That bottle you buy at the supermarket to clean your white clothes has its own name, and it’s not chlorine. This is a common misconception: the correct ingredient name is sodium hypochlorite. Bleach is a term for a class of chemicals called oxidizers. Oxidants are highly reactive chemicals that will cause many organic compounds such as dyes, pigments, and food stains to break down, resulting in a bleaching or “bleaching” effect. This high degree of reactivity is beneficial in certain applications but can also cause problems.

Most household bleaches are made up of only 6% sodium hypochlorite. The rest of that gallon-sized bottle is 94% plain H2O. However, the type of bleach the average pressure washer uses is a higher industrial grade of 10-12% sodium hypochlorite. There are over 50 types of products around the world called bleaches or bleaching agents, a vague term since the word in its simplest definition just means that it will remove color. Dyes and pigments have alternating double molecular bonds that create the color. The oxidation reaction of the bleaches breaks these molecules at the double bond making their chromosomes shorter and therefore absorbing light at shorter wavelengths. This process makes what used to be colored now look white. Some bleaches or bleaching agents simply make the double bond into a single bond that does not allow light absorption.

A popular type of bleach in recent years is the slower-operating, less-reactive oxygen or peroxygen bleach, such as sodium percarbonate, persulfate, or sodium perborate. These work by releasing oxygen, but this time hydrogen peroxide is the active ingredient. Hydrogen peroxide bleaches have less bleaching action and are slower acting. This allows it to be used on many colored surfaces and colored fabrics.

Bleach, the bubbling effect and the connection with France

Bleach is an alkaline solution created by bubbling chlorine gas, with electrolysis, through a sodium hydroxide solution commonly called bleach to adjust its pH to 12-13%. This adjustment improves its stability. Liquid hypochlorite bleach was first discovered in 1787 in France, near Paris, by a chemist named Claude Louis Berthollet. Bleach is known as Eau de Javel in France, after the town where it was first made. It was originally used to bleach textiles and it was not until Louis Pasteur and his work with it in the late 19th century that it became widely used as a sanitizer and disinfectant. This is the main reason bleach is used in conjunction with pressure washing today – it has excellent disinfectant properties and its ability to kill and discolor mold, mildew and mildew stains. Bleach kills mold microbes by reacting with (oxidizing) and damaging their cell membranes and cell proteins. For normal surface disinfection purposes, solutions of 50-100 ppm (parts per million) of bleach in water may be used. To remove mildew stains, higher levels of 1-3% chlorine are needed. For swimming pools, 1-3 ppm of chlorine should be maintained. Chlorinated isocyanurates and calcium hypochlorite are more stable powders than liquid bleach and are therefore more used in swimming pools. When dissolved in water they form hypochlorites and act as a liquid bleach. Bleach can remove color in amounts as little as 1-3 ppm with water. did you know Liquid bleach will slowly lose chlorine content over time with exposure to air, and even faster at high temperatures or exposure to sunlight. That’s why pool chlorine levels are constantly checked and why bleach bottles are never clean. Liquid bleach should be tightly sealed and stored in a cool, dry, well-ventilated area. For example, in the heat of summer, a 12% bleach solution can lose 1% in a week, up to 10% in two weeks, and be as low as 8% in a month, but in the cold of winter that can be reduced. half. This is what the manufacturers of Clorox bleach say. “Bleach solutions should be refreshed daily. Once diluted, bleach breaks down quickly, primarily to salt and water.”** And that “Clorox® Regular-Bleach should be replaced each year and stored as directed for maximum performance.” optimum.”* * For pressure washers, it would be best to only buy what you can use in a few months and only mix cleaning solutions with bleach as needed and not store large amounts in clear or semi-clear containers exposed to the sun. .

Mold? Bleach alone is not enough

For years, pressure washers have used water-only bleach to clean a surface like a house or concrete that has mold and mildew on it. But bleach alone with water will cause beads and uneven application results. The addition of a compatible detergent will allow the solution to “wet” the surface giving consistent results. Take great care to ensure that the detergent is suitable and labeled for use in chlorine solutions. Contact the detergent manufacturer if you are unsure. Using an incompatible detergent can be dangerous! Another additive TSP (trisodium phosphate) is recommended by some companies and industries, such as the asphalt roofing manufacturing association, even today. In fact, they recognize their bleach recipe as the only way to get rid of the black streaks that form on their roof shingles. The black discoloration found to stain asphalt roofing material is actually an algae or mold called Gloeocapsa Magma. The asphalt shingle is itself the food source for algae. They recommend a lye recipe that will safely kill algae, but only on the surface. Using 12% bleach, solutions range from one cup of TSP, one gallon of bleach, and five gallons of water, to one cup of TSP and 2.5 gallons of bleach and water.* Molds have roots called hyphae, and once that penetrate under and into material surfaces will simply regrow when conditions are right again, including shade and moisture or water that is 90% bleach or higher. So even with the act of cleaning up mold and mildew with bleach and water, that can give the fire new fuel to start a new cycle of mold growth. Please note that TSP has been banned in laundry products in some parts of the country, primarily near the oceans, such as the Chesapeake, MD and San Francisco, CA areas. You may need to check with your local clean water authority before using TSP-mixed products that could get into your water system. There is no real method to dispose of unused bleach other than first neutralizing the chlorine and then lowering the pH before disposal. To do this correctly, you must take it to a RCRA-listed generator or treatment facility.

Vegetation and Pollution – Care

Bleach does have some concerns when used in pressure washing. The least of which is that if not sufficiently rinsed and diluted with large volumes of water, the runoff can kill vegetation, plants, and grass surrounding the house, sidewalk, or driveways. Bleach must also be stored properly and should generally never be mixed with anything other than water or specifically labeled chlorine-compatible detergents. Never mix ammonia bleach and ammonia-based cleaning solutions. Mixing bleach with compounds that contain ammonia or nitrogen will produce extremely irritating and explosive compounds called chloramines. If mixed with acids, it forms a less stable chlorine solution called hypochlorous acid which will then release toxic chlorine gas into the air. Commercial bleach contains extra alkali in its formulations to keep the solution at a very high pH of around 12 to prevent chlorine from becoming gaseous, but acids can easily neutralize this excess. Mixing bleach with incompatible chemicals can cause anything from minor skin, eye, nose and throat irritations to extremely dangerous situations of deadly fumes that will burn lung tissue and cause respiratory arrest or death or the generation of explosive gases. You should never reuse containers that have previously held bleach for mixing or storing any other chemicals or cleaners for this very reason, unless they have been thoroughly rinsed. When working with pressure washing bleach, worker protection should be safety glasses, impervious gloves, waterproof apron and boots over a long-sleeved shirt and long pants. You should also check the equipment the bleach runs through regularly to make sure no metal parts have been compromised. The manufacturers of Clorox® state: “Many spray bottles contain metal parts in the trigger spray. Bleach will corrode these parts over time.”** It is always smart to thoroughly rinse all metal parts of the dispenser with clean water and not leave solutions behind. of chlorine rested. on them when not in use.

If handled properly and treated with respect, bleach is a friend to the pressure washing industry due to its disinfecting action, mildew removal, and bleaching capabilities.

*www.asphaltroofing.org, technical bulletin “Algae Discoloration of Roofs”

**www.clorox.com