In the Name of God
Technical specifications of grating
Bearing bar grating
:
A piece of grating that can bear the pressure applied to the grating, and it is placed on respective supports. To make it, a standard bar is used. According to customer’s demands, it is possible to produce bearing bars in any dimension and thickness required.
Cross bar:
A part of grating that plays the role of adjusting the grating mesh and creating a connection between bearing bars. no force is entered into it. Therefore, its thickness does not affect the grating resistance. This part can be produced from strips, half-strips, serrated, or four-sided twisted rebar.
Mesh or meshing:
It is usually indicated by two numbers (X*Y) in which X represents the space between bearing bars, and Y is the space between cross bars. By reducing the space between bearing bars, grating resistance can be increased. but the space between cross bars does not have an effect on grating load bearing.
B: Strip in half-strip grating
No. | Bearing bar | Cross bar | Mesh (meshing) | Weight
(one square meter) |
Concentrated
load bearing |
Extensive load bearing |
1 | 30*3 | 15*3 | 30*30 | 40.94 kg | 981 kg/m2 | 1962 kg/m2 |
2 | 30*3 | 15*3 | 30*50 | 36.11 kg | 981 kg/m2 | 1962 kg/m2 |
3 | 30*3 | 15*3 | 30*100 | 32.48 kg | 981 kg/m2 | 1962 kg/m2 |
4 | 30*5 | 15*3 | 30*30 | 56.25 kg | 1541 kg/m2 | 3083 kg/m2 |
5 | 30*5 | 15*3 | 30*50 | 51.42 kg | 1541 kg/m2 | 3083 kg/m2 |
6 | 30*5 | 15*3 | 30*100 | 47.79 kg | 1541 kg/m2 | 3083 kg/m2 |
It should be noted that the strip dimensions mentioned in the table are the most common application of grating and the general standard for manufacture. but according to the customer’s request and design drawings. gratings can be produced with any strip and mesh specifications.
Grating types and technical specifications:
A: Stripped Grating
No. | Bearing bar | Cross bar | Mesh (meshing) | Weight
(one square meter) |
Concentrated
load bearing |
Extensive load bearing |
1 | 30*3 | 30*3 | 30*30 | 52.92 kg | 981 kg/m2 | 1962 kg/m2 |
2 | 30*3 | 30*3 | 30*50 | 43.29 kg | 981 kg/m2 | 1962 kg/m2 |
3 | 30*3 | 30*3 | 30*100 | 36.07 kg | 981 kg/m2 | 1962 kg/m2 |
4 | 30*5 | 30*5 | 30*30 | 83.54 kg | 1541 kg/m2 | 3083 kg/m2 |
5 | 30*5 | 30*5 | 30*50 | 67.79 kg | 1541 kg/m2 | 3083 kg/m2 |
6 | 30*5 | 30*5 | 30*100 | 55.98 kg | 1541 kg/m2 | 3083 kg/m2 |
It should be noted that the strip dimensions mentioned in the table are the most common application of grating and the general standard for manufacture, but according to the customer’s request and design drawings, gratings can be produced with any strip and mesh specifications.
Sample gratings made
Also, produced gratings are manufactured in accordance with the international standard ANSI MBG 531 and are subject to quality control inspections.
This part is used to fix gratings on respective supports at the installation site. Its components are like eyebrows, prongs and bolts.
Serrated grating:
In places where there is a possibility of slipping due to the high humidity or the use of slippery materials in the environment. to solve this problem, gratings can be made serrated by creating grooves. Depending on conditions and designer’s drawings, both bearing and cross bars can be made (serrated).
Grating coating:
Paint coating compared to galvanized coating is done with a lower coating thickness and a more affordable price. The paint type is based on customer’s request.
Light polyethylene coating:
Light polyethylene coating with a thickness of 600 to 700 microns is a suitable and safe coating for areas in direct contact with acid or corrosive chemicals.
Hot-dip galvanizing:
To prevent corrosion in gratings and to increase the useful life of gratings, they are galvanized. All parts are galvanized in accordance with Standard ASTM A123. (Average thickness 80 microns)
C: Belts in rebar grating
No. | Bearing bar | Cross bar | Mesh (meshing) | Weight
(one square meter) |
Concentrated
load bearing |
Extensive load bearing |
1 | 30*3 | 30*30 | 42.08 kg | 981 kg/m2 | 1962 kg/m2 | |
2 | 30*3 | 30*50 | 36.79 kg | 981 kg/m2 | 1962 kg/m2 | |
3 | 30*3 | 30*100 | 32.82 kg | 981 kg/m2 | 1962 kg/m2 | |
4 | 30*5 | 30*30 | 57.39kg | 1541 kg/m2 | 3083 kg/m2 | |
5 | 30*5 | 30*50 | 52.10 kg | 1541 kg/m2 | 3083 kg/m2 | |
6 | 30*5 | 30*100 | 48.13 kg | 1541 kg/m2 | 3083 kg/m2 |
It should be noted that the strip dimensions mentioned in the table are the most common application of grating and the general standard for manufacture. but according to the customer’s request and design drawings, gratings can be produced with any strip and mesh specifications.
B: Strip in half-strip grating
No. | Bearing bar | Cross bar | Mesh (meshing) | Weight
(one square meter) |
Concentrated
load bearing |
Extensive load bearing |
1 | 30*3 | 15*3 | 30*30 | 40.94 kg | 981 kg/m2 | 1962 kg/m2 |
2 | 30*3 | 15*3 | 30*50 | 36.11 kg | 981 kg/m2 | 1962 kg/m2 |
3 | 30*3 | 15*3 | 30*100 | 32.48 kg | 981 kg/m2 | 1962 kg/m2 |
4 | 30*5 | 15*3 | 30*30 | 56.25kg | 1541 kg/m2 | 3083 kg/m2 |
5 | 30*5 | 15*3 | 30*50 | 51.42 kg | 1541 kg/m2 | 3083 kg/m2 |
6 | 30*5 | 15*3 | 30*100 | 47.79 kg | 1541 kg/m2 | 3083 kg/m2 |
It should be noted that the strip dimensions mentioned in the table are the most common application of grating and the general standard for manufacture. but according to the customer’s request and design drawings, gratings can be produced with any strip and mesh specifications.
- References, standards and technical definitions:
- Quality and production standards:
The collection of appropriate experiences and approaches has been summarized in order to achieve the best results and prevent the repetition of mistakes in standards. Arak Rail Company has tried to meet the expectations and demands of employers by applying standards and guidelines for the production of gratings, and has been able to offer the country’s industry with a high quality product in accordance to the world day standards. The products of this company are manufactured and controlled in accordance with the following standards:
- ANSI/NAMM-MBG 531 (American National Standards).
- BS 4592-1 (British Standard).
- DIN24531-1 & DIN24537-1 (Deutsches Institute fur Normung).
- BGI 588 (Instruction Sheet for Gratings).
- RAL-GZ 638 (Quality Assurance for Gratings).
- Technical definitions:
Bearing bars:
A set of parallel members with each other and usually with a rectangular section, which is primarily responsible for bearing the force caused by loading, and at least from the two ends, leaning against appropriate supports, are called grating bars.
Cross bars:
The main task of cross bars is to connect the bearing bars to one another; to maintain integrity; and to prevent their buckling; so, the role of load bearing is ignored by cross bars.
Banding bars:
The bars that are placed at the two ends and sides of gratings are called banding bars, which usually have the same height with bearing bars.
Pitch:
The space from a center to a center of both bearing bars is called bearing bars pitch and the space from a center to a center of both cross bars is called cross bars pitch.
Mesh:
The space between two bearing bars and two cross bars is called grating mesh.
Length of grating:
The external size of gratings in the direction of bearing bars is called grating length.
Width of grating:
The external size of gratings in the direction of cross bars is called grating width.
Span:
The internal space of supports from each other is called span. The most important factor in designing each grating is the span size and direction or the same direction for bearing bars.
Support:
It is called part of the structure that is typically placed on it. How to place gratings on supports requires compliance with its certain standards.
Serration bars:
To avoid slipping in certain areas, serrated bars are used.
- Permissible tolerances:
In the following tables, the maximum dimensional deviation for stairs and gratings is available separately.
Manufacturing tolerances:
- In banding that does not have the bearing role. bearing bars with a space of 120 mm are welded to the banding. but in gratings which the banding is in the bearing position, all bearing bars must be welded to the banding.
- D and D1 are the diameter size and W and W1 the transverse size of the grating panel.
Stretching and spacing among cross bars Bearing bar lean and cross bar location
Installation tolerances:
- Stairs: (in accordance with the standard MBG531 & BS4592):
To produce stairs, the grating panel is first cut to desired dimensions, and then, other parts of stairs are connected to the grating. This forms a set of reliable, standard and safe stairs for using in stairs and the access between floors.
The main components of stairs include:
- Grating: The main part of stairs consists of ordinary grating panels which can be used in both simple and serrated forms.
- Side plate: For easy connection of stairs to the structure, a side plate is used which how to drill it for different types is variable in accordance with the standard.
- Nosing plate: This part of the serrated plate is manufactured with a width of 32
to 36 mm and its tasks include as follows:
- Increased strength of stairs.
- Increased friction and avoidance of slippage.
- Increased safety due to curvature in the front.
- Distinguished edge of stairs in the structure and installation location to increase the safety factor.
In the following, there are some important elements and parameters in designing stairs in accordance with the standard MBG531.
-
Serrated gratings (anti-slip):
When oil, moisture, ice, or specific working conditions cause slippage on the platforms or gratings of corridors. serrated gratings with their anti-slip advantage, create more complete contact between the two levels.
Electro-forged gratings themselves have anti-slip effects due to the use of twisted bars.
- Numbering, galvanizing and packing:
- Numbering:
Gratings must be numbered with a predefined reference number for easy access at installation site. The numbering method of parts is conducted based on customer’s service standard or in accordance with the standard BS4592.
-
Galvanization:
Hot-dip galvanizing is a commonly used method to resist grating against environmental humidity and corrosion. This action means zinc coating on primary raw materials as immerged in a mixture of molten metals, including zinc-based aluminum and nickel. This type of coating is suitable for grating due to its high adhesion and non-fragility as a result of the use of individuals and machines. The average weight for galvanized coating is approximately 610g per square meter. In other words, the thickness of coating is about 80µm, which is different depending on the dimension of bars used (according to the following table).
The standard used in galvanizing is in accordance with ASTM (A123) (USA), BS729 (UK), and DIN EN ISO 1461.
Minimum average coating thickness | Minimum topical coating thickness | Grating thickness mm |
45 | 35 | 1.5>thickness |
55 | 45 | 3>thickness>1.5 |
70 | 55 | 6>thickness>3 |
85 | 70 | Thickness>6 |
- Installing gratings (using clamps):
Installing gratings to the structure is possible in two common ways, depending on the location and use of grating, one of these two methods is used to install gratings:
- Use of welding: In this method, the grating is directly welded to supports; thus, the ends of bearing bars to a length of 20 and height of 5 mm are welded to the structure and the piece is fully fixed (in accordance with MBG531 Standard). Attending to this is necessary that in this method, after welding due to galvanization damaged by welding, a coating restoration operation must be performed.
- Use of clamps: In places where there is no possibility of welding or the use of grating is in such a way that may be displaced, a special clamp is used. For a complete connection, two of these sets are used on each side of the grating.
- Minimum information required for an order:
- Read the brochure carefully.
- Referring to Table 1-3 based on the span, loading force and other working conditions, select the grating type you want.
- Prepare drawings:
- Production drawings with all required details must be provided, and any restrictions on the dimensions and use need to be mentioned.
- Direction of bearing bars of gratings should be determined accurately.
- Location and specifications of nosing plates, reinforcement sheets and fittings.
- Detailed specifications and number of stairs required.
- Specifications of coating required for gratings.
- Number of clamps.
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Address: Pars Moshabak Pardis Company, St. 308, Phase 1, Arak Industrial Park No. 3 (Kheirabad).
Contact No.: +98-8633553585
Fax No.: +98-8633553989
Cellphone No.: +98- 9186282942 (Ahadi).
Email: gratingpmp@yahoo.com.