How Access Floors can Contribute to Contamination


Access flooring has been installed in computer centers for 30 years now. Their age is starting to show. Let's take a look at the problems that develop with a raised floor and how they can contribute to microcontamination.

  • The most common structural problem is a condition known as lateral instability. This is when the floor system is loose and unstable. This allows debris to fall between the cracks and land in the air supply plenum. Raised floors are supposed to be level with no gaps or cracks.
  • Vertical instability or rocking panels also contribute to contamination. When this condition exists, debris, dust and other contaminates fall into the subfloor supply plenum and contaminate the air flow. Aside from contamination, rocking panels should be eliminated. They create a safety hazard for your employees, and if left to rock, other problems will develop.
  • Missing edge trim is a common sight in computer rooms. It is the absence of trim on a raised floor panel which creates a "canal" or "dirtway" for contamination to hide, and eventually work its way into the supply plenum. This causes dirt and dust to collect on the grid and causes rapid aging of a floor system.
  • Contamination is invited under the floor when the raised floor is cut, and those cutouts are not properly sealed. This is accomplished with a special type of trim which allows for a piece of foam rubber to cover the opening. It's also efficient for your raised floor to be sealed to maintain the static pressure of the air plenum.
  • Rust that is on the floor components must be removed, and the cause eliminated. Rust is usually caused by improper maintenance (water mops), a leak under the raised floor or overhumidity of the air conditioning. The rust flakes off and becomes a damaging particulate which travels at high velocities.


There can be multiple problems contributing to contamination under an operating computer floor:

  • Plenum debris is a common sight when subfloors are not maintained. This debris should never be allowed to accumulate. Your raised floor is a supply plenum for your air conditioning and it is not filtered before it gets to your computer equipment. Regular subfloor vacuuming will eliminate harmful particulates.
  • The forced air from the air conditioning system and the blowers within computers are designed to keep the electronic components operating at the temperature which ensures long life and maximum reliability. An excessive amount of soot will reduce the airflow across a component. This will increase the component's temperature and shorten its life.
  • A computer room needs to be cleaned on a regularly scheduled basis. This is particularly important after an installation or upgrade. Besides the obvious places such as the tops of system cabinets and the floor surface, periodically clean underneath the raised floor and any other dust catching surfaces such as duct work and raised floor airflow panels. Specialized computer room cleaning companies use techniques and equipment designed to efficiently clean without recontaminating the computer environment or disturbing operation.


The following considerations may be helpful when instructing personnel in cleaning procedures:

  • Avoid the use of harsh cleaning solutions and chemicals containing ammonia, chlorine or harsh detergents.
  • Do not sweep because airborne dust will be generated.
  • Use a dry lint-free dust mop on an access floor.
  • Spot cleaning should be performed with a damp mop.
  • Powder cleaners should never be allowed in the facility, for carpet or hard surfaces.
  • Make sure the products being used have been tested according to NEMA standards and that the chemicals do not interfere with the static dissipating properties of your floor.
  • Have your raised floor professionally cleaned at least two times a year.
  • Purchase a low or lint free dedicated mop, along with a seamless bucket and mark ACCESS FLOOR ONLY. In house maintenance people need training on your facility. Insist the janitorial service use this dedicated mop in your areas only.


Let's talk about janitors for just a minute. They are major contributors to contamination in your facility because they do not understand the critical nature of operating computer equipment. They do a series of things which can be harmful because they are not educated on data centers. It's just another room to clean.


Janitors will bring the same mops used to clean the bathrooms and the kitchen in your computer room. The chemicals and wax that build up in the mops are mopped onto your access floor. After the floor dries, it is not clean. It is contaminated. And if there was wax on the mop, then the floor you paid dearly for to dissipate the static electricity has been temporarily insulated...insulated by the barrier of wax.


Another way janitors bring particulates in is by bringing a giant 64 gallon garbage can on rollers, wheel it up your ramp, and then proceed to empty the garbage cans in the computer room inside the room. This creates high flying particulates. Not only do you have the garbage from your room to worry about, but you now have the entire buildings particulates to deal with in your closed room.


It is important to get other operating facility references on anyone who enters your facility for any reason to perform work. Make sure they understand the function of your room, and your equipment.


A computer facility is a dynamic environment where many activities occur on a regular basis. Maintenance and upgrades are done on the computer system, the air-conditioning system, the public telephone network and the architectural elements within the facility. Installation of new and additional power, data, security, or fire protection circuits is a recurring event. With proper planning it should be possible to perform these activities with minimal contamination.

It is important to remember that in your indoor artificial work environment there typically isn't any fresh air. Frequent cleaning of your work environment should be performed regularly to keep equipment operational. In addition to your computer system, airborne contamination can be hazardous to your health.