Controlled Environments By Rupert Langston

Definition: Controlled Environments Almost all Industrial processes require clean air to protect a product or process of production. Clean the air required by the product or process Surround the product/process with clean air Offer enough air flow to keep potentially dirty air away from process

Types of Controlled Environments: Cleanroom Federal Standard 209E “phased out in favor of ISO 14644-1” defines a clean room as “a space in which the concentration of airborne particles is minimized and the relevant parameters, e.g. temperature, humidity, and the controlled environment’s air pressure are controlled as necessary” Types of Cleanrooms: “There are two types based upon method of air distribution.” Non Unidirectional-(previously known as non-laminar flow)-were originally known as conventional cleanrooms. Unidirectional- which means one direction or laminar flow cleanrooms.

Cleanroom Types Conventional Laminar Flow

Filtration For Cleanrooms In conventional clean rooms HEPA filters are usually located at the end of a sequence in a mechanical room. In laminar flow cleanrooms the HEPA/ULPA filters are located in the wall or ceiling and are the last component the air passes before entering the clean space Each filter and frame system must be “leak free” to prevent any dirty air bypass. In the frame system this is accomplished by various types of gasket material. In down flow HEPA filter modules the air is supplied to each individual filter. These type filters may require dampers to control airflow to the individual unit.

Filter Type & Installation Filter Installation –picture Down Flow Module –picture

ISO/TC209 14644-1 Cleanliness is expressed today in the terms of the ISO (International Standards Organization) guidelines. Today, there are 9 levels of cleanliness in the ISO 14644-1 Cleanliness in select classes of cleanrooms is determined by the type of filter-HEPA/ULPA

ISO 14644-1 Classification Picture

Controlled Environment: Industrial Finishing- paint spraybooths All paint operations draw air out of the controlled environment-(the box) Air replaced in a paint spray booth is called Air Make-up-This air is provided to cause outward flow towards the Exhaust Air filter area. These filters are sometimes referred to as Arrestors. Air supplied to the BOX is referred to as Supply Air or Intake Air. This air is filtered with Intake filtration products that based upon the process or desired efficiency provide various levels of performance for the work space.

Booth Types: Crossdraft Picture

Booth Type: Downdraft Picture

Paint Booth Supply Air Filtration No particles greater than 5 microns Diffusion media is designed to provide 99% efficiency on particles > than 5 micron and to create uniform air flow across the painting surface. Particles > than 8 microns can cause blemishes to painted surfaces like automobiles.

Paint Booth Exhaust Air Filtration Multiple types of paint arrestors are available. Expanded paper-paper polyester Fiberglass pads/rolls Fiberglass/poly combination Synthetic media Baffle type-Styrofoam/paper Water wash-water curtain

Paint Spray Booth Exhaust Filtration Disposal of combustible filters is critical. They must be stored in air tight containers Some dispensed filters can not be land filled. Some are to be incinerated. Certain specialized industrial paint operations may require specialized filtration. For instance Aerospace, Wood Finishing, Automotive OEM and Auto body shop repair.

Controlled Environment: Nuclear Energy Filters are used as safeguards in the handling and processing of useful or spent nuclear fuel. Most applications have make up, supply and exhaust air. Traditionally, HEPA are used. Nuclear Exhaust Systems are subject to strict guidelines for quality and testing DOD filters must be tested at qualified DOE filter test sites.

Controlled Environments: Computer Equipment / Photographic Large Computer rooms require 45-85% filtration. The 45 % conditioned cool air or in warm return air and 85% when outside air is necessary. There are occasional filters with HEPA media used to eliminate particles. Very small dust particles can cause problems in the photographic processing industry. HEPA filters are used in controlled areas where processing occurs to eliminate small particle contamination.

Process Tank Storage Filtration Filtration is required as you fill a tank with liquid due to the air being removed from the space within the tank. Likewise the air going in must be filtered to prevent contamination.

Specialized Industry Filtration Sewage Plant- These facilities require high efficiency 95% in their compressed aeration systems. The process of converting sewage into sludge requires a unique process including the filtration of fine particles that could plug the aeration process. Textile Plant- Most airborne particles are lint. These particles are controlled with synthetic filters. In systems with heavy concentrations of lint rotary “drum” self cleaning filters are used regularly.

Specialized Industry Filtration Gas Turbines- Filtration for gas turbines is important in two areas. 10 micron and larger can cause erosion of turbine compressor blades 5 micron and smaller particles cause deposits on and fouling of turbine blade Urban areas suggest 95% filtration Cleaner environments can use 85% filtration to keep the equipment clean

Specialized Industry Filtration Paper Mills- Select areas must be kept under positive pressure to keep corrosive gases out which can cause with control room electrical equipment. Telecommunication Equipment Rooms- This technology driven industry requires a wide range of filtration products. Primarily 65%-95%, depending on the analog or digital technology which equates directly to the size of particles.

$$$---All Industries---$$$ All processes require filtration which equates to sales All processes are unique and require a degree of specific knowledge The NAFA organization and its affiliated programs can provide you with that necessary knowledge NAFA associates can provide you with the necessary products and technical support for those products.