The cleanroom, conceived as an artificial environment specially engineered to minimise the concentration of airborne pollutants, has undergone many improvements and refinements since Willis Whitfield installed the first one at Sandia National Laboratories in 1962. Today, cleanrooms play a vital role in manufacturing processes in the pharmaceutical and microprocessor industries, as well as other sectors where it is imperative to control airborne contaminants.
It’s likely that cleanrooms will undergo further developments as the trend toward miniaturisation in manufacturing makes sensitive materials increasingly vulnerable to the negative effects of contamination.
What this all means for you? As someone involved in the management of controlled environments, you need to remain up to date on evolving standards in cleanroom processes. That includes understanding the huge importance of cleanroom attire for keeping these environments safe and operating effectively.
The science behind the uniform
In cleanrooms, ensuring that the level of airborne contaminants stays below an acceptable threshold can be difficult. Tools, equipment, machinery, and circulating air can all harbour pollutants that interfere with microprocessors, biomedical matter, and other sensitive materials.
The biggest source of contaminants, by far, is human personnel. Unlike inanimate objects, human beings cannot be sterilised. Even when sitting perfectly still, they continuously spread around dead skin, hairs, microbes, and other pollutants.
Therefore, it is necessary for cleanroom personnel to wear specially designed clothing that can serve two functions:
- preventing natural human contaminants from infecting the environment
- protecting the wearer from hazards in the immediate area
The specific properties of apparel to be worn in a cleanroom depends on the unique characteristics of the environment in question, but it is common for this type of clothing to include the following design characteristics:
Non-linting material: Ordinary workplace apparel has small fibres that occasionally fall loose. This is bad news for cleanrooms with delicate microprocessors. Lint-free clothing solves this problem.
Resistance to arc flashes: OSHA regulations require employees to wear clothes resistant to flash flames whenever the threat of an electrical arc flash is present. An arc flash can exceed 35,000 °F (19,400 °C), so it’s extremely important for specialised FR (flame resistant) cleanroom clothing to help protect personnel from this dangerous phenomenon.
Anti-static carbon fibres: Static electricity is another hazard that can harm electronic equipment, especially in oxygen-rich environments. Electronics can be damaged even by very weak static shocks that are not detectable by human beings. Anti-static or electrostatic discharge (ESD) apparel reduces this risk.
High-density fabric: This protects against heat and corrosive liquids.
Proper cleanroom apparel can be an important part of HACCP compliance, so it’s important to understand what goes into that widely recognized standard.
What it takes to be HACCP compliant
Hazard analysis and critical control points (HACCP) is a system that was originally intended to promote food safety and remains most commonly associated with that function. It has found increasing acceptance in other industries as well, such as the pharmaceutical sector.
The HACCP system consists of seven "points" that collectively help eliminate safety issues:
- Conduct a hazard analysis: Check for potential problems in the process
- Identify critical control points: Pinpoint specific areas where hazards can interfere with the workflow
- Establish critical limits: Calculate the parameters that must be observed at each control point
- Establish monitoring procedures: Create measures to track activity at each control point
- Establish corrective actions: Institute procedures for fixing problems when they are detected
- Establish verification procedures: Ensure that all relevant devices are functioning accurately
- Establish record keeping procedures: Create a process for recording and storing accurate data
For cleanrooms, HACCP compliance involves both using the right kinds of uniforms as well as establishing procedures for their proper handling.
Advances in uniform cleaning technology
Most cleanroom clothing is reusable, which is good news for laboratories that otherwise would have to incur huge expenses by continually purchasing new apparel.
However, it is essential to ensure that this apparel is cleaned properly; contaminated clothing defeats the whole purpose of wearing it.
Fortunately, overburdened labs can turn to third-party organisations to provide cleaning services.
When vetting your options, make sure you choose one that is Clean Green Certified through TRSA. Where required, this service should offer a sterilisation validation programme that utilises gamma radiation to achieve a 10-6 sterility assurance level (SAL).
Reusing cleanroom clothing is an eco-friendly solution that lowers facility expenses and reduces your overall carbon footprint.
Gowning procedures
Like so many beneficial accessories, cleanroom apparel must be used correctly to obtain its full range of benefits. It requires a precise sequence of actions to ensure that the clothes do not become contaminated.
Exactly how this sequence goes depends on the needs of the particular facility, including its ISO cleanroom classification. There is no standardised gowning procedure that applies to every environment.
In general, though, the gowning procedure involves thoroughly cleaning exposed skin (including the removal of cosmetics) and any clothing that will be worn underneath the cleanroom apparel.
Jewellery must be removed or at least completely covered. Personnel must be able to don their clothing while preventing it from touching the ground, where it can pick up contaminants, at any time during the process.
Many cleanrooms place a sticky mat before the entrance to remove dirt and other contaminants from the shoes of personnel.
Types of cleanroom attire
Certain types of cleanroom apparel are designed to cover the entire body, while others are intended to cover particular areas, depending on the needs of the facility.
A wide variety of hoods, goggles, face masks, gloves, coveralls, boots, and footwear coverings are available from uniform manufacturers.
Cleanroom managers have access to a wide range of sterile and non-sterile uniforms and apparel capable of accommodating the safety requirements of their facility.
