For the selection of the proper grating, you must take into account the following, in order to have the most advantageous economical solution.
1) Type of area to be covered
2) Existence or non of supports
3) Define loads and contact areas
4) Construction Materials
5) Geometrical and dimensional requirements
6) Surface processes
7) Type of gratings
1. Important prerequisite is to know the purpose and use of the grating, like:
If grates are going to be used for flooring, for simple applications such walkways, for use with female high heels, for industrial use (light or heavy), water channels, ramps for cars, for stair steps , for fences, for railings, and many other applications.
2. Of great importance is the way the grating is supported as it affects the cost of production. You should know: If grate is placed in frame, which may be present or not, the frame depth in order to determine the profile of the margin bars (see Draw 1), the width of the bearing, which defines the final size of grate and thus we can determine the real opening (L), which we need to calculate strength of the grate.
If there is no support, the grill should be "hung on" from the horizontal sides of a metal angle or nail a metal angle in the channel or to get profile (z type) or at the end with legs to support the grate through the channel (see Draw 2).
In industrial metal flooring will need to know the seating surfaces of the grids, they determine the clear L (span), the direction and size of the bearing bars in order to get the desired strength (see Draw 3).
On the use of ladders (stair-steps), we should know if our step will be placed in a closed frame or be supported on the 2 opposite sides (screwed or welded).
In fencing, we should know the thickness of the wall, which plays a primary role in the way of support, specifying the form of columns.
3. The determination of loads and surface, is influences the future course of the grate. It is very important to know the surface of load in order for our grating to be really what is needed.
If loads have specific direction (if its vehicle), we can locally enhance our grate for these loads and the rest of the structure to accept grating with lower strength, so we have a less costtly solution.
Also an important part in the study, is the contact surface (imposition) of loads.The better we prescribe them, the better results we will have for our study and the cost of the grate.
The table below shows the class load (DIN 1072) for vehicles.
As concerns the vehicle categories, except the contact surface, and the load ,key role has the direction of movement of the vehicle (see Draw 5).
Motion parallel to the bearing bars is more favorable than the movement which is vertical to them. Also important is the geometric shape of the contact surface (i.e. if it is rectangular or square).
4. We can choose, depending on the use , the nature of environmental conditions or other requirements, among three materials:
- St37-2 (DIN 17100) or Fe 360 En 10025
- Stainless Steel 304
- Aluminum 6063
St37-2: the most simple, common material for all applications, hot-dip galvanized or black or painted in the color of your choice. The most cost saving material.
Inox 304: When conditions or regulations, demand it, such as in kitchens, restaurants, chemical plants, ships, slaughterhouses, animal farming or use of freshwater - saltwater, decoration etc.
AL 6063: Usually where weight construction and possible electrolytic corrosion between the materials play a major role.
5. The external dimensions of the grates must be such as to allow the installation on the frame or supports. If the grate is not rectangular, we need at least the diagonal and all sides. All dimensions should be as accurate as possible. For channels with large length, gratings are divided into several pieces, so we must predict a gap between them around 1-2 mm.
According to DIN 24537, the exterior dimensions of gratings should have a tolerance +0 / -4 mm. We try to have +0 /-2mm. The geometrical deviations which may be due either to deformations while welding or because of hot galvanization or material trends, or poor construction, must be within the limits of the RAL - GZ 638.you.
6. In agreement with our customer, the grates can accept (depending on material) various surface processes, such as hot deep galvanization / sandblasting / paint in the color of your choice.
Sandblast: Can be applied to all kinds of grates and all materials if required. By sandblasting we achieve better grip for galvanization or color and so we have a longer life of the coating.
Regarding the grates of aluminum or stainless steel, because in the process of welding, the welded points show blackness or bruising, we can clean them by sandblasting with very fine grain, leaving the final product with a matte texture and soft gray color (see menu / photos )
Hot Deep Galvanizing: Made according to DIN 50976, outsourced. The appearance, thickness, and the mechanical properties of the coating is a function of the following:
-Chemical composition of the object to be galvanized
-The surface conditions presented in the metal, i.e. whether it is good or bad finished.
-The mass of the object
-The galvanization conditions
-The coating density is ~ 7,2 gr/cm3. For local measurements should apply the following:
7. After all the above we are able to choose the type of grating..