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Puraflo

Posted by Price Critical Environments on January 12, 2021 at 10:38 AM

Cleanroom Technologies for Commercial Applications

For decades, fan filter units with HEPA filtration have been used in cleanrooms and other ultra-clean spaces to eliminate particulate and contaminants in the occupied zone. Now with the world focused on indoor air quality, this cleanroom technology is being used for commercial spaces.

FFU Exhaust

Derived from our industry leading line of Fan Filter Units (FFU), the Puraflo provides HEPA filtration and increased room air changes, effectively reducing the concentration of and therefore the probability of exposure to airborne contaminants. Ideal for use in a variety of commercial spaces including personal care homes, medical and dental clinics, schools and offices, the Puraflo is quick and easy to install with no impact on the existing HVAC system.

Ultra-Clean Airflow & Energy Efficiency

Increasing the air change rate in any space effectively reduces the concentration of airborne contaminants. In many commercial applications, like schools and offices, the existing HVAC system provides two air changes per hour (ACH) meaning the volume of air in the space is completely replaced every 30 minutes. Increasing the air change rate to 4 or more air changes per hour means that the volume of air in a space will be filtered and replaced at least every 15 minutes, significantly reducing the concentration of contaminants in the space. For a visual example of the effect of air change rate on the concentration of airborne contaminants, watch the Puraflo video.

Puraflo filters and recirculates room air to remove 99.9% (at 0.3 μm particle size) of contaminants from the air before redistributing that air to the space. Recirculation through individual Puraflo units allows for room-level control and energy expenditure, reducing overall energy consumption, and allowing for smaller building-wide systems.

FFU Exhaust flow with MERV and HEPA filtration

MERV 8 pre-filter and HEPA filter remove 99.9% of airborne contaminants

 

Application Versatility

Ideal for retrofit applications, Puraflo is simple to install and functions completely independently of the existing HVAC system, eliminating the need for costly infrastructure changes while providing ultra-clean recirculated airflow.

  • Ceiling-mount installations free up valuable floor space and allow the Puraflo to be located throughout the room to maximize contaminant removal and occupant comfort.
  • Portable, floor-mount options provide the fastest installation and allow the unit to be easily transported if necessary.
  • For clean air fast, temporarily use Puraflo in a floor mount configuration, and later have the same unit ceiling mounted for a permanent clean air solution.

Various construction options allow this versatile product to be configured to best suit your specific application.

Note: Puraflo and supply diffuser are shown close together in the exhaust, recirculation, and supply configurations below for illustrative purposes. These images are not an installation recommendation.
 

Exhaust Construction

Contaminated room air is drawn in through the face of the unit, passed through the HEPA filter, and recirculated to the space through a standard ceiling diffuser. This configuration allows selection of the discharge diffuser to optimize thermal comfort and air distribution in the space. In all applications, the recirculation diffuser should be located several feet away to avoid air discharging directly into the Puraflo.

FFU filters room air and discharges through square plaque diffuser

 
Exhaust Construction

 

Recirculated Construction

Contaminated room air is drawn in through the face of the unit, passed through the HEPA filter, and discharged through two outlets – one ducted to the outdoors and the other to a supply diffuser recirculating filtered air to the space. This configuration is ideal for applications like dental offices and patient rooms where a negative room pressure as well as an increased air change rate is desired.

FFU - recirculated constructionRecirculated Construction

 

Supply Construction

Contaminated room air is drawn in through the inlet on the back of the unit or a standard return grille, passed through the HEPA filter, and redistributed to the space with a laminar airflow pattern. This configuration is well suited to:

  • Small rooms or offices where additional mixing diffusers cannot be accommodated,
  • Atriums with high ceilings where a downward column of air is advantageous, and
  • Non-ducted applications like open ceilings or floor mount configurations.

FFU - Supply Construction

Supply Construction

 

Dental Operatory

FFU in dental operatory application

Room Specifications Details

Room Size: 125 ft2

Ceiling Height: 9 ft

Room Volume: 1,125 ft3

Additional Air Changes: 8

Flow Rate: 150 cfm

Sound: <35 NC

Equipment:

- 1x Puraflo Reverse Flow or Dual-Outlet Reverse Flow (24 in x 24 in)

- 1x Supply Diffuser

Rotary tools used during dental procedures may create aerosolized contaminants that can be detrimental to the wellbeing of dentists and hygienists. The amount of time required for removal of airborne contaminants from a space varies based on the air change rate. As an example, increasing from 4 ACH, typical in many dental operatories, to 12 ACH reduces the time to remove 99.9% of airborne contaminants from 104 minutes to 35 minutes.

In dental offices the reverse flow Puraflo should be located near the patients feet so that contaminated air is drawn away from the dental practitioner, and filtered air should be supplied from behind the patient’s head to wash the work space with clean air.

Optional use of a dual-outlet reverse flow Puraflo allows a portion of the airflow to be exhausted while the remainder is recirculated, simultaneously creating a negative pressure environment and increasing the air change rate to flush contaminants from the space.

For more information on dental applications, visit our website.

 

Personal Care Home

FFU in personal care home application

Room Specifications Details

Room Size: 200 ft2

Ceiling Height: 9 ft

Room Volume: 1,800 ft3

Additional Air Changes: 6

Flow Rate: 180 cfm

Sound: <30 NC

Equipment:

- 1x Puraflo Reverse Flow (24 in x 48 in)

- 1x Supply Diffuser

Reducing the concentration of airborne contaminants is of the utmost importance in personal care homes and other spaces with at-risk occupants. Increasing the air change rate in these spaces can help reduce the concentration of, and therefore the probability of exposure to, airborne contaminants. One Puraflo unit processing 180 cfm will provide an additional 6 ACH in a 200 ft2 patient room (with 9 ft. ceilings).

In these applications the reverse flow Puraflo unit should be located near the door, with the recirculation diffuser located over the patient bed. This configuration provides clean airflow to the patient and encourages the movement of less-clean air toward the exit.

 

Patient Isolation Room

FFU in patient isolation room application

Room Specifications Details

Room Size: 150 ft2

Ceiling Height: 9 ft

Room Volume: 1,350 ft3

Additional Air Changes: 8

Flow Rate: 180 cfm

Sound: <30 NC

Equipment:

- 1x Puraflo Dual-Outlet Reverse Flow (24 in x 48 in)

- 1x Supply Diffuser

Negative pressure isolation rooms are used for patients with easily communicable airborne disease. When there is a shortage of isolation rooms, existing hospital patient rooms can be converted to negative pressure isolation rooms by creating 0.01 in. w.g. negative pressure and by increasing from 4 to 12 ACH, in accordance with ASHRAE 170 requirements.

The dual-outlet reverse flow Puraflo allows a portion of the airflow to be exhausted while the remainder is recirculated, simultaneously creating a negative pressure environment and increasing the air change rate.

In these applications the Puraflo should be located directly over the patient’s head so that contaminated air is draw directly out of the room, and filtered air should be supplied toward the door so that airflow is encouraged to move from clean to less-clean areas of the room.

For more information on patient isolation rooms that allow the user to easily change between normal operation of a patient room and isolation mode, visit our website.

 

Waiting or Reception Area

FFU in waiting room/reception application

Room Specifications Details

Room Size: 300 ft2

Ceiling Height: 10 ft

Room Volume: 3,000 ft3

Additional Air Changes: 4

Flow Rate: 200 cfm

Sound: <30 NC

Equipment:

- 1x Puraflo Reverse Flow (24 in x 48 in)

- 1x Supply Diffuser

Waiting and reception areas are typically densely populated and can see a lot of foot-traffic from many different people each and every day. Puraflo can be used in waiting and reception areas to increase the air change rate and remove airborne contaminants from the space.

Waiting and reception areas vary in size based on the application, whether it be in a medical center, office building, or multi-family housing complex. As an example, a single reverse flow Puraflo unit operating at 200 cfm can provide an additional 4 ACH for a 300 ft2 waiting area with 9 ft. ceilings.

The Puraflo and the corresponding supply diffuser should be positioned for maximum removal of airborne contaminants in the space and to avoid filtered air discharging directly into the Puraflo. Selection of the discharge diffuser should promote room air mixing and thermal comfort.

 

Classroom

FFU in classroom application

Room Specifications Details

Room Size: 1,000 ft2

Ceiling Height: 9 ft

Room Volume: 9,000 ft3

Additional Air Changes: 2

Flow Rate: 300 cfm

Sound: <35 NC

Equipment:

- 1x Puraflo Reverse Flow (24 in x 48 in)

- 1x Supply Diffuser

Puraflo can be used in schools and classrooms to increase the air change rate (ACH) and reduce the concentration of airborne contaminants.

A typical classroom is approximately 1,000 ft2 with 9 ft. ceilings. One reverse flow Puraflo (24 in. x 48 in.) can supply two additional air changes to a classroom with a flow rate of 300 cfm.

The Puraflo and the corresponding supply diffuser should be positioned for maximum removal of airborne contaminants in the space and to avoid filtered air discharging directly into the Puraflo. Selection of the discharge diffuser should promote room air mixing and thermal comfort.

 

Open Office

FFU in open office application

Room Specifications Details

Room Size: 1,200 ft2

Ceiling Height: 10 ft

Room Volume: 12,000 ft3

Additional Air Changes: 2

Flow Rate: 400 cfm

Sound: <40 NC

Equipment:

- 1x Puraflo Reverse Flow (24 in x 48 in)

- 1x Supply Diffuser

Open offices are densely populated areas with minimal fresh supply air and lots of recycled air. HEPA filtration and an increased air change rate can help reduce the concentration of contaminants in crowded office spaces.

The number of Puraflo units required in an office is dependent on the number of air changes desired and the volume of the space. One reverse flow Puraflo unit operating at 400 cfm supplies enough airflow for an additional 2 ACH for every 1,200 ft2 of office space (with 10 ft. ceilings).

The Puraflo and the corresponding supply diffuser should be positioned for maximum removal of airborne contaminants in the space and to avoid filtered air discharging directly into the Puraflo. Selection of the discharge diffuser should promote room air mixing and thermal comfort.

 

Easy Maintenance

Maintenance is an essential consideration with any piece of equipment; the Puraflo offers many unique features to reduce and expedite maintenance.

  • Quickly and easily replace both the MERV 8 and HEPA filter from the room-side. Note the MERV 8 pre-filter is not room-side replaceable on supply style units.
  • Filter replacement schedule varies based on application, environmental conditions, and user preference. Generally:
    • MERV 8 pre-filters should be replaced every ~6 months
    • HEPA filters should be replaced every ~2 years
  • MERV 8 pre-filter captures large particulate, extending the life of the HEPA filter.
  • Integrated knife edge and HEPA filter gel track allow for tool-free installation and replacement.
  • Optional face-mounted color LED alerts the user when the filter is loaded and due for replacement, or if the motor is not operating properly. A green LED indicates normal operation, a yellow LED indicates a loaded filter and a red LED indicates an issue with the motor.
FFU with room-side replaceable filtersRoom-side replaceable MERV 8 pre-filter and HEPA filter

 

For more information on the Puraflo and how to apply it, visit our website or contact criticalenvironments@priceindustries.com.

Collage of critical environment products over an image of an operating room

Topics: HVAC, Design Engineering, Critical Environments, Filtration

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