Pass Through to Cleanrooms: Concept, Benefits and Usefulness

Have you heard about pass through? Do you at least know its functionality and importance for compliance with regulations in a classified environment?

In this material, you will find all this and much more. Special characteristics of the equipment, applications, equipment found on the market, step by step of the product transfer process, will be some of the subjects covered. By the end of reading the material, you will have extensive knowledge about this essential equipment for maintaining product purity in controlled environments.

What is it, and what is the purpose of pass through?

“Pass through” or “pass box”, the names may vary, but the tool, functionality and purpose are exactly the same: the equipment is used to transfer materials between the clean rooms. It is primarily installed with the main objective of avoiding the so-called “cross-contamination”. That is, it prevents a product from carrying contamination from one part of the process to the other.

It works like this: a certain product that is in a room with an “x” classification that will move to a room with a “y” classification, in the case of opening a simple door, it would generate a classification loss, in this case, the pass through keeps always one of the closed doors.

It can also be used in cases where the product has not yet gone through the cleaning or decontamination process, consequently, it can be loaded with many particles of dirt that are transported through the air. Therefore, before handling this product in question, it is of fundamental importance to transition through the junction box, so that it can be transported from one stage of the process to the other, free from any type of contamination.

It is inside the equipment that decontamination and safe transfer of products is guaranteed. In this way, contamination is not carried between the process areas. Once the product is inside the transfer case, it is properly sterilized so that it can be received by the other part of the process.

Basically, communication is carried out between the two parts (or areas) of the process, through the pass through, without contamination. Such junction boxes for clean rooms are built in aluminum, painted steel or AISI 304 stainless steel structure.

Pass through functionality in cleanrooms

In a clean room project, the interconnection of the two parts of the process is done through two double-glazed doors. And, in a complementary way, an interlocking system with electromagnetic closure and green/red signaling for opening control is installed.

The interlocking system is precisely to ensure that the two doors of the equipment do not open simultaneously, causing a uniform air flow, perfect decontamination of the products that are inside the equipment. That way, there is no risk of the door, for whatever reason, opening and compromising the entire process.

There is also the option of adding UV lamps, air supply with filtration, return and other accessories available according to the needs of each production, that is, depending on each customer. The implementation of supply and return, for example, allows this junction box to be classified, that is, considered as a small room with all the parameters of a common room.

Check out the applications of a pass through:

• Foods;
• Builders;
• Cosmetics;
• Packaging;
• Hospitals;
• Dairy industry;
• Feed industry;
• Pharmaceutical industry;
• Chemical industry;
• Veterinary industry;
• Laboratories;
• Mechatronics.

Pass through features

The junction boxes have a metal cabinet, they must be specially constructed to guarantee an excellent seal. The finishing of the equipment can be in painted plate or stainless steel plate, with special protection and prepared against chemical agents.

It is also possible to make some improvements to the equipment. There are technological options that can be added to the pass through, such as a glass, polycarbonate or acrylic window, key, electric or magnetic locks and door interlocks.

Equipment features:

What types of pass through are available on the market?

Different models of junction boxes are available on the market, which are often custom-made for each project and always with full focus on the needs of each production line of its customers. Therefore, models and sizes are quite variable. It is necessary to analyze case by case, so that the pass through to be used can meet in an extremely satisfactory way all the needs of use of the equipment.

How important is it to carry out the correct transfer of products?

As noted above, transfer boxes are used with the main purpose of preventing contamination from reaching clean areas. This equipment has the ability to perform contamination entry control in a clean area or classified environments. It is an essential tool to maintain the quality of the products and the integrity of both parts of the process.

Consequently, the activities carried out in these areas will be in compliance, complying with good manufacturing practices and, thus, guaranteeing the desired quality of the products handled at the end of the process.

There are some regulatory standards that deal specifically with the subject, check out the one that specifically concerns medicines:

RDC 17/2010

Art 307. The production of sterile preparations must be carried out in clean areas, where the entry of personnel and materials must be made through antechambers.

Art 408. The two antechamber doors cannot be open at the same time, and there must be a system to prevent this from happening.

The size of the pass through depends on the size of the objects that will pass through it. Therefore, when designing the cleanroom, it is important to know what activity will be done in that room and what materials will pass through it. Having knowledge of the type of product is essential. That way, you can design it in the ideal size for your need.

There are a variety of junction boxes available on the market, check out some types below:

• Painted steel;
• Stainless steel;
• Special;
• With exhaust duct;
• With filtration system;
• With inflation;
• With UV lamp;
• Active pass through;
• Guillotine door.

active pass through

The active pass through is an equipment developed with unique technology for the market. In addition to all the essential functionalities of a pass-through box, this type of specific equipment has an independent insufflation and return system for pass-through filtration.

These proprietary filtration systems further ensure the quality and purity of the product that will be transferred from one process area to another. The filters aim to retain microscopic particles, such as bacteria, fungi, spores, among others. As such, the unique active pass-through technology efficiently contributes to maintaining purity in hazardous environments.

Use of pass through

The installation of the equipment generally takes place at a convenient time for all heights. In the case of transferring heavier items, for ergonomic reasons the ideal is that the equipment is installed at a height very close to the ground.

The pass through is used in a similar way to antechambers, following the method of transferring material from outside to inside the clean room, check the process in detail:

As with the antechambers, the pass through must have an interlock. This prevents one door from being opened if the other is not closed, thus preventing contamination.

About Asmotec

Asmotec has an outstanding performance in the manufacture and installation of clean rooms and special materials in aluminum and stainless steel. It invests in technology and professional training to constantly grow and innovate. It provides complete solutions for cleanroom engineering, acting in a specialized, ethical and transparent way in all phases of the process: project development, manufacturing, installation and maintenance.