Article 40 –Escalator Electromagnetic Radiation hazards
Introduction of escalator electromagnetic radiation hazards
escalator Electromagnetic radiation hazards are another important risks of escalators. Electromagnetic (EM) radiation is inevitable in the modern world and it exists in many forms surrounding us such as radio waves, microwaves, X-rays, and gamma rays.
Although electric and magnetic radiations are two different fields of study, they are inextricably linked and, therefore, are studied together as electromagnetic field (EMF).
Even sunlight is a form of EM energy; however, the visible light only contains a small portion of the Electromagnetic spectrum, which contains a broad range of electromagnetic wavelengths. Electromagnetic waves carry energy and transfer it through interaction with objects. The more the amount of energy is, the stronger the electromagnetic radiation will be.
Electromagnetic radiation consists of Low- frequency and high-frequency radiation. The low-frequency does not directly affect human health and is a type of non-ionizing radiation, while the high-frequency radiation is classified as ionizing radiation which could have negative effects on human health.
Escalators & moving walks as well as other machines can emit electromagnetic radiations or get affected by them from their surroundings as mentioned in the following:
Electromagnetic radiation generated by escalators and moving walk
No electronic system or device is an exception when it comes to generating electromagnetic waves. Escalators could also emit electromagnetic radiation during their normal operation. However, such radiation could be eliminated or reduced by considering EMC (Electromagnetic Compatibility). In addition, the internal power supply units must be constructed and arranged in a way that the appearance of false signals at the outputs of safety devices, which occur due to switching, is prevented. Moreover, based on the required standard, inadmissible disturbances (noise, immunity) in electronic components must not be created by voltage peaks that arise due to the operation of the escalator and must comply with EN 12015:2014 and EN 12016:2013.
There are some ways to suppress the emission of electromagnetic radiation as below:
- Preventing the integration of unnecessary switching operations
- Separation of noisy circuit
- Implementing the spread spectrum method
- Reduce emission by the lower signal level design
Electromagnetic radiation received from outside by escalators and moving walks:
Escalators and moving walks could receive Electromagnetic radiation such as low or high-frequency radiation, radio-frequency radiation, and microwaves during their normal operation.
Unwanted signals could be received by the control panel of escalators (interference by conductivity). Also, there are always cables of different sizes in a circuit or a system, which sometimes act as antennas, and could receive electrical and magnetic interferences. The quality of the shielding material and the cable screen grounding are two basic elements of cable performance.
Grounding is a significant way to minimize the RF effect and also shielding cables can minimize these effects to the lowest level possible. Signal wires are grounded on one or both ends and are surrounded by an outer conductive layer. Also, a conductive metal housing layer that performs as an interference shield consisted of sections and RF gaskets could be used to prevent any leakage.