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Stainless Steel Cleaning
and Maintenance in the Building |
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| Stainless Steels naturally resist
corrosion. Therefore, a supplementary protection to ensure the
durability of its aspect is not required. A regular maintenance
cleaning is necessary to protect its aesthetic and its resistance
to corrosion. Therefore, stainless steel isn’t that different
from any other construction material, such as glass, that also
needs regular cleaning. These recommendations are to ensure
an efficient and favourable cleaning for a maximum resistance
to corrosion.
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Stainless Steel's
auto-repairing mechanism |
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| First of all, it is very important
to understand the reasons why stainless steel is so resistant
to corrosion. Stainless steel has a thin and transparent passive
layer on its surface. Even though this passive layer is very
thin, it can instantly reconstruct itself under the effect of
oxygen contained in air or water. So, in case of a scratch or
degradation, the reconstructed passive coat will continue protecting
the steel against corrosion. This is why stainless steel doesn’t
need any extra protection coat to maintain its luminous and
shiny aspect, even after years of use.
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Initial
Cleaning |
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| The first cleaning is generally
done by the master builder before the product is delivered to
the customer. So, if the stainless steel product was correctly
protected, only maintenance cleaning is required.
During the construction, transport and assembly, a protective
adhesive plastic film is installed to protect the stainless
steel components. If offers an excellent protection against
degradation and soiling, but some plastic films alter when exposed
to UV rays and can be difficult to remove. The adhesive film,
after peeling, may also leave traces on the stainless steel’s
surface. The protective film must be removed when no longer
required, right after the end of the assembly. Peeling will
be proceeded from top to bottom.
Cement stains may be removed by using a solution containing
a small part of phosphoric acid. This treatment is followed
by an abundant rinsing, preferably with demineralised water,
and drying. Using demineralised water reduces the chances of
having new traces on the steel. Surface treatment specialized
businesses can provide these products. Products containing hydrochloric
(even diluted) should not be used on stainless steel. If this
happens, rinse abundantly with water.
Building professionals are not always informed about the risks
of using products containing hydrochloric acid on stainless
steel pieces. To prevent any risks, users should modify the
order of operations, which means to finish the tiles and to
clean ceramic elements before installing nearby stainless steel
components.
Iron particles that can come from tools or a contact with a
steel scaffolding, etc. must be avoided. The discharge of steel
while welding, cutting, piercing, and polishing or carbon steel
(not stainless) would rapidly generate rust. While corroding
itself, these particles may damage the passive film that protects
stainless steel and attack it, in spite of its good resistance
to corrosion in normal circumstances.
At the beginning, the dirt may be removed with a nylon sponge
such as “Scotch-Brite”, used commonly in the kitchen.
Another solution is to remove it with a product for stainless
steel containing phosphoric acid.
In case of corrosion, and depending on its seriousness, an
acid metal-cleaning may be used or the surface may mechanically
be brought back to its original state. Pastes containing metal-cleaning
elements exist for local applications on the building site.
Make sure to use these products strictly conforming to the given
instructions to work safely and respect the environment protection
legislation. Often, specialized companies will do the work directly
on the building site. Metal-cleaning will restore the steel’s
resistance to corrosion but it may also modify its look. Other
mechanical treatments may be needed to restore its original
finish. It will then be necessary to avoid any contamination,
first of all by protecting the stainless steel parts while doing
other work or by placing the stainless steel elements after
finishing the work that could contaminate the steel.
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Maintenance
cleaning |
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| For outdoor works, such as facades,
rain is generally good enough to clean off dust and other dirt,
but it does so unevenly depending on its height and exposition.
While performing the usual cleaning, a particular attention
must be given to hidden areas to clean off accumulations of
contamination agents found in the air. This is very important
in marine and industrial environments, where heaps of chloride
and Sox in the air may engender localized corrosion if it isn’t
removed efficiently.
For indoor works, fingerprints may be something to worry about.
There is a large range of special products for stainless steel
and many of them work for largely exposed areas (where there
is a lot of people). During the making of the product, the choice
of surfaces less sensible to fingerprints may contribute to
reduce the frequency and the cost of cleaning.
On mat finishes, often chosen for indoor, fingerprints may
appear right after installation. These will disappear progressively
after a few washes.
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Cleaning
Products |
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| To erase fingerprints and other
marks, the use of soapy water or a light detergent is usually
efficient and safe.
Sprays are easy to use and cover the surface with a light film
that gives it an extra shine. These products remove fingerprints
and prevent them from reappearing. After application of these
products, it is necessary to wipe the surface with a dry cloth.
“Mirror polished” stainless steels may be cleaned
with window products if they do not contain chlorides.
For more stubborn stains, non-abrasive cleaning gels are efficient
and should be also convenient to remove water traces and other
colorations. After cleaning, the residues must be rinsed off
with water (preferable demineralised water, as those sold for
flatirons and for car batteries) and dried to avoid drips and
water traces. Scrubbing powders should be avoided as they could
scratch the surface.
Oil and grease stains may be removed with solvents like white
spirit or acetone that won’t corrode the stainless steel.
The solvent must not be poured directly onto the stain, it may
be hard to completely remove it afterwards. It is recommended
to use the product many times, to pour it onto a soft and clean
rag until the dissolved oil or grease stain has disappeared.
Paint or graffiti must be treated with alkaline scouring for
paint or solvent bases. Scrapers or knives are prohibited to
avoid scratching the stainless steel surface.
Wrongly maintained surfaces may be treated with products used
for chromed surfaces. Products used for polishing automobile
paint may also be used. It is very important that these products
don’t scratch finely polished surfaces.
Another solution is to use a product for stainless steel containing
phosphoric acid, then to rinse with demineralised water, and
to dry. To maintain a uniform aspect, this treatment must be
done evenly on the surface.
Before beginning any cleaning operation, one must check if
the supplier has given a safety slip and that it is well understood
by the operator. Products not to be used on stainless steel
are:
• Chlorine based products (such as hydrochloric acid),
• Bleaches
• Silverware cleaning products.
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Cleaning Tools |
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| A humid rag or chamois usually
works to remove any normal dirt, fingerprints, etc.
For tougher stains, “scotch brite” sponges usually
give good results. Ordinary metallic pads (steel wool), or metallic
steel brushes are prohibited. It not only scratches the surface,
it also risks contaminating the steel with iron particles which
can lead to rusting when exposed to humidity.
Fine-grained polished products, like 180 brushed finishes and
others must be polished in the polish’s direction.
After using water for washing or rinsing, the surface should
be dried to avoid rings, mostly in some areas where the water
is harder. The use of demineralised water will avoid these rings.
To avoid contamination with iron particles, make sure that
the tools haven’t been previously used to clean “normal
steel” (carbon steel). Materials used for cleaning stainless
steel must strictly be used for it.
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Cleaning
periodicity |
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| Inside buildings, the periodicity
for cleaning stainless steel elements is not different from
any other materials. To reduce the costs and efforts for maintenance
and to avoid damaging the surface, the cleaning must be done
before any visible accumulation of dirt or fingerprints.
Outside, stainless steel is exposed to potentially more aggressive
environments such as :
• marine environment,
• industrial environment,
• salt spreading,
• patina caused by air and traffic dirt.
These environments may cause the apparition of brown stains.
We recommend cleaning these surfaces as frequently as the building’s
windows. Depending on the amount of dirt and the importance
of the deposits, it is suggested to clean the stainless every
6 to 12 months or every 3 to 6 months for heavier deposits described
above. To eliminate such soiling, a stainless steel cleaning
product containing phosphoric acid is recommended.
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