The transition bridge is designed for safe passage to any areas inside and outside a construction site or a finished structure. Sometimes the transition bridge is designated mp.
Bridges are divided into:
- industrial, for buildings, industrial structures - for access and transition to serviced facilities.
- household - for roof maintenance, crossing the road, etc.
First, let's look at industrial bridges.
Industrial metal catwalks
Industrial metal crossing bridges are used for safe movement across areas of industrial facilities, such as workshops, filling stations, and any industrial production. All bridges must be made of metal to ensure the required rigidity and reliability. The flooring is made mainly of expanded metal or corrugated sheets, to eliminate the effect of shoes sliding on the transition surface, fencing and handrails are made of metal profiles - pipe, angle, channel.
Metal bridges are:
- stationary - motionless, or movable, but maintaining its shape.
- folding - for convenience. They are unfolded only for work, and then removed. To ensure ease of installation, gas pistons and counterweights are used.
Main and additional handrails and protective fencing must be installed.
Below you can look at the photos of the transition bridges in detail.
These folding bridges also relate to and complement them in the overall metal structure.
Bridges are also used if you need to get around any obstacle, for example a pipe, wires, road, etc. Let's look further.
Bridge crossing over pipeline and trenches
The transition bridge over the pipeline and trenches is designed to safely bypass these obstacles.
It is a metal structure with decking, handrails and protective fencing.
Transitional bridges for roofing
2.3.1. During construction, installation, repair, maintenance and other work at height, ladders are used:
a) attached three-joint sliding doors that meet the requirements of GOST 8556-72;
b) single-arm, inclined, attached, vertical, hinged and free-standing, meeting the requirements of GOST 26887-86;
c) collapsible portable (of seven sections), designed for lifting onto supports with a diameter of 300 - 560 mm to a height of up to 14 m;
d) stepladders, ladders (wooden, metal).
2.3.2. On ladders and stepladders, the inventory number, the date of the next test, and affiliation with the workshop (site, etc.) are indicated: for wooden and metal ones - on bowstrings, for rope ones - on tags attached to them.
2.3.3. The length of ladders should be no more than 5 m.
2.3.4. Extension ladders and stepladders are equipped with a device that prevents them from moving or tipping over during operation. The lower ends of ladders and stepladders should have sharp-pointed fittings for installation on the ground. When using ladders and stepladders on smooth supporting surfaces (parquet, metal, tiles, concrete, etc.), they must be equipped with shoes made of rubber or other non-slip material.
2.3.5. The upper ends of ladders attached to pipes or wires are equipped with special hooks that prevent the ladder from falling due to wind pressure or accidental shocks.
Suspended ladders used to work on structures or wires must have devices that ensure they are firmly secured to the structure.
2.3.6. Ladders and platforms should be installed and secured to the structures being mounted before they are lifted. The dimensions of the extension ladder must ensure that the worker can work while standing on a step located at a distance of at least 1 m from the upper end of the ladder.
2.3.7. When working with ladder at a height of more than 1.3 m, a safety belt must be used, attached to the structure of the structure or to the ladder, provided that it is secured to a building or other structure.
2.3.8. Places where ladders are installed in areas of vehicle traffic or organized passage of people must be fenced or guarded during the work.
2.3.9. Splicing of wooden ladders is allowed by firmly connecting them with metal clamps, bolted overlays, etc. followed by a static load test of 1.2 kN (120 kgf).
Splicing more than two wooden ladders is not permitted.
2.3.10. Install additional support structures from boxes, barrels, etc. if the ladder is not long enough, it is not allowed.
2.3.11. The slope of ladders when lifting workers onto scaffolding should not exceed 60 degrees.
2.3.12. Extension ladders without working platforms may be used only for the transition of workers between individual tiers of a building or for performing work that does not require the worker to rest on the building’s building structures.
2.3.13. Install ladders at an angle of more than 75 degrees. without additional fastening they are not allowed in the upper part.
2.3.14. Stepladders are equipped with devices (hooks, chains) that do not allow them to move apart spontaneously while working with them. The slope of the stepladders should be no more than 1:3.
2.3.15. It is not allowed to work from the top two steps of stepladders that do not have railings or stops.
2.3.16. More than one person is not allowed to be on the steps of a ladder or stepladder.
2.3.17. Raising and lowering a load on a ladder and leaving tools on it is not allowed.
2.3.18. It is not allowed to work on portable ladders and stepladders:
a) near and above rotating mechanisms, working machines, conveyors, etc.;
b) using electric and pneumatic tools, construction and installation guns;
c) when performing gas and electric welding work;
d) when tensioning wires and to support heavy parts at height, etc.
To perform such work, scaffolding and stepladders with upper platforms protected by railings should be used.
2.3.19. It is not allowed to install ladders on flight steps stairwells. To perform work in these conditions, scaffolds should be used.
2.3.20. Before starting work, the stability of the ladder must be ensured, and it must be ensured by inspection and testing that the ladder cannot slip out of place or be accidentally moved.
When installing an extension ladder in conditions where displacement of its upper end is possible, the latter must be securely secured to stable structures.
2.3.21. When working from an extension ladder in places with heavy traffic of vehicles or people, to prevent it from falling from accidental shocks, regardless of the presence of tips at the ends of the ladder, the place of its installation should be fenced or guarded. In cases where it is impossible to secure the ladder when installing it on a smooth floor, a worker wearing a helmet must stand at its base and hold the ladder in a stable position. In other cases, supporting the ladder below with your hands is not allowed.
2.3.22. When moving a ladder by two workers, the ladder must be carried with its tips backwards, warning those oncoming to be careful. When carrying a ladder by one worker, it must be in an inclined position so that its front end is raised above the ground by at least 2 m.
2.3.23. For vertical stairs, stairs with an angle of inclination to the horizon of more than 75 degrees. at a height of more than 5 m, starting from a height of 3 m there must be fences in the form of arcs. The arcs should be located at a distance of no more than 0.8 m from one another and connected by at least three longitudinal stripes.
The distance from the stairs to the arc should be at least 0.7 m and no more than 0.8 m with an arc radius of 0.35 - 0.4 m.
2.3.24. Stairs with a height of more than 10 m must be equipped with rest areas at least every 10 m in height.
2.3.25. The use of portable metal ladders in switchgears with voltages of 220 kV and below is not permitted.
2.3.26. In open switchgears with voltages of 330 kV and above, the use of portable metal ladders is permitted subject to the following conditions:
a) the ladder must be carried in a horizontal position under the continuous supervision of the work foreman, duty officer or employee from the operational and repair service with an electrical safety group of at least IV;
b) a metal chain must be attached to the ladder, constantly touching the ground.
2.3.27. Stairs with metal reinforcement along the string should be considered metal and their use in electrical installations should be carried out taking into account the requirements of paragraphs. 2.3.25, 2.3.26 Regulations.
2.3.28. Stairs and stepladders are inspected by the workman before use (without a log entry).
2.3.29. Ladders must be stored in dry rooms under conditions that prevent accidental mechanical damage.
2.3.30. Platforms hung on stairs or building structures must comply with the requirements of GOST 26887-86.
2.3.31. For the passage of workers performing work on the roof of a building with a slope of more than 20 degrees, as well as on a roof with a coating that is not designed to bear the load from the weight of workers, ladders with transverse bars to rest their feet are installed. The ladders are secured during operation.
2.3.32. Gangways and bridges must be rigid and have fastenings that prevent them from moving. The deflection of the decking at the maximum design load should not be more than 20 mm.
2.3.33. If the length of ladders and bridges is more than 3 m, intermediate supports must be installed under them. The width of ladders and bridges must be at least 0.6 m.
2.3.34. Ladders and bridges must have handrails, edges and an intermediate horizontal element. The height of the handrails must be at least 1 m, the side edges - at least 0.15 m, the distance between the handrail posts - no more than 2 m.
2.3.35. Communication between the tiers of scaffolding is carried out via rigidly fixed stairs.
2.3.36. Connecting adjacent sections of aerial scaffolding with transitional platforms, stepladders and ladders is not allowed.
2.3.37. Gangways must be made of metal or boards with a thickness of at least 40 mm. The gangway must have strips with a cross section of 20 x 40 mm to support the feet every 0.3 - 0.4 m.
2.3.38. The width of the gangway must be at least 0.8 m for one-way traffic and at least 1.5 m for two-way traffic and have railings at least 1 m high.
2.3.39. The permissible load is clearly indicated on the gangway.
2.3.40. Installation and removal of fencing and protective equipment should be carried out using a safety belt attached to belay device or to securely installed building structures. Work must be performed in a technological sequence that ensures the safety of work.
Installation and removal of fences must be carried out by specially trained workers under the direct supervision of the work manufacturer.
(PB 08-624-03)
1. The distance between individual mechanisms must be at least 1 m, and the width of working passages - 0.75 m. For mobile and block-modular installations and units, the width of working passages is allowed at least 0.5 m.
2. Objects that require a worker to rise to a height of up to 0.75 m to service are equipped with steps, and for heights above 0.75 m - stairs with railings. In places where people pass over pipelines located at a height of 0.25 m or higher from the surface of the ground, platform or floor, transition bridges must be installed, which are equipped with railings if the height of the pipeline is more than 0.75 m.
3.Marching stairs must have a slope of no more than 60° (for tanks - no more than 50°), the width of the stairs must be at least 65 cm, for stairs for carrying heavy loads - at least 1 m. The distance between steps in height should be no more than 25 cm. Steps should have an inward slope of 2-5°.
On both sides, the steps must have side strips or side trim at least 15 cm high, eliminating the possibility of a person’s feet slipping. Stairs must be equipped with 1 m high railings on both sides.
4. Tunnel-type stairs must be metal wide at least 60 cm and, starting from a height of 2 m, have safety bars with a radius of 35-40 cm, fastened together with strips. The arcs are located at a distance of no more than 80 cm from one another. The distance from the most distant point of the arc to the steps should be within 70-80 cm.
Stairs must be equipped with intermediate platforms installed at a vertical distance of no more than 6 m from one another.
The distance between the steps of tunnel-type stairs and stepladders should be no more than 35 cm.
5.Working platforms at height must have a flooring made of metal sheets with a surface that prevents slipping, or boards with a thickness of at least 40 mm and, starting from a height of 0.75 m, railings 1.25 m high with longitudinal strips located on a distance of no more than 40 cm from each other, and a side with a height of at least 15 cm, forming a gap of no more than 1 cm with the flooring for liquid drainage.
At maintenance sites completed before the publication of these Rules, it is allowed to drill holes with a diameter of at least 20 mm along the perimeter of the platform deck with a distance between holes of at least 250 mm.
6. Work associated with the danger of a worker falling from a height must be carried out using a safety belt.
7. Safety belts and halyards should be tested at least twice a year with the static load specified in the manufacturer’s operating instructions by a special commission with the execution of a report. In the absence of such data in the operating instructions, the test should be carried out with a static load of 225 kgf for five minutes.
8. For fire and explosion hazardous industries (oil treatment plants, tank farms, etc.) application wooden flooring prohibited.
Temporary use of wooden flooring made from boards with a thickness of at least 40 mm is allowed when carrying out work from scaffolding during the repair of completely stopped equipment and apparatus, buildings and structures.
9. All potentially dangerous places at oil and gas production facilities (open tanks, transmissions, etc.) must have fences that block access to them from all sides.
Open the doors of the guards or remove the guards after the equipment or mechanism has completely stopped. Starting the equipment or mechanism is permitted only after all removable parts of the fence have been installed and securely secured.
10. The height of the railings must be at least 1.25 m (for drive belts at least 1.5 m), the height of the lower belt of the fence must be 15 cm, the gaps between individual belts must be no more than 40 cm, and the distance between the axes of adjacent racks - no more than 2.5 m.
When using handrails for drive belts with outside Metal front shields are installed on both pulleys in case of a belt break. It is allowed to use railings to block access to moving parts of equipment and mechanisms, if it is possible to install fences at a distance of more than 35 cm from danger zone. If this is not possible, the fence should be made solid or mesh.
11. The height of the mesh fencing for moving equipment elements must be at least 1.8 m. Mechanisms with a height of less than 1.8 m are completely enclosed. The size of the mesh cells should be no more than 30´30 mm. Mesh fencing must have a metal frame (frame).
31. Places of passage and access to technical devices which require lifting a worker, or service personnel to a height of 0.75 m, are equipped with steps, and at a height above 0.75 m - with stairs with railings. In places where people pass over pipelines located at a height 0.25 m and above from the surface of the earth, platform or floor, transition bridges must be installed, which are equipped with railings if the height of the pipeline is more than 0.75 m.
32. Flight stairs should have a slope of no more 60
degrees (for tanks - no more than 50 degrees), the width of the stairs must be at least 0.65 m, for stairs for carrying heavy loads - at least 1 m. The distance between the steps in height should be no more than 0.25 m. The width of the steps should be at least 0.2 m and have an inward slope of 2 - 5 degrees.
On both sides, the steps must have side strips or side cladding with a height of at least 0.15 m, eliminating the possibility of human feet slipping. Stairs must be equipped with 1 m high railings on both sides.
(Changed edition. Amendment No. 1)
33. Tunnel-type stairs must be metal with a width of at least 0.6 m and have, starting from a height of 2 m, safety arches with a radius of 0.35 - 0.4 m, fastened together with strips. The arcs are located at a distance of no more than 0.8 m from one another. The distance from the most distant point of the arc to the steps should be within 0.7 - 0.8 m.
Stairs must be equipped with intermediate platforms installed at a vertical distance of no more than 6 m from one another.
The distance between the steps of tunnel-type stairs and stepladders should be no more than 0.35 m.
34. Working platforms and service areas located at height must have a flooring made of metal sheets with a surface that prevents slipping, or boards with a thickness of at least 0.04 m, and, starting from a height of 0.75 m, railings with a height of 1, 25 m with longitudinal strips located at a distance of no more than 0.4 m from each other, and a side with a height of at least 0.15 m, forming a gap with the flooring of no more than 0.01 m for liquid drainage.
45. In places where people cross over rows of pipelines laid on the surface of the ground, as well as over ditches and trenches, transitional walkways with a width of at least 0.65 m with railings at least 1 m high should be installed.
