The information below is extracted from the research paper: "Fluence (UV Dose) Required for up to 99% disinfection from Viruses, Bacteria, Protozoa and Algae"  that can be downloaded also on our website at the links below:

PDF: Fluence (UV Dose) Required to Achieve Incremental Log Inactivation of Bacteria, Protozoa, Viruses and Algae

Germicidal action of UV radiation

The effectiveness of sterilization or disinfection with UV light depends on the exposure, time, wavelength and irradiance.

• Exposure or fluence (sometimes called dose) is measured in mJ/cm² (where 1 mJ/cm² = 10 J/m²)
• Exposure time is measured in seconds (s), minutes (m) or hours (h)
• Irradiance is the flux of radiant energy per unit area, in other words how much of the UV radiation power (measured in W = 1000 “miliwatts” mW = 1.000.000,00 “microwatts” μW ) reaches the surface. Irradiance is measured in mW/cm² or W/m² (1 mW/cm² = 10 W/m²) and is dependent on the radiant power, distance and dispersion of the radiation emitted by the lamp source.

Many studies that show the effectiveness of UV light in disinfection or sterilization present in their findings the inactivation of virus or bacteria for a given Exposure in an amount of time, for a given UV wavelength. However, it is difficult to centralize or build a database with so many variables. The most common solution to this problem is to present the fluence required to achieve a log reduction from 1 to 5.

 Log reduction explained

"Log reduction" is a mathematical term (as is "log increase") used to show the relative number of live microbes eliminated from a surface by disinfecting.  For example, a "5-log reduction" means lowering the number of microorganisms by 100,000-fold, that is, if a surface has 100,000 pathogenic microbes on it, a 5-log reduction would reduce the number of microorganisms to one, equal to 99.999% kill rate.

   

Effective and cost efficient disinfection or sterilizing of surfaces, water and objects has become of huge importance. The current COVID-19 (coronavirus) pandemic made this extremely clear. It created a extreme buying spree for everything that can be used in fighting it.  Never before seen shortages of disinfectants, surgical masks, gloves, ventilators and more, happen all across the globe.

The situation is made worse by the fact that many of the materials used for sterilisation are single use and have to be disposed afterwards. More have to constantly produced, exacerbating supply issues. It is time for a more efficient way of killing virus and bacteria, it is time for disinfection with UV light.

"UV light annihilates viruses and bacteria by destroying their ability to reproduce. "

Using ultraviolet (UV) light to disinfect or sterilize¹ has actually been embraced by some hospitals since years, by using large, industrial-grade machines to kill microorganisms (including COVID-19) in hospital rooms or on furniture, objects, clothing or instruments. However, such machines are prohibitively expensive for private or business use, as a mobile platform with UV lamps can cost more than 60.000 USD². They are also dangerous for people and have to be used only in empty rooms.

With the current advance in UV LED lighting technology, smaller versions of safe to use UV disinfection lamps can now be available to consumers and companies looking to clean pretty much everything, from office spaces, elevators and living rooms, to phones, computers and even toilet seats.

Widespread use of UV light to fight virus and bacteria can now happen with the technology of continuous disinfection with low intensity UVA light from lighting emitting diodes (LEDs).

Growing plants under artificial lighting in closed and fully controlled environments is a method of growing use and global impact.

Industrial scale indoor agriculture could become the main factor that keeps at bay famine and related conflicts. With increasing population, diminishing area of agricultural land, pollution, global warming and migration to grow plants in a reliable, predictable and efficient way will become even more important in the future.

Basic science concepts related to Horticulture lighting

A key factor in the success of indoor plant growth is the efficiency of the lighting system in the process of inducing plant growth, compared with sunlight. 

To build a very efficient lighting system some basic scientific concepts should be known.

Plants grow via a process called Photosynthesis that converts electromagnetic radiation – light – into chemical energy used for growth and development. The other ingredients needed are carbon dioxide (CO2), nutrients and water. The process itself is not particularly efficient, with only 4 to 6 percent of the absorbed radiation converted into chemical energy, but this is the engine that drives most life on the planet.

Photosynthesis and PAR radiation

The electromagnetic radiation required for Photosynthesis is defined as Photosynthetically active radiation (PAR), with the spectral range of 400 to 700 nanometers. Only radiation in the above interval can be used by photosynthetic organisms in the process of photosynthesis, to fix the carbon in CO2 into carbohydrates.

We should note that the electromagnetic radiation called visible light or simply light for a typical human eye has a spectral range from about 380 to 740 nanometers.

A common unit of measurement for Photosynthetically active radiation PAR is the photosynthetic photon flux (PPF), measured in units of moles per second. For many practical applications this unit is extended to PPFD, units of moles per second per square meter.

Growing plants in closed and fully controlled environments, under artificial lighting is method of growing popularity. There is also increasing competition to have results at a low cost and as fast as possible, thus the lighting system plays a crucial role.

Below you will find a quick guide how to build the most efficient lighting system.

1) Research, research

Understand what spectrum and intensity of light your plants need.

You can start by reading our detailed article about horticulture lighting here

2) Choose the right PPFD and light color for your plants

With the latest technology achievements, special or full spectrum white light LEDs are the most efficient and cost effective light sources for plant growth. With 3000K white color temperature you will have more pleasant looking plants while with 5000K you obtain faster growth.

With our Nichia 757 Rsp0a LEDs with white light for special spectrum for plant growth or full spectrum Nichia Optisolis CRI98 LEDs your plants will grow up to 50% more than conventional light, including standard white LEDs, a combination of red and blue LEDs or a fluorescent tube, for lower energy consumption.

The light ceiling or illuminated stretch ceiling is a new and very interesting trend in interior lighting. By using a translucent material of many square meters in size with a backlight system a diffuse, uniform and relaxing illumination of interior space can be created. The main advantage of this type of lighting is the absence of glare, as the light sources are spread over a large area and hidden behind the material.  

Illuminated ceilings usually use as the backlighting source LEDs of low or medium brightness (5 to 50 lumens) placed on strips or modules.  As the illuminated surface has a wide area such low power lighting is the best choice. 

Illuminated stretch ceilings can have personalized shapes and even can feature translucent images. Such, they can influence the overall design of a space much more than other lighting fixtures. From the lighting design point of view the uniform light should be complemented with spotlights or lamps that could attract attention to certain areas or objects.

Properly designing and installing an illuminated ceiling has a unique set of challenges which we will address in this article. 

A new trend in lighting is the line of light, made with an LED strip inside an aluminum profile with translucent white cover. Such a linear light fixture can be many meters long, form geometric shapes, and is a type of direct lighting.

Compared with indirect cove lighting, also a popular trend in lighting design, lines of light are more energy efficient but can have greatly increased glare. For this reason direct lighting with lines of light should be designed with care and almost always be dimmable. 

Let's see how we can achieve the best results with lines of light.

A cove luminaire is a light line that can be made via an LED strip that is hidden within a Cove in the wall or ceiling that illuminates an adjacent surface. Light is reflected from this surface into the room to be illuminated. For this reason, light lines are generally referred to as cove or indirect lighting.

Cove lighting is a popular trend in lighting design, focusing on human nature and the behaviour of natural light. It is widely used today, with light lines as the main method of lighting interiors.

The attraction is the similarity with the natural light. With the right light source we could imagine that the bay is actually a hidden window to the outside from which the sunlight streams in.

Let's see how we can achieve the best results with cove lighting.

1. Use of energy-efficient light sources

Choose LED modules or strips with high energy efficiency, at least 100 lm/w, and place them within the coving light so that most of the emitted light uses the reflective surface, wall or ceiling that directs it into the interior. Waste of energy for lighting the interior of the bay should be avoided. LED strips with 120-180° are recommended, which should be placed at an angle if possible:

Surfaces that are more absorptive than reflective, like dark paint or wood should be avoided unless the design is primordial to energy efficiency. White ceilings produce the best results.

2. Select an LED light source with the correct light output.

The Color Rendering Index or CRI, for short, is a one number quantification of how good (or bad) an artificial source is at reproducing colors, compared with reference standard illuminant modeled after daylight. The highest number is 100, for daylight and incandescent lamps/halogen lamps, while gas discharge lamps are between 17 and 96, with even a negative value for sodium low pressure (the yellow type used in street lamps).

It was introduced by the International Commission on Illumination (CIE) in 1974, because of the wide variation in the ability to reproduce colors with the white light emitted by the many types of gas-lamps then on the market.

Today, with over 40 years of use, the CRI index is firmly rooted in the lighting industry and among professionals. However, it has failed to gain much traction among the general public due to the fact that soon after its introduction it became not really relevant when making a purchase decision for lighting.

The reason was that most lamps were built for specific applications that required a minim CRI value so one could not go wrong with the choice of lamp.

From 2000s onward, LED technology changed this. It is the first lighting source that can be used for every application and have the full range of performance and quality level, including the ability to accurately reproduce colors. Therefore, it is imperative you choose the LEDs with the correct CRI level for your application. 

IP RATING IN THE BATHROOMS – BATHROOM IP ZONING

What IP rating is required in the bathroom it depends on the IP zoning, which we will explain by dividing the bathroom into areas or “zones“, which are classified using the numbers 0, 1, 2 – see the illustration below.

LED strips or luminaires – the bathroom lights – are then assigned a certain “IP rating” which indicates how much protection they provide against ingress of water and other particles. Each zone has a minimum IP requirement that must be met if a fitting is to be installed in this area.

The new Color Tunable Series from Nichia are game-changing single surface, tunable white LEDs that allow the user to smoothly transition color temperature from warm white to cold white.

The series are ideal for many applications, such as commercial, retail spot lights and residential downlights. Retail stores can change the light color based on their display or objects in it. Families will be able to change the color temperature of their home to best suit their natural biological rhythms.

Nichia’s color tunable LEDs are available in the standard 757 package and chip-on-board (COB).

Nichia 2-1 Tunable White 757 LED 2700-6500K

The game changing NF2W757G-MT in the standard 757 package use a new patented technology to allow smoothly transition from warm white 2700K to cold white 6500K. The significant innovation is its ability to accomplish color tuning under a small, single light emitting surface (LES), thus achieving superb color uniformity with high color quality, up to 90 CRI. The 2-in-1 tunable white 757 enables thinner, sleeker optical designs, eliminating the need for bulky mixing chambers.

Nichia 2-1 Tunable White COB LEDs 2700-5000K

The Nichia COB 2-1 Tunable White Series are available in two sizes, 24x19mm (NVCWJ024Z-V1MT) and 19x16mm (NJCWL024Z-V1MT), and make posible to build lighting fixtures with adjustable color temperature from warm white 2700K to pure white 5000K.,Nichia's color tunable COB provides a smaller light emitting surface and better color mixing than other options on the market.