Through lack of training or supervision, people who enter a cleanroom to maintain or service machinery can be a considerable hazard. The maintenance technician, unless instructed otherwise, will apply the same techniques as they do outside the cleanroom. Service personnel from outside firms may be completely untrained in cleanroom contamination control techniques. The following is a list of procedures that should be considered for maintenance and service personnel

• Maintenance and service technicians should only enter a cleanroom with permission.
  
  
• Maintenance and service technicians should be trained in cleanroom techniques, or closely supervised when they are within the cleanroom.
  
  
• Technicians must wear the same, or equally efficient, cleanroom clothing as cleanroom personnel, and use the same techniques to change into cleanroom clothing when entering and exiting cleanrooms. They should never enter the cleanrooms (especially at weekends, or when no one else is around) without changing into cleanroom clothing.
  
  
• Technicians should ensure they remove dirty boiler suits, etc. and wash their hands before changing into cleanroom clothing.
  
  
• Tools that are used routinely for maintaining the cleanroom should be cleaned (and sterilised, if required) and kept stored for sole used within the cleanroom. Tools should be made from materials that do not corrode. For example, stainless steel is much preferred to mild steel tools , which may rust.
  
  
• If a service engineer or contractor brings tools into the cleanroom (especially those from outside the cleanroom organisation), then they must be cleaned. A wipe-down with a cleanroom wiper moistened with isopropyl alcohol (often 70%, in water) is a suitable method. Only the tools or instruments needed within the room should be selected, decontaminated, and put into a cleanroom compatible bag or container. This has the advantage of leaving behind cases or briefcases, with their associated scraps of paper, fluff etc., which are potential sources of contamination; these should not be allowed into the room.
  
  
• Spare parts or items, like fluorescent light tubes, which have wrappings, should have the wrappings removed outside the manufacturing area and the parts wiped down.
  
  
• Written methods should be kept for each activity, so that contamination control techniques can be incorporated within a specification. These should be adhered to.
  
  
• Any instructions or drawings on non-cleanroom paper must not be taken into the cleanroom. They can be photocopied onto cleanroom paper, or laminated within plastic sheets, or placed in sealed plastic bags.
  
  
• Particle generating operations such as drilling holes, or repairing ceilings and floors should be isolated from the rest of the area. A localised extract or vacuum can also be used to remove any dust generated.
  
  
• Technicians should not bring any materials into a cleanroom that are given on a list of 'contaminating material'
  
  
• Technicians must tidy up when they are finished and ensure that the area is then 'cleanroom cleaned' by a person with suitable knowledge. Only cleaning agents, materials and equipment that has been approved for use in the cleanroom should be used.