Computer Systems

Reducing the exposure of computer equipment to ashfall is the most effective mitigation action. Experiments suggest that laptops may shut down due to overheating when covered in ash, but relatively little enters the internal compartment. After cleaning, the laptops in these experiments restarted successfully.

How to prepare:

The most effective mitigation is to avoid exposure of electronic equipment to ash. This can be achieved by sealing the equipment, or the building in which it is housed. Ensure that there are stocks of protective equipment such as plastic sheeting and duct tape.

Limiting ash ingestion into buildings which house electronic equipment is also effective.

• Identify single entry/exit point into building.
• Close and seal all other doors and windows.
• Identify areas to be sealed off within building.
• Monitor cooling systems (i.e. HVAC units).

How to Respond:

• If possible, move any outdoor electronic equipment indoors prior to an ashfall.
• Set up 'ash lock' on single entry/exit point into building (see companion poster for further details).
• Seal off areas housing sensitive and/or critical electronics.
• Cover non-essential equipment with plastic sheeting and shut down if necessary.
• Avoid cleanup until ash has stopped falling. However in some cases immediate action may be required to prevent loss of function of critical equipment.
• If possible, shutdown electronic equipment before cleaning to avoid possible short circuits.
• Electronic equipment can be carefully cleaned using low pressure compressed air or a soft brush.
• Avoid excessive rubbing as this may scratch delicate surfaces.
• Use a vacuum cleaner to clean rooms to avoid recontamination of cleaned areas.
• Monitor HVAC systems (). Minimise use if necessary.

Techniques for cleaning from Labadie (1994) (which may still be relevant):

• Clean and condition surrounding air to keep ash out of equipment.
• Cotton mat filters used in separate clean rooms were found to be best for filtering particles, but they reduce the air flow. A solution is to use larger fans to maintain required air flow. Rack-mounted equipment can be modified to add a larger fan, but smaller instruments or components with a built-in fan would require design change to increase fan capacity. Use fluted filters as a compromise; increases surface area but reduces air flow by only about 20%.
• Digital integrated circuits can vary 5-10% in performance (depending on type of circuit) and still be acceptable. It is difficult to generalize about other equipment (e.g. high-voltage power supplies).
• Humidifying ambient air (for example, wetting carpets) will help to control ash reentrainment.
• Ash on equipment can be blown out with compressed air. If the air is too dry, static discharge could damage sensitive components (for example, integrated circuits). If the air is too damp, the ash will stick. Relative humidity of 25-30% is best for compressed air.
• Cleaning with a pressurized water-detergent mix and a hot water rinse is quite effective. However, this process requires at least partial disassembly.
• Ash should be blown or brushed away from power supplies.
Ash may have high static charge and be hard to dislodge, thus equiring brushing to dislodge particles.
• Accelerate filter change; use pre-filters. Change to absolute filters; these will keep out particles down to 1 micron and smaller.
• Keep computer power on to operate filtration, but don't run (especially disk drives).
• Maintain 'room-within-a-room' configuration; restrict access; re-circulate air; accelerate cleaning of the critical area.
• Keeping ash out of buildings will also help protect electronic equipment.

See Also: