We are affected by the planned adjustment to the colour of the glass panes by our glass supplier.

According to information provided by the supplier, the substrate will now be significantly lighter during the dying process. The technical data will change slightly as a result (the appearance of the glass panes will also change).

Our supplier will complete orders with a delivery date from 01/11/2015 using the new/lighter substrate.

If replacement glazing is required, we please ask that you provide us with information on the date on which the glass panes were installed.

In the case of already processed orders and when provided with information by us, our supplier will endeavour to also produce this glass with the old “green” colour tone (subject to the availability of the corresponding raw glass).

General information on glass cleaning:

Glass can withstand a lot – but not everything...

The following cleaning instructions apply to all glass products used in buildings. When cleaning glass, always use plenty of clean water to avoid the scouring effect of dirt particles. Suitable manual aids include soft, clean sponges, chamois leathers, cloths or rubber wipers. The cleaning effect can be supported by using neutral cleaning agents or standard household glass cleaners. If the dirt is composed of grease or sealant residue, use standard cleaning solvents such as white spirits or isopropanol. Do not use any chemical cleaning agents such as alkaline solutions, acids or media containing fluorides.

The use of pointed, sharp metallic objects, e.g. blades or knives, can cause surface damage (scratches). A cleaning agent must not visibly attack the surface. It is not permitted to use glass scrapers to clean the full surface of the glass. If damage to glass products or glass surfaces caused by cleaning is observed during cleaning work, stop the cleaning work immediately and obtain the necessary information to avoid causing any further damage.


Ensure that you observe the manufacturer's instructions when you clean glass panes coated on the side exposed to the weather and single pane safety glass. Do not use any abrasive cleaning agents!

Acceptable irregularities according to the technical regulations for metalworking - construction technology

Hot-dip galvanising

Hot-dip galvanising is corrosion protection and not an optical design feature such as a paint coating because neither the metalworker nor the galvanizing company can influence elements such as the silicon or phosphorous content that affect the appearance. Furthermore, the design of the product generally comprises different profiles, pipes or sheets. These have different alloy components that will have various coating thicknesses and different looking surfaces after the hot-dip galvanising process.

The existence of darker and lighter areas (e.g. net-like patterns or dark grey areas) or minor irregularities on the surface are not grounds for refusing to accept the products. The formation of (white or dark) corrosion products, primarily consisting of zinc oxide (due to storage under damp conditions after the hot-dip galvanizing process), is not grounds for refusing to accept the products insofar as the zinc coating still meets the required minimum thickness.

Reworking and lumpy zinc coatings

Steel parts drip during the hot-dip galvanising process. It is possible that the zinc dripping from the parts may solidify and form lumps or runs during this process.

If these lumps are relatively small, they will not cause any problems and should be left as they are. They will not negatively impact the corrosion protection. It is not good practice to knock these lumps off or to use a grinding tool to rigorously remove them because there is a risk that the zinc coating could be removed down to the bare steel.

Any zinc lumps or runs that are very sharp should always be removed to avoid any risk of injury. The use of a hand file or mechanical grinding using an angled grinder with a flexible disc is recommended for completing this process. Another option for removing the undesired lumps of zinc is to melt the excess zinc using a cool welding flame.

Zinc lumps over welded seams indicate that a welding electrode containing silicon was used for the welding process. The zinc will accumulate to a lesser extent if you use filler materials with a lower silicone content.

It will never be possible to prevent the zinc coating spreading over previously completed flat welding seams and consequently this does not constitute a defect.

Tips for the cleaning and maintenance of stainless steel in the construction sector 

ISBN 2-87997-056-3       © Euro Inox 2002, 2003

1. Introduction

Stainless steels are inherently corrosion resistant and thus do not need any organic or metallic coatings to enhance their corrosion resistance and appearance. However, stainless steel surfaces should also receive a certain level of maintenance so that they retain a good aesthetic appearance and any deposits that could compromise, amongst other things, their corrosion resistance are removed. In this respect, stainless steels are no different to other decorative and functional construction materials such as glass.

The purpose of these guidelines is to inform end users about effective and inexpensive methods for retaining the outstanding properties of stainless steel surfaces in the long term.

2. The self-repair mechanism of stainless steel

First of all, it is important to understand why stainless steel is corrosion resistant. The alloying elements in steel form a thin, transparent "passive layer" on the surface. Although this protective passive layer is only a few atoms thick, it protects the material even after the surface has been damaged because it instantaneously reforms in the presence of oxygen from air or water. This explains why an additional protective layer is not required. The original corrosion protection is retained even after decades of intensive use.

3. Basic cleaning

The first basic cleaning is generally carried out by our company. If the stainless steel parts have been protected against dirt in an adequate manner, this basic cleaning is no different to later maintenance cleaning.

A plastic film is often used to provide effective protection for the stainless steel parts during transport, storage, processing and installation. However, some of these protective films are not permanently resistant to light and UV radiation and they can become difficult to remove after a long period of time. Adhesive residues can also stick to the surface that are difficult to remove. Therefore, it is advisable to remove the film as soon as it is no longer needed for protection on the construction site. This process should always be carried out from top to bottom.

Lime and mortar splashes can be removed using diluted phosphoric acid. Then rinse the area thoroughly with clean water. Using demineralised water will also reduce the risk of water stains.

Many manufacturers offer cleaning agents specifically designed for this purpose. Mortar remover for tiles or diluted hydrochloric acid must not be used on stainless steel under any circumstances. If these cleaning agents are accidentally spilt on stainless steel, immediately rinse the area using lots of clean water.
Iron particles from tools, scaffolding and means of transportation must be removed immediately. Grinding dust, shavings and welding splashes which originate from work on construction steel located near to the stainless steel will rust quickly if deposited on the stainless steel. This rusting can break through the passive layer on the stainless steel and result in localised pitting corrosion.

If these contaminants are identified in good time, they can be removed using normal household (ferrite-free) cleaning sponges or special cleaners.

If corrosion has already occurred, mechanical treatment or (preferably) pickling of the surface is unavoidable.

If this is the case, please contact us on tel. +49 (0)7133/97479-0. We will advise you on how to proceed.

4. Maintenance cleaning

In the case of outdoor applications, any damaging deposits are normally washed off due to rainfall. Areas that are not reached by the rain should be cleaned to ensure that airborne contaminants do not accumulate on the surface. This is particularly important in marine and industrial atmospheres if the selected type of steel is not designed to handle the chlorides and sulphur oxide that can accumulate in these areas.

In the case of indoor applications, the most important thing is to avoid and remove finger marks. There are a wide range of finishes available for stainless steels, some of which are particularly designed for use in highly frequented public areas. Suitable finishes that will reduce cleaning costs later on can thus already be selected at the planning stage.

Brushed and polished finishes are a popular choice and may show finger marks at the very beginning but they become less noticeable after the surfaces have been cleaned a few times.

5. Cleaning agents

A dishwashing detergent is usually sufficient for removing fingerprints. Some manufacturers of cleaning agents offer special products that supplement the cleaning action with a care component. These cleaning products completely remove fingerprints and leave behind a fine film that gives the treated surface a uniform appearance. After applying the product, polish the surface with a dry cloth. Your national advisory association (refer to the member's list for the addresses) can provide advice on products and where to purchase them. 

Bright-annealed and mirror-polished surfaces can be cleaned using chloride-free glass cleansers.
Normal household cream cleansers can be used on more stubborn stains and are also suitable for cleaning off water stains and light discolouration. After cleaning, rinse the surfaces with clean water. Washing down the surface with demineralised water (available in supermarkets e.g. for steam irons) will prevent water stains forming when drying. Finally, rub the surfaces dry. Scouring powders are not suitable because they can scratch the surfaces.

Heavy oil and grease marks can be removed using alcohol-based cleaning products and solvents, e.g. methylated spirit, isopropylalcohol or acetone. These products do not cause any damage to the stainless steel. It is important to ensure that the dissolved dirt is not spread over a large section of the stainless steel surface during cleaning. Therefore, the cleaning process should be repeated using clean cloths until all traces have been removed.

Heavily neglected surfaces can also be treated with metal polishes, such as those designed for cleaning chromium-plated parts on cars. Polishes designed for re-finishing old car paint are also an option. However, it is important to ensure that these products do not leave any abrasive marks on the stainless steel.
The instructions and guidelines relating to occupational safety and environmental protection must be strictly observed during cleaning.

The following cleaners may not be used on stainless steel:

  • Cleaners containing chloride, especially those products containing hydrochloric acid
  • Bleaching agents (if accidentally applied or spilt on stainless steel surfaces, rinse thoroughly with clean water)
  • Silver cleaners

6. Cleaning utensils

A damp cloth or chamois leather is usually sufficient for removing fingerprints.

For more stubborn dirt, normal household (non-ferrous) cleaning sponges can be used. Ferrous scouring pads, steel wool and steel brushes must not be used on stainless steel under any circumstances because they could leave behind iron particles on the stainless steel surface.

Soft nylon brushes can be used for cleaning surfaces with patterned finishes. Steel brushes, especially those made out of carbon steel, will damage the surfaces.
Brushed and polished surfaces (2G, 2J, 2K according to DIN 10088/3) should always be wiped in the direction of the finish and not across it.
If water has been used for cleaning – especially in regions with hard water – wipe the surface dry afterwards to prevent water stains. Using demineralised water will avoid this problem.

To prevent any cross contamination with iron particles, ensure that cleaning utensils have not been previously used for "normal" steel. 
Cleaning utensils for use on stainless steel surfaces should preferably be reserved exclusively for that purpose.

7. Cleaning intervals

The cleaning intervals for stainless steel surfaces indoors are generally no different to those for other surfaces. In order to keep the effort and cost of cleaning to a minimum, ensure that the surfaces are cleaned before any heavy soiling has accumulated.

In outdoor areas, stainless steel can be exposed to a range of potentially corrosive conditions e.g.: 

  • Marine atmospheres
  • Industrial waste gases
  • Water splashes containing de-icing salts
  • Air pollution and vehicle exhaust emissions

All of these factors can cause discolouration in the long term. Cleaners containing phosphoric acid will reliably remove this type of discolouration. 

Experience has shown that it is good practice to clean stainless steel surfaces at the same intervals as glass surfaces. Therefore, maintenance cleaning should be carried out every 6 to 12 months in environments with light soiling and every 3 to 6 months in areas with heavy soiling.