Microcontamination in the Computer Room
         Closely paraphrased from a booklet by Carol Blake "A Guide To Access Floor Maintenance"
         Access Floor Systems, Inc., Abita Springs, LA
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. 
Lateral Instability

The most common structural problem is a condition known as lateral instability. This describes          
a floor system which 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

Vertical instability, 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

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

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
Forced Air

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.          


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.          
Fresh Air

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.