A cleanroom ultrapure fogger is a fog generator using liquid nitrogen and DI water, or liquid nitrogen and WFI water, to create an ultrapure fog for 70 minutes providing 4.5 cubic meters fog / minute to visualize airflow and turbulence with 20 feet visible airflow distance in clean rooms, sterile rooms, ISO suites.
The AP32, cleanroom ultrapure fogger has been superseded by the AP35 Ultrapure Fogger. The AP32 Liquid nitrogen fogger provides the highest volume of fog to visualize airflow for long periods up to 70 minutes providing airflow visualization of 20 feet distance. No cleanup is required after fogging! – Request
UltraPure fogger – The AP32 nitrogen fog generator is used in clean rooms, ISO suites, sterile rooms to provide visualization of airflow, flow patterns, dead spaces and turbulence. Nitrogen fog generators support Pharmaceutical guidelines, USP 797 In-Situ Airflow Analysis; and ISO guidelines, ISO 14644-3 Annex B7 guidelines.
The ultrapure fogger uses liquid nitrogen (LNG) and DI Water (DEMI Water) or Water for Injection (WFI) to generate about 4.5 cubic meters fog per minute for a typical 70 minutes with 20 feet of visible airflow distance. Water for Injection is often used in ISO suites, sterile rooms and clean rooms. Liquid nitrogen is filled into an LNG dewar, while DI Water is filled into a Stainless Steel chamber. Both liquids are then brought to a boil, creating nitrogen vapor and water vapor. The boiling process creates an ultra pure nitrogen and water vapor. The two vapors then mix together to form a nominal 3 micron vapor droplet at an extremely high fog density. The ultrapure fog exits at very low pressure, making it buoyant in the airflow. It is highly visible and does not create a disturbance as it enters the airflow. Ultraure foggers provide the greatest visible distance of 20 feet or more to visualize airflow turbulence and patterns. The high fog density is superb to visualize airflow, and when using video, the dense fog is easily tracked in the airflow in a sterile room, clean room and ISO suite. The nitrogen fog generator does not generate any contaminants in the airflow and evaporates back to the same elements we breathe, that being oxygen, nitrogen and hydrogen. Although DI water is quite clean, the stainless steel chamber is grounded which helps to add additional purity to the 16 Meg Ohm DI water during the boiling process. The very high density of ultrapure fog provides superb visualization of airflow, patterns and turbulence. It also has the advantage of providing increased visual distance of the moving airflow. Ultrapure cleanroom foggers create the most pure form of fog that can be used in clean rooms, ISO suites and sterile rooms. The AP35 fogger provides excellent, specified performance, out performing other LN2 foggers with twice as much fog volume and fog density which cost about the same as the AP35.
A nitrogen fog generator creates a particle free, non-contaminating fog, leaving no contamination or residue behind, thus no cleanup after fog use is required. The nitrogen based, ultrapure fog enters the airflow at very low pressure and does not create airflow turbulence. It is CE Mark and compliant to ISO and USP guidelines, and can be used in Class 1 – 100,000 clean rooms for airflow, turbulence visualization, flow balancing and contaminant transport studies.
When budget is lower, basic Fogger OK, minimal output turbulence
When 50 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
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
CRF4 Cleanroom DI Water Fogger, 1.5 cubic meters fog/minute
When fogger PORTABILITY is a must
When fog visibility for 10-15 feet distance is acceptable
When 45 minutes of fog duration is useful with quick turnaround
When fogging ≥ Class 1 and above in semiconductor and pharmaceutical cleanrooms
When fogging “hard to get at” areas
16 Meg ohm DI water is standard
Do not permit DI Water to go stagnant in the water chamber
** Use gloves when handling CO2 ice
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.
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 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
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.