Cleanroom Housekeeping

A high standard of housekeeping practice is essential in maintaining a cleanroom. When putting in place a cleaning regime it should be considered that personnel are usually the predominant source of particulate contamination. It follows, therefore, that clean down activity should be during low occupancy periods.

Cleaning should be undertaken when no work is being performed in the room, and account should be taken in the allocated period for the time required to reduce the increased contamination level, caused by cleaning activity, by the filtration systems. It is recommended that cleaning be scheduled for the period immediately following the end of a shift, allowing the room design conditions to be re-established during the night or over a weekend. Cleanroom cleaning should initially be undertaken on a daily basis until experience is established on the actual operating performance of the facility. A detailed cleaning procedure should be produced and implemented.

Minor vacuuming of dry floors and work benches can be performed during room operation, if necessary, provided that both the equipment and procedures used ensure a minimum of disturbance to any settled particulate.

The following aspects may be considered:

1. Cellulose mops and sponges may be used with water for wash down. However the water used must be of appropriate quality and leave no residue.
2. High grade plastic buckets should be used and not be subject to flaking.
3. Ladders of anodised aluminium construction only are recommended if necessary.
4. Vacuum cleaning should ideally be done with a central or external mounted vacuum cleaner, or failing that, with a carefully selected portable machine fitted with a terminal HEPA filter.
5. All housekeeping equipment is a potential source of contamination and movement of these items in and out of the cleanroom should be carefully planned. They should be vacuumed and cleaned thoroughly before entering the cleanroom, or better still retained in the cleanroom change area.
6. Each operator should be responsible for cleaning his/her station at periodic intervals during the working shifts. This assists in the proper management of the cleanroom and prevents mishandling of work pieces by cleanroom maintenance personnel. Cleaning materials for this purpose should be positioned at various points through the cleanroom airlock.
7. During clean down it is recommended that filter faces be vacuumed off at regular intervals to prevent build up of minor particles due to electro-static charging or other problems. Care must be exercised when approaching filter faces to avoid any risk of filter membrane damage.

Vinyl Floors and Walls (where applicable)

The frequency of maintenance necessary will depend upon the location of the floor and the amount of traffic. However the following points will serve as a guide in addition to the manufacturers recommendations enclosed:

1. Floor coverings are pure vinyl and do not require any dressing.
2. Solvent based cleaners, gel cleansers containing pine oil and soft soap or phenol are not recommended.
3. High concentrations of alkaline detergents should never be used as damage to floor coverings will result.
4. Hot water may be used on untreated floors.
5. Floor dressings or additional finishers are not recommended in cleanrooms.
6. Daily:
   1. Vacuum loose dirt and litter
   2. Damp mop when necessary
   3. Remove spillages when they occur by using mild detergent in cold water
   4. Stubborn marks may be removed using a nylon pad
7. Weekly:
   1. Damp mop, or machine scrub, using a mild neutral (non-foaming) cleaner
   2. Rinse floor thoroughly with clean water then follow by allowing the floor to dry naturally or vacuuming.