Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY
AIR CLEANER PURIFIER TYPES
AIR FILTERS for HVAC SYSTEMS
AIR FILTERS, OPTIMUM INDOOR
AIR LEAK DETECTION TOOLS
AIR LEAK SEALING PROCEDURE
AIR POLLUTANTS, COMMON INDOOR
AIR QUALITY IMPROVEMENT STRATEGIES
AIR TEST FOR MOLD: ACCURACY
AIR TEST SAMPLING CASSETTE STUDY
ALLERGEN TESTS for BUILDINGS
ANIMAL ALLERGENS / PET DANDER
ANIMAL ENTRY POINTS in BUILDINGS
ANIMAL or URINE ODOR SOURCE DETECTION
ASBESTOS CLEANUP COMPANIES
ASBESTOS IDENTIFICATION IN BUILDINGS
ATTORNEYS and EXPERT WITNESSES
BACKDRAFTING HEATING EQUIPMENT
BIBLIOGAPHY for ENVIRONMENTAL HEALTH, MOLD, IAQ
BIOGAS PRODUCTION & USE
BOD WASTEWATER TEST
BLOWER DOORS & AIR INFILTRATION
BLEACHING MOLD, Advice about
BOOK MOLD, Moldy Book Cleaning
BOOKSTORE - ENVIRONMENTAL
BUILDING SAFETY HAZARDS GUIDE
CACTUS FUNGI / MOLD
Carbon Dioxide - CO2
CAR MOLD CONTAMINATION
CARBON MONOXIDE - CO
Carbon Nanotube Hazards
CAR MOLD CONTAMINATION
CARPETING & INDOOR AIR QUALITY
CAT DANDER in buildings
CEILING PAINT TEXTURED ASBESTOS
CEILING TILES, ASBESTOS
CRLL PHONE Radiation Hazards
CHIMNEY INSPECTION DIAGNOSIS REPAIR
CHINESE DRYWALL HAZARDS
CHEMICAL CONTAMINANTS in WATER
CHEMICAL ODOR SOURCES
CHLORINE IN DRINKING WATER
CHLORINE in WATER, HOW TO TEST FOR
CHLORINE IN SEPTIC WASTEWATER
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
CPSC Indoor Air Pollution Book Online Copy
DIRECTORY of MOLD / ENVIRONMENTAL EXPERTS
DIRT FLOOR MOLD CONTAMINATION
DISINFECTANTS & SANITIZERS, SOURCES
DISINFECTING BUILDINGS with BLEACH
DRYWALL MOLD TESTING
DRAFT HOODS - gas fired
DRAFT MEASUREMENT, CHIMNEYS & FLUES
DRAFT REGULATORS, DAMPERS, BOOSTERS
Diethylstilbestrol - DES
DUCT SYSTEM & DUCT DEFECTS
DUST ANALYSIS for FIBERGLASS
DUST, HVAC CONTAMINATION STUDY
DUST SAMPLING PROCEDURE
EMERGENCY RESPONSE, IAQ, GAS, MOLD
EMF MEASUREMENT PROCEDURES
ENVIRO-SCARE - PUBLIC FEAR CYCLES
EXTERIORS of BUILDINGS
FIBERGLASS INSULATION MOLD
Fireplaces & Woodstove Contaminants
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOOR TYPES & DEFECTS
GASES, EXPOSURE, TESTING
GAS DETECTION INSTRUMENTS
GAS EXPOSURE LIMITS & STANDARDS
GLARE, Sunlight/Lighting Control
GLUES ADHESIVES, EXTERIOR CONSTRUCTION
HEATING OIL EXPOSURE HAZARDS, LIMITS
HUMIDITY CONTROL & TARGETS INDOORS
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INDOOR AIR QUALITY METHODS COMPARED
INSULATION INSPECTION & IMPROVEMENT
LEAD POISONING HAZARDS GUIDE
LEED Building Designation & IAQ
LIGHT, GUIDE to FORENSIC USE
LIGHTING, EXTERIOR GUIDE
LIGHTING, INTERIOR GUIDE
GAS LP & NATURAL GAS SAFETY HAZARDS
LEGIONELLA LEGIONNAIRES' DISEASE
METHANE GAS SOURCES
MILDEW in BUILDINGS ?
MOISTURE CONTROL in BUILDINGS
MOLD: A COMPLETE GUIDE to TEST CLEAN PREVENT
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOLD or INDOOR AIR EMERGENCY RESPONSE
MOLD TEST KITS
MOTHS, MOTHBALL ODORS
MSDS Material Safety Data Sheets
MVOCs & MOLDY MUSTY ODORS
NOISE / SOUND DIAGNOSIS & CURE
ODORS GASES SMELLS, DIAGNOSIS & CURE
OIL, HEATING, EXPOSURE HAZARDS, LIMITS
OIL HEAT ODORS & NOISES
OIL SPILL CLEANUP / PREVENTION
OIL TANK LEAK & ODOR CAUSES
OIL TANKS INSPECT LEAK TEST ABANDON REGS
OUTHOUSES & LATRINES
OXYGEN - O2
OZONE for MOLD OR ODORS
PAINTS & COATINGS ODORS IN BUILDINGS
PARTICLE SIZES & IAQ
Particulates & Allergens Indoors
PESTICIDE EXPOSURE HAZARDS
PET ALLERGENS / PET DANDER
PET STAINS & MARKS in BUILDINGS
PET STAINS on WALLS
PLASTIC CONTAINERS, TANKS, TYPES
PLASTIC Plexvent / Ultravent RECALL
PLASTIC ODORS-SCREENS, SIDING
PLUMBING SYSTEM ODORS
PVC - VINYL BUILDING PRODUCTS
RADON HAZARD TESTS & MITIGATION
SAFETY HAZARDS GUIDE
SAFETY HAZARDS & INSPECTIONS
SEPTIC & CESSPOOL SAFETY
SEPTIC SYSTEM ODORS
SEPTIC TREATMENTS & CHEMICALS
SEWAGE & SEPTIC CONTAMINANTS
SEWAGE CONTAMINATION in BUILDINGS
SEWAGE CONTAMINANTS in FRUIT / VEGETABLES
SEWAGE EJECTOR / GRINDER PUMPS
SEWAGE NITROGEN CONTAMINANTS
SEWAGE PATHOGENS in SEPTIC SLUDGE
SEWAGE BACKUP, WHAT TO DO
SEWAGE BACKUP TEST & CLEANUP
SEWAGE BACKUP PREVENTION
SEWER LINE REPLACEMENT
SEWER GAS ODORS
SEWER GAS ODORS in COLD WEATHER
SMELL PATCH TEST to Track Down Odors
SOUND CONTROL in buildings
STAIN & BIODETERIORATION AGENT CATALOG
STAINS on & in BUILDINGS, CAUSES & CURES
STAIRS, RAILINGS, LANDINGS, RAMPS
STONE CLEANING METHODS
STONE VENEER WALLS
STRAW BALE CONSTRUCTION
STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
STUCCO PAINT FAILURES
STRUCTURAL DAMAGE PROBING
STRUCTURAL WOOD ASSESSMENT
SULPHUR & SEWER GAS SMELL SOURCES
TEST KITS for DUST, MOLD, PARTICLE TESTS
Thermal Expansion Cracking of Brick
THERMAL EXPANSION of HOT WATER
THERMAL EXPANSION of MATERIALS
THERMAL IMAGING, THERMOGRAPHY
THERMAL IMAGING MOLD SCANS
THERMAL MASS in BUILDINGS
THERMAL TRACKING & THERMAL BRIDGING
TRAPPED MOLD BETWEEN WOOD SURFACES
TRIM, INTERIOR INSTALLATION
TRUSS UPLIFT, ROOF
TRUSSES, Floor & Roof
UREA FORMALDEHYDE FOAM INSULATION, UFFI
URETHANE FOAM Deterioration, Outgassing
UV LIGHT BLACK LIGHT USES
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VAPOR BARRIERS & HOUSEWRAP
VAPOR CONDENSATION & BUILDING SHEATHING
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL Siding or Window PLASTIC ODORS
VOCs VOLATILE ORGANIC COMPOUNDS
WASTEWATER TREATMENT BASICS
WATER ODORS, CAUSE CURE
WATER TANK SAFETY
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TEST CHOICES & WATER TEST FEES
WATER TREATMENT EQUIPMENT CHOICES
WATER, WELLS, WATER TANKS: TESTING GUIDE
WETLAND SEPTIC SYSTEMS
WINDOWS & DOORS
WORLD TRADE CENTER 9-11 DUST PHOTOS
How to use a black light or UV light: this article describes uses of UV light in building investigations. We describe the use of a black light, UV light to screen buildings for pet urine or urine from humans or other animals even where no stains are visible in or around buildings.
We also use UV light to screen buildings for other body fluids, including blood (see BLOOD in ART WORKS, TESTING FOR). Small black lights are available from pet supply stores, art supply stores, and forensic and police equipment suppliers and are generally inexpensive.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
One of the most effective uses of UV light in building investigations is the tracking down of odors & contaminants such as urine, urine stains, or odors & allergens from pets, rodents, or other animals, even human. But because a large number of materials will fluoresce under a black light, we need to give some thought to how to interpret what our UV light is actually revealing when we shine it on a building material or surface. Also see LIGHT, GUIDE to FORENSIC USE.
Watch out: While in our OPINION the ordinary use of UV flashlights and UV lamps for purposes of building or environmental inspection or security screening constitutes no unusual health risk, excessive or inappropriate exposure to high levels or protracted durations of ultraviolet light may be unsafe and possibly carcinogenic. A much cited study indicated that "The risk was not significantly or consistently raised for exposure to fluorescent lights at home or at work."
Question: using a black light to track down iridescent powder substance in carpet
I discovered this as I was using a black light to look at some iridescent fishing lures the other evening. I noticed several yellowish glowing spots in the bedroom carpeting. This caused me to check the living room and dining area carpeting, where I found the same type yellowish glowing areas.
The areas are ‘dusty’ in appearance and appear in a variety of patterns. I further checked the baseboards, some less trafficked areas behind the bed and other furniture, and the furniture and counter surfaces and found the same yellowish areas.
It quickly returns after cleanup. These areas do not appear in normal daylight, but do appear under a black light. Of course, the iridescence is greater at night when I can darken the apartment, but it can be seen under the black light during the day. It should also be noted that my feet and toe nails show the same yellowish glow. I walk around bare footed in my apartment.
Bathing removes the powdery substance from my feet and my physician says I have no mold or other infection in my feet. It should also be noted that when I purchased my black light over a year ago, for fun I checked out my apartment and carpeting for mold, pet urine, etc. and found none.
I will be checking with a local 'home' inspection type company next week regarding this.
Thanks for you help, - J.N. 07/21/2012
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem concerning building contaminants or conditions. That said, there are a number of materials that will fluoresce under an ultraviolet UV or "black light", even clean white sheets appear to do so.
At above left we illustrate our darkroom test set-up for light source comparisons, in this case with a "blacklight" or UV ultraviolet light bulb (Woods lamp) installed in our test fixture using a 13W bulb produced by Feit Electric (photo at left).
You may have spotted pet urine stains and pet urine-contaminated dust from carpeting, or insect fragments, or possibly some urea-containing materials.
The observation that many materials contain fluorescent molecules means that interpreting light or presumed stain patterns needs to be done with some sense of location, age, material, and context.
We should explain the mechanism of fluorescence before listing things that fluoresce under black light or really UV light: According to a nice Q&A by the U. Illinois physics department, although infra-red and ultraviolet spectrums or frequencies are beyond what the human eye can see (some animals can see in these light frequency ranges),
The actual wavelength of black lights or UV bulbs that operates in the UV range is 280-410nm usually narrowed to 368-371 nm wavelength light. Because UV flashlights or bulbs may also emit some energy in the wavelength range that is visible to humans, when you plug in a lamp that contains a "black light" bulb, it won't appear to emit zero "light" (that you can see), but it emits so little light in the range visible to humans that these bulbs are popularly called "black lights".
We have had a number of discussions with forensic investigators and building inspectors, have tested several UV light devices, and have experimented with the forensic use of UV light in our lab and in the field. And of course there are numerous expert sources for this topic.
In general inspectors find that you can use a good quality ultraviolet light source even in daylight (notice the use of small UV flashlights for document checks in airport security screening procedures). But for weak or dilute sources of fluorescent materials, such as very dilute fluorescein septic dye that might appear in a waterway up to a week after a septic loading and dye test, screening the target using ultraviolet lighting under low light or dark conditions is still more effective.
Catalog of Materials & Products that "glow" or fluoresce under Ultra Violet Light - UV light, Black Light
Here is a list of examples of fluorescing materials you might commonly see during an investigation inside or around a building. In parentheses our c=XX note indicates common colors you will see from each material when it is exposed to ultra violet light in a dark area. Use a UV flashlight, a "black light" bulb in a portable light fixture, or similar equipment to screen for these or other fluorescing substances in and around buildings.
UV light or black light information, sources, suppliers
 About.com - Chemistry http://chemistry.about.com/cs/howthingswork/f/blblacklight.htm
 Several light & forensic suppliers, e.g. Doje's (see our article on checking for blood in art work by Frida Kahlo)
 U. Illinois Dept of Physics, http://van.physics.illinois.edu/qa/listing.php?id=1913
 Glow Paint Industries, an Australian company ( 07-5483-9181) http://www.glowinthedark.net.au/ claims to provide the world's longest list of products that glow in the dark, listing toys, party supplies, home improvement products, recreation & sport products, paints, and more.
 UV WATER DISINFECTION, PORTABLE discusses using a tiny portable UV light to attempt to disinfect drinking water and UV -ULTRAVIOLET LIGHT TREATMENT discusses larger capacity ultra violet light water disinfection systems selection, installation, use, maintenance, diagnosis.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Check the FAQs just above, 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.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.