Explosion Proof Germicidal Lamp Applications for HVAC Disinfection in Industrial Facilities|
Article - November 20, 2017 By LarsonElectronics.com
Explosion Proof Germicidal Lamp Applications for HVAC Disinfection in Industrial Facilities
Ultraviolet (UV) fixtures come with a plethora of uses and applications. From non-destructive testing (NDT) to non-invasive sterilization, UV light can be used to uncover harmful traces of foreign contaminants and abnormal conditions with minimal effort.
For thorough disinfection, HVAC systems utilize UVC bands measuring between 200 – 280 nm, with peak absorption occurring at roughly 254 nm. Called the germicidal range, such beams are capable of inactivating harmful bacteria and mold. When UV light hits bacteria, it is absorbed by the microorganism, causing mutation to the microbe’s DNA structure. The effects are instantaneous, but also ceases immediately after exposure. Without carryover treatment, operators must prioritize irradiation to ensure full application of UV light.
When used in food manufacturing facilities, UVC lamps disinfect vegetables and liquids on the processing line. For such applications, UV treatment is broken down into three phases. The first phase eradicates most of the microorganisms lingering on the surface or inside the liquid.
Next, another (weaker) dose of UV light is administered to remove bacteria that may have survived the first wave of UVC beams – a common occurrence in liquids with suspended components or surfaces with uneven characteristics. A last wave of UV light is applied to ensure thorough disinfection, before the product enters the next phase of production (packaging).
UV Light Inside HVAC Systems
Like food manufacturing plants, HVAC units can use UVC lamps to keep critical components clean and well maintained. Inside the systems, the fixtures are closely mounted to the target area:
• Aerial Sterilization: This type of HVAC disinfection focuses on cleaning air that is moving in and out of the system. The fixture is typically installed in the return air duct.
? Effectiveness/Applications: Aerial sterilization using UV lighting systems are widely used in hospitals, clinics and laboratories. In a trial conducted at Duke University Medical Center and the University of North Carolina Hospital System, UVC lamps were deployed to eradicate Acinetobacter, Clostridium difficile or vancomycin-resistant enterococci (VRE). After the trials, researchers concluded UVC to be effective in decreasing colony-forming units (CFUs)– from 52 CFUs (before UVC treatment) to 1 CFU, resulting in a 98.1 decrease in the formation of VRE.
• Coil Sterilization: UVC lamps for HVAC units may also target air handler coils. This type of light is considered to be the most common, making it a great addition for HVAC owners looking for solutions beyond air filters. UV lights for HVAC coils operate 24/7 and take on very thin, cylindrical forms.
? Effectiveness/Applications: Coil sterilization using UVC fixtures is mostly implemented in commercial spaces and poorly ventilated indoor locations. In a trial involving a 286,000 square-foot building in Oklahoma, UVC lamps were installed in HVAC systems to deter fungal contamination. Researchers leading the study were able to verify the effectiveness of UVC lamps for coil sterilization, based on a decreased concentration of fungal spores in floors where HVAC systems were equipped with UV disinfection lights.
For seamless maintenance, HVAC units that incorporate UVC lamps for sterilization should include a sight glass or an indicator light to notify operators about the status of the fixture. Without such features, specialists would have to power down the light and manually remove it from the system, when performing inspections.
Explosion Proof UV Lamps for Hazardous Locations
Industrial facilities that handle or store flammable substances or compounds must use special UV lamps that prevent dangerous ignitions. Called explosion proof lights, the units are reinforced with non-sparking materials and enclosed flame paths that contain flammable interactions inside the fixtures.
The lights are classified, based on the type of combustible substance in the hazardous location (Class I = flammable liquids, gases, vapors; Class II = flammable dust, metallic dust; Class III = flammable fibers, flyings). These classifications can be further broken down into Division 1 and/or Division 2. Division 1 refers to the 24/7 existence of flammable hazards in the work site. Division 2 is defined as locations wherein flammable compounds may exist temporarily or during abnormal conditions.
Larson Electronics is a leading industrial lighting manufacturer with over 40 years of experience in the industry. The company specializes in rugged lights, LEDs, corrosion resistant luminaries for marine applications, explosion proof fixtures, solar-powered lights and portable lamps for outdoor use. Larson Electronics also provides temporary power distribution units, security monitoring devices and custom-built lighting solutions for businesses.