Ultrapure LN2 Fogger, smoke generator, liquid nitrogen fogger, visualize airflow, airflow turbulence

Applied Physics, Inc.

Clean Room Fogger, CRF4

Ultrapure Nitrogen Fogger, AP35


Calibration Wafer Standards

PSL Wafer Standard

Contamination Wafer Standards

Particle Wafer Standards

Cleanroom Fogger, CRF2

LN2 Nitrogen Fogger

PSL Spheres, Polystyrene Latex Beads

Silica Nanoparticles in DIH2O, 15ml or 100ml volume

Smoke Studies to Visualize Airflow and Turbulence

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1-720-635-3931 or 303-999-6837

LN2 Ultrapure Fogger

The ultrapure fogger has been in use prior to 2001, using liquid nitrogen and Deionized Water or Water for Injection to create a very dense, ultra pure fog to provide superb visualization of airflow patterns, flow direction, turbulence and dead zones for up to 70 minutes in clean rooms, ISO suites, sterile rooms, barrier isolators and medical rooms. The AP35 provides 5 cubic meters ultrapure fog per minute with about 533 ml fog density each minute minute, superb for visualizing airflow and turbulence. More than 20-30 feet of air flow visualization is provided in the clean room. 3D airflow modeling is accomplished very well and no contamination is created and no clean up of any kind is required after visualizing the airflow. The AP35 ultrapure LN2 fogger supports airflow visualization guidelines as defined by USP797 Insitu Airflow Analysis, ISO 14644-3, B7; Federal Standards 209E and its replacement ISO Standard 14644-1 and 14644-2.
A Ultrapure Nitrogen Fogger uses LN2 and De-ionized Water or WFI water to generate a very dense, ultrapure fog for the best visualization of airflow patterns, direction, turbulence, dead zones and airflow velocity in clean rooms, ISO suites, sterile rooms, barrier isolators and medical rooms. Adjustable fog output is provided from 2 to 5 CUBIC METERS per minute of ULTRAPURE FOG with more than 20-30 feet visualization of turbulence in the airflow and around equipment. 3D airflow modeling is superb with the AP35 Ultrapure fogger. No contamination is created and no clean up of any kind is required after fog process is complete.

AP35, Ultrapure Nitrogen Fogger: 5 Cubic Meters of fog / Minute for about 70 minutes operation, 533 ml Fog Density/Minute - Request a Quote

The AP35 Ultrapure Nitrogen Fogger is superb in supporting video and visual fog requirements with a highly dense ultrapure fog output. This exceeds the closest competitor by 200% in fog density with 200% more visual fog distance and about 200% more fog operating time. The AP35 is a superb fogger for airflow visualization needs in pharmaceutical ISO suites and semiconductor clean rooms.

Ultrapure foggers are compared in fogger performance by determining Fog Density over time!

High fog density is what is needed to visualize airflow and turbulence for long distances. Fog density affects how visual the airflow is and controls the distance the airflow is visible to your eye or to a video camera. To determine fog density, the liquid volumes of the fogger is needed, combined with the operating time of the fogger. Which ultrapure Nitrogen fogger is best for the cost? The AP35 uses 35 L of LN2 and 5L of water. 40 total liters liquid generating dense fog for about 70 minutes. Since all liquids are consumed, the Fog Density calculation is: 40 liters / 70 minutes operation or about 533 ml per minute fog density. Competitive foggers convert less than 10L of LN2 and under 3 L of DI Water, which calculates the fog density at about 250 ml fog density per minute during a 25 to 35 minute operation. The AP35 Ultrapure Fogger produces twice the fog density, twice the visual airflow distance and 3.5 times the fog volume as compared to other ultrapure fogger, and the cost of the AP35 is nearly the same as other competitive LN2 foggers.

Nitrogen Fog Generator, UltraPure, Clean Room Fogger, 5 cubic meters per minute - Request a Quote

UltraPure fogger - The AP35 LN2 fogger is used in clean rooms, sterile rooms and ISO suites providing visualization of airflow, flow patterns, dead spaces and turbulence. Nitrogen fog generators provide a high purity fog to support Pharmaceutical guidelines, USP 797 In-Situ Airflow Analysis, ISO 14644-3 Annex B7 guidelines and Federal Standards 209E in semiconductor clean rooms. It uses a modular design for simple operation and maintenance.

A Nitrogen Fogger uses two sources to produce an ultra pure fog. The process combining the liquid nitrogen and DI water includes boiling the liquid nitrogen and DI water. As the LN2 and DI water boils, the vapor droplets are combined to form the highest purity of fog and highest fog density, which is not matched by any other type of fogger. UltraPure fog provides the greatest visible distance of the airflow turbulence, patterns. The ultrapure fog can easily describe how airflow is balanced in a sterile room or ISO suite. The nitrogen fog generator is sometimes referred to as a smoke machine by facility staff. In fact it does not produce smoke at all, which would be a particulate type of fog. The manner in which the nitrogen fogger produces fog causes DI Water and liquid nitrogen to boil in separate LN2 dewar. The DI water comes to high temperature forming a water vapor composed of vapor droplets less than 2 microns in diameter. Although DI water is quite clean, there is some remaining residue in the DI water. During the DI Water heating process, any remaining residue in the DI water gets attracted to the walls of the DI Water chamber, which is grounded. This helps to provide an ultra pure fog using a typical 16 Meg Ohm Distilled water or WFI water for injection. The water vapor droplets then pass over the Liquid Nitrogen Dewar, where the LN2 boils at room temperature. The resulting combination of water droplet and nitrogen droplet forms an ultrapure fog droplet at a nominal 2-3 micron diameter; which creates a very dense, low pressure, ultra pure fog. The high density of ultra pure fog droplets provides the best visualization of the airflow and turbulence, increases the distance at which one can see the airflow and it is the most pure form of fog that can be used in a cleanroom.

An ultrapure, nitrogen fog generator creates a particle free, non-contaminating, high purity fog, leaving no residue behind as the ultra pure fog evaporates back to the air components that we breathe, nitrogen, oxygen and hydrogen. The fog enters the airflow at very low pressure, thus it does not create a turbulence, making the UltraPure nitrogen fogger the best cleanroom fogger suitable for use in Class 1 - 100,000 clean rooms for airflow, turbulence visualization, flow balancing and contaminant transport studies around process tools. This ultra pure fog is typically used to support USP 797 In-Situ Airflow Analysis in Pharmaceutical sterile rooms, barrier isolators and ISO 1-9 suites.

Watch video of the LN2 UltraPure Fogger
AP35 nitrogen fog generator
Ultrapure Fog Generator, 5 cubic meters fog volume / minute for about 70 minutes with about 533 ml per minute fog density and from 20 - 30 feet visible airflow

Performance of the AP35 Ultrapure LN2 Fogger- Request a Quote

Metric AP35 Cleanroom Ultrapure Fogger Other Ultrapure Foggers
FOG Duration about 70 minutes about 25-40 minutes
FOG Volume Output 5 cubic meters / minute, adjustable 2 - 5 cubic meters / minute output 1.5 cubic meters per minute, constant output
Total FOG Volume about 375 cubic meters, ultrapure fog, during 70 minute cycle about 80 to 90 cubic meters, ultrapure fog, 25-40 minute cycle
Fog Density (ml/minute) supports visible fog distance 533 mL per minute converted to ultrapure fog 250 to 265 ml per minute converted to ultrapure fog
Visible Fog Distance 20-30 feet visible airflow distance 10-15 feet visible airflow distance
FOG Type Ultrapure Fog using LN2 + (DI Water or WFI Water) Ultrapure Fog using LN2 + (DI Water or WFI Water)
Class of Clean Room Use Class 1 to 10,000 Class 1 to 10,000
Compatible Guidelines USP 797 Insitu Airflow Analysis, ISO 14644-3 Annex B7, Federal Standards 209E in Semiconductor Cleanrooms USP 797 Insitu Airflow Analysis, ISO 14644-3 Annex B7, Federal Standards 209E in Semiconductor Cleanrooms
Type of Room Clean Rooms, Sterile Rooms, ISO Suites, Medical Rooms Clean Rooms, Sterile Rooms, ISO Suites, Medical Rooms
Water Boiler volume 5.0 liters 2.0 to 3.0 liters
LN2 Dewar volume 35 Liters
6 Liters to 10 Liters
Method of Operation Direct or Remote Wireless
Direct Power Only
Method of Movement Rolling enclosure
Hand Carry
Liquid Weight 28.14 kg (62.04 lbs) LN2 and 4.8 Kg (10.6 lbs) Water
Standard Power Requirements 110 VAC, 50/60 Hz, 10A 110VAC, 50/60 Hz, 10A
Optional Power 220VAC, 50/60 Hz, 15A; 100VAC 50HZ, 15A 220 VAC, 50/60 Hz, 10A; 100VAC 50HZ, 10A
Dimensions, Inches 1095mm x 540mm x 766mm
Dimensions, Metric 42.7 inches x 21.06 inches x 29.9 inches
Full Weight 77 kg (170 lb.)


The CRF4 Clean Room Fogger is used in smoke studies with a pure fog output. No contamination is emitted and no clean up is required after use. Operating instructions are provided in a PDF manual.

Theory of Operation: Ultrasonic cavitation using DI water or Pharmaceutical WFI Water. Use of any other liquids or chemicals will void the warranty.

The transducer life is ~5000 hours, which is protected from electrical damage when water level is too low. The water level sensor will interrupt the input voltage to the transducer module, should the water level drop to a low level to protect the life and reliability of the transducers.


  1. The CRF4 clean room fog generated is composed of 5-7 mincron water droplets. AVOID USING IN IMMEDIATE VICINITY OF ELECTRICAL APPLIANCES, WATER SENSITIVE PRODUCTS AND EQUIPMENT.
  2. The fan will operate with no water in the reservoir with the power switch in the ON position. This will aid in drying when the chamber is drained.
  3. The clean room fogger is intended to be used on a flat surface. When draining the fogger, tip the fogger to the rear and water will draing out of the CRF4 through the fog outlet port. DO NOT OVERFILL OR TIP THE FOGGER DURING OPERATION.

Cleanroom Ultrapure Fogger Features - Request a Quote

AP35 Fog Curtain
Ultrapure Nitrogen Fog Generator with Fog Curtain

Cleanroom Ultrapure Fogger Advantages - Request a Quote

Very dense, Stream Fog
Very dense, Stream Fog

* Fog distance measured at 40% humidity and air velocity of 90fpm. Visual fog distance decreases as humidity decreases or as airflow velocity increases.

20-30 feet visible fog distance
20-30 feet visible fog distance

Which Clean Room Fogger or Smoke Generator Is Best For My Applications?

Cleanroom UltraPure Fogger, 5 Cubic Meters per minute for 90 minutes with 20-30 feet visible distance.
  • When high fog purity, high fog volume and long visible airflow is needed
  • To visualizing airflow in large clean rooms, ceiling to floor
  • To fog exit velocity must not create turbulence
  • To needing to do 3D airflow modeling of airflow
  • When needing to do visualize airflow in larger cleanrooms
  • When 90 minutes of high purity fog duration is needed
  • When fog visibility of 20-30 feet distance is required
  • To fog Class 1 to Class 10,000 semiconductor, medical, pharmaceutical clean rooms

* Use Hand Gloves and Face Shield when filling LN2
Use 16M ohm DI water or WFI Pharmaceutical Water
Clean Room Fogger, 9cfm, 60 minutes Operation
  • When budget is lower, basic Fogger OK, minimal output turbulence
  • When 60 minutes of fog duration is useful with quick turnaround
  • When fog visibility for 6-8 feet distance is acceptable
  • When fogging gray areas behind the cleanroom
  • When fogging ≥ Class 10 or above in semiconductor or pharmaceutical clean rooms

CO2 Fogger, Vapor DiH2O Fogger, average 4cfm over 10 minutes
  • When Fogging Hazardous areas, No Electrical Outlet Available
  • When fog visibility for 5-6 feet distance is acceptable
  • When 10 minutes of fog duration is useful
  • When fogging small areas
  • Class 10 or above in semiconductor or pharmaceutical clean rooms
  • When fogging work benches

16 Meg ohm DI water is standard or WFI Water
Do not permit DI Water to go stagnant in the water chamber
** Use gloves when handling CO2 ice

Fogger Technology

The three types of foggers manufactured for use in the semiconductor and pharmaceutical industry are described below.

Ultrapure LN2 Fogger: This type of smoke generator or clean room fogger provides the highest volume, density and purity of fog. Purity is created by bringing the water to a high temperature, creating a vapor, while simultaneously using gravity to remove the residual mass from the vapor. This process removes any bacterial agents and residual particulate matter from the vapor. The pure vapor is then passed over an LN2 bath, which naturally boils at room temperature. The water molecules bond with nitrogen molecules, creating a nominal 3um fog droplet. The volume of water and nitrogen molecules that combine is extremely high in quantity, creating a dense, high volume, ultrapure fog output with exit temperatures of about 78 degrees F with an exit pressure of less than 0.5 lbs, so as not to disturb the surrounding airflow. The fog is ultrapure leaving minimal, if any, trace particles behind. It evaporates to its gaseous hydrogen, oxygen and nitrogen components, which are natural to the Cleanroom environment. The high density of the fog increases the duration and travel distance of the fog. This fogger can be used in a Class 1 - 10,000 cleanroom environments of pharmaceutical and semiconductor facilities; such as sterile rooms, hospital rooms, medical rooms and cleanrooms.

DI Water Fogger: This type of fogger has less fog density (less capability to visualize airflow) than the UltraPure Fogger described above, but more density than the CO2 fogger described below. The DI water fog is generated by atomizing DI water into water droplets, which are nominally 3-10um in size. The water droplets may contain residual particulate matter remaining in the DI water, but this would be very trace amounts. If the facility manager operates a class 10 to Class 10000 Clean room, the use of a DI Water Fogger poses no problem. However, Cleanroom Engineers who manage facilities operating at Class 1 to Class 10 performance may desire to use an ultrapure fogger. Although some DI Water foggers are described as ultrapure, unless the DI water is vaporized to remove bacterial agents and residual particulate matter, the fog is not ultrapure. The 3-5lb output pressure of a DI water fogger also distorts the airflow patterns, thus adding to the turbulence. The temperature output is typically less than the surrounding room temperature, thus a fog generated from the atomized water droplets will sink momentarily in a typical 70 degree room temperature.

CO2 Fogger: This type of smoke generator or CO2 Fogger is designed for low volume, non-process critical applications such as bench airflow testing. The fog is created using CO2 ice as the fogging agent. The fog contains elements of the CO2 and the user must determine if the residual CO2 components are acceptable in a process environment operating Class 100 to Class 10,000. The 3-5lb output pressure of a CO2 fogger also distorts the airflow patterns, thus adding to the turbulence. The output starts at about 3cfm and slowly decreases to 0 CFM in about 10 - 12 minutes.

Smoke Sticks

Smoke Sticks are used in some Pharmaceutical Clean Rooms around the world. Below is a discussion on the use of smoke sticks used to visualize airflow and turbulence?

A smoke stick is often used visualize airflow turbulence, but smoke sticks are filled with particulates and chemicals. Smoke is created using chemical reactions; thus the smoke is SPUTTERING (sputter) or popping out of the smoke stick in a non-consistent pattern with velocity, but little volume. It is a particle smoke, compared to a visible, pure water based fog, thus smoke sticks are a contaminating smoke. The smoke stick generates an inconsistent flow or pattern of smoke, but it is low cost, which is why some managers allow use of smoke sticks in their Pharmaceutical clean rooms.

Compare a smoke stick to a Clean Room Fogger or an UltraPure LN2 fogger, both which produce a constant volume of fog with a consistent fog output and pure fog. Di Water foggers produce a consistent flow of visible water vapor, which enters the airflow to visualize the airflow patterns and turbulence, then begins to evaporate, returning back to the hydrogen, oxygen and nitrogen components that we breathe. No particulate contamination, no chemical contamination. Water based foggers produce a constant volume of fog at a constant rate, which provides consistent visualization of airflow patterns and turbulence. The Smoke Stick has to be waved around to see what kind of airflow pattern there is, while a Di Water fogger is simply placed in position and produces a flow of fog that can be directed 360 degrees to easily describe the airflow patterns and turbulence. In addition, tubes are now available to create "fog curtains", or a wall of fog, which smoke sticks can not produce.

How many smoke sticks are used per smoke cycle? How much labor is needed to clean up after smoke stick use. Do you need to Clean all the walls where the smoke stick was used. How did the chemical particulates and particles affect the process area? These are critical questions for a pharmaceutical manager. Did the contaminating particles and chemicals get into the drug process?

How much labor is used to cleanup after smoke stick use and if the cleanup did not get every chemical particle, then some smoke chemical material is added to the Pharma process or trapped in a filter somewhere, until it escapes into the Pharma process. That is a quality control issue for that company using smoke sticks.

The low labor cost of using smoke sticks is the reason facility managers may use smoke sticks, but are the chemical and particulate effects to the pharma process being analyzed? Non-contaminating fog does not emit particulates, requires less labor and does not contribute any unwanted chemicals to the Pharma process. A Di Water Fogger provides these advantages in fog volume, fog consistency and fog purity, which easily outweighs the low cost of smoke sticks, the high cost of labor for cleanup and the detrimental affects to quality control!

Smoke Sticks - quality side of the drug product: The smoke chemicals are not of the same chemistry as the drug product, thus smoke chemicals and particulates could migrate into the drug process. There is no guarantee the cleaning process removed all the unwanted particulates and chemicals, from for example, a glove box or isolation box. The chemicals and particulates eventually migrate to the air filter system, which is not 100% effective. If this is the case, the quality and purity of the drug process is affected. Drug quality is the basis of product credibility, which is a valuable asset in customer relations.

Smoke Sticks - labor side of the drug product: The smoke is generated by a chemical reaction, which causes the smoke to sputter into the environment. The smoke is inconsistent in volume, thus the smoke stick is unpredictable for airflow visualization. The chemicals migrate to equipment and walls, which then must be cleaned, and requires an added labor cost. The use of Smoke sticks generates an inefficient smoke, not a consistent fog.

A Di Water Fogger produces a water (H2O) droplet that evaporates back into hydrogen and oxygen, the air we breathe. No clean up is required, at all. No additional time delays and clean up labor is not required. The fog is consistent in volume and constant in output to describe the airflow patterns and turbulence. These are equipment, quality and application concerns to consider when the need for airflow visualization is considered.

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