Thursday, October 29, 2009

Ductless Fume Hoods Really Superb!! [watch video ductless fume hoods]

Ductless fume hoods really amazing!!. Just imagine, from about 5 million particles in the working area, ductless fume hoods filtered to "0". Yes, zero. Ductless fume hoods are really efficient and practical product for your laboratory.

Well done to Sentry Air System, Inc. Their product really effective. Watch the video of ductless fume hoods by Sentry Air System from beginning until the end. You will see amazing results produced by this portable fume hoods.

Ductless fume hoods or portable fume hoods by Sentry Air System are using high quality of HEPA filters. It can purify the air up to 99.97% of particles at 0.3 microns in size. From the performance test dated 19th June 2009, by using ductless fume hoods model SS-340-PCR (Portable Clean Room), Sentry Air System managed to prove that their ductless fume hoods is really efficient. Before the test started, the particles in the air recorded at 5.6 millions per cubit foot. Just after 1 minutes operations, it's resulted at zero particles per cubit foot. This is really amazing, if you are using ductless fume hoods for your lab.

Watch the video of ductless fume hoods performance test by the Sentry Air System below:

(This video credited to Sentry Air System, Inc - one of the best manufacturer of ductless fume hoods in the market. Contact them now for more info)

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Monday, October 26, 2009

Ductless Fume Hoods by Esco

In my last article, I have showed you the video of the ductless fume hoods. From the video you can see how the ductless fume hoods works. In this article, I would like to share some information about ductless fume hoods by Esco.

Esco has emerged as a leader in the development of controlled environment, laboratory and cleanroom equipment solutions since 1978. One of the products is ductless fume hoods. Other products that sold in more than 100 countries are biological safety cabinets, fume hoods, laminar flow clean benches, animal containment workstations, cytotoxic cabinets, hospital pharmacy isolators, PCR cabinets, thermal cyclers and instrumentation.

The Esco Airstream Ductless Fume Cabinet or ductless fume hoods is the second generation of their original and most popular ductless fume hoods product. Esco products offering a sensible balance of quality, performance features and cost-effectiveness. Their recirculating design of ductless fume hoods requires no external ducting and exhaust fan.

Ductless fume hoods by Esco not allow gases discharged directly to the environment. All toxic fumes are carbon-filtered by the ductless fume hoods. It will create environmentally friendly. Their ductless fume hoods are using microprocessor-based control / alarm system with US patent pending sensing technology.

Due to the effectiveness of Esco ductless fume hoods or Airstream Ductless Fume Cabinet, Esco technology now is use throughout North America, Europe and Asia. Their product is certified to major Eusopean and American Standards. Esco’s ductless fume hoods comply with International Standards. Esco Airstream Ductless Cabinets have been independently tested and certified by Invent-UK, Ltd to meet and exceed the requirements of US Standard ANSI/ASHRAE 110-1995, British Standard BS 7989 – 2001, British Standard BS 7258, French Standard AFNOR NF X 15-211, French Standard AFNOR NF X 15-203 and European Standard EN14175.3.

Every product of ductless fume hoods produced by Esco’s factory is thoroughly tested to the two major international standards requirements. The International Standards are:

1. BS 7989:2001 Standard for filter efficiency and capacity tests for ductless fume hoodsGaseous phase filter test for capacity and efficiency for the ductless fume hoods is using propan-2-ol according to British Standard 7989:2001. The purpose of this test is to ensure that the re-circulating by ductless fume hoods is capable of meeting the filter capacity requirements specified in 8.5.2 of the BS 7989:2001 Standard. Acceptance criteria: The filter, when challenged continuously at 800ppm (+/-50ppm) of propan-2-ol, shall maintain the concentration of propan-2-ol in the exhaust stream at below 40ppm throughout the period of evaporation of 1 litre of propan-2-ol and below 400ppm throughout the period of evaporation from 1litre to 2litres of propan-2-ol.

2. ASHRAE 110-1995 Standard for containments tests for ductless fume hoods
1. Flow Visualization for local smoke visualization and gross smoke visualization
2. Face Velocity Measurement: Cross Draft Velocity
3. Tracer Gas Test: Static Tracer Gas Test, Surface Scan Test and Sash Movement Effect

Ductless fume hoods by Esco, also knowned as Esco Airstream Ductless Fume Cabinet and Streamline Ductless Fume Cabinet is one of the best ductless fume hoods in the market. Contact them for details information of ductless fume hoods.

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Tuesday, October 20, 2009

Ductless Fume Hoods - Watch Video for Demonstration

In my previous articles, I have talked about ductless fume hoods. For this post, I would like to share with you a video demonstration of ductless fume hoods. This ductless fume hoods manufactured by a reputable company in ductless fume hoods industry, Sentry Air System, Inc.

Sentry Air System produced ductless fume hoods in veriety of size and functions. It is built with stringent quality control measures, and superior craftsmanship. If your application requires a hooded type enclosure on the work surface, the Sentry Air Ductless Fume Hoods may be an excellent choice.

Ductless fume hoods by Sentry Air System installed with powerful fan on top of the fume hood. The ductless fume hoods also using combination of Hepa filters and carbon filters provides strong suction across the inlet area. These compact and efficient ductless fume hoods feature unique hinged folding side panels, a high-density polyethylene base, a clear polycarbonate top, and a hinged sloping front lid.

Watch video to see demonstration of the ductless fume hoods.

Watch video for ductless fume hoods demonstration.

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Friday, October 16, 2009

The 35 Terms You Must Know in Ductless Fume Hoods Industries

In Ductless Fume Hoods industries, or generally in fume hoods industries, there are many terms and technical words. It is hard for you to understand about ductless fume hoods if you do not understand the terms. To ease you, below is glossary of some common terms practically used in ductless fume hoods industries.

1. Air Foil: Shaped or streamlined member at ductless fume hoods entrance. It function is to enhance air flow into the ductless fume hoods.

2. Air Volume: Rate of airflow of ductless fume hoods that calculatted in cubic
feet per minute (CFM)

3. ASHRAE: American Society of Heating, Refrigerating,and Air Conditioning Engineers, a professional organization. They are authorized organization to sets industry standards for fume hoods testing procedures

4. Auxiliary Air: To supply external air delivered to the chamber of a fume hood to reduce air consumption

5. Baffle: A panel to control the air pattern that flowing through the ductless fume hoods. It is installed across back of hood interior.

6. Blower: A fan that installed in the ductless fume hoods as a device to blow the air consisting of impeller, scroll and motor.

7. Bypass: Compensating opening that helps maintain constant volume exhaust from fume hood, regardless of sash position

8. Canopy Hood: Ceiling-suspended ventilating device for noncritical use with heat, water vapor, odors, etc.

9. CFM: Cubic Feet Per Minute, the rate to measure of air volume processed by ductless fume hoods

10. Combination Sash: Horizontal panels in a vertically rising frame, installed in the ductless fume hoods face that provides access to the hood interior

11. Constant Volume: Type of fume hood exhaust system that
exhausts the same volume of air, regardless of sash position

12. Containment: Extent to which fumes are confined within
the ductless fume hoods compartment

13. Damper: As a device to control air volume in the duct

14. Demonstration Hood: Fume hood with glass panels on two or three sides to improve visibility for demonstrating experiments in a classroom setting

15. Exhaust Volume/Parameters: Volume of air exhausted by the fume hood; quantity of air required to maintain desired face velocity,calculated in cubic feet per minute (CFM)

16. Face Velocity: Speed of air flowing into the ductless fume hood
through the sash (the opening) that measured in feet per minute (FPM)

17. FPM: Feet per minute to measure the air velocity

18. Liner: The interior sides, back, and top, including baffle of fume hoods

19. HEPA : HEPA stand for High Efficiency Particulate Air to retain particles of filters of ductless fume hoods.

20. Lintel: Portion of fume hood front located above access opening

21. Louvers: Slit-like openings in the lintel that allow bypass
air to enter the hood when the sash is closed

22. NFPA: Stand for National Fire Protection Association

23. Negative Pressure: The situation where by the pressures lower than one atmosphere

24. Positive Pressure: The situation where by the pressures higher than one atmosphere

25. Restricted Bypass Fume Hood: Fume hood operating type, designed with limited bypass area; commonly used in conjunction with Variable Air Volume (VAV) exhaust
systems and restricted sash opening designs

26. Sash: Sliding glass panel set in the fume hood face that
provides access to the hood interior

27. Service Fitting/Plumbing: Water faucets and gas valves
mounted on or fastened to the fume hood

28. Static Pressure: Air pressure, or resistance, in fume hood
or duct, expressed in inches of water

29. U.L. 1805: Underwriters Laboratories certification that
verifies conformance to electrical, mechanical, and
airflow standards

30. PAO : Poly Alpha Olefin a tester to rate the ability of HEPA filters in ductless fume hoods

31. Variable Air Volume (VAV): Type of fume hood exhaust
system that typically maintains constant fume hood face
velocity by adjusting blower motor speed or a balance
damper in response to changes in sash position

32. Velocity: Speed of air, measured in feet per minute (FPM)

33. Velocity Pressure: Force per square inch applied by
moving air

34. Volume: Quantity of air, usually measured in cubic feet
per minute (CFM)

35. Work Surface: Top material; area in fume hood where
apparatus rests and where work takes place

By knowing the common terms of ductless fume hoods as above, it will make you easier to understand about ductless fume hoods.

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Sunday, October 11, 2009

Ductless Fume Hood - Read The Review Now!!..

Ductless fume hoods are a portable unit of fume hoods. No ducting used and this unit is not connected to the building exhaust fan. So, ductless fume hoods do not release the fumes or vapors to the environment. Ductless fume hoods recycle existing room air while cleaning the chemical mixture. The room air will be sucked and filtered in the ductless fume hoods. The cleaned air will re-circulated into the work place. This process will continuously take place during the operation.

Due to the certain procedure, chemical used and safety issues of ductless fume hoods operation,there was a research had been done by Division of Occupational Health and Safety,Office of Research Services, Office of the Director of NIH. Below is the research report of ductless fume hoods that I got from .

Division of Occupational Health and Safety,
Office of Research Services, Office of the Director, NIH

I. Introduction
In late December of 2004, a working group was formed to review the use of ductless fume hoods in the laboratories of the NIH. Members of the working group were LT Jason Barr, CIH; Mr. Alfred Ferruggiaro, CIH; Mr. Mark Gibson, CIH; Ms. Polly McCarty, CIH, CSP; Mr. Herb Jacobi; Mr. Rand Mortimer; and Dr. Randolph Larsen.

On January 6, 2005, the working group held its first meeting to begin the collection and review of information and policies on the use of ductless fume hoods. The final meeting was held March 9, 2005 to complete the review of materials and reach a consensus opinion.

II. Background
Ductless fume hoods are stand alone, bench top enclosures that use self-contained carbon and/or HEPA filters to remove fumes, vapors and particulates from air drawn into the device and then recirculated into the lab. The intent is to offer a replacement for a conventional chemical fume hood attached directly to the building exhaust system. For proper and effective use filters must be discarded and replaced when they near a chemical saturation point.

In 1989, the then Occupational Safety and Health Branch of the Division of Safety, conducted a study of ductless fume hoods. The ductless fume hoods were evaluated for face velocity, air flow patterns, spill control, noise levels, chemical breakthrough alarm response, and the solvent retentivity of the carbon filters. The results of the study indicated that the units would not adequately contain a 500 ml spill, the sensitivity of the chemical breakthrough alarm was not reliable and that filter breakthrough concentrations were seen within 12 to 24 hours depending on the solvent used and its concentration (0.9 ppm benzene, 44 ppm n-hexane and 24 ppm carbon tetrachloride). Based on these results, ductless fume hoods were not approved for use at the NIH.

In December 2004, NIAID requested the installation of two ductless fume hoods at the Twinbrook III facility. NIAID proposed to use one unit to store and use ethanol and xylene for slide processing (volume of chemicals stored ~2.5 liters). The second unit would be used to process tissue stored in formalin (volume of chemical stored ~0.5liters). As a result of the request, The Division of Occupational Health and Safety (DOHS) agreed to review the policy on the use of ductless fume hoods at the NIH.

III. Information Review
For the policy review, the working group looked at information from several sources. The sources included manufacturer information and specifications, policies and procedures from other research institutions, and recommended standards and practices related to occupational safety and health.

IV. Manufacturer Information
The working group reviewed information from six manufacturers; Misonix, Inc., Sentry Air, Captair, NuAire, AirClean Systems, and Air Science USA.

In general, the manufacturers have products that are similar. The basic unit is a workstation where air, pulled through an adjustable front opening by an interior exhaust fan, picks up contaminants and is then cleaned by being pulled through a series of carbon and/or HEPA filters. The cleaned air is recirculated back into the room. All of the manufacturers offer monitors that alarm upon detection of decreased air flow below set points and vapor or gas emissions due to breakthrough. The alarm would indicate that the filters are approaching saturation.

The manufacturers include some selection criteria based on the amounts and types of chemicals and procedures to be used in the unit.

Ductless fume hoods are marketed as cost saving alternatives to standard laboratory chemical fume hoods. Advantages cited by the manufacturers are quicker installation time and lower installation costs by not having to install duct work and fans. Other cited advantages include energy savings due to not exhausting conditioned air to the outside, and portability of the units.

V. User Policies
The working group reviewed policies, procedures, and information from many research institutions including: The Centers for Disease Control and Prevention (CDC), the Environmental Protection Agency (EPA), NCI-Frederick, Auburn University, East Carolina University, Iowa State University, Michigan State University, Northwestern University, Princeton University, State University of New York, University of California, University of Hawaii, University of Kentucky, University of Massachusetts, University of Minnesota, University of Wisconsin-Madison, and University of Vermont. These institutions were looked at because they had a published policy on ductless fume hoods. Not all research facilities were found to have specific policies on ductless fume hoods.

Of the institutions reviewed, the CDC, EPA, NCI-Frederick, East Carolina University, John Hopkins University, University of California, University of Vermont, and University of Wisconsin-Madison specifically do not allow the use of ductless fume hoods at their facilities. The reasons for not allowing their use included; concerns with channeling in the carbon filters, concerns with handling filters contaminated with chemicals, costs related to disposal of the filters as hazardous waste, tracking and maintenance requirements for the changing of the filters, potential for contaminated air being recirculated into the lab, inadequate ability to contain and control chemical spills, and concerns about the appropriateness of their use in research labs because of the varied and unpredictable nature of research work.

Of the institutions that do allow the use of ductless fume hoods, their installation and use are discouraged and requires specific approval only after an extensive use review. There are also various typical restrictions that include; limiting use to chemicals with low toxicity, use where the hood is used only for the control of nuisance odors and dusts of procedures that would normally be conducted on the bench top, where very small amounts of chemicals are used, not for the storage of chemicals, and not for operations where there is continuous operation of the hood.

VI. Recommended Standards and Practices
The working group reviewed three standards that had sections pertaining to ductless fume hoods. These were: “Prudent Practices in the Laboratory”, The National Academies Press; American National Standards Institute (ANSI), “Laboratory Ventilation, ANSI/AIHA Z9.5 – 2003”; and National Fire Protection Association (NFPA) Standard 45, “Standards on Fire Protection for Laboratories Using Chemicals”.

In summary, the first two standards state that ductless fume hoods have very limited applications in research laboratories due to the wide variety of chemicals used in most labs and should only be used with chemicals of low hazard and where the access to the hoods and the chemicals used are carefully monitored. In the third standard, NFPA is more explicit. Section 6.4.1 States that "Air exhausted from laboratory hoods and other special exhaust systems shall not be recirculated." Following this Section is a reference to Appendix A (A6.4.1). This section states "Ductless laboratory hoods that pass air from the hood interior through an absorption filter and then discharge the air into the laboratory are only applicable for use with nuisance vapors and dusts that do not present a fire or toxicity hazard".

Under the ANSI/AIHA Z9.5 standard, a Hazard Evaluation and Analysis must be conducted for any ductless fume hood. Ductless fume hoods must have prominently posted signage informing operators and maintenance personnel on the allowable chemicals used in the hood, type and limitations of filters in place, filter change schedule, and a notice that the hood recirculates air in the room. Warnings are included that many chemicals of low molecular weight can be stripped from the filter and reenter the room on the flow of air through the filter, resulting in a contaminant exposure to others in the room that is over a longer time span and at a lower concentration. Also, the collection efficiency and breakthrough properties of the filters may change where multiple air contaminants are used, resulting in earlier filter breakthrough.

VII. Working Group Summary
After review of the information collected, the working group expressed severe reservations about the use of ductless fume hoods at the NIH. These are:
1) There is a great variety of chemicals used in the research environment at the NIH.
The filters for ductless fume hoods are specific for only a limited number of chemicals. As research directions change, the ductless fume hood may not offer adequate protection for researchers and facilities. A standard chemical fume hood that meets NIH specifications will accommodate almost any change in chemicals
being used.

2) Chemicals used in a standard chemical fume hood are eliminated from the lab by the
exhaust system. With a ductless fume hood, the chemicals adsorbed to the filter remain in the lab and the potential exists for their release back into the lab in an uncontrolled manner. Unless the filters are carefully packed, they are prone to “channeling” where voids form in the filter banks and hazardous chemicals can bypass the filter. When the filters near a saturation point, they exhibit breakthrough where the chemical vapors that should be trapped in the filter are released into the lab air.

The charcoal filters can exhibit selectivity. Chemicals previously adsorbed onto the
filter can be de-adsorbed and released into the lab air when the filter is exposed to
other chemicals for which the charcoal has a greater affinity. The reliability of the
hood sensors to detect and alert the user when the above conditions occur is
questionable. We have first hand knowledge of the difficulties involved with
maintaining different types of sensors.

3) In the event of chemical spills, the standard chemical fume hood will exhaust the
vapor out of the lab. The ductless fume hood will have only a limited ability to trap
high concentrations of vapor before breakthrough occurs.

4) Standard chemical fume hoods are very simple to use and require no operator
intervention, unlike ductless fume hoods. With ductless fume hoods, someone must determine the proper filter medium, monitor the hood to be sure no one uses an improper chemical (one that is not filtered by the medium in use), be sure to turn the hood on and off before and after each use, determine when the filter needs to be changed and change it. Opportunities for improper use are great.

5) The appropriate use of ductless fume hoods require very controlled conditions. At the NIH we do not have highly controlled conditions. There are a great variety of
hazardous chemicals in any one lab. There are regular staff changes and frequent
changes in research directions.

6) The NIH does not allow recirculation of air in lab buildings where, theoretically, the concentration of hazardous materials would be relatively low. It does not seem prudent to allow recirculation of air from containment equipment where there is potential for high concentrations of hazardous chemical material. NFPA 45 prohibits recirculation of laboratory chemical fume hood air.

7) To ensure that proper filter selection and maintenance occur, someone must be
selected to be responsible. Since this would be a collateral duty to research, there is a real chance that this process will be over looked. Examples of this in the lab
environment are common - ensuring gas cylinders are secured; completing waste tags
for chemical waste containers; proper chemical storage; routine testing of eye wash

8) Someone, again, collateral duty, must be responsible for ensuring no one uses a
chemical for which the filter medium is ineffective.

9) Improper use of a ductless fume hood can lead to a false sense of safety. Again,assigning responsibility for control a of ductless hood would be a collateral duty and cannot be performed 24/7. Potential for misuse is greater than for a standard chemical fume hood.

10) Filter maintenance and disposal are hidden costs which must be budgeted for each
year. There is also the disposal issue. The charcoal filters can weigh 35 to 45 lbs.
The disposal method at institutes that do allow their use is via the chemical waste

11) Personnel who are not conscientious may obtain this type of equipment. We have
past experience with researchers/investigators using equipment for purposes other
than that for which it was designed.

12) Designers/planners may see this as a reason NOT to put standard chemical fume
hoods into labs (they will be value engineered out).

13) In benchmarking, we have determined that other comparable research agencies, both
governmental and academic, do not permit the use of this type of equipment for the
same reasons we do not.

14) It is the position of ANSI that ductless fume hoods have limited application in research laboratories due to the wide variety of chemicals used in most labs, and should only be used with chemicals of low hazard and where the access to the hoods and the chemicals used are carefully monitored. NFPA states, “Air from laboratory hoods should not be recirculated and ductless fume hoods in laboratories are only applicable for use with nuisance vapors and dusts that do not present a fire or toxicity hazard".

VIII. Conclusions
The working group has reached the conclusion that the overall safety of NIH personnel should not be dependent upon a system considered by several agencies to be undependable (breakthrough, channeling, chemical selectivity, sensor accuracy) and reliance on personnel action (selection of proper filters, use of inappropriate chemicals once filter medium is selected, regular maintenance and replacement of filters, turning equipment on and off before and after each use, not allowing equipment to be offered for surplus, etc.) should be avoided.

It is the conclusion of the working group that these devices are not appropriate for a research environment such as NIH. The current policy of not permitting ductless fume hoods in labs should be maintained.

Report End

The above report is base on the ductless fume hoods product research in that particular years. Even though not all application is appropriate to use the ductless fume hoods, the manufacturers from time to time increasing their product to fulfill customer requirement and needs. Nowadays, many upgrade version of ductless fume hoods has been manufactured and selling in the market. Choose the best ductless fume hoods that suitable with your procedures.

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Friday, September 25, 2009

Why Go For Ductless Fume Hoods?

Ductless fume hoods or conventional chemical fume hoods? Why nowadays most people in the industries choose ductless fume hoods? Any problems with conventional chemical fume hoods? The answers are here. There are some advantages to use ductless fume hoods compare with the conventional fume hoods. Read more to know why ductless fume hoods become famous and first choice in the industries.

Ductless fume hoods are a portable unit. There is no connection to the building structure beside the power cord. It is easy to move or relocate your ductless fume hoods to any place that you want. It is easy to shift the ductless fume hoods from room to room to fulfill your current needs. This type of fume hoods can be moved easily and operational in minutes by yourself. No third party needed.

To compare ductless fume hoods with conventional chemical fume hoods, the conventional types have a ducting. The ducting connected to the building exhaust system. It is not a mobile or portable unit. To relocate or shift the conventional chemical fume hoods is not easy. You cannot do it yourself. You need third party or contractors to move the fume hoods to other location. It needs time and proper planning especially when to design the new ducting layout and also doing new ducting installation. The new location must be accessible to the building exhaust system. That is why people in the industries prefer ductless fume hoods.

In term of cost, ductless fume hoods is cheaper compare with conventional chemical fume hoods. The operation and installation cost of ductless fume hoods (also known as HVAC-free fume hoods) is substantially lower than that of a conventional fume hoods. No cost for ducting installation for ductless fume hoods. No building exhaust fan connection needed. No blower need to purchase. See, how much we can save by using ductless fume hoods.

Ductless fume hoods are not required any complicated installation. Basically, they are shipped and ready to use. Just simply remove from the shipping container and placed it at your service room. Each unit of ductless fume hoods has been regulated and certified for operation immediately. What other cost incurred for the ductless fume hoods? Very minimum. Once the ductless fume hoods installed, the cost that you need to bare is the filters replacement. It cost you approximately from $300 to $2000 per year.

Ductless fume hoods also do not affect the cost of heating and cooling like the conventional chemical fume hoods operation process. For conventional fume hoods cabinet, heated and cooled air is pumped out of the room into the environment via exhaust system. The exhausted air is then replaced by outside air that needs to be heated or cooled and cleaned. All these need money to run the process.

Most ductless fume hoods in the market have an advanced monitoring system (advisable to get this type of ductless fume hoods). This unit type installed with automatic controller to monitor airflow and filter condition constantly to ensure the safety of the operators. Each unit of ductless fume hoods has a solid state gas detector. Its function is to monitor the carbon filter bed for saturation. The ductless fume hoods are also installed with alarms that audible and visible to alert the operators of filter saturation. The alarms already set per current ACGIH standards for TLV of known chemicals. State-of-the-art airflow sensor takes a constant reading of face velocity. Then, it will provides information in linear feet per minute (LFM) on the LCD monitor screen that the operators easily can monitor. So, ductless fume hoods are safe for you.

If we want to talk about environmental friendly, ductless fume hoods is the best option to choose. This is because ductless fume hoods do not release the fumes or vapors to the environment. All cleaning process is only in the room. Ductless fume hoods recycle existing room air while cleaning the chemical mixture. Once the bonded carbon filter saturated, it can safely disposed of in a landfill. For the conventional chemical fume hoods, the room air will be processed in the room and release to the environment. This process may release the air together with the harmful fumes and vapors which will harm the environment. So, ductless fume hoods are the best for the environment.

Ductless fume hoods are the best option for the industries compare with the conventional chemical fume hoods. Even though not all application is appropriate to use the ductless fume hoods, the manufacturers from time to time increasing their product to fulfill customer requirement and needs. Choose the best ductless fume hoods that suitable with your procedures.

P.S : Above picture of ductless fume hoods are manufactured by Esco Technologies, a trusted and experienced manufacturer of ductless fume hoods, since 1978.

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AMAZING!!.. Ductless Fume Hoods Works

Yes,.. it's amazing!! If you look at how ductless fume hoods works, it is really amazing. It can filter at 0.3 microns size of particles from the air. Just imagine how ductless fume hoods efficiency to clean the environment in your work area. That is why ductless fume hoods are so important especially for those industries that really need clean working environment. The Laboratory, Medical, Sterile Assembly, Pharmaceutical, Manufacturing and Industrial facilities need ductless fume hoods to clean the air in the rooms. The fume hoods will purify the air in the rooms and will re-circulate back the purified air into the room. This process will continuously take place as required during operation within the work area.

In the industries, ductless fume hoods are equipped with HEPA Filters and Activated Carbon Filters to run the process of air purifying. It will provide air purification to the lab. What are HEPA filters and how important HEPA filters to the function of ductless fume hoods? HEPA stand for High Efficiency Particulate Air. The standard HEPA filters can filter 99.97% at 0.3 microns of size particles from the air. So, HEPA filters with Activated Carbon Filters in ductless fume hoods functioning as fumes, vapors and particles removal.

The standard HEPA filters used in the ductless fume hoods industries are rated by the ability to retain the particles of 0.3 microns in size. It will be tested with Poly Alpha Olefin (PAO). HEPA filters attached with a thin pleated sheet of boron silicate micro-fibers with aluminum separators. It is particulate filters which will retain airborne particles and microorganisms (gases pass freely trough). Filtration process in the ductless fume hoods occurs by five distinct methods or five primary mechanisms which are sedimentation, electrostatic attraction, interception, inertial impaction and diffusion.

For those industries that need particle-free work areas, ductless fume hoods are designed for it. It will increase the productivity as it preventing the product or process from contaminants introduced by many sources like from the equipment itself, personnel or from the product. Despite ductless fume hoods are not a substitute for efficient aseptic technique, it does help to ensure sterility when used properly.

There are two basic categories of ductless fume hoods in the market. We categorized the ductless fume hoods base on the air stream, either the air stream come from horizontal or vertical. So, we called horizontal flow hoods and vertical flow hoods. Both types of ductless fume hoods offer same degree of product protection by a constant flow filtered air in the room. For applications where the process generates vapors, solvents, chemicals or other fine powders, vertical flow hoods are recommended to be used in the lab. In certain cases when noxious fumes are being used, vertical flow exhaust hood will be utilized. Either fume hoods floor designed or table top mounted designed will be chosen for the lab is base on the space availability.

For the horizontal designed of ductless fume hoods, the filtered air flows in the fume hoods are parallel to the work surface that toward the operators. So, this type of flow hoods only provides product protection. Cell culture work, which falls into low risk categories (e.g., Medical Research Council Level A) required the horizontal flow hoods as their procedures.

Anything beyond the low risk level, a vertical flow hoods safety cabinet is a necessity. The vertical ductless fume hoods are designed to provide the ideal clean-air environment, particle-free and bacteria-free within the work place as required for laboratory work, manufacturing industries, testing, inspection or pharmaceutical procedures. It is not only clean the air, but also protect the products, personnel and the environment.

In the market, there are wide ranges of ductless fume hoods that provide a particle-free Class 100 (ISO 5) to the environment of work place. This is the important function of HEPA filter in the ductless fume hoods to protect products in Class 100 (US Fed Std 209E). Choose your ideal ductless fume hoods wisely that ideal with your lab and suitable function for your operation.

P.S : The above picture shows how ductless fume hoods works, air sucked into the ductless fume hoods and re-circulate clean air into the working area.

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Thursday, September 17, 2009

Ductless Fume Hoods - MUST READ THIS FIRST

Firstly, you must read the information about ductless fume hoods. You must know the basic information about ductless fume hoods before you explore what is ductless fume hoods is all about. If the basic thing you did not know, is quite difficult for you to understand when come to the technical aspect of the ductless fume hoods. So, you must read this article first.

Ductless fume hoods are a stand alone unit of fume hoods cabinet. The ductless type unit enclosures use self-contained carbon to remove fumes, vapors and particulates from air. How it works? It will draw the air from the room into the hoods. The air will be filtered in the ductless fume hoods. The cleaned air will re-circulated into the room or lab. This process will continuously take place as required. Some ductless fume hoods are using HEPA filters and some use self-contained carbon together with HEPA filters to extend the efficiency.

What is the different between ductless fume hoods and the conventional fume hoods? Ductless fume hoods are a stand alone unit. It has no ducting as what conventional chemical fume hoods unit has. The ductless fume hoods workstation can be transferable and relocate to any place as you want. It is a portable unit. For conventional chemical fume hoods unit, it is attached directly to the building. The unit ducting is connected to the building exhaust system. This factor made it not convenience when we want to do relocating of the fume hoods. Quite a major renovation must be done to relocate the conventional chemical fume hoods unit especially when it is involved with the existing building exhaust system.

Ductless fume hoods are a “must have” device for certain industries especially that really need clean working environment. Ductless fume hoods with HEPA filters and activated carbon filters are used to provide air purification in the room. In my next article, I will touch more deep about how ductless fume hoods works.

P.S: The above ductless fume hoods photo is from Air Science, a reliable and trusted manufacturer of ductless fume hoods located at FT Myers, FL USA (certified ISO 9001).

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