Appearance and Composition
These are usually cylindrical tablets used to prevent bad odors in washrooms. The chemicals composing the block may vary. The original formulations were of naphthalene and later para-dichlorobenzene (pDCB), both now known to be hazardous to health by inhalation. Most urinal blocks are now para-dichlorobenzene-free. In some areas, the use of para-dichlorobenzene toilet blocks has been banned; in other areas para-dichlorobenzene blocks or "para blocks" are still used.
The block's functionality is enhanced by saturating it with a scenting compound and quaternary ammonium compounds.
They come in a variety of shapes and sizes, and weigh from about 20 grams up to about 100 grams when new.
Para-dichlorobenzene and naphthalene blocks do not actually dissolve in water or urine, but only sublimate into the air, creating an odor that masks the smell of urine. Urinal-deodorizer companies now produce water-soluble versions made from surfactants, which offer some active cleaning efficacy. The new water-soluble blocks improve the cleaning of the pipes to remove some of the cause of odor problems. Some recent formulations also include bacterial strains which, coupled with the surfactant cleaning power, can completely eradicate odors and blockages caused by the buildup of solids in the traps and pipes.
Some manufacturers claim that these "biological blocks" can enable completely no-flush waterless urinals to be fitted.
Read more about this topic: Urinal Deodorizer Block
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