How to Disinfect Stainless Steel in Cleanrooms and Labs
Stainless steel is commonly found in laboratory and cleanroom equipment and work surfaces. Cabinets, tables, benches, racks, and stools are just some of the objects that are frequently made out of this durable material. Austenitic stainless steel, including 304 and 316 grades, is noted for its non-magnetic qualities, and is the most generally seen type of stainless steel in these environments.
Stainless steel has a number of characteristics that make it particularly useful for labs and cleanrooms, including:
- Corrosion resistance
- Heat resistance
- Ease of cleaning
- Non-porous surface
- High tensile strength
- Anti-static properties
However, it is vital to understand that stainless steel will not keep these beneficial qualities in the long term without proper maintenance. Stainless steel should be cleaned and disinfected on a routine basis. Neglecting these cleaning tasks may eventually cause a stainless steel surface to become corroded with rust and/or embedded with pathogens.
The COVID-19 crisis has brought an additional sense of urgency to the matter of disinfecting stainless steel equipment and objects. According to a study in The New England Journal of Medicine, the SARS-COV-2 virus ("Coronavirus") can survive up to three days on stainless steel.1
The cleaning of a stainless steel surface must be performed with the correct liquids and materials to avoid inflicting damage. What follows is a brief overview of a safe, effective way to clean your stainless steel materials in a lab or cleanroom.
The Importance of Cleaning Stainless Steel
When exposed to oxygen, stainless steel naturally forms an extremely thin layer of chromium oxide. This layer acts to protect the underlying steel from the effects of corrosion. Keeping this layer in optimum condition is the key to proper stainless steel maintenance.
Fortunately, stainless steel does not become worn out or dull with proper cleaning. In fact, stainless steel thrives on routine cleaning, as it keeps its chromium oxide layer healthy. You can clean stainless steel surfaces as often as you prefer, with no fear that you’re causing damage to them.
Keeping stainless steel clean is essential for ensuring that you’ll be able to disinfect it properly when needed. When dirt and other contaminants are allowed to remain on the surface of stainless steel, they tend to erode its all-important layer of chromium oxide. Over time, this allows corrosion to set in and ruin that smooth surface. That’s why it’s a good idea to clean stainless steel even if there are no disinfectants on hand. Try to wash it at least once a week.
Again, however, it is necessary to cleanse these surfaces correctly. Not all cleaning materials are suitable for use on stainless steel.
What to Avoid When Disinfecting Stainless Steel
When cleaning stainless steel equipment, there are a few common supplies that you should not use:
- Tap water/hard water – Normal tap water from the kitchen or the shower has a tendency to leave behind water spots. If you must use this type of water, don’t leave it standing for long on the surface. Do a thorough job of wiping it off to prevent water spotting. Deionized water is definitely preferable, however.
- Bleach and chlorine – Too abrasive for stainless steel, they can harm the chromium oxide layer.
- Steel wool – Although they may seem to be useful in getting rid of tough stains, these kinds of scouring pads can create tiny abrasions where microorganisms can hide. They sometimes also leave behind tiny iron particles.
- Brushes – These too can cause problems for the coating of your stainless steel.
So how do you disinfect stainless steel? Here are a few simple cleaning tips.
Cleaning Stainless Steel the Right Way
First, put on your personal protective equipment (PPE). Gloves should be used at minimum; it's also a good idea to get some goggles or a face shield.
Before you disinfect stainless steel, you should remove stains, if any are present. Microfiber cloths or other soft cloths are best so you don’t scratch the surface. Usually, all that is needed is warm water (preferably deionized, as previously mentioned). If particularly troublesome stains are present, a mild (neutral) detergent or soap can be used.
Rub the towel in the same direction of the grain in the stainless steel. Afterward, use a fresh towel or lint-free cleanroom wipes to dry it off.
To disinfect, it’s recommended that you use sterile or non-sterile 70% isopropyl alcohol.
- Pour the alcohol into a spray bottle.
- Spray the surface you want to disinfect.
- Take a clean cloth, dip it into the alcohol, and wipe the surface.
- Rinse with warm water.
- Dry with another clean cloth.
Although some people have a tendency to think of stainless steel as nearly indestructible, this isn’t the case. Without proper care, it will gradually lose the characteristics that make it an attractive material for labs and cleanrooms. The good news is that it’s not difficult to clean and disinfect your stainless steel equipment. If you’re looking for some help with maintaining a contaminant-free work environment, we invite you to learn more about what we can offer you at Prudential Cleanroom Services.