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BONNET GRANDE CUISINE
Rue des Frères Lumière - Z.I Mitry Compans
F-77292 MITRY MORY Cedex
5 MAINTENANCE
5.1 FOREWORD RELATING TO STAINLESS STEELS
Stainless steel is a steel grade so designed that a thin protective sheet is formed on the metallic surface, which protects it against corrosion
(Oxide film resulting from the chemical reaction of oxygen on the metallic surface).
Anything hindering the formation of this sheet, or facilitating its partial destruction (Food residues, overflow of liquids, stagnant liquids,…) reduces
the resistance of stainless steel to corrosion.
Whilst the composition of stainless steel enables it to withstand some chemical aggression better than classical steels, you must not think that
stainless steel is indestructible.
3 main factors contributing to corrosion should be watched for:
- The chemical environment in general: * Different brines (Salt concentration, Sauerkraut…)
* Chlorides contained in particular in:
- cleaning products
- bleach.
- The temperature: Any chemical environment is made considerably more aggressive to stainless
steel as the temperature rises.
- The duration: The longer the contact time between stainless steel and the chemicals, the more
noticeable the consequences of corrosion will be.
The combination of these three factors may lead to the eventual destruction of parts of the equipment, even if they have been made in very high
quality stainless steel.
Note that when stainless steel becomes corroded, it is extremely rare that this is generated by the steel itself. Generally, cleaning
products, which are not appropriate or are improperly used, lack of maintenance or extreme conditions of use are often found to be the
cause of the damage.
WARNING!
The manufacturer will not be held responsible for cases of corrosion resulting from these conditions and the warranty will not apply.
A list of the most frequent causes follows, to allow you to better identify possible inappropriate use and to ensure the long service
life of your equipment.
5.2 THE COMMONEST CAUSES OF CORROSION
Floor cleaning
Floors (prior to handover or during a kitchen deep clean) are often cleaned with very aggressive products. If the product is sprayed, without
necessary precautions, any splashes on the appliances may result in the corrosion of legs, bases and low level trims.
Worse still, if the area is not properly ventilated after application, the vapour from these products may settle on the equipment and result in
corrosion spreading to the entire surfaces.
Inappropriate cleaning product (Bleach, Acids, Soda)
If inappropriate products, such as bleach, acid or soda dilutions, (all products which are not especially designed for the maintenance of
stainless steels) are used, irreversible etching of the stainless steel surfaces can occur.
Cleaning product applied when the temperature is too high
All cleaning products are more aggressive at higher temperature. In principle the temperature of any surface must not exceed 60°C, or
permanent staining (blackening) of the stainless steel will result.
Inadequate rinsing after cleaning
After cleaning the surfaces should all be rinsed thoroughly to remove any chemical residue. If this is not done the residue will continue to act
over time with the risk of starting the corrosive process.
Worse still, if the affected surface is submitted to temperatures higher than 60°C (inside of an oven, a well or tank,...), the impact will be
greater and corrosion, will almost inevitably occur.
Stagnation of cleaning products
In the same way, all the areas that can trap chemicals, especially the channels, gutters, drainage manifolds, traps etc. must be subject to
careful and plentiful rinsing. (Use a nylon brush to reinforce the action of rinsing with clean water).
Salt concentration
Salt, much in use in kitchens, is often found to be the origin of pitting that can even penetrate the stainless steel. Spillages on any surface
should be cleaned at once.
Particular case of cooking in boiling salted water:
Salting water in a tank or well presents a major risk: never put cooking salt into the well before the water and remember that salt can
concentrating on the base of the well. Salt should be added to the water and stirred until it dissolves, the risk is reduced using table salt which
dissolves faster.
Intensive use with brine
Certain products, such as sauerkraut (acid juices), fish and sea food (presence of salt), and in general, all brines, must be subject to particular
attention. In the case of occasional use there should be no problem if equipment is carefully and systematically cleaned after each use.
In the case of intensive use, all the cooking equipment (ovens, boiling pans, even utensils) must be selected with a grade of stainless steel
specifically adapted to use in such an environment.
