air shower has the 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.The Role And Design Of Air Shower Tunnel
HOW DOES AN AIR SHOWER OPERATE?
Typically an air shower can be operated in three (3) distinctly different ways depending on process requirements:
Two way, one way
AIR SHOWER 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.How to Choose Your Air Shower Room
AIR SHOWER 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 via 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 entrance door without activation the cycle. Both doors cannot be open at the same time.Air Shower Room-Why the Market Price Varies Greatly
AIR SHOWER 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 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. depending upon the particle size, particle removal can be up to 90%. The larger the 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 illustrated during the air shower cycle to insure contamination removal is as efficient as possible.Cleanroom Air Shower and Pass-through Box
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 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 defeating the whole purpose of the air shower. The individual must center himself in the shower and execute several complete 360° 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 through 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 maintenance can become a major source of contamination.
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