UV inspection lamp
Finds what the eye cannot, and then tells you something misleading afterwards. Both halves are worth knowing.
In detail
Professional cleaners survey for animal urine with a UV lamp before they touch anything, because not all urine deposits show as stains and the ones that do not are the ones that keep producing odour. The survey decides where the work happens; without it, treatment goes where the visible mark is rather than where the contamination is. The part almost nobody is told is what the lamp says AFTER cleaning. A treated area often still fluoresces, and it is not because urine remains: the fluorescence comes from phosphorus left by the breakdown of phosphocreatine, which has bonded to the fibre in the way a dye does and is very difficult to remove without damaging the carpet's own colour. So a glowing patch after a professional clean is not evidence of a job half done, and a householder who buys a lamp to check the work will reach the wrong conclusion. It is a diagnostic that is excellent before treatment and unreliable as a measure of success afterwards.
Why
- UV inspection lamp is explained by Why a smell comes back when the weather turns
Sources for this page
Sources
Consumer Floor and Furnishings Care Information: carpet topics
Institute of Inspection, Cleaning and Restoration Certification (IICRC) · Trade or professional body
Relied on for: That professionals use a black or UV light to identify urine areas invisible to the naked eye because not all urine stains show, that a treated area may still fluoresce afterwards, that the fluorescence is phosphorus from the breakdown of phosphocreatine chemically bonded to the fibres like a dye, and that continued fluorescence does not mean the urine was incompletely removed. (states this directly)