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UVGI technology at a glance_Part_II

Articles UV-C
23.08.2024
UVGI technology at a glance_Part_II - Light Progress
How exactly do UV-C lamps work? What are their advantages and considerations for safe use?
In this article we will look in more detail at some key aspects that are crucial to the effectiveness and durability of UV-C-based solutions.

1. CONSIDERATIONS ON THE RELATIONSHIP BETWEEN UVC RAYS AND MATERIALS SUCH AS GLASS, QUARTZ, AND PLASTIC
When discussing UVC technology, it's crucial to understand how ultraviolet rays interact with various non-metallic materials such as glass, quartz, and plastic. The transparency and resistance of these materials to UVC rays directly affect the effectiveness of disinfection and sterilization applications. In this paragraph, we will explore the properties of various non-metallic materials and the implications of their use in UVC systems.

Transparency of Glass and Quartz to UVC Rays
Glass and quartz differ significantly in their transparency to UVC rays, which are ultraviolet rays with wavelengths between 200 and 280 nm.
  • Standard Glass: Ordinary glass is generally not transparent to UVC rays. The silica and other compounds in glass absorb UVC light, preventing it from passing through. This makes regular glass unsuitable for applications that require the transmission of UVC radiation, such as in sterilization or disinfection processes.
  • Quartz: In contrast, quartz is highly transparent to UVC rays. Quartz glass, particularly fused quartz, allows UVC light to pass through with minimal absorption. This property makes quartz an ideal material for UVC lamps and other devices where the effective transmission of UVC radiation is critical.

Benefits of Using Light Progress UVC Lamps Coated with Quartz
UVC lamps coated with quartz offer several key advantages:

  • Enhanced UVC Transmission: Quartz has excellent transparency to UVC radiation, allowing for maximum transmission of UVC light. This ensures that the lamp emits a high level of UVC energy, which is critical for effective disinfection and sterilization.
  • ​Increased Durability: Quartz is highly resistant to thermal shock and can withstand high temperatures. This makes UVC lamps with quartz coating more durable and long-lasting, especially in environments where the lamps are used continuously.
  • Improved Safety: Quartz can help contain hazardous materials, such as mercury, used within UVC lamps. This containment reduces the risk of exposure in the event of lamp breakage, enhancing the overall safety of the device.
Resistance of Plastic Materials to UVC Rays
The resistance of plastic materials to UVC rays is a crucial topic, especially in fields like sterilization and disinfection, where UVC rays are used to eliminate microorganisms. UVC rays, part of the ultraviolet light spectrum with wavelengths between 200 and 280 nanometers, have high energy that can damage various materials, including plastic polymers.

Plastics exposed to UVC radiation can undergo significant degradation, manifested by yellowing, brittleness, and loss of mechanical properties. The chemical structure of the plastic plays a key role in its resistance: polymers like polyethylene (PE) and polypropylene (PP) are generally more susceptible to damage, while others, such as polytetrafluoroethylene (PTFE), known for its high chemical resistance, offer greater resistance to UVC rays.

Transparency of Plastic Materials to UVC Rays
The transparency of plastic materials to UVC rays varies significantly depending on the type of plastic. In general, most common plastics, such as polyethylene (PE) and polypropylene (PP), are not transparent to UVC rays. These materials tend to absorb UVC radiation, reducing the effectiveness of the rays in passing through them. This absorption can also lead to the degradation of the plastic material over time, making it brittle or discolored.

However, there are some specialized plastics, such as PTFE (polytetrafluoroethylene) and certain forms of acrylic, that have higher transparency to UVC rays. These materials are designed for applications where UVC transmission is required, but they are generally less common and more expensive.

UVLON™ protective sleeve by Light Progress
The UVLON sleeve is a special thermo-shrinked sleeve made of FEP (Fluorinated Ethylene Propylene), designed specifically for Light Progress UV solutions. The sleeve can be applied on UVC lights and allows UV-C light effects (up to 85% penetration through the sleeve) while providing the following advantages:
  • Provides mechanical protection for each UV-C tube, enhancing the safety of the UV system;
  • Increases the lifetime of the UV lamps;
  • Effectively shields food, air, water, and other items from potential glass fragments and mercury leaks in case of accidental UVC lamp breakage;
  • Is highly durable, offers low adhesion to any substance, and is resistant to wear, aggressive chemicals, as well as extreme temperatures;
2. MERCURY IN UV-C LAMPS: SAFE AND CONTROLLED USE
The mercury used in UV-C lamps is present in very small quantities and managed safely.
The mercury content in Light Progress' low-pressure lamps is less than 10 mg per lamp.
This element is used to emit ultraviolet radiation at an optimal wavelength for disinfection. Thanks to advanced technology and strict manufacturing standards, the amount of mercury is contained in sealed glass tubes, thus reducing risks even in the event of breakage.

No Transport Limitations for UV-C Lamps
A particularly positive aspect is that the transport of UV-C lamps is not subject to significant restrictions. The laws on the transport of hazardous materials recognise that the amount of mercury is so small that it poses no real risk to human health or the environment. UV-C lamps can therefore be transported without special restrictions, facilitating their use in numerous contexts, from healthcare facilities to domestic environments.

3. UVC LAMP WARM-UP TIME AND ON/OFF CYCLES
The switch-on time of UV-C lamps plays a crucial role in their ability to disinfect effectively:
  • Optimum Switch-on Time: For effective disinfection, the lamp must be switched on long enough to deliver the correct dose of UV-C radiation.
  • Warm-Up and Maximum Effectiveness: Some lamps, especially low-pressure mercury lamps, require a short warm-up period (from 2 to 5 minutes) to reach maximum radiation output.
  • On and Off Cycle: UV-C lamps are most effective when used in continuous cycles, as frequent switching on and off can reduce lamp life.​

4. OPERATING TEMPERATURES AND UVC LAMP PERFORMANCE
Ambient temperature significantly impacts the performance of UV-C lamps, especially low-pressure mercury lamps:

  • Optimal Temperature Range: Traditional lamps perform best between 20°C and 30°C. Temperatures that are either lower or higher can reduce UV-C radiation emission effectiveness.
  • ​Effects of Extreme Cold: At temperatures below 10°C, UV-C emission can drop drastically. Specific solutions, such as Light Progress products designed for cold cells or similar environments, can address this issue.
  • Effects of High Heat: Temperatures above 40°C can negatively affect UVC device performance. In such cases, cooling systems or covers to protect against direct sunlight exposure should be used for outdoor installations.


TALK TO AN EXPERT: Our product specialists are fully available for free consultation on UVC systems and potential adaptations to your needs. Visit the CONTACT page and call one of our branches to schedule an appointment.

F.A.Q.

Ultraviolet rays are electromagnetic waves which are part of light. Electromagnetic waves are divided into three main wavelength bands, expressed in nanometers, nm: Ultraviolet rays (UV) 100-400 nm Visible rays (light) 400-700 nm Infrared rays (IR) 700-800,000 nm UV rays are in turn identified in three bands:

  • UV-A (315-400 nm) with tanning properties;
  • UV-B (280-315 nm) con proprietà terapeutiche e di sintesi della vitamina "D";
  • UV-C (100-280 nm) with germicidal properties.

UV-C rays (100-280 nm) have a strong germicidal effect and reach their maximum efficacy at the 265 nm wavelength. The germicidal effect of UV-C radiation covers bacteria, viruses, spores, fungi, moulds and mites; this is mainly due to the destructive effect of the UV-C rays on their DNA, which damage their reproductive system and prevent them from replicating.

Bacteria, Viruses, Spores, Fungi, Mould, and Mites are all sensitive to, and can therefore be eliminated with, UV-C light. Mircrobes cannot acquire resistance to UV-C light, unlike that which occurs using chemical disinfectants and antibiotics. UV rays are ecological. Polluting the environment is inevitable using normal disinfectants. Directly inhaling the vapours, or swallowing food products contaminated by any contact with said chemical disinfectants, can also give rise to a number of serious risks. In cases where chemical disinfectants cannot be eliminated (food, pharmaceutical, healthcare industries, etc.), using ultraviolet rays for disinfection allows a reduction in their use, with considerable economic savings and greater care for the environment, while maintaining and almost always improving the level of disinfection. UV-C light devices can be installed in environments and on machinery and be programmed to maintain the same level of disinfection day and night, guaranteeing ideal hygiene conditions, without highs and lows. On the contrary, chemical disinfectants are effective only during their actual use. Using LIGHT PROGRESS equipped luminaires, operating costs are negligible; it could be said that “LIGHT PROGRESS” UV-C systems do not require maintenance except for the normal replacement of the lamps. The cost/benefit ratio is considered excellent; the devices are both powerful and long-lasting. Hence the elimination of germs using UV-C technology is low-cost and highly effective compared to (or in combination with) other systems.

UV-C really does work when applied correctly and with the necessary precautions. The difference between a quality project and an unsuccessful application is in-depth knowledge and experience gained over time. Since 1987, Light Progress has been carrying out successful projects all over the world and has acquired a clientele of major companies in all sectors that require verified hygienic conditions to produce quality products and services.