To assure quality is maintained in all cleanroom and restricted areas, housekeeping maintenance must be performed daily. Improper cleaning leads to contamination and ultimately loss in end user product quality. Contamination can be broadly categorized into two categories, films and particulates, both of which can cause “killer defects” in miniature circuitry. Contamination in a cleanroom can lead to expensive downtime and increased production costs. Once a cleanroom is brought to standard it must be cleaned and maintained regularly to maintain those standards.
Solution: Each cleanroom will be different and local standards and requirements will vary, but for example, a class 100 cleanroom would require you wipe down your work area once per shift, with a full wipe down of walls, trim, and all other surfaces once weekly in addition to the other various maintenance performed hourly, daily, or weekly. Skipping these regular wipe downs allows particles to collect over time.
2. Using a Flat, Non-Folded Wiper
Failing to fold your wiper is not only wasteful, it risks contaminate being spread around the surface instead of being removed.
Solution: To maximize each wipers life span fold the wiper into quarter folds, giving multiple clean surfaces to use. Hold the unfolded sides in your hand and group the unfolded edges between our thumb and forefinger. Always discard used wipes according to procedure.
3. Using One Wiper for an Entire Area
Using a single wiper for an entire area is really only cleaning as far as the proper folded wipe method will go, so about eight swipes. After each side of a wiper is used, it is considered contaminated and by continuing to use that wipe it is no longer cleaning the surfaces but spreading contaminates farther.
Solution: Swipes should be done in one direction and only overlap 10% to 25%. Turn the wiper so that each new swipe is done with an unused portion of the wiper, once each fold is used the wiper can be refolded so the other side can be used, maximizing the lifespan. Each wiper should clean eight swipes with this folding method, use as many wipes as required for proper contamination removal. Once finished with each wipe dispose of according to site procedures and continue until entire surface has been wiped down.
4. Wiping From Dirty/Wet Areas to Clean/Dry Areas
As you can see cleanroom wiping is all about containing and removing contaminates without spreading them to other areas. Spills or other large contaminations should first be dealt with by isolation, using cleanroom approved sorbent materials to contain the mess, followed by a thorough cleaning. When cleaning a cleanroom space it is very important to transition from dirty to clean without re-contaminating clean areas.
Solution: Wipe up and dispose of the bulk of the contaminate, then following the procedures of using a wipe properly, clean from the clean/dry areas into the wet/dirty areas, never the other way around. This way you are drawing the contaminates in and removing them instead of cleaning outwards, spreading the containmates over a wide range of previously clean areas.
5. Wiping in a Circular Motion
Wiping cleanroom surfaces in a circular motion, not surprisingly, spreads particulates and contaminants over clean areas. It won’t matter if you use an entire package of wipers, or how you fold them if a circular technique is used.
Solution: Start by pressing down firmly and swiping parallel in one motion across the surface. After each swipe, turn your wiper so the next swipe will be done with a clean side. Keeping track of which areas you have already cleaned and overlapping only about 10% is critical to ensuring that the surface is being completely cleaned and no streaks of particulate are left behind.
6. Using a Dry or Overly Wet Wiper Instead of a Damp One
The point of cleanroom wiping is trapping and removing contaminate and particulate, as we’ve learned. So using a perfectly dry wiper with no moisture will trap some contaminants but for the full benefit, your wiper should be damp.
On the opposite end of the spectrum using a soaking wet wiper will only create a larger mess and leave behind dirty residue over your entire surface requiring that the surface be cleaned again, wasting time and money.
Solution: The type of cleanroom wipers you purchase will depend on many factors, the cleanroom class, the size, company procedures, ect. It may be more cost efficient for a smaller, lower class cleanroom to use dry wipers with a separate cleanser whereas a large scale or highly stringent cleanroom would benefit from a pre-soaked wiper eliminating the need for a second product.
When using a dry wiper with separate cleaner apply the cleaner to the wiper once folded, taking care not to let the cleanser bottle and the wiper come in contact to minimize cross-contamination. Pre-soaked wipes eliminate the need for a second product, and they can be folded into quarters and used immediately.
7. Using a Wiper That is Not Appropriate for the Cleanroom
Cleanrooms come in many shapes and forms depending on the product being produced and industry, state, or government regulations. Cleanrooms are divided into classes, as you can see in the diagram below.
Each class of cleanroom will have their own specific set of rules and allowances. You can see the particle allowances in the chart above, which means those levels must be maintained to meet cleanroom class requirements. This particle allowance dictates the procedures and products that can be used in the cleanroom so making sure that you are using a wiper that falls in line with acceptable tolerances in crucial. Wipes are manufactured in many ways to accommodate various levels of cleanliness and specific regulations. Here are just a few material examples:
And all of these wipes have various styles and edge types such as:
Knife Cut Edges
Laser Cut Edges
Solution: You must be familiar with your cleanroom class and your company procedures as well as any government regulations or industry standards that dictate acceptable materials or particulate levels based on what is being manufactured so that you can make the proper selection. Most established cleanrooms will usually have a specific product approved for purchase. Production Automation can work with you to help you select the right product for your cleanroom. Visit our site at www.gotopac.com or simply call us at 888.903.0333 Monday through Friday or email us at firstname.lastname@example.org. We also have a new Live Chat feature that you can use to connect with a sales rep at anytime during your shopping experience.
Article reprinted from Clean Air Products, manufacturers of air showers, cleanrooms, and cleanroom accessories.
A cleanroom provides a controlled environment in which companies can produce contaminate-free products. Air showers are a vital component of maintaining that clean environment. They protect the cleanroom by using high velocity jets of air to remove loose particles of contamination from people and products before entering a cleanroom, thereby reducing product defects and increasing production yields. The cleanroom itself will require less maintenance because the contamination lead, or build up, will be at a lower level. Cleanroom high efficiency particulate arresting (HEPA) filters are going to last longer because of the air shower system. WIthout the pre-cleaning performed by air showers, the main cleanroom air filtration would absorb the entire contamination load, resulting in the increased energy consumption and maintenance costs.
How do Air Showers Work?
Air showers are self-contained, air recirculation systems installed at entrances to cleanrooms and other controlled environments to reduce cleanroom contamination as workers enter the clean production space. Their operation is similar to a pressure washer system at an automated car wash. For example, a car enters the wash chamber, doors close at both ends, and high pressure streams of water from all angles blast the particles of dirt from the car. The cleaning cycle ends, a light comes on and the exit door opens.
With the air shower, a worker passes through the entry door and a sensor activates interlock magnets which then close the door. High velocity streams of Class 100 filter air, from a large number of precisely placed, adjustable nozzles or vertical slots, is blown onto workers as they raise their arms and rotate in place. The high velocity air creates a flapping effect on the workers clothes which produces a “scrubbing” action, removing particulates from their cleanroom garments. Indicator lights then signal the end of the cleaning cycle and the cleanroom door is opened. Typically, it takes about 4 to 8 seconds for the cleaning time and then another 2 to 4 for the blower to wind down and give the air shower time to purge the contaminated air prior to the worker exiting. An adjustable microprocessor controls the cleaning and wait times.
Sources of Contamination
People are the main source of cleanroom contamination and anyone entering a cleanroom must follow preparation procedures to reduce the amount of contamination. Depending on the cleanroom cleanliness requirements, workers will put on a full cleanroom suit which covers nearly the entire body, or just a gown, cap or hood over their street clothes. Air showers are needed for a final cleaning step before entering a cleanroom because the “gowning” process disturbs the and releases contaminates from street clothes that can settle onto the “clean” garments. Special garments made from smooth-surface synthetic materials such as Tyvek® and GORE-TEX® are designed to minimize the mechanical bond of particulates and easily shed contaminates. Natural fiber materials such as cotton or wool tend to have rough surfaces, producing a high mechanical bond with particles, making them difficult to clean. Air showers allow cleanroom garments to be used multiple times before a thorough cleaning is necessary, further lowering operation costs.
Air Shower Cleaning Capacity
The intent of an air shower is to quickly and efficiently clean particulate contaminates from workers before entering a clean space. Power and capacity are the two factors that influence the effectiveness of an air shower. Cleaning power is determined by nozzle velocity and can be described as the speed in which air is pushed through the nozzles. It takes high velocity air to dislodge the particulate contamination and the higher the velocity or cleaning force, the more effectively the contamination can be removed.
Capacity is the volume of air circulated in the system. More air volume means faster cleaning and removal of contamination through filtration and recirculation system. The most effective air shower units produce nozzle velocities of 7,800 feet per minute (fpm) and circulate 1,900 cubic feet per minute (cfm) of air. Velocity is measured at the nozzle and cleaning effectiveness deteriorates as the workers’ distance from the nozzle increases. Therefore, to be most effective, air showers should have a high number of air nozzles and be positioned as close to the workers as possible. Typically, the space between the nozzles on opposite air shower walls is about 36 inches and standing between nozzles, an average-sized worker is be positioned about 8 inches away from any one nozzle. At that distance, the worker is experiencing air velocity in the 6,500 to 7,000 fpm range, which is still an effective cleaning force.
Air Shower Design
Similar in design to an airlock, air showers typically have two doors that cannot be opened at the same time – accommodating only one person at a time. Workers enter one side and exit on the opposite side. When one door is opened, the other door’s magnet is energized which prevent the door from opening. During the cleaning cycle, both doors are energized (locked) to prevent anyone from entering or leaving before the cycle is completed. Typically, emergency power off (EPO) buttons are available on internal and external walls if door interlocks are installed.
Air shower designs range from a single batch system where one person uses the shower at a time, to a tunnel-like system for larger groups to pass through more quickly (see figure 4). The size of the unit is usually determined by the number of people that need to enter a cleanroom in a time. Tunnels are becoming more common because the amount if cycle time needed for a 30- or 40-person shift change.
Most air showers are modular and can be configured into various sizes and shapes to fulfill specific customer requirements. The straight-through design, with nozzles on two opposing walls, cleans workers with more ease. However, depending on space of facility requirements, a 90-degree design can be used where users enter on one side and exit to the right or left at a 90-degree angle. This configuration does not have the same number of air nozzles as the straight-through design and requires the worker to turn 360-degrees during the cleaning cycle to ensure sufficient cleaning before leaving the chamber. Other designs may have double doors or even three doors for entry and exit (see figure 5).
Structure materials are typically stainless steel, painted steel, or laminated particle board. Most air showers shells are constructed of steel and painted with a strong, durable, cleanroom-compatible finish. For some medical, pharmaceutical, or extremely wet environment stainless steel construction is ideal. Some manufacturers offer economy units made of laminated particle board, but due to possible temperature and humidity fluctuations this type of construction is subject to delamination, easy physical damage, and joint loosening, all of which may generate particulate or biological contamination.
The air shower’s recirculating air filtration systems typically use two sets of filters, the first is a pre-filter for catching the bulk of the contaminants, and the second is a high-capacity, 99.97% efficient HEPA filter. System blower units are mounted in the ceiling, or of there are facility height restrictions, they can be mounted on the external wall. All routine maintenance is done from the inside, with the pre-filters changed on a regular basis.
Air Shower Selection Criteria
When selecting an effective air shower system, the following should be considered:
System should be modular, allowing for easy configuration, shipment, and assembly
Shell should be made of stainless or painted steel
Blower system must supply high velocity, high volume air
Recirculating filtration system should use pre-filters, followed by high capacity HEPA filters
Units should have magnetic door interlock systems with appropriate controls
Whether it is ensuring high semiconductor yields, or a flawless paint finish, a wide variety of industries use air showers as part of their cleanroom operations. Semiconductor, medical device, bio-tech, microelectronic, optics, pharmaceutical, aerospace, nanotechnology, and automotive industries require contaminate-free environments and commonly use air showers as part of their operation.
While air showers typically are used for cleaning gowned personnel before entering a clean environment, they can also be used to remove particulate as workers leave hazardous work areas before going out into the general public, or preventing cross contamination when moving from one workspace to another.
Air showers are just one, but very important, factor in ensuring good cleanroom performance. Proper worker training, documented procedures, and a well-maintained system will increase production yields, and reduce product defects and costs.
How Can Production Automation Help?
Production Automation has worked with many types of cleanroom situations and manufacturing processes, and we are available to give you expert advice and guide you through planning, purchasing, and implementing your air shower.
Call us at toll-free at 888-903-0333, email us at email@example.com, or use our Request for Quote form and we will contact you, usually within 24 hours.
The TargetBlower is an in-tool ionizing blower designed to control static charge in near critical environments. With ±5V or better balance, it meets the requirements for those targeted areas that need stable electrostatic protection. The TargetBlower‘s space-saving design is perfect for point-of-use applications found in semiconductor final manufacturing and in other automated process tools. The unique chassis with a built-in collimator ensures directed ionized airflow at the target, efficiently eliminating hazardous static charge.
A self-cleaning ionization system makes the TargetBlower a convenient device that delivers consistent, excellent performance without requiring time-consuming adjustments or maintenance.
±5 balance or better
Automatic emitter cleaning system
Collimated chassis directs ionization to target area
Enhanced features include Factory Monitoring System (FMS) connection and alarm LED
Compact size with no separate control box
Provides electrostatic protection to the most sensitive of devices
Uninterrupted ionization is ensured with minimal user maintenance required
Optimized point-of-use protection is perfect for automated in-tool applications
Ionization status is easily monitored directly at the tool or from a remote location
Charge protection for even the most space-limited automation tools
Innovative Air Ionization Technology
The TargetBlower features an emitter wire design consisting of a thin filament electrode that generates a flowing ion air stream that produces greater ion generation. As a result, the TargetBlower is able to deliver excellent discharge balance without the aid of external sensors in the close confines of tool equipment.
The self-cleaning ionization system is programmed to operate every seven days with the TargetBlower is continuously on at any speed. Turning the TargetBlower off/on will activate the self-cleaning system and restart the seven day count cycle. This means that once the TargetBlower is installed, no continuous maintenance is required, ensuring ionization without interruption.
After initial setup to meet the application environment specifications, no further adjustments to the TargetBlower are necessary. The TargetBlower features internal circuitry designed to ensure uninterrupted, balanced performance.
The TargetBlower‘s small size and unique form factor provides flexibility in choosing a mounting location that allows the best ESD protection.
Input Voltage: 24 VDC, 5.5W (max)
Indicators: Green LED for power, red LED for alarm
Controls: Balance adjustment; fan high/off/low switch
Connectors: Telephone-style RJ handset input for external power supply or tool power; 2-pin terminal for FMS relay closure output
Ion Emission: Pulsed high frequency
Emitter Wire: Tungsten corona wire
Airflow: 15 cfm (typ)
Discharge: <4sec @ 1ft¹
Balance: ±5 or better¹
Cleanroom Class: Meets ISO 14644-1 Class 5; Fed Std. 209E Class 100
Mounting: Two 6-32 mounting screw holes on bottom of blower
Operating Environment: Temperature 50-90°F (10-32°C); humidity 30-60% RH (non-condensing); will provide specified performance with operated in an environment meeting the cleanliness requirements for ISO Class 7 (Fed. Std. 209e Class 10000)
Ozone: 0.015ppm (typ)
Chassis Material: Static dissipative plastic
Dimensions: 4.2H x 2.6W x 3.4D in. (10.7H x 6.5W x 8.7D cm)
Desiccators: Unique Stainless Steel Solutions from Palbam Class
Palbam Class developed its first desiccator cabinets for the Semiconductor Industry. Due to the demands of this industry all the cabinets are manufactured from the cleanest materials possible.
Most manufacturers offer stainless steel accessories for their desiccators. Palbam Class uses only stainless steel. All modular designs – and “plug & play” if you have a product which requires protection from: Particles + Moisture + Oxygen then Palbam Class offers you unique solutions.
Nitrogen is the standard medium for contamination-free storage because it is relatively inert – it neither reacts with stored materials nor carries moisture – and because it can be isolated and purified relatively inexpensively.
Palbam Class Desiccator cabinets are set up so that an appropriate flow of nitrogen forces out all moisture and contamination-laden air. Because nitrogen has a lower specific gravity than air, it is introduced into the upper section of the desiccator, the heavier air is then purged out of the bottom.
Bench Top N2 Desiccator
Palbam Class Bench Top N2 Purge Desiccator Cabinets cut nitrogen expenses by up to 80%. Automates clean, dry bench top storage; eliminating moisture & oxygen related degradation and optimizing yields. Ideal for semiconductor components, biological and pharmaceutical samples, and other sensitive materials. Fully integrated turnkey system takes 30 seconds to install.
Desiccator has built in RH% sensor and display panel – allowing user to monitor real-time relative humidity levels within the cabinet. The easy to use control panel allows user to enter the required RH% level – the cabinet then regulates N2 input to ensure the desired RH% levels are maintained.
Fabrication materials: 304 Stainless Steel with an electropolished finish and static dissipative PVC window.
Safety Factor: Many uncontrolled N2 cabinets rely on a continuous flow of N2 into the cabinet. This N2 is also being continuously leaked into the cleanroom atmosphere – with the potential risk that this implies to the safety of the operators.
Palbam Class desiccator cabinets minimize the N2 usage and therefore minimize the N2 leakage into the cleanroom atmosphere.
Isolators are increasingly installed in pharmaceutical production laboratories due to the increased handling of hazardous drug ingredients as well as the need for smaller batches and more flexible production environments. Isolators can potentially lower the installation and maintenance costs compared to large-scale cleanroom environments. While manufacturing facilities have established SOPs for isolators, this article focuses on the importance of proper cleaning and wiping procedures.
Isolators and Decontamination
Decontamination is the reduction or removal of biological or chemical agents, including non-active particles to non-hazardous levels to products, processes, or the environment by means of physical or chemical procedures.
Specifically in pharmaceutical manufacturing environments, research laboratories, and hospital pharmacies, the effective decontamination of biological agents like bacteria, viruses, fungi, protozoa, prions, and spores is essential.
Isolators like fume hoods, bio-safety cabinets, and glove-boxes are used to create environments with low levels of environmental pollutants such as biological agents, aerosol particles, and dust. These separative devices have a controlled level of contamination, specified by the number of particles with a defined size per cubic meter, providing controlled environments that are specifically tailored to the needs of its operator. This classification of cleanrooms and isolators, however, is not taking into account specific requirements regarding biological contamination. In order to maintain the low levels of environmental pollutants, isolators have to be decontaminated on a regular basis.
Isolator cleanliness levels are defined by different clssifications, shown in Table 1 and Table 2. These classifications are evaluating the environmental pollution by particles, however, not taking into account specific requirements regarding biological contamination. In order to maintain the low levels of environmental pollutants, isolators have to be decontaminated on a regular basis.
Quality supervisors in facilities using isolators have to determine the acceptable level of biological agents in their respective environment and decide on the method to achieve these levels. Several factors influence the choice of method and materials.
Isolators are used in a variety of industries working with different material and under different requirements. Potential contaminates in isolators can therefore range from biological contaminates (e.g. pharmaceutical industry, hospital pharmacies), radioneclides (e.g. pharmaceutical industry, research laboratories), to general particulate contaminates (e.g. semiconductor industry).
Chemical Agents: Inactivation
Spills of hazardous chemical agents in isolators or potential reaction products immobilized on isolator surfaces have to inactivated or diluted to non-hazardous levels. The chemicals and chemical processes used for inactivation depend on the contaminant.
Biological Agents: Disinfection and Sterilization
To reduce the level of biological agents in an environment, disinfectants/sanitizers and sterilants can be used. Sanitizers and disinfectants are terms used in different industries for the same kind of product. Whereas the food and food-processing industry uses the term sanitizers, the pharmaceutical industry, laboratories, and hospitals are predominantly using the term disinfectant.
Disinfection describes a process that eliminates many of all pathogenic microorganisms on inanimate objects, except bacterial spores¹. On the other hand, Sterilization describes a process that destroys or eliminates all forms of microbial life and is carried out by physical or chemical methods². Depending on the biological agent and the material or media holding it, sterilization can be achieved through the application of heat, chemicals, irradiation, high pressure, or filtration. It is essential to understand the difference between both processes to assure that contamination level requirements of work environments are met. Whereas some commercial and technical literature us confusing readers by using both terms interchangeably, it should be noted that Disinfection and Sterilization describe two processes with very different requirements in outcome. It is not appropriate to talk about partial sterilization or even replace the word disinfection with sterilization.
The efficacy of sterilization depends on a number of factors like:
Prior physical cleaning (effective surface and biofilm reduction)
Presence of organic and inorganic load-level and type of microbial contaminants
Concentration of sterilant
Exposure time of sterliant
pH, temperature, and humidity of environment
Geometry of object and spaces
Physical properties of objects
Frequent application of sterilization processes is facing two major challenges; the potential build-up of resistance against the used sterilization agent as well as disadvantageous interactions with humans and surfaces that get in direct contact with these agents. The applied processes have to be well understood in order to avoid these detrimental effects.
The efficacy of different sterilization methods has been evaluated and reported by a number of publications. Tested microbial agents include bacteria, spores, and viruses³†‡. As discussed in this article, microbiological agents may show a significant difference in resistance to the discussed sterilization methods. Therefore previously mentioned factors (the efficacy of sterilization depends on a number of factors such as in list one as well as the specific resistance to microbiological agents) play a vital role in the selection of the appropriate aterilization method.
Cleaning of Isolators
Decontamination or leaning, the reduction or removal of biological or chemical agents, including non-active particles is a multi-step process that depends on the contaminant and the required cleanliness level.
In isolators with processes using chemical agents the successful inactivation of these agents precedes any removal attempt in order to avoid further contamination of the environment or reaction with the isolator surfaces and cleaning materials. After successfully inactivating hazardous chemicals, high absorbency wipes are used to physically remove the reaction products.
When choosing isolator cleaning tools and materials, it is recommended that operators introduce the least amount of particle and fiber generating materials into the isolator. Typically a cleanroom laundered 100% continuous filament polyester knit material with sealed edges is recommended for use to clean surfaces inside the isolator. Additionally isolator cleaning tools with replacement covers that have been tested for particle and fiber release are appropriate to extend the reach of the cleaning area as well as providing ergonomic benefits to the operator.
One can also use cleanroom wipes with specific surface treatments to allow the wiper to capture and retain particulate contamination, resulting in more efficient cleaning and reduced likelihood or re-contamination of critical surfaces.
The recommended steps to be performed when cleaning a contaminated surface do not change and are the same for all kinds of contaminants.
Always clean from the cleanest to the dirtiest surface
Clean with overlapping strokes and change wiper surface with each stroke
If using an isolator cleaning tool or mop, change out cover material with each surface side of the isolator
In the case of isolators with biological contaminants, like bacteria, spores, and viruses, regular sterilization might seem to be sufficient in killing the microbial agents. However, it is extremely important that prior to sterilization, a physical removal of these contaminates is done in order to avoid a subsequent buildup of biofilms that would increase the resistance to sterilization attempts in the future. Biofilm is composed of polysaccharides that consist of carbon, hydrogen, and oxygen. Hydrogen and oxygen are most likely to be found in most isolators with natural atmosphere, leaving killed microbial agents behind would provide the required carbon for bacteria to reproduce and form new biofilms.
Cleaning Process SOP
Developing a Standard Operating Procedure (SOP) for your isolators is a difficult task and depends on the very specific requirements of a facility’s processes and regulation in its industry.
As a rule of thumb, Table 3 can serve as a general guideline to develop your own SOP††.
Questions to ask yourself:
What contaminates am I concerned about?
Would they contaminate my processes (inside) or the environment (outside)?
Are these contaminants inert, chemically-, biologically-, or radio-active?
What contamination limits have to be considered?
The use of an isolator cleaning tool should also be considered to allow efficient cleaning†† of hard-to-reach areas and guarantee an equal pressure distribution of your cleaning material (wipes/pads) on the isolator surface. The applied pressure is a determining factor in the physical removal of contaminants from a surface.
Proper decontamination and cleaning of isolators is critical to the long term success of materials produced in these environments. Reducing the risk of cross contamination starts with a full understanding of the type of potential contaminants introduced before, during, and after the production process. Sterilization and spraying with disinfectants alone are not enough to remove residual particles that could result in the buildup of biofilms. Proper wiping and rinsing protocols are needed to ensure the total removal of contaminants and the cleanliness of the isolator.
Production Automation understands the needs of cleanrooms, pharmacies, and laboratories so we strive to bring our customers the highest quality, the widest selection, and the technical support they need to identify and purchase the proper consumables needed.
PAC is proud to announce that we are now carrying Berkshire brand cleanroom wipes in a variety of styles and sizes. To take a look simply click this link! SHOP BERKSHIRE CLEANROOM WIPES NOW
Healthcare Infection Control Practices Advisory Committee (HICPAC), “Guideline for Disinfection and Sterilization in Healthcare Facilities”, 2008
McDonnell, G.; Russell, A.D.; “Antiseptics and Disinfectants: Activity, Action, and Resistance” Clinical Microbiological Reviews, Jan. 1999, p. 147-179
Mehmi, M.; Marshall, L.J.; Lambert, P.A.; Smith, J.C.; “Evaluation of Disinfecting Procedures for Aseptic Transfer in Hospital Pharmacy Departments” PDA Journal of Pharmaceutical Science and Technology, Vol. 63, No. 2, p. 123-138
Ergonomics is a topic we’ve covered numerous times on the Production Automation blog, but it is a topic that is relevant in so many industries. Whether you work on a production floor in a factory or in an office, or even at home, ergonomics play a large role in our health and well-being. Before we go into BioFit’s ergonomics, let us introduce you to the company.
BioFit is a leader in chair design and fabrication of earth-friendly, ergonomic seating for health care, educational, technology, laboratory, industrial, and office work-spaces.
BioFit is built on a foundation of over 60 decades of ergonomic expertise, beginning with the implementations of solutions for labs and educational markets in the 1940’s. From the onset, BioFit realized that carefully maintaining a traditional sense of Midwestern values – integrity, friendliness, hard work, community, and environment – is just as critical as the craftsmanship that they put into today’s products as well as the research and engineering continually underway in the development of tomorrow’s.
BioFit’s commitment to quality is guaranteed by upfront, nothing-to-hide warranties on every product. Their entire seating lines are rated as Leadership in Energy and Environmental Design (LEED®) compliant for use in commercial interiors, qualifying specifiers for LEED® building credits. BioFit products are made to last and are manufactured to last for 13 years or longer.
BioFit understands the design of a piece of furniture is as individual as the person using it. Their knowledge of ergonomic science and workplace intricacies allows them to create pieces that assure harmonic user and product interactions – increasing comfort, productivity, and accordingly, positive bottom-line results.
Here is what BioFit has to say about seating ergonomics:
Ergonomics is the science of designing and arranging things to help ensure the safe and efficient interaction between the things and the people who use them. At BioFit Engineered Products, this means designing seating that helps protect users from musculo-skeletal disorders and repetitive motion injuries while aiding their performance in the accomplishment of particular tasks.
The first things to look at when designing seating of any specific purpose is the layout of the work-space where the chair will be used, the tasks to be performed, and how the chair is expected to function in that context. Of the five key risk factors in ergonomic injuries, it’s important to remember that the chair offers control over posture only. Excessive repetitive movements, use of manual force, exposure to extremes in temperature and contact with vibration all have unique consequences. Yet, an ergonomically correct chair can give users an advantage by putting them in healthier working positions.
While there is no single correct posture for continual sitting, changing posture frequently in a fully adjustable ergonomic chair remains the most important factor in alleviating sitting problems. Additionally, ergonomic seating can also help maintain attentiveness in staff, increasing performance. That’s why it’s important to know the difference between true “ergonomic” seating and products merely labeled as such. Ergonomic seating produced by BioFit includes proven components and options such as:
A five legged pedestal base
Fully adjustable and cushioned armrests
A seat that allows for even weight distribution
Easy-to-use height adjustment
There is simply no substitute for a durable, ergonomically correct chair. BioFit chairs are scientifically designed and independently tested to meet the most demanding standards for use in a variety of environments.
Production Automation is happy to be adding BioFit chairs to our website. BioFit offers a variety of chairs in a Quick Ship program which Production Automation now offers! Each line can be used in a variety of environments and all of them can be made ESD, Cleanroom, or a combination of both. Click on any of the links below to start shopping BioFit products.
BE Series: Larger & more ergonomic with great durability. Used in industrial, lab, healthcare, and critical environments.
BT Series: Durable, tough, & reasonably priced. Used in industrial, lab, healthcare, and critical environments.
EE Series: large ergonomic contour seat is a comfort solution in plants, labs, offices, and cleanrooms.
ET Series: Ergonomic support in these chairs makes them win-win for industrial applications as well as lab, office and cleanroom.
Fast Ship Program Details:
Order up to 15 chairs per day per customer, simply choose the model and available options from Production Automation’s BioFit section (SHOP HERE) and BioFit will ship within 72 hours!
Production Automation is always available to answer any questions or concerns you have during or after placing an order, we can be contacted at 888-903-0333 or at firstname.lastname@example.org.
For 20 years, ergoCentric has been committed to providing the lowest total cost of ownership in the industry – not the lowest price, or the coolest looking chairs, although both price and aesthetics are important.
Total Cost of Ownership is an “estimate of all direct and indirect costs associated with an asset or acquisition over its entire life cycle.”
Providing the lowest total cost of ownership is the result of a continuous effort to help the customer reduce every cost that relates to the purchase and use of their task seating.
The upfront price of a task chair is only a small portion of the total cost of the chair. Prior to the initial purchase, some questions need to be asked.
What is my potential administration cost for repair and maintenance?
Is the labor cost included in the manufacturers’ warranty?
What is the cost of making changes to chairs to accommodate changes in employees or employee needs?
Is there a cost for fitting special needs employees with customized chairs?
Is training on the proper usage available? What is the cost?
What productivity increases can be anticipated?
Will lost time claims be reduced?
Employers understand the concept of lowest total cost of ownership and life cycle costs. However, many have not taken the time to understand all the costs relating to task seating over time, or they assume all office seating suppliers are the same. As a result the life cycle cost analysis that is applied to new computer systems, for example, are not always applied to the purchase of new task seating.
Task chairs affect productivity in the same way computer systems do and therefore deserve the same kind of cost benefit analysis.
Bundling Furniture Purchases
There was a time when a case could be made for one stop shopping. Not anymore. There are a number of variables in creating an ergonomically friendly workstation, with task seating being at the top of the list. Task seating has an enormous impact on the health/welfare and productivity of employees. To purchase based on volume pricing or convenience just doesn’t make economic sense when one applies Lowest Total Cost of Ownership.
Given the huge impact task seating has on the health and productivity of employees, task seating should always be separated in the selection and tender processes from other furniture that is purchased. It is too important to be an afterthought and can end up costing far more than may be saved by the perceived efficiencies of one stop shopping or volume pricing.
Ergonomists and Interior Designers
The advice of professional ergonomists is crucial. Ergonomics is an intensive course of study, requiring a four year university degree and continuing education, and yet many corporations do not seem to appreciate the value ergonomists can bring to their bottom line. An ergonomist will apply their skill to lessen the impact on the human body that is caused by repetitive and excessive physical stress – essentially they ensure tools, machines, and other equipment optimize human well-being and overall system performance.
Interior design is a multi-faceted profession in which creative and technical solutions are applied within a structure to achieve a built interior environment. These solutions are functional, enhance the quality of life and culture of the occupants and are aesthetically attractive. Designs are created in response to and coordinated with code and regulatory requirements and encourage the principles of environmental sustainability.
When it comes to task seating we feel the advice of an ergonomist should be blended with the sills of the professional interior designer to ensure that the end user gets the lowest total cost of ownership.
Purchasing the Right Chair
While purchasing task seating may seem like a simple task – ” a chair is a chair” – it is important to consider the total cost of ownership and long-term ramifications of the chair being purchased, both from a financial and ergonomic point of view. Seating can so greatly affect the health and safety of the workforce that it should be considered separate from other office furniture purchases in order to properly evaluate all options and price points. To do this, the assistance of professional ergonomists in tandem with interior designers is often the best choice to balance long term health benefits with aesthetics.
At ergoCentric Seating Systems, their sole mission and focus is to design and manufacture the best ergonomic chairs in the world.
Working closely with ergonomists and health practitioners to continuously improve and refine their chair designs, ergoCentric Seating Systems offers a wide range of aesthetically pleasing task, executive, guest and stackable seating for the office environment.
ergoCentric’s industrial and high-tech seating meets the specialized requirements of factory, laboratory, ESD, and Cleanroom settings.
Seating for your increasingly diverse workforce
Our workforce is changing. Immigration, an aging population, the need to accommodate disabilities and an increase in sizes make it impossible for one chair, no matter how adjustable, to fit every person.
ergoCentric Seating Systems are ergonomically designed to accommodate 100% of your diverse workforce. In addition to making the most adjustable chairs on the market, modularity is a key component of ergoCentric’s business model.
Comfort, health and productivity
The human body was not made for sitting. Lack of proper support while seated adds stress to the body, which over a period of time, can lead to muscle fatigue, circulatory problems and even spinal injuries. A proper ergonomic chair provides the support so essential to your health and the comfort you need to be productive.
Recommended by ergonomists and health care practitioners to reduce stresses caused by the seated posture, ergoCentric is also the first company to have its chairs recognized by the Canadian Physiotherapy Association.
Regulations, cost, location, size, performance – How do you choose the right cleanroom?
Selecting a cleanroom for a new business or product is not a difficult process. There are many considerations and options, but focusing first on requirements will help make the decision-making process easier.
Cleanroom Selection Criteria
Rules mandated by government regulations, ISO guidelines, or customer requirements are the first consideration in selecting the right cleanroom. For example, government regulation USP 797 outlines specific requirements for the manufacture of pharmaceutical products, and ISO 14644-5:2004 guidelines specify basic requirements for cleanroom operations. Most often regulations of customer specifications will dictate the cleanliness of level or required rating, which provides a good starting point for choosing the right cleanroom.
Cost is an important consideration, especially if starting a new business or new product line. Prices can vary greatly from custom, fixed wall construction to modular, free-standing, soft wall, or hard wall prefabricated cleanroom systems. Fixed wall rooms are typically most expensive, with soft wall cleanrooms being the least expensive. Additionally, size, shape, configuration, and accessories will affect the overall cost.
The location of the cleanroom site within the existing building structure, and the number of processes and workers in the cleanroom will determine the size and shape of the room.
In addition to meeting performance needs, many companies consider the visual aesthetics of a cleanroom very important, wanting to project a high-tech image with visual appeal to attract new customers.
Advantages of Modular Cleanrooms
Modular, free-standing cleanrooms have many distinct advantages over their fixed wall counterparts. using modular rooms greatly reduces design, engineering, and construction time, thereby reducing costs. Since they are not an integral part of a larger structure, modular rooms can be taken down and moved to other facilities, or even sold as an asset. Fixed wall cleanrooms do not have this flexibility.
Expanding a modular cleanroom can be easily accomplished by taking off a wall and adding another module. The prefabricated design allows the room to be expanded, relocated, or reconfigured into a different shape or made into multiple smaller rooms.
All air handling and filtration equipment modules are built into the modular room ceiling. Hook-ups for electrical and plumbing are engineered in as part of the design.
The amount of time it takes to construct a modular room is much less than constructing a permanent walled structure. It can take several months to construct a fixed wall cleanroom because of the amount of design, engineering, and the various trades involved. However, a fairly sophisticated modular room can be constructed in a week or two. On-site assembly of a modular cleanroom is also less disruptive to surrounding operations in comparison to their fixed wall counterparts.
Modular cleanroom systems offer potential tax advantages for businesses. They are not typically considered part of the building and can often be depreciated faster than built-in, fixed wall cleanrooms. Tax consultants can provide specific tax advantage information.
Modular, Solid Wall Cleanroom Construction Considerations
There are two basic types of modular, solid wall cleanrooms: recirculating and non-recirculating. Product and process requirements will determine which type of room is best suited for a company’s needs.
Recirculating cleanrooms recirculate the air within the cleanroom and prevent it from mixing with the outside air, allowing for better control of the temperature and humidity. Air is recirculated back to the high efficiency particulate absorbing (HEPA) filters located in the cleanroom’s ceiling. This is accomplished by using air return chambers in the room’s walls or through existing walls of the building. The recirculating cleanrooms will have less contamination loading on the HEPA filters because the system is recycling previously cleaned air. With less contamination loading, the filters will last longer and preform better.
Non-recirculating, sometimes called single pass rooms, draw in air from above the room into the ceiling HEPA filters. The filtered air is then blown into the cleanroom and exits through an approximate two-inch space located below the walls or through adjustable wall grills. Non-recirculating cleanrooms are less costly to construct than recirculating rooms due to the lack of return air duct-work.
Cleanroom Performance Considerations
Most business are aware of their cleanroom performance requirements because of customer, industry, or government specifications. These performances requirements identify the cleanroom class level required at a given state or condition. There are three levels of condition (states) for testing and characterizing the performance of cleanrooms: as-built, at-rest, and operational. Specific test methods for these three classifications are outlined in ISO 14644-3:2005.
Most cleanrooms are rated and sold in the as-built category- an empty room with the filter system running, but without workers and production equipment. However, adding workers and equipment will introduce contamination and affect the room rating. A cleanroom may rated ISO 6 at rest, but at ISO 7 during operation (See Table 1). To comply with performance requirements, the as-built empty room should be tested and benchmarked, followed by testing and documentation of the at-rest or operational states if not in compliance, corrective steps need to be taken. These steps can range from examining the production process and number of workers in the cleanroom, to testing the room’s air flow performance.
To ensure optimal cleanroom performance, air flow design and frequency or air changes should be evaluated. Cleanrooms are classified according to the number and size of particles permitted per volume of air in a specific amount of time. There is a relationship between cleanroom class ratings and the room’s air changes per hour. For a cleaner room rating, more air exchanges become necessary.
For example, a typical ISO 7 Class room will have 60-150 changes of air per hour, while an ISO 6 Class room will have 150-240 changes (See Table 2).
All areas within a cleanroom should have similar air changes during each hour to ensure required performance. For example, a cleanroom with only one air return or exit, located at the opposite end of the fan and filter, will produce stagnant air spots. This type of design causes air to flow almost horizontally across the room to the venting location, in a line-of-sight fashion. Areas of inadequate air movement retain higher levels of contamination. Adding or moving air returns will enable a more vertical and even air flow, improving overall air quality. The right balance of filter systems and air returns must be maintained to create positive air pressure inside the cleanroom. Positive air pressure produces an outward air movement, preventing the inflow of contaminates and assisting in expelling particles generated by workers and equipment.
Cleanroom air flow performance can be cost-effectively upgraded by adding fan-filter modules (FFM). For example, FFMs cover approximately 5-15% of an ISO 8 Class cleanroom ceiling. Upgrading to an ISO 7 Class cleanroom requires 15-25% ceiling coverage, and coverign 25-40% of the ceiling changes the room to an ISO 6 Class (See Table 2).
To make a cleanroom fully functional, a variety of additional accessories, from lighting and doors to furniture and changing rooms, need to be considered. Accessories can be selected while working with the modular cleanroom company during the room design and specification phase.
Most cleanrooms have adjacent gowning areas where workers change into special garments, minimizing particulate contamination before entering the production area of the cleanroom. Some gowning rooms are equipped with air showers as a way to further reduce particulate contamination that might settle on the surface of a cleanroom garment. Some gowning rooms may have special benches for people to use while changing into boots, gloves, gowns, and masks.
Many companies may use the gowning room for transferring production material and equipment in and out of the clean environment. However, pass-though or double-door airlocks are more efficient and keep the introduction of particulate contamination to a minimum.
Specially produced cleanroom furniture and tools should be used because they are designed for low particulate generation. For example, tables are smooth and sealed so they don’t shed particulates and can be easily wiped down.
The modular cleanroom location within a building is very important. Physical space, temperature/humidity, and cleanliness will affect selection decisions and overall project cost.
Most modular cleanrooms can be installed with as little as 25 inches of clearance over the inside clear height of the room on non-recirculating rooms, and about 30 inches with recirculating rooms.
A typical cleanroom should operate at about 66-70 degrees Fahrenheit to ensure a comfortable environment for workers wearing garb such as lab coats, head coverings, gloves, and masks.
Non-recirculating cleanrooms provide better temperature control between the interior cleanroom and the surrounding building space. The room air does not mix with the external air and only requires cooling to compensate for the internal heat load. Processes requiring humidity control will require special environmental control systems and are usually only available with recirculating cleanrooms. Typically, systems are made just to add or just remove humidity depending on the surrounding environment.
Installation of a modular, hardwall cleanroom is quick and easy. With modular systems everything is prefabricated at the factory, so specialists are not needed to assemble the room, just local trades or internal people. It’s not uncommon to start a project on Monday and finish on Friday.
Regular cleanroom maintenance is very straightforward and is needed to ensure cleanroom performance and certification.
Interior surfaces are wiped down daily on a regular basis or before each shift using a solution of deionized water and 10% alcohol. The cleanroom floors are routinely mopped as well. Vertical surfaces, such as walls can be cleaned less frequently depending on product requirements. All contact points such as door handles and user-operated equipment should also be wiped down on a daily or shift basis, again, depending on process requirements.
HEPA filters have a pre-filter that needs to be changed regularly- depending on loading. The HEPA filter modules are fairly maintenance free, but are required to be certified every year. Additionally, proper air flow and leak checks are usually part of the regular certification for a cleanroom.
Certification of a cleanroom can be performed by either internal personnel or external companies. Most companies prefer an external, third-party firm to perform the certification, providing them with an independent analysis. Customer or product requirements may require independent certification.
Determining the right cleanroom for a new product or business requires balancing many selection aspects- from process requirements and cost, to performance and construction. The decision process is not complex, but a clear understanding of cleanroom requirements, regulations, operation, and available options will make cleanroom specification and design easier.
Production Automation wants to make choosing the right cleanroom as easy as possible. If you have any questions or concerns please contact us at 888-903-0333 or by email at email@example.com. Production Automation also offers a Hardwall or Softwall Cleanroom Quote Form to help get all the information we need to provide you with an accurate quote, to get started simply follow one of the links posted below:
OK, so “easy” may not be a word that comes to mind for designing such sensitive environments. However, that doesn’t mean you can’t produce a solid cleanroom design by tackling issues in a logical sequence. This article covers each key step, down to handy application-specific tips for adjusting load calculations, planning exfiltration paths, and angling for adequate mechanical room space relative to the cleanroom’s class.
Many manufacturing processes need the very stringent environmental conditions provided by a cleanroom. Because cleanrooms have complex mechanical systems and high construction, operating, and energy costs, it is important to perform the cleanroom design in a methodical way. This article will present a step-by-step method for evaluating and designing cleanrooms, factoring in people/material flow, space cleanliness classification, space pressurization, space supply airflow, space air exfiltration, space air balance, variables to be evaluated, mechanical system selection, heating/cooling load calculations, and support space requirements.
Step One: Evaluate Layout for People/Material Flow
It is important to evaluate the people and material flow within the cleanroom suite. Cleanroom workers are a cleanroom’s largest contamination source and all critical processes should be isolated from personnel access doors and pathways.
The most critical spaces should have a single access to prevent the space from being a pathway to other, less critical spaces. Some pharmaceutical and biopharmaceutical processes are susceptible to cross-contamination from other pharmaceutical and biopharmaceutical processes. Process cross-contamination needs to be carefully evaluated for raw material inflow routes and containment, material process isolation, and finished product outflow routes and containment. Figure 1 is an example of a bone cement facility that has both critical process (“Solvent Packaging”, “Bone Cement Packaging”) spaces with a single access and air locks as buffers to high personnel traffic areas (“Gown”, “Ungown”).
Step Two: Determine Space Cleanliness Classification
To be able to select a cleanroom classification, it is important to know the primary cleanroom classification standard and what the particulate performance requirements are for each cleanliness classification. The Institute of Environmental Science and Technology (IEST) Standard 14644-1 provides the different cleanliness classifications (1, 10, 100, 1000, 10000, and 100000) and the allowable number of particles at different particle sizes.
For example, a Class 100 cleanroom is allowed a maximum of 3,500 particles/cu ft and 0.1 microns and larger, 100 particles/cu ft at 0.5 microns and larger, and 24 particles/cu ft at 1.0 microns and larger. Table 1 provides the allowable airborne particle density per cleanliness classification table.
Space cleanliness classification has a substantial impact on a cleanroom’s construction, maintenance, and energy cost. It is important to carefully evaluate reject/contamination rates at different cleanliness classifications and regulatory agency requirements, such as the Food and Drug Administration (FDA). Typically, the more sensitive the process, the more stringent cleanliness classification should be used. Table 2 provides cleanliness classifications for a variety of manufacturing processes.
Your manufacturing process may need a more stringent cleanliness class depending upon its unique requirements. Be careful when assigning cleanliness classifications to each space; there should be no more than two orders of magnitude difference in cleanliness classification between connecting spaces. For example, it is not acceptable for a Class 100,000 cleanroom to open into a Class 100 cleanroom, but it is acceptable for a Class 100,000 cleanroom to open into a Class 1,000 cleanroom.
Looking at our bone cement packaging facility (Figure 1), “Gown”, Ungown” and “Final Packaging” are less critical spaces and have a Class 100,000 (ISO 8) cleanliness classification, “Bone Cement Airlock” and “Sterile Airlock” open to critical spaces and have Class 10,000 (ISO 7) cleanliness classification; ‘Bone Cement Packaging” is a dusty critical process and has Class 10,000 (ISO 7) cleanliness classification, and ‘Solvent Packaging” is a very critical process and is performed in Class 100 (ISO 5) laminar flowhoods in a Class 1,000 (ISO 6) cleanroom.
Step Three: Determine Space Pressurization
Maintaining a positive air space pressure, in relation to adjoining dirtier cleanliness classification spaces, is essential in preventing contaminants from infiltrating into a cleanroom. It is very difficult to consistently maintain a space’s cleanliness classification when it has neutral or negative space pressurization. What should the space pressure differential be between spaces? Various studies evaluated contaminant infiltration into a cleanroom vs. space pressure differential between the cleanroom and adjoining uncontrolled environment. These studies found a pressure differential of 0.03 to 0.05 in w.g. to be effective in reducing contaminant infiltration. Space pressure differentials above 0.05 in. w.g. do not provide substantially better contaminant infiltration control then 0.05 in. w.g.
Keep in mind, a higher space pressure differential has a higher energy cost and is more difficult to control. Also, a higher pressure differential requires more force in opening and closing doors. The recommended maximum pressure differential across a door is 0.1 in. w.g. at 0.1 in. w.g., a 3 foot by 7 foot door requires 11 pounds of force to open and close. A cleanroom suite may need to be reconfigured to keep the static pressure differential across doors within acceptable limits.
Our bone cement packaging facility is being built within an existing warehouse, which has a neutral space pressure (0.0 in. w.g.). The air lock between the warehouse and “Gown/Ungown” does not have a space cleanliness classification and will not have a designated space pressurization. “Gown/Ungown” will have a space pressurization of 0.03 in. w.g. “Bone Cement Air Lock” and “Sterile Air Lock” will have a space pressurization of 0.06 in. w.g. “Final Packaging” will have a space pressurization of 0.06 in. w.g. “Bone Cement Packaging” will have a space pressurization of 0.03 in. w.g., and a lower space pressure than ‘Bone Cement Air Lock” and “Final Packaging” in order to contain the dust generated during packaging.
the air filtering into the ‘Bone Cement Packaging” is coming from a space with the same cleanliness classification. Air infiltration should not go from a dirtier cleanliness classification space to a cleaner cleanliness classification space. “Solvent Packaging” will have a space pressurization of 0.11 in. w.g. Note, the space pressure differential between the less critical spaces is 0.03 in. w.g. and the space differential between the very critical “Solvent Packaging” and “Sterile Air Lock” is 0.05 in. w.g. The 0.11 in. w.g. space pressure will not require special structural reinforcements for walls or ceilings. Space pressures above 0.5 in. w.g. should be evaluated for potentially needing additional structural reinforcement.
Step Four: Determine Space Supply Airflow
The space cleanliness classification is the primary variable in determining a cleanroom’s supply airflow. Looking at table 3, each clean classification has an air change rate. For example, a Class 100,000 cleanroom has a 15 to 30 ach range. The cleanroom’s air change rate should take the anticipated activity within the cleanroom into account. A Class 100,000 (ISO 8) cleanroom having a low occupancy rate, low particle generating process, and positive space pressurization in relation to adjacent dirtier cleanliness spaces might use 15 ach, while the same cleanroom having high occupancy, frequent in/out traffic, high particle generating process, or neutral space pressurization will probably need 30 ach.
The designer needs to evaluate his specific application and determine the air change rate to be used. Other variables affecting space supply airflow are process exhaust airflows, air infiltrating in through doors/openings, and air exfiltrating out through doors/openings. IEST has published recommended air change rates in Standard 14644-4.
Looking at Figure 1, “Gown/Ungown” had the most in/out travel but is not a process critical space, resulting in 20 a ch., ‘Sterile Air Lock” and “Bone Cement Packaging Air Lock” are adjacent to critical production spaces and in the case of the “Bone Cement Packaging Air Lock”, the air flows from the air lock into the packaging space. Though these air locks have limited in/out travel and no particulate generating processes, their critical importance as a buffer between “Gown/Ungown” and manufacturing processes results in their having 40 ach.
“Final Packaging” places the bone cement/solvent bags into a secondary package which is not critical and results in a 20 ach rate. “Bone Cement Packaging” is a critical process and has a 40 ach rate. ‘Solvent Packaging” is a very critical process which performed in Class 100 (ISO 5) laminar flow hoods within a Class 1,000 (ISO 6) cleanroom. ‘Solvent Packaging” has very limited in/out travel and low process particulate generation, resulting in a 150 ach rate.
Step Five: Determine Space Air Exfiltration Flow
The majority of cleanrooms are under positive pressure, resulting in planned air exfiltrating into adjoining spaces having lower static pressure and unplanned air exfiltration through electrical outlets, light fixtures, window frames, door frames, wall/floor interface, wall/ceiling interface, and access doors. It is important to understand rooms are not hermetically sealed and do have leakage. A well-sealed cleanroom will have a 1% to 2% volume leakage rate. Is this leakage bad? Not necessarily.
First, it is impossible to have zero leakage. Second, if using active supply, return, and exhaust air control devices, there needs to be a minimum of 10% difference between supply and return airflow to statically decouple the supply, return, and exhaust air valves from each other. The amount of air exfiltrating through doors is dependent upon the door size, the pressure differential across the door, and how well the door is sealed (gaskets, door drops, closure).
We know the planned infiltration/exfiltration air goes from one space to the other space. Where does the unplanned exfiltration go? The air relieves within the stud space and out the top. Looking at our example project (Figure 1), the air exfiltration through the 3- by 7- foot door is 190 cfm with a differential static pressure of 0.03 in w.g. and 270 cfm with a differential static pressure of 0.05 in. w.g..
Step Six: Determine Space Air Balance
Space air balance consists of adding all the airflow into the space (supply, infiltration) and all the airflow leaving the space (exhaust, exfiltration, return) being equal. Looking at the bone cement facility space air balance (Figure 2), “Solvent Packaging” has 2,250 cfm supply airflow and 270 cfm of air exfiltration to the ‘Sterile Air Lock”, resulting in a return airflow of 1,980 cfm. “Sterile Air Lock” has 290 cfm of supply air, 270 cfm of infiltration from ‘Solvent Packaging”, and 190 cfm exfiltration to “Gown/Ungown”, resulting in a return airflow of 370 cfm.
“Bone Cement Packaging” has 600 cfm supply airflow, 190 cfm of air filtration from ‘Bone Cement Air Lock”, 300 cfm dust collection exhaust, and 490 cfm of return air. “Bone Cement Air Lock” has 380 cfm supply air, 190 cfm exfiltration to ‘Bone Cement Packaging” has 670 cfm supply air, 190 cfm exfiltration to “Gown/Ungown”. “Final Packaging” has 670 cfm supply air, 190 cfm exfiltration to ‘Gown/Ungown”, and 480 cfm of return air. “Gown/Ungown” has 480 cfm of supply air, 570 cfm of infiltration, 190 cfm of exfiltration, and 860 cfm of return air.
We have now determined the cleanroom supply, infiltration, exfiltration, exhaust, and return airflows. The final space return airflow will be adjusted during start-up for unplanned air exfiltration.
Step Seven: Assess Remaining Variables
Other variables needing to be evaluated include:
Temperature: Cleanroom workers wear smocks or full bunny suits over their regular clothes to reduce particulate generation and potential contamination. Because of their extra clothing, it is important to maintain a lower space temperature for worker comfort. A space temperature range between 66°F and 70° will provide comfortable conditions.
Humidity: Due to a cleanroom’s high airflow, a large electrostatic charge is developed. When the ceiling and walls have a high electrostatic charge and space has a low relative humidity, airborne particulate will attach itself to the surface. When the space relative humidity increases, the electrostatic charge is discharged and all the captured particulate is released in a short time period, causing the cleanroom to go out of specification. Having high electrostatic charge can also damage electrostatic discharge sensitive materials. It is important to keep the space relative humidity high enough to reduce the electrostatic charge build-up. An rh or 45% +5% is considered the optimal humidity level.
Laminarity: Very critical processes might require laminar flow to reduce the chance of contaminates getting into the air stream between the HEPA filter and the process. IEST Standard #IEST-WG-CC006 provides airflow laminarity requirements.
Electrostatic Discharge: Beyond the space humidification, some processes are very sensitive to electrostatic discharge damage and it is necessary to install grounded conductive flooring.
Noise Levels and Vibration: Some precision processes are very sensitive to noise and vibration.
Step Eight: Determine Mechanical System Layout
A number of variables affect a cleanroom’s mechanical system layout: space availability, available funding, process requirements, cleanliness classification, required reliability, energy cost, building codes, and local climate. Unlike normal A/C systems, cleanroom A/C systems have substantially more supply air than needed to meet cooling and heating loads.
Class 100,000 (ISO 8) and lower ach Class 10,000 (ISO 7) cleanrooms can have all the air go through the AHU. Looking at Figure 3, the return air and outside air are mixed, filtered, cooled, reheated, and humidified before being supplied to terminal HEPA filters in the ceiling. To prevent contaminant recirculation in the cleanroom, the return air is picked up by low wall returns. For higher class 10,000 (ISO 7) and cleaner cleanrooms, the airflows are too high for all the air to go through the AHU. Looking at Figure 4, a small portion of the return air is sent back to the AHU for conditioning. The remaining air is returned to the circulation fan.
Step Nine: Perform Heating/Cooling Calculations
When performing the cleanroom heating/cooling calculations, take the following into consideration:
Use the most conservative climate conditions (99.6% heating design, 0.4% drybulb/median wetbulb cooling deign, and 0.4% wetbulb/median drybulb cooling design data);
Include filtration into calculations;
Include humidifier manifold heat into calculations;
Include process load into calculations;
Include recirculation fan heat into calculations.
Step Ten: Fight for Mechanical Room Space
Cleanrooms are mechanically and electrically intensive. As the cleanroom’s cleanliness classification becomes cleaner, more mechanical infrastructure space is needed to provide adequate support to the cleanroom. Using a 1,000-sq-ft cleanroom as an example, a Class 100,000 (ISO 8) cleanroom will need 250 to 400 sq ft of support space, a Class 10,000 (ISO 7) cleanroom will need 250 to 750 sq ft of support space, a Class 1,000 (ISO 6) cleanroom will need 500 to 1,000 sq ft of support space, and a Class 100 (ISO 5) cleanroom will need 750 to 1,500 sq ft of support space.
The actual support square footage will vary depending upon the AHU airflow and complexity (Simple: filter, heating coil, cooling coil, and fan; Complex: sound attenuator, return fan, relief air section, outside air intake, filter section, heating section, cooling section, humidifier, supply fan, and discharge plenum) and number of dedicated cleanroom support systems (exhaust, recirculation air units, chilled water, hot water, steam, and DI/RO water). It is important to communicate the required mechanical equipment space square footage to the project architect early in the design process.
Cleanrooms are like race cars. When properly designed and built, they are highly efficient performance machines. When poorly designed and built, they operate poorly and are unreliable. Cleanrooms have many potential pitfalls, and supervision by an engineer with extensive cleanroom experience is recommended for your first couple of cleanroom projects.
Visit Production Automation’s Cleanroom Construction section HERE, or email questions to firstname.lastname@example.org
At Gibo/Kodama Chairs, they design chairs for hours of productivity. From the shape of their seats to the density of their foam, from the ease of control adjustments to their ergonomically designed support system, Gibo/Kodama designs fit and productivity into every chair. You’ll find Gibo/Kodama chairs in production lines, biomedical labs, office environments, anywhere productivity is vital to a company’s well being. Gibo/Kodama’s technical seating, including ESD and Cleanroom chairs, is used by the top companies of our nation. And all of Gibo/Kodama’s products are proudly made here in the USA.
Learn more about the different types of Gibo Kodama Chairs we offer:
The Stamina 3000 Series is very well known and is highly regarded as one of the best chairs on the market for Cleanroom, ESD, and general production applications. The Series continues to be specified as the standard chair for many of the Fortune 1000 companies. Multiple height ranges available, from desk height to high bench. Numerous options make it easy to fit most end users and their applications.
The Synchron 4000 Series is a capacious version of the Stamina 3000 Series. A larger person will appreciate the size of the seat and back. Both add comfort and support where it is needed most. A heavy-duty independent tilt control easily withstands the daily rigors of the common 24/7 workplace.
The Rèspon Series Special Task Chair features and independent tilt control and a uniquely shaped back with a ratcheting mechanism for easy height adjustment. This model is a standard in many local and national government facilities. It is offered in both desk height and bench height.
The Stamina 7000 Series offers all the features of the 3000 Series, but uses a uniquely shaped saddle seat. The saddle seat helps to keep the user properly seated, particularly where slick cleanroom suits contribute to slippage problems. It also allows easier access to the footring used on bench height models.
The Harsh Environment 9000 Series incorporates a polyurethane seat and back to handle the harshest environments. To resist corrosion, special attention has been taken to cover or coat all exposed metal, including control, back upright and handles. All threaded knobs and caster stems are stainless steel. These innovations make this chair ideal for most corrosive and wet applications.
The P3000 Series features a very durable, solid, polyurethane seat and back. This feature makes this an economical choice of a clean room application. Seat angle, back angle, and back height adjustments are easily made using the standard “Ergo Tilt” control. The contoured seat and back add comfort and support for prolonged sitting.
Gibo/Kodama Medical Stools offers the exceptional comfort of a highly contoured seat and the ergonomic function of a lockable, rocking, forward tilt control. These features add exceptional comfort and support for the medical or dental profession.
The Class 10 Cleanroom/ESD Chair provides maximum comfort while meeting current cleanroom standards. Special features to ensure Class 10 rating include: heavy-duty urethane bladders to seal in seat and back foam, an air exchange system to prevent foam outgassing, plastic control covers and specially filtered cylinders.
Class 100 cleanroom option is available for the following series: C1000PL, Stamina C3000, Synchron C4000, and Stamina C7000. All cleanroom chairs are upholstered with vinyl, use polished aluminum or chrome plated components, and incorporate depth filtration ventilation in both seats and backs.
Chairs are an important component in creating an ESD safe environment for sensitive equipment or products. As a recognized leader in the industry, Gibo/Kodama Chairs offers an ESD option on many of their chairs. In addition to using high quality components and a precise manufacturing process, they test all of their chairs prior to shipping to ensure they meet the ANSI/ESD STM12.1-2006 Standard.
We are pleased to have recently added Superior Uniform Group’s Worklon® series garments to our website, which are now available for purchase.
Worklon® provides a comprehensive line of apparel for cleanrooms, controlled environments and ESD sensitive areas. Markets served include Pharmaceuticals, Automotive, Semi-conductor and Food Processing.
Worklon® manufactures cleanroom and controlled environment apparel and accessories for the ultimate defense in particle control, electrostatic dissipation, fluid resistance and bacteria filtration for peripheral areas of the High Tech Industry. ESD Lab Wear is offered in a variety of fabrics and styles.
Choose from materials such as:
Maxima High Density: A densely woven 100% polyester fabric. Maxima High Density offers excellent barrier protection against bacteria, fluids, and particles. This fabric is gamma compatible and autoclavable. (ESD Version: 99% polyester, 1% carbon yarn)
Integrity 1800: 99% polyester and 1% carbon yarn creates a static dissipative fabric. This material is highly fluid repellent and contains an antimicrobial treatment to inhibit bacteria growth and reduce bio-burden. This material is also gamma compatible and autoclavable.
Burlington C3: A densely woven, static dissipative fabric made or 99% polyester and 1% carbon yarn. This material has excellent durability.
More fabric options available including: Polyester Taffeta, Polyester Herringbone, Micro-Stat, and Work-Stat.
The Worklon® Series also carries a variety of boots and shoe covers, with a choice of hypalon soles or molded soles.
Hypalon Soles: Polyester substrate with static dissipative hypalon coating. The material is flexible, skid/abrasion/chemical resistant. Gamma compatible and autoclavable.
Molded Soles: Once piece injection molded, custom nitrile rubber. good resistance to slipping, scuffs and chemicals. Static dissipative and durable. Also gamma compatible and autoclavable.
For added protection in cleanrooms and for worker comfort, Worklon® offers Intersuits in both standard and ESD versions.
Microdenier Sandwash with Nano-Dry Technology: 100% polyester microfiber fabric has a luxurious silk-like hand and appearance. Excellent opacity, drapability and moisture wicking capability. Gamma compatible and autoclavable.
Microdenier Sandwash ESD with Carbon Yarn Grid & Nano-Dry Technology: 99% polyester, 1% carbon yarn that provides superior static dissipation and moisture control. Lightweight with a soft hand, this fabric is extremely comfortable and offers low particulation. Also gamma compatible and autoclavable.
Now that you have a better idea of the fabrics to choose from, please browse through the categories of products we have available in the Worklon Brand:
Pre-engineered, modular design cleanrooms are cost effective without the inconvenience of conventional “stick-built” construction.
Once Through Design
Once-Thru Design is also known as single pass. Ambient air is drawn into the SAM Fan Filter Units at ceiling level. The filtered air passes into the cleanrooms and is transferred out of the room through grilles at the bottom of the walls.
Lighting: 4-Lamp cleanroom light fixtures with energy efficient T8 electronic ballasts. Fluorescent lamp tubes are not included.
Ceiling Panels: Cleanguard ceiling panels with sealed edges for spaces not occupied by SAM Fan Filter Units or light fixtures.
HEPA Filters: SAM 2′ x 4′ Fan Filter Units, 115V with 99.99% HEPA Filter, variable speed control and all other standard specifications as manufactured by Clean Rooms International.
Electrical: Electrical connections to the building power source are to be completed on site by a qualified electrician at buyer’s cost.
Assembly: Legend Cleanrooms are knocked down for shipment. Detailed assembly instructions are included with shipment.
Submittal Drawings: A prepared submittal drawing will be sent with Order Acknowledgment after a purchase order is received. To qualify for a 5 business day lead time, options, modifications, or revisions will not be possible.
Options: If options, modifications or revisions are required, additional lead time will be necessary. Contact Production Automation for information on effects on lead time and pricing.
Legend Cleanroom Designs
Provides Controlled Environment: Legend Hardwall cleanroom Wall Panels and Components are engineered to provide a secure controlled environment within the cleanroom.
Non-Progressive Design: As needs change, Legend wall panel modular design offers the ability to relocate or expand the cleanroom in the future.
Special Sizes: Wall panels can be made in special sizes for entry areas, gowning rooms and air-locks, ensuring that the cleanroom pressure remains constant. Extra-high, legend wall panel systems can accommodate large equipment which can require ceilings higher than the standard eight feet.
Load Considerations: Three factors are considered when determining which wall system to use for load-bearing cleanrooms. The first factor is the amount of total weight on the cleanroom wall, the second factor is the span distance between all four of the cleanroom walls and the third factor is the height of your wall. Consult with Production Automation for detailed information about your cleanroom project.
Once Through Design: Ambient air is drawn into the SAM Fan Filter Unit at ceiling level. The filtered air passes into the cleanroom and is transferred out of the room through grilles at the bottom of the walls. Refer to figures 1 and 2.
Recirculating Design: Recirculating cleanrooms are ideal when temperature or humidity control is required. Refer to figure 3.
Legend Cleanroom Classes
How are Cleanroom Standards Determined?: The number and size of particles allowed in the room determines the classification of air cleanliness.
Guidelines for selecting filters: PAC can help make the calculations necessary to achieve the desired ISO or U.S. Federal Standard 209 Class. The correct quantity of HEPA or ULPA grade filters will be selected using air changes per hour as the most effective method for meeting class requirements.
Installation, Testing and Certification: A network of authorized installers enables Cleanrooms International to offer complete installation services or testing and certification, which Production Automation can help arrange if needed.
Accelerated Depreciation: Conventional construction becomes a permanent part of the host building and requires the straight-line method of depreciation over as long as 39 years, depending upon current law. A shorter depreciation life for the modular cleanroom results in a quicker write-off and faster payback for the cost of the room.
Modular cleanrooms built from Legend Cleanroom Systems can qualify for accelerated depreciation vs. conventional construction. Consult with your accountant to determine if favorable depreciation rules apply to your purchase of a Legend Cleanroom System.
A Discussion about Air Showers, from Liberty Industries “Air Shower Newsletter”
Do they really reduce contamination?
The efficacy of air showers in the contamination control process has been a source of debate for several years.
Tests have been conducted which prove the effectiveness of air showers. The tests do show that an air shower does reduce particulate. For the most part, reduction in particulate matter is dependent upon the particle size, the type of garment worn, the cycle time, and directly relates to the air shower design and how it is used and maintained.
As a percentage of the total cost of the modern cleanroom, the cost of an air shower is virtually insignificant. In any application where contamination is critically important- such as life science, biomedical, pharmaceutical, parenteral drug, microelectronics, aerospace, and precision manufacturing- air showers should be considered essential equipment.
If its use could eliminate contamination of one expensive batch of pharmaceutical chemicals or the rejection of one semiconductor wafer, for example, it is m0ney well spent. Perhaps millions of dollars could be saved.
In addition, from a psychological point of view, having operating personnel pass through an air shower before entering the work area, reinforces the fact that cleanliness to the operation is essential. This, hopefully, reinforces the concept that protection of the product from personnel is a significant concern.
A brief history of the emergence of contamination control technology:
In today’s modern world of manufacturing and research, and development, contamination control has become a necessary of the manufacturing process. In fact, without it, many of the advances made in the last twenty years or so would not have been possible.
Contamination control technology is not confined to any one industry. Its practice transcends specific industries and is used, to some degree, in just about all manufacturing and research and development processes.
Without contamination control technology, the developing broad field of life sciences encompassing biotech, biomedical, pharmaceutical, parenteral drug, microelectronics, aerospace, and precision manufacturing would not have been able to achieve some of the discoveries that have been made to date nor the discoveries yet to be made. While nanotechnology, a new emerging field of study in which its research is done at the at the atomic or molecular level, could not exist without the advancements made in contamination control technology over the years.
Dealing with the issues of contamination control on a microscopic or smaller scale has lead to the creation of the modern cleanroom and along with it, the air shower.
The primary focus of a cleanroom is to control the levels of contamination by creating a differential pressure between the cleanroom and the surrounding area and to filter the air entering the room to prevent the entry of unwanted particulate matter and to change the air in the room with an air-handling system to purge particulate matter created within the room. The cleanroom itself is constructed of materials that tend to resist particulate generation, hence minimizing additional contamination. More sophisticated cleanrooms can also control temperature and humidity in the workspace.
In the conventional cleanroom, low velocity air enters from the ceiling plenum through perforated diffusers and carries out contamination through wall exhausts close to floor level. In the laminar flow cleanroom, air is introduced uniformly at low velocities into a space confined on four sides and through an opening equal to the cross sectional area of the confined space- a technique that stratifies the air and minimizes cross-stream contamination.
To keep this particulate matter from being recycled, both types of rooms use HEPA (High Efficiency Particulate Air) Filters. HEPA Filters are manufactured from glass fiber, accordion-style pleated filters that can be up to 99.99% efficient in removing particles .03 microns and larger. For more stringent requirements , an ULPA (Ultra Low Particulate Air) Filter may be used. An ULPA filter has the ability to remove a higher percentage of 0.3 micron particles than a HEPA filter.
Contamination vs. Particulate Matter:
So far in this discussion the terms “particulate matter” and “contamination” have been used interchangeably.
A contaminate is any foreign substance that will have a detrimental effect on whatever you are trying to accomplish. This most significant form of contamination in cleanrooms is submicroscopic matter that are distributed in the air in the form of fine particles or fibers or carried into the cleanroom and redeposited by workers.
To be technically correct, however, it should be pointed out that not all particulate matter is a contaminate. To be considered a contaminate, a particulate matter must meet three criteria:
It must be able to migrate to the vulnerable area, either by air currents, by fluids, or through transference from personnel
It must be significant in number
It must have physical properties that cause damage
Sources of Contamination:
Just about all industrial activities produce contaminates. Operating personnel present the most significant source contaminates – hair, skin, dandruff, as well as nasal and oral emissions- to name a few. While contaminates can and do differ in terms of hardness, size, shape, translucency, color, ect. their size in most cases, determines the degree of potential harm they can cause.
There is a very delicate balance between the contamination level, the number of personnel in a cleanroom and how they go about performing their assigned tasks. Some contamination is inevitable. In reality, there is very little you can do about this natural propensity to create contaminates except to instruct workers in correct cleanroom procedure and to deal with the unavoidable contamination as it arises. This is what cleanrooms have always done. You can certainly help matters by limiting the amount of contaminates that any specific individual brings in from the outside.
An air shower can be an integral part of the contamination control process because it can minimize the amount of contaminates brought into the cleanroom from the outside:
An air shower is nothing more than a device meant to limit the contamination brought into a controlled area such as a cleanroom. It works by moving air over the worker at a specific high velocity for a specified period of time. In a properly designed air shower, particles are driven off and away from the body and deposited on the upstream side of the HEPA or ULPA filters.
Air showers have been used effectively in the cleanroom industry for over thirty-five years and have been instrumental in reducing the level of contamination brought into the cleanroom.
Normally positioned between the cleanroom and the outside environment, an air shower is a chamber equipped with a blower unit, interlocking doors, HEPA filters and prefilters, a recirculating air system and multiple air nozzles. Various size nozzles are arranged on the walls and ceiling in a predetermined pattern for the most effective removal of loose particles, dust, or other particulate matter from the garments.
Filtered air is blown through the nozzles directly against the individual standing within the air shower, creating a flapping and shearing effect designed to remove loose contaminates prior to entering a change room, wash room, ante-room, or cleanroom. The air is sucked and taken from the chamber, stripped of its contaminates through the filtration system, and recycled back to the air shower to continue the cleaning job.
Today’s air shower is equipped with a powerful blower unit, solid state electrical control panels complete with safety monitors and and emergency shut down capabilities that may be activated from both the interior and exterior of the unit. Fluorescent lighting flush ceiling mounted for maximum brightness.
Is there a difference between Air Showers and an Air Lock?
An air shower is usually built into an air lock. It is important to remember that there is a big difference between the two.
An air lock is a room, corridor or some other space which separates the cleanroom from a less clean area. Generally, it has two doors at opposite ends and is frequently designed with an electrical or mechanical interlock so that one door cannot be opened unless the other one is closed. Its purpose is to prevent the loss of valuable cleanroom air whenever a person leaves or enters the room and also to prevent contaminated air from entering the cleanroom when a door is opened. It also has the ability to conserve energy.
While an air shower can function in this capacity, it also has the additional advantage of being able to actively clean off contamination from the person entering the cleanroom with jets of filtered air coming out of the nozzles.
Typically an air shower can be operated in three distinctly different ways depending on process requirements:
Two Way, One Way
One Way Operation:
Exit door locked at rest, entrance door unlocked. When the user enters the air shower, the entrance door closes and locks; then the air shower cycle starts.
At the end of the cycle, the entrance door stays locked and the exit door unlocks so that the user can leave.
When the exit door is closed, it locks again and the entrance door unlocks.
The air shower is now ready for use again.
Two Way, One Way Operation:
The air shower is used in both directions, but operates the air shower in only one direction.
Only one door at a time can be opened.
Both doors are unlocked at rest. The user enters the air shower via the entrance door. At the end of the air shower cycle, he leaves the exit door.
Or a user can enter the unit via the exit door, once the exit door closes the user can immediately leave via the door without activation of the cycle. Both doors cannot be opened at the same time.
Two Way Operation:
In this mode, the cycle runs in both directions.
only one door at a time can be opened. The user can go in either direction and the air shower will cycle.
Test data has been obtained which prove that air showers are effective in reducing contamination brought into the cleanroom.
Data developed by a Japanese company several years ago indicates that, depending on the particle size, particle removal can be up to 90%. The larger particle the higher the efficiency.
It is to be noted that proper operating protocol in using an air shower weighs greatly on its effectiveness. Training is of utmost importance to insure reduced contamination levels in cleanrooms and to ensure that the air shower is operating at maximum effectiveness. Proper protocol suggests personnel should be trained to rotate continuously 360 degrees, with hands on their heads, as shown during the air shower cycle to insure contamination removal is as efficient as possible.
The Air Force has very exacting standards regarding acceptable levels of contamination while at the same time, has equally exacting standards when it comes to investing in equipment. In order to determine the efficacy of air showers the Air Force conducted tests of it own.
The test consisted of sending a team of twenty operating personnel through two air showers, one located before the entrance to the change room and the other before the entrance to the cleanroom itself with a cycle time of eight seconds each. operators were instructed to raise their arms and make a 360 degree turn. Prior to the entrance to the first shower, outer garments are removed and stored. Once passed the first air shower, the individual enters the change room where he puts on the cleanroom garments and goes through the second air shower, entering the cleanroom. After each test condition, the cleanroom was allowed to return to normal contaminate level before a new test was begun and collections of samples were made.
As can be seen, the level of contamination removal was at least 44% with at least one air shower in operation. With two air showers in operation, contamination removal was 80%.
Further independent testing on the type of material workers are clothed in demonstrates that what the worker wears can make a significant difference in the amount of particulate removed by the air shower as indicatd in the chart below:
Today’s Air Showers can keep a significant amount of residual contamination from entering a cleanroom workplace as long as certain criteria are met:
The air shower must be properly designed and sized to maintain effective and efficient operations
At a minimum, HEPA filters are 99.99% efficient at 0.3 microns or optional ULPA filter at 99.999% efficient at 0.12 microns
Sufficient “wash down time” – at least 45 seconds – must be allowed in the air shower
The air supplied to the shower must be finely filtered to prevent personnel from being impinged with contaminants during the actual cleaning cycle
A fixed nozzle pattern must be followed and the nozzles must be preset to direct air in a downward flow to produce a shearing, wash down effect. It is essential to have a fluttering of garments strong enough to loosen dust.
The garments themselves must be made of material such as Tyvek, teflon, dacron, or nylon that is less likely to shed than cloth; comfort and cost must not be the determining factor
The air shower must operate at a negative pressure. In other words, the pressure in the air shower must not exceed the pressure outside. The pressure must be less than the cleanroom side to prevent contaminates
Very importantly, personnel must act responsibly, i.e., when they stand off-center or crouch in a corner to avoid the air flow, they are defeatign the whole purpose of the air shower. The individual must center himself in the shower and execute several complete 360 degree turns during the 45 second duration of the air shower, with hands positioned over the head.
The individual must remain in the air shower for several moments as specified in the company’s protocol after it has stopped to allow enough “purge time” or “dwell time” so that the particles may drift downward throught the floor grate and are not drawn into the cleanroom by the movement of the individual as he leaves the air shower
Air showers, like cleanrooms, or for that matter any process equipment, must be properly maintained in order to function properly. Lack of proper maintance can become a major sorce of contamination.
Production Automation is a proud distributor of Liberty Air Showers with many options to suit your particular needs and requirements. From stainless steel and High/Low Volume showers, to custom projects.
Beacuse of the many varients that go into pricing these air showers, please contact us if you are interested in purchasing a Liberty Air Shower and we will be more than happy to work with you to find the exact product you need at the best pricing.
We can be contacted via email at email@example.com , or you can call us monday through friday at 888-903-0333, or a third option would be to follow the request quote link on the right hand side of our blog.