It’s well documented that Coronaviruses are 3x more suspectable to germicidal UV c-band light (radiation) than other viruses such as Influenza A. See table.

EMA can quickly design a custom germicidal lamp retrofit system using high-output UV-C lamp technology to transform your fan system into a COVID-19 killing machine with 99% 1st pass kill rates.

These systems can deactivate COVID-19 airborne bioaerosols thereby transforming traditional return AHUs into systems that reduce COVID-19 zone level contaminants as dramatically as a 100% OA lab AHU at 6 air-changes per hour (without the associated energy costs).

It does this by de-activating (“killing”) 90% - 99% of the COVID-19 returning from the zones in either the supply fan section or the return ductwork, providing 90% - 99% COVID-19 viral-free supply discharge-air to your office zones, dramatically reducing re-distribution of COVID-19 by your fan to other uninfected zones in your building and reducing COVID-19 build-up within zones.

Virus Type % RH Virus Diameter Airborne De-activation Factor (k) U.V. Dose required 99% Kill / De-activation
Coronavirus (incl. SARS) ssRNA 50% 0.125 µm 0.00377 cm2/µWatt sec 1225 µWatts sec/cm 2
Influenza A ssRNA Lo 0.098 µm 0.00119cm2/µWatt sec 3875 µWatt sec/cm2

Factors affecting dose and results include exposure time, plenum depth, air speed, UV lamp output, ambient air temperature, lamp configuration, spatial constraints, plenum metal reflectivity, humidity and lamp maintenance, etc

Note: EMA designs will be less affective in crowded conference rooms and other gathering spaces, where additional measures should be considered by the owner. UV systems do not replace the need to perform viral wipes on surfaces, tables, keyboards etc. and only serve to improve the current situation without warranty or guarantee.

Airborne disinfecting UV intensities are significantly higher than those used for coil & drain pan contact disinfectant because exposure time at coils & drain pan are measured in hours where exposure time for airborne disinfection are measured in seconds or fractional seconds due to the high speed of the air.

Special message from Steve Di Giacomo:

I have good news and bad news.
The bad news is this Fall we anticipate another SARS corona virus spike.
The good news is SARS corona virus is one of the easier viruses to kill with U.V. lamps, in fact it is 3x easier to de-activate then the Influenza A (flu).

Your HVAC fan systems can quickly be retrofitted to deliver SARS corona virus free sterile air with 1 st pass “kill” rates of 90% to 99% by installing U.V. (ultraviolet) (253.7 nm wavelength) germicidal lamps within your fan’s plenum, typically downstream or upstream of your cooling coil, or any accessible plenum. For areas of congregation such as conference rooms, lobbies and reception EMA is recommending you consider Upper Chamber U.V. wall packs can be easily installed, typically at 7’ height (these are often used in hospitals and ORs).

There are many factors that affect a good design and project costs. In order to help you properly retrofit your HVAC fan systems I will need to confirm air-speed (velocity), plenum cross sectional area, plenum length (run), and accessibility so that I may determine overall U.V. Exposure times needed to determine UV intensities, #of lamps, and lamp wattages.

EMA’s Process
  1. Drop me an email at with your contact info and building address and I will send you a Data checklist for your building operator to fill out, to get the ball rolling.
  2. Identify which Virus you want to deactivate or Kill /sterilize (typically SARS corona virus)
  3. EMA will follow-up with you by phone / email to review the returned check-list and to discuss next steps, and sign a consultant agreement.
  4. EMA will determine your “Kill” Dose required for 90% to 100% first pass de-activation of the virus based on standard engineering calculations.
    1. Natural Log e (1-kill rate) /k, where the k-value (cm 2 / micro-watt second) is specific to COVID-19
    2. “Kill” or de-activation Dose in microwatt-sec/cm 2
  5. EMA will determine Virus-to-UV Lamp Exposure times based on lamp configuration, air-speed and length of plenum, etc.
  6. EMA will determine your customized U.V. Light Intensity required to deliver the correct/desired “kill”/ de- activation Dose.
  7. EMA to issue bid docs that will specify proper U.V. Light Intensity to deliver desired kill dose to experienced Vendors.
    1. EMA to generally obtain one to two bids for your property
      1. Bids from vendors will confirm Dosage at specified Intensity
    2. If you move forward with the work, EMA to approve submittals, answer/create RFIs, and commission the work.

  1. EMA consulting engineering fees are generally $0.10 to $0.20 per CFM.
  2. Contractor costs for installed fan systems range from $0.30 to $0.90 or more per CFM per HVAC system.


UVGI is scientifically proven to deactivate viruses and bacteria in air, water and on surfaces. UVGI upper room wall packs, air-handler and plenum Lamp retrofit strategies are recommended by ASHRAE. However, there are a large number of factors that control and affect infection rates within buildings, therefore, there are no explicit or implicit guarantees or warranties that adopting and deploying UVGI technology will eliminate or significantly reduce infection rates or disease transmission rates within your building. Other factors that affect infection rates and disease transmission include, but is not limited to, zone temperature, zone relative humidity, ventilation effectiveness, zone pressurization, occupant densities, occupant densities of diseased occupants, air filtration, etc. EMA shall not be liable for or bound in any manner by, and Buyer has not relied upon, any express or implied, oral or written information, warranty, guaranty, promise, statement, inducement or representation pertaining to the subject technology including but not limited to, warranties of fitness or merchantability, regarding or with respect to the subject technology.