Insider’s guide to UV lights and COVID-19

HVAC and UV lights

At Baker Plumbing, we are always trying to find the best and most effective approaches to solve the problems presented to us by our clients. Today we were asked to address the problem of bacteria within an HVAC system. As a professional HVAC contractor in Calgary, we immediately suggested the use of a UV light source inserted directly into the supply air of the HVAC system. You can watch a quick 1 minute video of it here :

BAKER and UV light install

UV light sources have long been used by the medical profession as a solution to eliminating infectious diseases and their sources. Learn more about UV below> NYC and UV Lights

Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency of approximately 30 PHz) to 400 nm (750 THz), shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.

Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. For humans, suntan and sunburn are familiar effects of exposure of the skin to UV light, along with an increased risk of skin cancer. The amount of UV light produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by the atmosphere.[1] More energetic, shorter-wavelength “extreme” UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground.[2] However, ultraviolet light (specifically, UVB) is also responsible for the formation of vitamin D in most land vertebrates, including humans.[3] The UV spectrum thus has effects both beneficial and harmful to life.

The lower wavelength limit of human vision is conventionally taken as 400 nm, so ultraviolet rays are invisible to humans, although some people can perceive light at slightly shorter wavelengths than this. Insects, birds, and some mammals can see near-UV

Sanitary compliance[edit]

A person wearing full protective gear, glowing in ultraviolet light

After a training exercise involving fake body fluids, a healthcare worker’s personal protective equipment is checked with ultraviolet light to find invisible drops of fluids. These fluids could contain deadly viruses or other contamination.

Ultraviolet light helps detect organic material deposits that remain on surfaces where periodic cleaning and sanitizing may have failed. It is used in the hotel industry, manufacturing, and other industries where levels of cleanliness or contamination are inspected.[83][84][85][86]

Perennial news features for many television news organizations involve an investigative reporter using a similar device to reveal unsanitary conditions in hotels, public toilets, hand rails, and such.[87][88]

Sterilization and disinfection[edit]

A low-pressure mercury vapor discharge tube floods the inside of a hood with shortwave UV light when not in use, sterilizing microbiological contaminants from irradiated surfaces.

Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Commercially available low-pressure mercury-vapor lamps emit about 86% of their radiation at 254 nanometers (nm), with 265 nm being the peak germicidal effectiveness curve. UV at these germicidal wavelengths damage a microorganism’s DNA/RNA so that it cannot reproduce, making it harmless, (even though the organism may not be killed).[97] Since microorganisms can be shielded from ultraviolet rays in small cracks and other shaded areas, these lamps are used only as a supplement to other sterilization techniques.

UV-C LEDs are relatively new to the commercial market and are gaining in popularity.[failed verification][98] Due to their monochromatic nature (± 5 nm)[failed verification] these LEDs can target a specific wavelength needed for disinfection. This is especially important knowing that pathogens vary in their sensitivity to specific UV wavelengths. LEDs are mercury free, instant on/off, and have unlimited cycling throughout the day.[99]

Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in municipal drinking water treatment. Many bottlers of spring water use UV disinfection equipment to sterilize their water. Solar water disinfection[100] has been researched for cheaply treating contaminated water using natural sunlight. The UV-A irradiation and increased water temperature kill organisms in the water.

Ultraviolet radiation is used in several food processes to kill unwanted microorganisms. UV can be used to pasteurize fruit juices by flowing the juice over a high-intensity ultraviolet source.[101] The effectiveness of such a process depends on the UV absorbance of the juice.

Pulsed light (PL) is a technique of killing microorganisms on surfaces using pulses of an intense broad spectrum, rich in UV-C between 200 and 280 nm. Pulsed light works with xenon flash lamps that can produce flashes several times per second. Disinfection robots use pulsed UV[102]

Additional resources see links below:

UV disinfection equipment to sterilize

ecm motors

Calgary Furnace Repairs, The Good, The Bad and The Ugly

Calgary Furnace Repairs

ECM motor swap

ECM motors, the good, the bad and the ugly

There are, however, some serious downsides associated with improper application of these motors in new and existing HVAC systems. Let’s take a candid look at the good, bad, and ugly of good and bad application of these great gems of technology. Calgary furnace repairs.

The Good
When a furnace or air handler with an ECM is installed on a good duct, coil, and filtration system with static pressures within proper design parameters, it can perform flawlessly. These systems can deliver precise airflow to match two-speed condenser designs and multi-stage gas furnace firing rates to deliver quiet, draft-free comfort in virtually any configuration.

These issues can be avoided with good pressure and airflow testing, both before and after equipment is replaced, and on every system you service. When you measure, you know. When you don’t measure, you’re just guessing that it will turn out OK.

Additional benefits of these brushless DC motors include low electrical consumption when operating within design TESP (Total External Static Pressure). When installed properly, systems with ECMs can improve dehumidification, reduce register noise, save energy, and provide trouble-free operation.

The Bad
In marginal systems with higher-than-design static pressures — for example a .5–in. TESP rated furnace with ECM on a .8–in. TESP system — the motor still may be able to maintain airflow close to design. The tradeoff is higher velocities often cause a noisy system and some coil blow-off. The extra torque often required to overcome the higher statics results in higher electrical consumption. This reduces actual equipment EER, which means your customer won’t get the savings of the higher efficiency matchup.

The Ugly
Systems with TESPs of 1.0 and higher, which are more typical than many non-performance-based contractors are willing to admit, can eat up to eight times the power they should be using. When this happens, some ECMs will ramp down and drop airflow significantly. Some older ECM motors will overheat and even fail when constantly running in over-amped conditions. Newer models are designed to drop airflow but time will tell on how well they will hold up.

Other consequences of high static installations include noise at the registers from higher air velocities. In extreme cases, filter media can be sucked out of its rack causing filter bypass. In very extreme cases filter media can be pulled into the fan, chopped up and blown through the system causing all sorts of damage.

So, what do you measure? The first thing you should do is install test ports on either side of the blower. Once you’ve installed the test ports, use a digital or analog manometer with a static pressure tip to measure pressure at each location.

High velocities and pressures created by ECMs on systems with dirty evaporator coils can also blow moisture off the coil surfaces into the supply ductwork. This can reduce the system’s dehumidification capability and cause numerous moisture-related indoor air quality issues.

The Answer
These issues can be avoided with good pressure and airflow testing, both before and after equipment is replaced, and on every system you service. When you measure, you know. When you don’t measure, you’re just guessing that it will turn out OK. Calgary furnace repairs.

So, what do you measure? The first thing you should do is install test ports on either side of the blower.

Once you’ve installed the test ports, use a digital or analog manometer with a static pressure tip to measure pressure at each location. TESP is calculated by adding the pressures before and after the fan. Other pressure readings will help you diagnose the cause of high statics – but that’s for another article.

Once you know your TESP and your fan speed setting look up delivered fan airflow on the manufacturer’s fan table. If you’re replacing or servicing equipment with an ECM, and the TESP exceeds rated capacity, be sure to look up motor amp draw in the manufacturer’s specifications.

Armed with this information you should do two things: First, alert your customer that their system has a high “blood pressure” problem that needs to be addressed. Second, diagnose the cause of the high statics and recommend solutions to bring them down to acceptable levels.

Of course, there is more to this in terms of troubleshooting and solving these issues. The bottom line is that while the ECM is a great motor, as the servicing or installing contractor it’s your responsibility to make sure its application does not cause unintended consequences detrimental to the health and well-being of your customers’ homes and HVAC systems.