Is infrared heating safe?
More and more often infrared lamps are used on terraces, giving thermal comfort in outdoor areas of commercial premises, providing heat and extending the stay of customers even on the coldest and harshest winter evenings. However, innovative and immediate heating techniques are not always the most suitable from a safety point of view. Let’s take a closer look at how infrared radiation works and the effect it has on the human body.
- Radiation heating: how it works
- Safe use of infrared lamps
- Solutions to ensure safety
Radiation heating in infrared lamps
Rooms or objects can be heated by contact or without contact.
Contact heating is called conduction if there is a source of heat, or convection if there is contact with a heated medium, such as air. If the heating takes place through contact, the warmer source transmits heat to the colder source, that then heats up to reach thermal equilibrium.
Infrared (IR) lamps, on the other hand, use non-contact heating, which is carried out by irradiation and radiation with IR ray wavelengths. The process can be optimized in terms of efficiency if the object to be heated has an absorption coefficient that is comparable to the action spectrum of the lamp used. The types of infrared rays can be short wave (IR – A), medium wave (IR – B) or long wave (IR – C). The object irradiated by the heat source, which in this case is the infrared lamp, absorbs at least 92% of the energy supplied by the source. Although the lamps are named according to the type of wave they emit, long, medium or short, in reality the transmitted waves are never of one single type, but have differing wavelengths due to interference with other waves of the same type. In fact, they are classified as lamps that work as:
– Medium wave metallic infrared
– Medium wave quartz infrared
– Short wave quartz infrared
Infrared lamps are used for the main purpose of heating, given their efficiency and versatility in the various service environments. They can meet any need, from industrial use, to use in restaurants or on private terraces.
Infrared lamps are often used for industrial purposes, to heat thin layers of semiconductors, to weld plastic materials, to harden resins, to fix printer toners, to harden cement and are so versatile that they can even be used to shrink sheeting, evaporate chemical solvents and to release residual stresses created by mechanical processes such as welding on metal.
Having listed the main features and their efficiency, are we sure that radiation heating by infrared lamps is safe?
Certainly, the correct installation of the lamps, according to the instructions and standards provided by the manufacturer, is the basis for the safe use of the product. Just as important, however, is the professionalism of the lamp installer. Besides correct installation, are we sure that a product that provides a type of heating by infrared radiation is not harmful to the environment or to human health?
To answer this, the evidence of scientific studies carried out to answer this question needs to be evaluated.
The investigation to further explore a study on the possible risks that man runs using these new types of heating was brought about by the local health authority (ASL) of Siena. The study was undertaken to assess the risks of exposure for workers and patrons, such as customers in bars.
The research was carried out taking into consideration a number of types of infrared lamps, in particular those with a nominal power between 1000 W and 2000 W. We would like to point out that there are laws and regulations designed to protect the health of operators, in particular establishing limits for ocular exposure to this radiation. In fact, from a medical point of view, if these limits are exceeded, the human eye is exposed to a risk of permanent thermal damage to the cornea.
In fact, studies show that most of the lamps emit optical IR-A radiations, which can cause permanent damage to the eyes even after a few seconds at too close distances, causing cataracts, corneal burns and progressive loss of transparency of the lens.
As for the effects of radiation from infrared lamps on the skin, other studies have been carried out. The type of wave (IR – A, IR – B, IR – C) has varying impacts on the skin, specifically, the lower the frequency, the deeper the wave penetrates. So undoubtedly the IR-A waves that reach the subcutaneous tissue can be the most damaging. The IR-Bs are slightly less worrying, reaching only as far as the dermis, and the irradiation of IR-C waves penetrating only as far as the epidermis, are relatively harmless.
It is important to know, however, that IR-A waves are used for medical purposes, precisely because of their penetrative capacity. Therefore, the use of infrared waves, when regulated by adequate standards and carried out by competent operators for appropriate purposes, do not create problems for human health. Obviously, exposure must not be prolonged and safety distances must also be respected. The correct application of systems of this kind is therefore of vital importance, as well as their correct installation.
Solutions to ensure security
First of all, it is necessary to use good quality infrared lamps, that have authentic certificates regulated by the appropriate laws. It is then essential to rely on competent and professional staff both for installation and use, and for putting the right safety systems in place.
Furthermore, it is not enough to rely on competent personnel: it is also useful to seek information privately and independently, as very often in the user manuals of these heaters there may not be a warning regarding medical risks. Therefore, it is good practice to keep a safe distance, limit exposure times, and use safety equipment when using machines operating via infrared heating.