Design Principles

The Theory

Air Flow.

ISO class 5 (Class 100) and cleaner facilities are designed based on laminar flow principles or, to be more precise; unidirectional filtered airflow in which parallel streams of air -moving at a uniform velocity of 0.3 to 0.45 meters per second- are blown across the room with as little turbulence as possible.

The principle is based on expelling any dust in the airflow by the shortest route. In general, the greater the frequency with which the air is renewed, the lower the contamination build up in the room and the greater the rate at which the impurities are diluted.

There are two types of laminar flow; vertical downflow or horizontal cross flow.

In a vertical downflow cleanroom, air enters the room via filters in the roof and exits through vents in the floor or base of the walls. Air can simply dissipate or be re-circulated from the base of the walls back up to the filtering system.

In a horizontal cross-flow cleanroom, filtered air enters the room from one side wall and is exhausted in the opposite sidewall and/or re-circulated via a bank of filters.

In both instances, the air velocity has to be established at a sufficiently high level to ensure that dust particles do not thermally migrate from the laminar flow.

Materials.

It is important that the materials used in the manufacture of cleanrooms can be kept sterile and so they should be smooth in surface finish, have a low outgassing rate and must not shed particulate.

Moorfield can adapt the materials used to meet specific process requirements. We also produce environments to meet ESD (electrostatic dispersion), microbiological and other hazardous guidelines.

The Application

Clean Cube

Clean Cube

Airflow

As with traditional cleanrooms, Clean Cube can accommodate either horizontal cross airflow or, more typically vertical down flow to suit the customer’s process requirements.

Materials

The Clean Cube design is based on a modular aluminium frame and non-shedding, low static Perspex walling. Clean Cube accommodates all the features found in a traditional cleanroom including; powder coated aluminium T section ceiling grid, vinyl faced ceiling tiles, sealed prismatic light units, PVC faced doors, anti-static vinyl flooring, PVC exhaust vents etc.

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Clean Hood

Clean Hood

Airflow

The Moorfield laminar flow hood can accommodate horizontal cross airflow or, more typically vertical down flow to suit the customer’s process requirements.

Materials

The Clean Hood design is based on a modular aluminium frame and non-shedding, low static Perspex sides. The electrics pack is mounted at a high level into a white PVC conduit trunking.

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Clean Shower

Airflow

Clean Shower can accommodate either horizontal cross airflow or, more typically vertical down flow to suit the customers’ process requirements.

Materials

The Clean Shower design is based on a modular aluminium frame with a non-shedding, low static Perspex curtain wall (sometimes called soft wall). Clean Shower can accommodate a traditional cleanroom ceiling including; powder coated aluminium T section ceiling grid, vinyl faced ceiling tiles and sealed prismatic light units. Clean-Shower can also utilize our non-shedding, low static Perspex walling.

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Clean Tent

Clean Tent

Airflow

Clean Tent works on the economic principle of clean conditions at the workstation area (i.e. point-of-use) utilising horizontal cross air flow, as in a conventional cleanroom but also using the positive pressure generated to keep the tent inflated. Air enters the work cabin through the filter at workstation level and travels in a laminar flow across the workstation envelope. At the fringes of the envelope, positively pressurised air diverges uniformly toward the zipper in the skirt thus preventing back eddies returning contamination to the envelope. At the end of the laminar flow stream, air is sent through to the gowning chamber and exhausted to ambient or collected via exhaust vents and redirected to be returned under pressure to recharge the HEPA. By this method, high-quality air is delivered to the workstation area (ie where it is required) without the need for 100% wall/ceiling filtering.

Materials

Clean Tent utilises modern advances in textile technology which have enabled synthetics to supersede solid based composites in both performance and technology resulting in a lightweight, low particulate portable work cabin that can produce a high-quality clean environment for the user at a very affordable price.

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