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ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY
ACCURACY vs PRECISION of MEASUREMENTS
AIR CLEANER PURIFIER TYPES
AIR LEAK DETECTION TOOLS
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
ANIMAL or URINE ODOR SOURCE DETECTION
BACKDRAFTING HEATING EQUIPMENT
BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ
BIOGAS PRODUCTION & USE
BLOWER DOORS & AIR INFILTRATION
BOOKSTORE - ENVIRONMENTAL
BUILDING SAFETY HAZARDS GUIDE
CARPETING & INDOOR AIR QUALITY
CHINESE DRYWALL HAZARDS
CHLORINE IN DRINKING WATER
COMBUSTION PRODUCTS & IAQ
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DRAFT MEASUREMENT, CHIMNEYS & FLUES
DUST SAMPLING PROCEDURE
EMERGENCY RESPONSE, IAQ, GAS, MOLD
ENVIRO-SCARE - PUBLIC FEAR CYCLES
ENDOCRINE DISRUPTERS at BUILDINGS
Fireplaces & Woodstove Contaminants
FLAME COLOR, BLUE vs YELLOW COMBUSTION
Formaldehyde Gas Hazard Reduction
GAS DETECTION INSTRUMENTS
GAS LP & NATURAL GAS SAFETY HAZARDS
GAS PRESSURES LP vs NATURAL GAS
HEATING OIL EXPOSURE HAZARDS, LIMITS
HOUSE DUST ANALYSIS
HOUSE DUST COMPONENTS
HUMIDITY CONTROL & TARGETS INDOORS
HYDROGEN SULFIDE GAS
Indoor Air Pollution Book Online CPSC
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
LP & Natural Gas Pressures
GAS LP & NATURAL GAS SAFETY HAZARDS
MOLD ODORS, MUSTY SMELLS
MSDS Material Safety Data Sheets
MVOCs & MOLDY MUSTY ODORS
Museum Artifact Preservation
ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER
OXYGEN - O2
PARTICLE SIZES & IAQ
PESTICIDE EXPOSURE HAZARDS
PLASTIC ODORS-SCREENS, SIDING
PLUMBING SYSTEM ODORS
PVC - VINYL BUILDING PRODUCTS
RADON HAZARD TESTS & MITIGATION
METHANE GAS HAZARDS
SEPTIC SYSTEM ODORS
SMELL PATCH TEST to Track Down Odors
SULPHUR & SEWER GAS SMELL SOURCES
UFFI UREA FORMALDEHYDE FOAM INSULATION
URETHANE FOAM Deterioration, Outgassing
VAPOR CONDENSATION & BUILDING SHEATHING
VENTILATION in BUILDINGS
VINYL Siding or Window PLASTIC ODORS
VOCs VOLATILE ORGANIC COMPOUNDS
WATER ODORS, CAUSE CURE
Safe use of gas leak detector tools: this document outlines warnings for people using gas detection tools and sensors 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.
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OPINION-DF: In 1991, for ASHI, the American Society of Home Inspectors I authored or edited several articles on the use of instruments to test for evidence of dangerous flue gas leaks such as carbon monoxide in residential buildings.
Shown at left, the TIF 8800 combustible gas analyzer, a very sensitive instrument.
We were excited by the possibility of improving the level of safety afforded by a professional home inspection by permitting home inspectors to use instruments to perform simple screening tests for toxic or dangerous carbon monoxide gas leaks. Inspectors were already using the TIF 8800 described above, but that wide spectrum instrument could not focus specifically on, nor give numeric levels of carbon monoxide gas alone.
Quite a few home inspectors rushed to buy and some continue to use any of a variety of excellent and sensitive specialized pocket-sized gas detectors designed to screen specifically for carbon monoxide. Particularly in parts of the U.S. where home inspectors had found that the level of expertise offered by their local gas distribution companies was a bit weak, they were anxious to have a more reliable safety check tool for buildings heated by natural or LP gas.
In my view these articles encouraging the use of carbon monoxide detection instruments in the hands of some of these home inspectors was a disaster.
High Speed Home Inspecting?
Home inspectors who were not technically inclined, home inspectors who were more focused on the bottom line (profit), and inspectors who were looking for a way to simply speed up their inspection while doing less work, simply purchased one of these instruments, turned it on, and left it to check the heating system for CO leakage while they, being efficient and fast fellows, went off to inspect something else.
In other words, some home inspectors stopped inspecting the heating system as thoroughly as they had before relying instead on the instrument to do their work for them. Those inspectors, thinking that their job was done, simply reported that the instrument did or did not detect any carbon monoxide, and they disclaimed further responsibility for the condition of the heating equipment or even for the accuracy of the test they had performed.
What was wrong with this approach of relying on gas detection tools:
In sum, there is a place for and good use for test instruments during building investigation, but they are not and should not ever be a substitute for a careful and thorough visual inspection and history-taking by an expert. Those "high speed" inspectors would have performed a better service for their clients by encouraging them to purchase and install smoke detectors and home-use carbon monoxide detectors than to hasten their inspection by using an unattended CO instrument in the home.
Our article CARBON MONOXIDE - CO includes a photograph of a simple and effective carbon monoxide detector intended for homeowner installation and use.
Gas Tube and Gas Pump Must be Compatible
Colorimetric 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 GastecTM detection tube distributor in the U.S., Gastec tubes that are currently available are not intended for use on the SensidyneTM gas detection pump.
Gas Tube Must Be Properly Sensitive to the 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 detector 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.
How Birdwatching Can Inform Building Environmental Investigations
Gas Detection Measurements Must be Made at the Proper Times
At CO DETECTION OPTIONS we explain that when using any gas detector tool to test inside of the air plenum for flue gas leakage, one critical test time is before the blower fan has come on.
Once the fan begins not only is building air in the plenum diluted, the pressurization of air around the heat exchanger is likely to change the direction of a combustion gas leak.
Our photo illustrates a second point, that there may be evidence of a problem (in this case bird guano or droppings in the building attic) even if the problem source is not visible or not present at the time of inspection. The birds are not home right now, but they've been having a nice time living in the attic of this home.
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 rubber caps to disintegrate, it actually "burned" or oxidized our copy of the MSDS paper form!
Frequently Asked Questions (FAQs) about using gas leak tools and instruments
Questions & answers or comments about how to test for toxic gas leaks, safety procedures & warnings.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
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Technical Reviewers & References
Gases: Toxic gases, indoor exposure levels, testing, identification