In our Brühl glossary, we have summarized all the relevant terms relating to machine and plant safety using Brühl safety fence systems. Arranged alphabetically, you can find the term that is important to you and its explanation by simply clicking on the corresponding field.

Axis dimension (AM)

Dimension of a component from the center of the first post to the center of the second post.

Stop direction

The stop direction is determined by the stop side. The stop side of a door is the side to which the door hinges are attached. A distinction is made here between DIN left (stop left) or DIN right (stop right).

Outward opening

As standard, the swing doors are designed so that the door leaf opens outwards (i.e. towards the operator's side).

Ground clearance

Height from the ground to the bottom edge of the lattice element. Ground clearance + grid height = fence height.

Inward opening

With inward-opening doors, the leaves open towards the machine side. This may be necessary if, for example, there is not enough space on the outside. It must be checked whether this is permissible in the respective safety concept. This option is not available for escape doors. They must always open outward in the direction of escape.

Frequency converter (FU)

The frequency inverter changes the mains frequency of the AC voltage (three-phase frequency) from 50 Hz to an adjustable value. The speed of the connected motor depends directly on the three-phase frequency and can therefore be controlled by the frequency inverter. The door can therefore be moved continuously slower and faster and functions such as "creep speed" or "slow start-up" are made possible.

Danger area

Area in or around a machine where a person is exposed to the risk of injury or damage to health. The hazard may be: either permanent during the intended use of the machine (movement of hazardous moving parts, arc during a welding phase, etc.) or unexpected (unintended, unexpected start-up, etc.).

Grid height

Grid height is the height of a grid element. Grid height + ground clearance = fence height.

Fighter profile

The transom profile is a horizontal connecting element of the frame, above the door leaf. This connection of the transom profile with the hinge and stop posts increases the rigidity of the door portal.

Conventional safety switches

Electromechanical safety switches equipped either with an integrated actuating element (type 1) or with a separate actuator (type 2).

Clear width (LB)

The clear width corresponds to the actual available passage width for doors.

Clearance height (LH)

The clear height corresponds to the actual available passage height for doors from the floor to the lower edge of the door sill.


Manipulation is the deliberate overriding or bypassing of protective devices and their components. Safety switches and other safety devices must be designed in such a way that the protective function cannot be changed or bypassed by hand or with a simple aid. Simple aids are: Nail, pieces of wire, adhesive strips, etc. No bypassing by simple means (BGI 575) is: disassembling parts, turning the safety switch away from its protective position, using a second actuator, bridging the contacts, etc. In terms of design, it should be considered that, despite protective devices, simple and intended operation of machines and systems is possible. If this remains unconsidered,

Machine safety

Machine safety colloquially describes protective measures on machines and systems with the aim of avoiding dangerous situations and their risks. The topic of machine safety is viewed from two perspectives. For the manufacturer of the machine, the aim is to place safe machines on the market on the basis of the Machinery Directive and to take safety measures into account as early as the design phase. The operator of a machine or system has the task of ensuring safe working with and on the machine for the protection of his employees.

Average speed

The average speed corresponds to an average value from the various traverse speeds.

Performance Level (PL)

Discrete level that specifies the ability of safety-related parts of a control system to perform a safety function under foreseeable conditions (definition according to standard EN 13849). In simpler terms, the performance level is a measure of the reliability of a safety function. A distinction is made between the performance level to be achieved (PLr; the "r" stands for "required") and the "actual" PL that is actually achieved. There are five performance levels, which represent different residual risks.

Position switch

Position switches are used to detect a position of movable protective devices. As soon as a position switch is used as a safety-related component, it is referred to as a position switch with safety function or a safety-related position switch. In this case, the switching element must contain at least one positive break contact.


The bolt tongue mechanically guides the actuator when it is retracted into the safety switch. The part of the bolt mounted on the door frame consists of a protruding bolt tongue in a guide, a handle and the actuator. The deadbolt receiver and the safety switch are mounted on the mullion side. When closed, the deadbolt receiver absorbs the forces acting on the door that would otherwise act on the switch and the actuator and could damage these components.

Slip resistance/class

Slip classes determine the slip resistance or surface properties of e.g. floor coverings.

Safety Integrity Level (SIL)

Safety Integrity Level describes the probability that a safety-related system fulfills the required safety functions under certain conditions.

Safety Edge

A safety edge detects a person or object and avoids potentially dangerous situations.

Protective device

Protective devices protect people, production goods and the environment from hazards.

Protective measure

A protective measure is a means of reducing the risk. There are protective measures on the design side and protective measures during operation of the plant.

Welding mesh / Spot welding mesh

Spot welded meshes consist of drawn wires that are electrically connected to each other at the crossing points. They are very stable.

Screen printing plate

Screen printing panels are plywood panels with a slip-resistant surface, which are often used in vehicle construction and for hard-wearing utility floors.

Load-bearing equipment monitoring

The load-bearing equipment monitoring system is an electromechanical safety device for preventing the gate leaf from falling down by triggering a signal in the event of a load-bearing chain breaking. Brühl gates with suspension means monitoring always have several suspension means and are designed in such a way that, in the event of failure of one suspension means, the signal of the suspension means monitoring is triggered and the other suspension means holds the leaf in position. In addition, the load-bearing monitoring system can be used to register a malfunction of the traversing unit, which immediately brings the sash to a standstill.

Tear plate

The tear sheet is a resilient and non-slip textured sheet. Rolling gives the sheets their almond-shaped "tears". The underside, however, remains smooth. The arrangement of the tears is designed to provide a high degree of slip resistance and ensure optimum liquid drainage.

Laminated safety glass (VSG)

Laminated safety glass consists of at least two panes of glass, between which a safety film is inserted. In the event of glass breakage, there is therefore no risk of injury, as the pane does not shatter, despite countless cracks.

Laminated safety glass with sound insulation

In laminated safety glass with sound insulation, a 1 mm thick layer of casting resin or a sound insulation film is used instead of the safety film. In both cases, very good sound insulation values can be achieved.

Fence height

The fence height is the total height of the protective fence from the ground to the top of the fence element. Fence height = ground clearance + grid height.

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