PPE is an important requirement for safety concerns but not the prime one. This is often considered as the ‘last safety resort’ when other methods of safety do not work efficiently. So, PPE features the lowest in the hierarchy of safety control measures, such as protective work environment and technical control of situations. In some cases, gloves as personal protective equipment are still used, along with other measures, to provide an ideal risk control environment.

Materials Used for Preparing Gloves

Gloves come in different fabrics and materials. Some of the common glove materials are:

• Latex: Latex is a natural rubber and is highly flexible. It is made from the liquids secreted by the rubber plant and by virtue of its conformity, latex gloves are comfortably used in precision activities, such as carrying out surgical procedures and other lab operations.
• Nitrile: It is a copolymer fabric which contains propane nitrile in different measurements. Based on its propane nitrile content, its chemical resistance and stiffness varies. The higher the content, the more the stiffness and chemical resistance.
• Polyvinyl chloride (PVC): It is a stiff material that is made softer by adding plasticizers. PVC is the perfect option for protective clothing and gloves in a cleanroom.
• Polyurethane: It is an anti-abrasion material that is coated onto other fabrics and used to make PPE.
• Neoprene: It is a synthetic rubber and is superior to latex. It comes with chemical resistance features and is widely used in chemical operations in labs.

Selection Tips for Gloves as PPE
The exact purpose of the work influences the selection of glove type.

• Prolonged use: If gloves are to be worn for a long time, they should be durable enough to perform efficiently. Low quality gloves can lead to the deterioration of its barrier properties and allow chemical to pass through.
• Protection against heat and cold: If gloves need to come in contact with direct heat, cold, abrasion or a cut, a special kind of safety gloves is better than rubber gloves.
• Protection against virus: If the work requires handling blood and body tissues, latex or nitrile gloves are suitable. These gloves are used in hospital operation rooms and are disposed after a single use.
• Protection against animal allergens: Since neoprene and nitrile gloves are highly chemical resistant, they are suitable to avoid animal transmitted germs and allergens while handling live animals or animal tissues in the laboratory.

Permeation Rate of the Glove Materials

Permeation rate determines the level at which the chemical will start moving through the material of the gloves. The higher permeation rate signifies the faster rate of chemical movement through the material. Therefore, the users should be aware that the gloves will infiltrate to some extent due to permeation. A high permeation rate can gradually degrade the material. The material may deteriorate and become stiffer or softer, depending on its type. The limit of this deterioration is that the material may start dissolving in the chemical.

Hazards of Deteriorated Materials

A professor in the USA died in 1997 while working in his lab from exposure to a chemical named dimethylmercury, which permeated through her latex gloves. During the same year, a researcher at Darmouth lost her life due to acute mercury poisoning. Dimethyl mercury has a higher permeation rate in case of latex gloves and though she replaced her gloves soon after the exposure, she could not escape the symptoms of mercury poisoning which developed several years later.

Therefore, it is vital to select appropriate gloves for different types of chemicals used. While working with highly toxic chemicals, select gloves made of a higher chemical resistance material.

Seam Technique for Disposable Apparel

Special kinds of seam techniques are used for sewing these garments in order to avoid the passage of particles inside or outside the apparel. There are particularly three kinds of seams:

• Interlocked stitching: Two pieces of garments are joined together with an interlocking stitching technique.
• Double needle stitching: Two pieces are interlocked and then sewed with a double needle.
• Layer bound stitching: A third layer of garment is put over the seam and stitched to ensure extra protection.

Materials Used for Disposable Apparel

There are different kinds of base materials that are used for constructing disposable apparel. To name a few of them, we have:

• Polypropylene: This is a cheap material and therefore ideal for disposable garments. It is used extensively to construct head caps, shoes and overall covers. However, their particle resistance capability is low compared to other materials.
• Polyethylene: It is efficient to resist fluids for a short period and widely used in cleanrooms and laboratories.
• Spunbond olefin: This is a very high quality and strong fabric for use in cleanrooms. This material has a very small pore size and therefore is an excellent barrier for dirt particles.
• Vinyl: Due to the chemical resistance properties of this material, it is commonly used in making disposable aprons and garment sleeves.

Different Kinds of Disposable Apparel
Disposable garments range from the covering of your mouth to overall coverage. Some of the garments used extensively by professionals while carrying out special procedures are:

• Aprons: Aprons are worn over the routine garments to cover the chest, stomach and thighs. Long coat aprons are open at the back and come with full long sleeves and fronts.
• Bouffant caps: They are constructed from polypropylene and worn to avoid contamination caused by the shedding of hair. An elastic band is used to keep this cap in place. Two primary sizes of diameters – 21 inches and 24 inches – are available in these caps.
• Beard covers: These covers are used to prevent environment contamination by shedding of facial hair. They are worn through elastics around the ear loops and cover beard, moustache and sideburn.
• Shoe covers: They are worn over the shoes in higher class cleanrooms and are usually prepared from polypropylene. Shoe covers come in various sizes, such as regular, large and extra large.
• Boot covers: Where shoe covers provide limited protection from contamination, boot covers are 18-20 inches high and give full protection. They also have an elastic band on the top and therefore can be easily worn with coveralls.
• Sleeve covers: In high tech labs, where engineers have to come in contact with highly chemical and harmful solutions, vinyl sleeve covers provide considerable protection. They have elastic at their ends and usually are 17-20 inches in length.
• Face masks: Face masks are made to cover the nose and mouth area in order to minimize the contamination spread through skin flakes, mucous and cosmetics. These masks are worn with the help of elastics around the ear loop.
• Coveralls: Coveralls used for high level cleanroom classes are designed with military collar and no pockets. They are usually worn with boot covers, caps, face veil and gloves in order to provide full body coverage.

Before donning any apparel, make sure that it fits properly and is comfortable. Special adhesive mats and air showers are also kept outside the cleanrooms. These attract a lot of particles from the body.

Use of Mats in Various Applications

Not only in clean rooms and laboratories, matting applications are used in a number of industries to ensure a clean and uncontaminated environment. Some of these industries are:

• Pharmaceutical industry
• Medical/chemical industry
• Operation rooms
• Computer rooms
• Electronic precision industry

Advantages of Sticky Mats

Sticky or adhesive mats are commonly used in various industries for the following advantages:

• Dust particles collected by the mat do not spread.
• A special kind of adhesive is used which does not leave any stain on the floor.
• After a layer is out of use, a new layer can be brought out by peeling the previous one.

Adhesive Characteristics of Cleanroom Mats

The most common characteristics of cleanroom mats are tack level, adhesive thickness and adhesive softness. These characteristics determine the efficiency of the adhesive in removing and holding contaminants from the surfaces before their entry into the cleanroom.

• Tack level: The tack level or level of stickiness of a mat is measured through PSTC-1 test and represented in grams. The right amount of tack level is crucial for maintaining the appropriate balance, which, if exceeded, can be hazardous. Since the purpose of the mat is to remove dirt from the dry adhesive-less surface, it just needs a higher coefficient than the surface attraction. A very low tack level (2-3 ozs) is sufficient for this purpose.
• Adhesive thickness: If the adhesive layer of the mat is extra thin, the dust particles will remain on the surface and shorten the reusability and performance of the mat. The thickness of the adhesive layer is, therefore, vital for the prolonged performance of the mat. When particles from the surface of the shoe sole or wheel come in contact with the mat, they get into the thick layer of the adhesive. It keeps the surface clean of contaminants and the mat continues to be suitable for further use. A washable mat comes with no adhesive coating and needs to be washed every time for removing the particles. Consequently, a shoe comes in contact with the particles shed by the previous shoe and is not perfectly clean. Therefore, adhesive mats are often preferred over the washable ones for entering cleanrooms.
• Adhesive softness: Adhesive softness is highly important for the efficient performance of each layer of the mat. When particles come into contact with the surface of the mat, they need some place to go. The softness of the adhesive layer makes sure that these particles are embedded into the layer instead of remaining on the surface, provided the layer has sufficient thickness to grab the particles.

If the adhesive is hard, this function will not happen and instead the dirt will stay on the surface which will reduce the performance of the mat. However, the adhesive should not have a high tack level, otherwise too soft an adhesive will stick to the surface of the shoe or wheel and contaminate the controlled environment of the cleanroom.

Therefore, the right amount of tack level, adhesive thickness and adhesive softness play a crucial role in the performance of the cleanroom mat application.

Stationery Products Used in Cleanrooms

Various apparatus manuals, forms, notebooks, binders and a variety of other products are required in a cleanroom for the purpose of noting down daily activities and important information.

• Spiral notebooks: Cleanroom notebooks are generally spiral bound and have a clear front and back cover. These notebooks are produced in highly controlled environments and should be opened in the clean environment to avoid any contamination.
• Binders: Binders are used for archiving and organizing various research papers, forms and documents in a cleanroom. They come in various sizes depending upon their use. Since binders come packed in cardboard boxes, they are not clean. So, it is mandatory to wipe them with a special cloth before bringing them into the cleanroom.
• Paper: Cleanroom paper is produced with a special kind of poly fibers and coated with latex. Paper color and weight depends upon the manufacturer.
• File folders: Folders come in 1/3 cut and 100 set minimums. They are used in cleanrooms to organize forms and other important papers. Like binders, they too are not clean and need to be wiped thoroughly before taking them to cleanrooms.
• Custom printed forms: Many users get the regular forms photocopied on the cleanroom paper. However, a preprinted form is originally cleaned and wrapped to maintain cleanliness right up to the point of its introduction into the cleanroom.
• Labels: Labels are available in various sizes, colors and materials. The typical material used for manufacturing a label is Tyvek or a biaxial polypropylene. These labels are wrapped around a plastic hub and there are normally 1,000 labels per roll.
• Tabs: Tabs or dividers are manufactured in 1/3 cut and 1/5 cut. The material is similar to that used on spiral bound notebooks. The outer corners of the tabs are rounded for their efficient and safe use in the cleanroom. They come in a variety of colors and every tab set is thoroughly cleaned and double shrink-wrapped for removing any kind of contamination.
• Manuals: Critical equipment used in the cleanroom come with manuals and operating guides for providing operating and maintaining guidance to the user. These manuals are available on either disk or paper. For disk manuals, a sample copy is produced by the manufacturer on a standard material for approval of the user. Paper manuals are just a combination of binders, papers and tabs as discussed above.
• Printer rolls: Thermal rolls are used in printers during the manufacturing process to record data. The poly film used in the printer cannot be torn, which reduces the contamination of the particles. The most common widths of thermal printers are 57mm, 80mm, 110mm and 216mm. Each roll is cleaned and double shrink-wrapped before shipment. Therefore, they should be opened only in the clean and controlled environment.
• Pens: Cleanroom pens are different from the ordinary ones and have special characteristics. The ink of these pens has low chemistry with sodium. These pens are available in red, blue and black ink with medium point.

Cleanroom stationery products are used in different industries to prevent the spread of virus and bacteria, reduce harmful effects and increase productivity. Almost every industry, such as pharmaceutical, medical, electronics, precision engineering, food industry, automotive and optical, requires these super hygienic documentation and paper products. Even the print industry requires them for digital reproduction with high resolution.

Tack mats are used for helping to remove particulate contamination from the bottom of personnel shoes and from the wheels of carts upon entry to a clean area.

NOTE, This does not mean tack mats will clean off all dirt!  If shoes or wheels are very dirty,they need to be cleaned prior to using the tack mats, outside of the clean area and away from the mats.

Use of the mats is very simple;

1. Just step on the mats twice with each foot before entering the clean area.
2. Roll all the wheels of a cart across the surface of the mat.

How do you know if the mat is doing its job?

1. If you can see that it is removing dirt from your shoes or cart wheels.  As the mats become used, they will be covered by tracks of other people and carts. When it looks like the surface is well covered by other tracks, or if the surface is no longer tack, it is time to renew the surface of the mat.

Danger, ESD Hazard!

When a tack mat surface is being renewed, or if the mat is replaced, a very large charge is generated, both on the mat, and on the material/personnel involved.  Before renewing a layer or replacing a mat, make sure that all ESD sensitive
material is at least 1 meter away, and remains so for at least 3 minutes.

How do I renew the surface of the mat?

The mats are layered, with generally about 30 layers in each mat, and each layer is numbered from the top down, so that the highest number is on the bottom. As the top layer becomes dirty and no longer tack, it is time to peel off that layer and expose the next layer underneath it. On one corner of the mat, there are numbered tags, and this is where you start to peel off the layer. Just peel off one layer at a time (make sure that the next consecutive number remains on the mat), and discard the layer that you just peeled off, preferably outside of the clean area and away from any ESD sensitive material.