by specialists.

Regardless of the gas measurement device or what analysis procedure is used, it is essential that the contaminant of interest be identifiable and measurable. Apart from a few exceptions in process monitoring, it is very unlikely that concentrations of other substances can be determined by subtracting the concentration of the gas which can be identified. For example, if the oxygen concentration is below the 17 or 19.5 Vol. % limit, it cannot be said which substance has displaced the oxygen without further investigation. In the case of very high carbon dioxide concentrations there is the danger of suffocation; likewise if there is a leak in a gas pipeline the presence of methane poses an explosion hazard. Other contaminants present in the ppm range would not influence the oxygen measurement enough to alert anyone to a potential hazard. Since many of the occupational exposure limits are in the range of 1 ppm, the measurement by difference technique is typically inadequate.

Before each measurement an assessment of the situation should be made as to what contaminants are in question, at what locations, at what times, and so forth, according to established safety procedures. Monitoring according to established safety guidelines will helpensure safety in the workplace and effective use of monitoring equipment.

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Company Profile

BuyDraegerSafety.com is an eCommerce Business Unit of the Instrumentation Group at Cross. We are based East of Atlanta, GA in Conyers. Our focus is Industrial Sales of Process Measurement, Safety Instrumentation and Control equipment. We are specialists in hard to solve flow, level, analytical and safety applications.