Bar Grating: Types, Technical Parameters, Installation and Fastening
In industrial and civil construction, bar grating is used to create walkways, work platforms, stairs and decking. This metal or composite structure combines load‑bearing capacity with low weight. The article reviews types of grating: welded, press‑locked, fiberglass, aluminum. Materials are described: galvanized steel, stainless steel, fiberglass. Dimensions, thickness, profile height, loads, weight per m², technical specifications and GOST are provided. Fastening methods using clamps, clips, hold‑down clips, top hold‑down clips and fasteners are detailed. Recommendations for installation and mounting on platforms, walkways, stair treads are given, along with ordering rules for drawings, manufacturing at the factory and obtaining a certificate.
1. What is Bar Grating: Structure and Materials
Bar grating is a flat grid consisting of load‑bearing bars and cross bars arranged at right angles. This structure provides rigidity with low weight and free passage of light, air and liquids. Main applications are platform covers for equipment maintenance, stairs, pedestrian walkways, trench covers, and gantries. Metal grating is made of steel or aluminum, while composite grating is made of fiberglass.
Basic materials:
- Galvanized grating of galvanized steel – the basic choice for most industrial facilities. Hot‑dip galvanizing protects the metal against corrosion for 20‑30 years.
- Stainless steel grating – for aggressive environments: chemical plants, food industry, offshore platforms.
- Aluminum grating – lightweight, rust‑proof, but with a lower load‑bearing capacity. Used on high‑rise buildings, temporary structures, ships.
- Fiberglass grating – made of fiberglass. Non‑conductive, resistant to acids and alkalis, 4‑5 times lighter than steel. Used in electroplating shops, water treatment plants.
According to the manufacturing method, welded and press‑locked gratings are distinguished. Welded – the intersections of load‑bearing bars and flat cross bars are joined by resistance welding. It offers high rigidity. Press‑locked – the elements are fixed in a die without welding, providing a neater appearance and higher corrosion resistance at the joints.
2. Technical Characteristics: Dimensions, Weight, Loads, GOST
The main parameters of bar grating are regulated by GOST R 56954‑2016 “Steel bar gratings” and the manufacturers’ technical specifications. Key dimensions:
- Height of the load‑bearing bar (profile) – 20, 25, 30, 35, 40, 45, 50, 60 mm.
- Thickness of cross bars – 2, 3, 4, 5 mm.
- Pitch (mesh) – the distance between load‑bearing bars from 20 to 60 mm, between cross bars – usually 38 or 50 mm.
- Typical combinations: 30×3 (height 30 mm, thickness 3 mm), 33×33 30×3 (mesh 33×33 mm at height 30 mm), 34×38 30×3 (mesh 34×38 mm), 33×11 30×2 (small mesh to prevent falling of small objects), 34×38 (one of the most common sizes).
Weight per m² depends on the profile height, thickness and pitch. For steel galvanized grating with a 34×38 mm mesh and a height of 30 mm and thickness of 3 mm, the weight of 1 m² is about 28 kg. At a height of 40 mm and thickness of 5 mm – up to 55 kg/m². The mass of aluminum grating is 2‑3 times less, and that of fiberglass grating is 4‑5 times less. The total weight of the batch is calculated for estimates and transport costs.
The loads that the grating can withstand are determined by limit state design. For pedestrian zones the allowable uniformly distributed load is 3‑5 kN/m², for technological platforms – up to 10‑15 kN/m², for vehicle passages (gantries) – up to 20 kN/m². The maximum span between supports depends on the load and profile height. For example, for a grating with a height of 30 mm under a load of 5 kN/m² the maximum span is 1.2 m, under 10 kN/m² – 0.8 m.
3. Types of Gratings by Manufacturing Method and Mesh Shape
Welded grating is preferred for heavy‑duty operating conditions. The load‑bearing bars are made of flat steel, while the cross bars are of serrated or plain flat bar. Load‑bearing pitch: 20, 30, 40 mm. Cross bar pitch: 38, 50, 76 mm. Standard panel width: 600, 800, 1000, 1200 mm, length – up to 6000 mm. Welded grating of galvanized steel is most often ordered for outdoor platforms.
Press‑locked grating is produced by cold pressing. The elements are inserted into a die and compressed under pressure, ensuring a monolithic structure without welding. The meshes are square or rectangular. Such gratings have an attractive appearance and are used in clean rooms and food production facilities.
Fiberglass grating is formed by pultrusion or contact molding. The meshes are most often square: 25×25, 38×38, 50×50 mm. It possesses dielectric properties and is not subject to corrosion in acidic and alkaline environments. Operating temperature range is –60 °C to +100 °C. Composite grating is a general term for fiberglass and carbon‑fiber gratings.
Aluminum grating is produced by welding or press‑locking. Its lightness facilitates installation at height. It is used on tower platforms, ships, and in architectural elements.
4. Fastening of Bar Grating: Clips, Clamps, Hold‑down Elements
Reliable fixation of the grating to the supporting beams or stringers is a critical safety requirement. Special fasteners are used for fastening. The main types are:
- Fastener (clamp) – an L‑shaped or U‑shaped element made of galvanized steel. It embraces the load‑bearing bar and is bolted to the support. Allows quick removal of the grating when necessary.
- Clip – an arc‑shaped band that presses the grating to the beam from above. Requires top access for tightening the nuts.
- Hold‑down clip – a flat part with a bolt hole. Placed into a grating mesh and pulls it down to the support. Does not protrude above the surface.
- Top hold‑down clip – a variant that is fastened from above onto the load‑bearing bar. Provides a rigid connection without lifting the grating.
- Top clip – a general term for clips installed from above.
The number of fastening points per panel is determined by calculation. For a typical 1000×1000 mm panel 4 clamps at the corners are sufficient. For narrow walkways fastening through every other load‑bearing bar is allowed. Under increased vibration the fastener spacing is reduced to 300 mm. For stairs, each tread is fixed with at least two clips. For stair treads anti‑slip inserts or serrated surfaces are mandatory.
Fastening elements must be of the same material as the grating or have an anti‑corrosion coating. For galvanized grating – galvanized steel, for stainless – stainless steel, for aluminum – aluminum. Bolts and nuts – stainless or galvanized with a fine thread.
5. Fabrication and Production: Factory, Drawings, Technical Specifications
Manufacture of bar grating is carried out at specialized factories. Production includes the following steps: cutting the strips, punching holes or serrations, welding or press‑locking of nodes, edge trimming, straightening, coating or galvanizing. For each order drawings of the cutting plan are prepared, indicating the panel dimensions, the location of cutouts for equipment, and the fastening details.
Technical specifications (TU) are developed by the manufacturer based on GOST R 56954‑2016. The TU define the permissible dimensional deviations, requirements for welded seams, quality of galvanizing, and inspection methods. Each batch of grating is accompanied by a quality certificate and a certificate of conformity. The manufacturer also provides a load table for the specific size.
When ordering grating of non‑standard dimensions or with a custom configuration of cutouts, the drawings are agreed with the factory. For installation layouts the positions of supporting beams and fastening points are indicated.
6. Installation and Erection of Bar Grating
Installation of the grating is performed after completion of the welding of the supporting steel structures and their priming. The installation steps:
- Checking the horizontality of the supporting beams with a spirit level. Height difference shall not exceed 2 mm per metre.
- Laying out the grating panels with a 5‑10 mm gap for thermal expansion. Panels are laid from one edge to the other.
- Fixing each panel to the beams with clamps, clips or hold‑down clips. The number of fasteners is according to calculation, but not less than 4 per panel.
- If necessary, welding panels together to form a monolithic deck. Welded seams are made every 300‑500 mm.
- Installing anti‑slip inserts on treads and in high‑traffic areas.
- Mounting of edge strips, guardrails, transition bridges.
- Finishing treatment: touch‑up painting of areas damaged during welding, checking the tightening of all bolted connections.
During installation at height, safety harnesses must be used. Welding or cutting of grating without protective earthing of the equipment is prohibited. After completion of the work, a visual inspection and a tightening check of every fastening are carried out.
7. Anti‑slip Properties and Safety
A mandatory requirement for gratings used in wet conditions, oil contamination or on inclined surfaces is the presence of anti‑slip protection. Provision methods:
- Serration (notching) on the upper edges of the cross bars. Diamond or one‑directional serration increases the friction coefficient.
- Use of inserts made of abrasive material (silicon carbide, aluminium oxide) pressed into the surface.
- Laying rubber or polyurethane inserts on treads and walkways.
- For stair treads, ready‑made treads with a yellow anti‑slip strip are used.
The coefficient of friction between the grating and the shoe sole must be not less than 0.4 in accordance with GOST R 56954. In wet zones gratings with a mesh size of not more than 30×30 mm are recommended to eliminate the risk of a heel catching or foot entrapment.
8. Application of Bar Grating: Platforms, Walkways, Stairs, Gantries
Bar grating is in demand in a wide variety of industries.
Platforms for equipment maintenance – the most widespread application. These include inspection walkways around machines and pumps, access platforms to valves, working zones on cranes and conveyors. The grating is laid on a steel frame made of I‑beams or channels.
For walkways – pedestrian walkways on the territories of plants, warehouses, filling stations, water treatment facilities. Bar grating ensures drainage and anti‑slip properties, reducing the risk of injuries.
For stair treads – grating is used as treads. The treads are made from a solid panel or assembled from two parts with a gap between them. The presence of guardrails and handrails is mandatory.
Stairs entirely (stringers, treads, landings) can be made from bar grating. Such stairs are lightweight, fire‑safe, and do not accumulate water or snow.
Equipment for gantries – unloading gantries, overflow bridges, platforms for tank maintenance. Here gratings with a high load capacity up to 20 kN/m² are used. Go to the trestle equipment section.
9. Calculation of Weight and Mass for Cost Estimate Documentation
The weight per m² and total mass of the grating batch are needed for preparing cost estimates, selecting the lifting capacity of mechanisms and transport costs. Manufacturer tables are used for accurate calculation. Approximate values for steel grating made of galvanized steel with a 34×38 mm mesh:
| Profile height, mm | Strip thickness, mm | Weight 1 m², kg |
|---|---|---|
| 20 | 3 | ~18 |
| 25 | 3 | ~22 |
| 30 | 3 | ~28 |
| 35 | 4 | ~40 |
| 40 | 5 | ~55 |
| 50 | 5 | ~70 |
For aluminum grating the weight per m² decreases by 2.5‑3 times, for fiberglass – by 4‑5 times. Knowing the covering area, it is easy to compute the weight of the batch and order a crane of suitable lifting capacity.
10. Certification and Compliance with Standards
Each batch of bar grating must have a certificate of conformity. Mandatory requirements:
- TR CU 014/2011 “Safety of automobile roads” – for pedestrian crossings and walkways.
- TR CU 010/2011 “On safety of machinery and equipment” – for service platforms.
- Fire safety certificate – for gratings used on escape routes.
The certificate confirms that the product has passed tests for load, corrosion resistance and welding quality. The quality certificate specifies the steel grade, the thickness of the zinc coating for galvanized grating of at least 40 µm, and the strength of welded joints. For fiberglass gratings the certificate contains data on dielectric strength and resistance to chemical reagents. Compliance with GOST R 56954‑2016 guarantees the stability of geometric parameters.
11. Ordering and Purchase of Bar Grating: What to Consider
To buy bar grating, it is necessary to determine the following parameters:
- Material: galvanized steel, stainless steel, aluminum or fiberglass.
- Type: welded or press‑locked.
- Profile height and strip thickness: for example, 30×3 or 34×38 30×3.
- Panel dimensions: standard or according to drawings with cutouts.
- Type and quantity of fasteners: top hold‑down clip, clamps, clips.
The order is placed at the factory or with a distributor. The products are presented in the bar grating section. Various sizes are available there, including 33×33 30×3, 34×38, 33×11 30×2. Accompanying elements can be ordered with the grating: wire mesh flooring (for fences and trays) – follow the link wire mesh flooring.
12. Conclusion
Bar grating is a reliable solution for creating industrial decking. The choice between welded, press‑locked, fiberglass or aluminum type depends on the operating conditions. Important parameters are profile height, thickness, weight per m² and allowable loads. High‑quality fasteners in the form of top hold‑down clips, clips, clamps ensure durability. Correct installation and mounting with compliance with technical specifications and GOST guarantee safe operation. The products are certified, supplied with drawings and a quality passport. You can purchase the grating from the manufacturer through the bar grating section.
