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Does Your Space Deserve the Most Advanced Room Air Cleaner?

October 14, 2020

By: Victoria Stevens

The American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) is the leading organization focused on researching and guiding proper HVAC system design and construction for maintaining comfort, health, and wellbeing of building occupants.  This includes controlling infectious disease contaminants in the air within a space. The ASHRAE Position Document on Infectious Aerosols (COVID-19) recommends that existing spaces have high-efficiency particle filtration paired with UV-C Lights (Ultraviolet light) to capture and destroy biological aerosols. Most of the document focuses on how to optimize the design of the HVAC during construction to control the flow of biological aerosols as well as the temperature, pressure, & humidity in the space for ideal conditions to minimize transmission risk.  These guidelines are critical for consideration in the design of future buildings but do not help occupants within current buildings. The easiest way to achieve this recommendation is through a mobile filter and UV-C system. The Nailor Mobile Air Cleaner - MAC-700, is the most advanced and economical mobile filtration unit with a UV-C system on the market.

The MAC-700 provides continuous filtration of the space air to help reduce the risk of biological aerosol transmission without the requirement to involve your existing HVAC system. The MAC-700 is designed to pull air from all sides to increase its ability to collect biomass and dust from the floor. The air will travel through a MERV 10 pre-filter, which captures large particles, UV-C light, and HEPA filter before recirculating purified near sterile air up into the room. The MERV 10 prefilter is in place after the single deflection entry to collect large particles and extend the HEPA filter life. ASHRAE article "HVAC and COVID-19" explains that "a MERV 10 pre-filter reduced the amount of deposited SARS-CoV-2 by approximately 70%...".  The air travels past the pre-filter to the UV-C light section. In the UV-C light area, the two lamps will kill 99.9% of viruses. The final 6" (152 mm) HEPA filter provides filtration that is 99.99% effective in the removal of microbial content from the airflow.

Cleaning Process

The ability for UV-C light to kill biological aerosols depends on the type of contaminant, intensity of the light, and the time of exposure.  UV-C light is more effective against organisms without outer shells like viruses.  The HEPA filter is more effective against larger particles, though they’re 99.99% effective down to .3µm.  The larger particles will generally be trapped at the beginning of the filter and sit in the UV-C light field extending the exposure time and increasing the effectiveness of disinfection.  The combination of the UV-C system and the HEPA provide the best possible solution for destroying and capturing all types of room contaminants.

Additionally, the unit is equipped with a modulating fan switch; that provides variable air volume control that enables the user to control the airflow depending on the size, occupancy, and sound requirements of the space.

The UV-C lights destroy the biological aerosols before they reach the HEPA filter using ultraviolet light with a wavelength of 254 nm. The lights are long-lasting to reduce the maintenance and replacement costs. The UV-C lights are safely placed before the HEPA filter, surrounded by a metal liner, and the door has a safety switch to deactivate the lamps if the door opens. The High Output UV-C Lamps were carefully selected to match the airflow provided by the fan and enable deactivation. The UV-C lights used in this model are contained in a Quartz glass lamp that eliminates any ozone-producing light from exiting the lamp. The units are tested to ensure that escaping UV-C radiation is below maximum limitations.

 

After the air goes through the pre-filter and the UV-C light, it passes the HEPA grade air filters designed for high efficiency of 99.99% on a 0.3 μm particle. The filter has a galvanized metal frame with a tight sealing gasket that fits in the unit perfectly. The Media produced from the glass microfibers is moisture resistant and will not support microbial growth.

Specifications

To increase the cleanliness of the air and reduce the risk of biological aerosols within your space, adding a Nailor MAC-700 system is the most advanced and quickest solution. The unit has an adjustable speed control ranging from 200 up to 700 CFM (ft3/min) of air which is perfect for offices, schools, restaurants, and nursing homes. Below is a table of the air changes per hour (ACH) for different types of occupancies.

A recent article from the ASHRAE Journal states… "The COVID-19 virus spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes…" The size of the virus attached to a droplet is larger than 5-10 μm. The virus is best collected as the water droplet dries and falls to the ground, allowing the MAC-700 to easily pull the virus into the bottom without distributing it up into the space air. The design of the MAC-700, and units like it, create low pressure zones at the discharge and intake.  The low pressure zone at the discharge induces room air around the unit up into the clean air flow.  Units with the air intake on one side only pull air from one direction, this allows the air around the other sides to be induced up into the clean air flow.  The MAC-700 provides the most optimized design by pulling air from all sides and reducing the amount of space air induced into the clean air flow.

Filtered air is released out the top of the unit towards the ceiling above the occupied space after going through a pre-filter, UV-C lamp, and HEPA filter. Some competitive products blast the discharge air horizontally into the occupied space creating drafts that can affect occupant comfort and spread existing virions throughout the occupied space. The MAC-700 recirculation momentum will allow occupants to continuously breathe fresh air.

The MAC-700 has a sloped top to inhibit stacking objects on top that might restrict the airflow from the outlet. The unit is equipped with braking locks, safety cut-outs, and can be placed in any location of a classroom. The average classroom in the US is 1,000 sq. ft; the  AC-700 will clean the air in the room over 4 times each hour.

The MAC-700 does more than ASHRAE recommended by adding a pre-filter with a HEPA filter making it great for kids. The inside of the unit is coated with two types of insulation. One insulation is around the UV-C lights for extra lamp safety and noise reduction from the fan. The other insulation found within the unit aids quiet operation.

The MAC-700 is great for any high-risk location, as well as any area that requires cleaner air. The mobile unit will collect dust and microbial air contaminants. Applications include offices, schools, restaurants, nursing homes, hospitals & doctor offices, salons, and stores.

Some Frequently Asked Questions:

How does this differ from an air purifier I would buy at Home Improvement store?
The MAC-700 can clean more air than the smaller products offered at big box retailers. The filter is much larger and can filter at higher efficiencies for longer than the smaller units. Also, the commercial construction will increase the return on investment over the lifetime of the unit.  The motor and power system is designed with integrated ground fault interruption protection, which allows this unit to be listed by ETL to UL 1995 rated.
 
How often do I change the filter?
A good rule of thumb is that the HEPA filter should be replaced from 18 months to 2 years and the pre-filter every 60 to 90 days.
 
What does it cost to operate?
To operate at max capacity for 10 hours a day for 210 day in a year (weekdays) it would cost $47 per year to run.

224 Watts/1000 x .10 $/hr. x 10 hr./day x 210

so at 10 hr./day for a year would be $47.

Why can’t I just add a HEPA filter to my current HVAC system?
HEPA filters require much higher pressures than the standard HVAC filters. Adding a HEPA filter to a current HVAC system would require thousands of dollars more than a portable unit worth to redesign. Just adding a HEPA filter without redesign would cause the system to underperform. The easiest course of action to create a cleaner room is to utilize a portable HEPA that can be turned off when the room is not occupied. The size filter of 6” was chosen to be easily replaceable and a common sized filter.

Contact your local Nailor representative for more information on how to get your MAC-700 today.

Resources:
ASHRAE Position Document on Infectious Aerosols, April 2020