A white room is a dedicated space where airborne particles are removed and the environment is tightly controlled to provide the ideal environmental conditions for manufacturing sensitive components.
White rooms manage air quality in a room, including parameters such as temperature and humidity. The level of contamination in a white room is measured according to the number of particles per cubic meter.
White Rooms in Detail
Air contains particulate matter that pollutes it. The particles can be tiny solids or liquids, including dirt, dust, soot, and liquid drops. White rooms have necessary infrastructure in place to reduce this particulate contamination and control environmental characteristics such as temperature, humidity, and pressure.
White rooms vary in size, and are based on a facility’s needs and solutions for contamination control. However, they all meet a specific airborne particulate cleanliness class. The classes define the maximum permitted number of airborne particles in a white room of which there are 9 ISO classes.
White rooms are classified according to the quality of air inside. The relevant laws include the Federal Standard 209 (A to D). According to this law, air cleanliness is measured according to the number of particles equal to or greater than 0.5 microns per cubic foot of air.
There is also the international ISO 14644-1.
The ISO standards range from ISO-1 to ISO-9, with higher classes permitting more particles per volume of air. Rooms graded ISO 1 allows no more than 10 particles of a size greater than 0.1 microns per cubic meter of air. On the other hand, a white room graded
ISO-2 has a particle limit of 100 of a size greater than 0.1 microns per cubic meter of air.
As the ISO number rises, the participle limit increases by a step-up factor of 10 with class and larger particle size for contaminants.
Air Filtration in White Rooms
The air inside the white room is processed by high-efficiency particulate air (HEPA) and ultra-low particulate air (ULPA) filters. These filters protect substances from harmful airborne contaminants in a variety of processes, such as:
HEPA is a filtration system that extracts up to 99.97% of particulates that are 0.3 microns (0.3 µm) in size or larger. ULPA filters, on the other hand, are Ultra Low Penetration Air filters that can remove at least 99.999% of particles of a size of 100 micrometers (0.1 µm) or larger.
HEPA and ULPA filters trap air particles through a complex web of fibers. The air contaminants are removed through sieving, diffusion, interception, or inertial impaction. The processes vary depending on the size of the particle.
Generally, the smallest particles are removed through filtration, medium-sized particles through interception, and larger particles through sieving and inertial impaction.
White Room Air Flow Principles
White rooms maintain contaminant-free air through laminar or turbulent airflow systems. Usually, in laminar or unidirectional airflow, the air in a designated space moves at a similar velocity and direction.
This creates a straight, uninterrupted path for air. The airflow is maintained through direct air jets in a downward straight path, as well as architecture that prevents the air from getting turbulent.
Turbulent airflow occurs when the air in motion doesn’t move in the same direction and velocity. In non-unidirectional airflow, air distribution occurs through induction. The air in the room mixes with new air to create a swirling effect, which dilutes the particle concentration.
What Are White Rooms Used For?
There are a wide variety of companies that need white rooms. For example, if you’re in a manufacturing process affected by air particles or contaminants, a white room is a necessity. Common industries that use white rooms include:
- Research facilities
- Medical facilities
- Electronics parts production
- Military applications
How is a White Room Kept Clean?
After getting a white room, the main question for operators is, “How do you keep a white room clean?” People need to get into the room, touch materials, carry substances, and produce products that can contaminate the air in the white room.
So, what are the best ways to keep your white room up to standard? Here are a few basic concepts to remember.
- White room PPE: Personal protective equipment (PPE) is mandatory for anyone who enters a white room. People are full of particles such as hair, dry skin, and dust on our clothes which can travel and contaminate the surrounding air. Therefore, the gowning process is vital to maintain the air quality in your white room.
- Dressing room: Generally, you should designate a dressing area with clearly defined boundaries to help workers know where to stand and prepare for white rooms. Wear a white room suit, complete with goggles and a mask, to prevent any particles on your skin, clothes, mouth, eyes, and nose from spreading into the white room.
- Furniture: The furniture in your room produces particles over time. As such, you need special furniture in your white room to prevent particle accumulation.
- Air shower: You might consider investing in an air shower to reduce the number of contaminants in your white room. The air shower blows off any particles entering the room via people, equipment, and materials. If you install an air shower, remind your staff to take an air shower before entering the white room.
- Sticky floors: Your floors are some of the biggest sources of air pollutants. To prevent foot-borne contaminants, use sticky floors and mats, which are more durable and more effective than conventional floors.
- Perfume and cosmetics: Keep all extra fumes from perfumes, lotions, make-up, hair, and gels outside the white room.
- Shoes: Shoes pick up all sorts of dirt, debris, and particles. Change into a clean pair of shoes in the gowning area, or wear protective covers over the shoes.
- Gloves: Be sure to wear proper donning and doffing of disposable gloves to eliminate particle contamination.
- Hair cover: Wear a hair cover and ensure all your hair is covered. Make sure you hold your hair in a firm style before wearing the head cover to avoid getting hair strands on the outer sides.
- Cleaning Equipment: Use vacuums to capture dirt and debris as you clean surfaces in the white rooms. Adhesive rolls and clean mops are also suitable for white rooms.
- Consumables: Use notebooks with polyethylene binding and white room papers to reduce paper contaminants. Labels made of polypropylene are also safe and free of leachables and gasses.
How Are White Rooms Designed?
Each white room varies in design, depending on the need. Some have hard or solid walls, and others have soft walls created from foil curtains. In soft wall cabins, PVC curtains protect the clean air against contaminants, while exhaust air escapes under the curtains. In hard wall cabins, the structure allows the availability of pure air classes in each room.
Hard wall cabins are suitable for white rooms with strict climate tolerances, while soft walls are suitable for more tolerable environments. Each design supports adaptable working spaces with work shelves, wet work stations, and enclosed inspection areas for people and materials. There are also pre-built white rooms, which can be assembled on-site.
However, cost-efficiency matters, and because of this, rental white rooms are suitable for small to medium-sized enterprises. Overall, thorough consultations enable cost transparency before constructing a white room.