Classification of machine safety guards
The safety guards are classified:
- according to use into movable and fixed protective grilles,
- according to material into steel or aluminium protective grilles,
- by function into barrier and safety light grids.
At the same time, there are certain requirements for machine safety guards or safety guard systems. They must fit the machine in terms of their dimensions and, if necessary, ensure easy access to it with the aid of doors. Their stability must be able to withstand the forces likely to be exerted by falling parts in the machine hall or the ejection of machine parts. Their nature and the distance from the machine must prevent accidental intrusion by the operator (DIN EN ISO 13857).
Compliance with the applicable standards and safety regulations is monitored by recognized expert organizations such as the TÜV. In German companies, a safety specialist must be appointed to monitor compliance with the standards. Protective grids in production plants are comprehensively planned. They have to withstand a wide range of accident scenarios.
Areas of application of machine safety guards
For effective accident and personal protection, machine guard grilles or guard grille systems are used wherever machines or vehicles move (warehouses, logistics) and/or cause hazards due to their own moving parts, even if they themselves are permanently mounted. In this context, the protective grids are often only one part of the overall safety concept, which also includes prohibition signs and, increasingly, light barriers. The latter cause an emergency shutdown of the machine if an operator approaches too closely. However, this measure does not protect against an accident caused by parts falling into the machine or parts being ejected from the machine. Therefore, machine guards or protective grating systems remain indispensable.
Their use is necessary in these places, among others:
Characteristics of the machine guards
- Conveyor belts
- Room dividers for warehouses
- Turbine halls
- Operator cabins (of cranes, among other things)
- Enclosures for production lines
- Room dividers for industry
- Protective grids on logistics vehicles
The protective grilles are made of metal profiles, which enables their modular construction. In addition, they have doors with tamper-proof suspensions. They can be stationary or mobile. In their variants, they can be assembled and disassembled by a single worker. The mesh sizes can vary. A common size is 20 x 100 mm with 3.0 mm wire thickness. The standard paint should be jet black, but other colours are often used.
Our standard colour is RAL 9005 deep black, as recommended in the Machinery Directive.
Furthermore, we also have frame and frameless elements in our program.
A practical example would be the protective grille around a turbine in a power station.
During normal operation, the turbine rotates at 3,000 rpm, which generates very high forces. However, the danger is less during normal operation than during start-up after a general overhaul (or during initial commissioning), namely when running through the critical speeds (several ranges below 3,000 rpm). It's true that the turbine has a solid housing that no one can reach into, and that should also prevent turbine blades from being ejected. But if the turbine does not pass through a range of critical speeds quickly enough during startup, an imbalance occurs that can cause a turbine blade or wheel to come loose, ejecting the part with a force that even the housing could not withstand. In this case, the machine guard or equivalent would be the next barrier.