Once again, here’s another edition of “One Engineer’s Opinion”, written by our own Lead Engineer, Bruce Longino. Bruce can be reached at blongino@mingledorffs.com.
ASHRAE Standard 62 is the Ventilation standard that mandates what is required in a commercial building to ensure good Indoor Air Quality [IAQ] for the occupants. Part of what is required by the standard is acceptable Outside Air or Ventilation Air Cubic Feet per Minute[CFM].
There are two ways to determine this Ventilation CFM. The first is Ventilation Rate Procedure [VRP]. The second is IAQ Procedure. The VRP is straight forward. ASHRAE 62 has tables with CFM per square foot and CFM per person for various applications. For example in an average size classroom the resulting CFM per student is 15. If the Engineer uses the IAQ Procedure, he/she must prove a method is provided that will sufficiently clean the air of Contaminates of Concern [COC] to allow a ventilation air rate as low as 5 CFM per student.
Concentrating on IAQ Procedure for classrooms, the COC is body odor. This is where the bi-polar ionization- also called Cold Plasma- comes in. There are devices called Bi-Polar ionization Generators that split water molecules in the air into positive and negative ions. These ions attach the components of body odor and break them down into harmless odor free compounds. This allows the Engineer to reduce the ventilation air while being assured that there will not be a body odor build-up.
There are huge other benefits to this technology. The ions that are generated also attack and kill many of the viruses, bacteria, allergens and mold spores in the building. This will help reduce illnesses that harm productivity.
Bi-polar ionization also helps remove particles from the air. The ions cause the small particles to amalgamate. This means they clump together into large particles that fall to the floor or are picked up in the HVAC filters.
To re-cap the benefits of bi-polar ionization:
[1]Reduces odors by turning an odiferous compound- such as ammonia- into its base elements that do not smell. Therefore OA CFM can be reduced to 5 CFM / person
[2]May kill viruses such as H1N1 swine flu (documentation pending).
[3]Attacks bacteria such as E coli.
[4]Reduces the number of active mold colonies.
[5]Attacks and eliminates some allergens.
[6]Reduces the indoor dust count by causing small dust particles to amalgamate into large particles so they can be filtered out of the air.
I- for one- think this is an amazing technology to do all these things and save the building Owner first cost as well as operating costs. This is possible because the ventilation air can be reduced by 2/3. This reduces the HVAC tonnage up front and operating cost for the life of the building.
The potential to reduce illnesses being transmitted between occupants reduces absenteeism. For a school system, this increases government funding bases on daily average attendance. For a business owner this increases productivity.
There are two basic technologies used to generate ions. The oldest technology uses glass tubes with stainless steel mesh. The newest technology employs stainless steel needles. The needlepoint method eliminates the need for expensive tube replacements. Another benefit of the needle technology is that it can be mounted in the return air duct before the filter. This way the positive and negative ions sanitize the filter and keep the cooling coil clean. This is especially important with MERV 13+ filters, because 46% of the circulating viruses are captured by the filter. Otherwise, the person changing filter can get sick when doing his job.
Bi-polar ionization has been around since the 1960s. However it is just started in conventional HVAC systems. This Engineer’s opinion is that it is one of the best technologies to come along in many years.
Got more questions about bi-polar ionization? Contact me at blongino@mingledorffs.com!