In plastics manufacturing, downtime for a facility comes at a cost. And it isn’t cheap. Whether the cause is a planned shutdown for maintenance or an unforeseen closure due to contamination or equipment failure, any lost time should be minimised as much as possible as the impact can be far-reaching.
From labour costs, including outside contractors and idled operators, to production costs, including wasted product and materials—downtime can seriously affect overheads. Through design, effective maintenance, and calibration, downtime can be reduced so that only the minimum time to maintain, test, and requalify the facility is required.
Contamination Control Strategy
The use of a Contamination Control Strategy (CCS) will effectively define critical control points that could potentially result in the contamination of a facility, and how these points can be assessed. By correctly implementing a CCS, the risk of downtime due to contamination will be greatly minimised. From the first steps of design to the procedures introduced and operator competency, a CCS should be used through the full lifecycle of the cleanroom. Controls may be implemented through cleaning procedures such as rotational cleaning, the use of continuous monitoring, or staff training.
How design affects downtime
The reduction of downtime starts earlier than you think in the lifecycle of the cleanroom. Future maintenance, service, and validation must be considered during the initial design of the facility. Downtime-reducing measures include designing a layout that allows engineers ease of access to critical systems that make up the cleanroom, or using systems that can be replaced and tested without breaking the integrity of the cleanroom.
During planned shutdowns of the facility, routine checks of the HVAC system—and any other systems required to support the use of the cleanroom—are checked. If the facility has been designed to allow easy access to these systems, engineers will be able to work efficiently, without obstructions slowing down the process.
The ability to segregate zones of a facility, to allow maintenance in one area while carrying out routine operations, will greatly reduce the impact of a shutdown. The use of decentralised air handling systems provides the option to shut down sections of the facility while maintaining routine operations in others. If there is suitable space, segregated change areas for each area will allow staff to enter and leave rooms that are still in operation, while other areas are down. Traditional AHU’s service the whole facility so it’s much more difficult to shut down separate zones.
Planned Preventative Maintenance (PPM)
Incorporating PPM into your maintenance schedule should result in a reduction in downtime. The concept of PPM means shifting from a run-to-fail strategy, to proactively seeking the prediction of required maintenance. Even when a facility is functioning normally.
In cleanrooms, PPM usually begins with monitoring. The use of routine or continuous monitoring of your facility is critically important to maintaining operations in a cleanroom. Not only will continuous monitoring pick up any out-of-specification results, such as high temperatures or increases in particulates, but the data can be analysed to determine any potential trends that may result in significant downtime to remedy. A shorter preventative downtime to remedy the change in results would be preferable over a full failure of the system, which could result in a significantly longer shutdown.
Equipment calibration
Routine continuous monitoring of a cleanroom usually requires supplementary monitoring systems to measure the environment of the room. Whether these are temperature and humidity data loggers or a particle counter, there is a requirement for these systems to be regularly calibrated to ensure the accuracy of the results generated. Without calibration, incorrect results may not flag potential issues which could result in facility downtime.
The calibration of equipment may result in site downtime if it is not planned for. For example, if a particle counter is required to carry out operations, and it is off-site for calibration, the cleanroom cannot function. There are several options to counter this potential situation:
- Purchasing spare equipment will allow for equipment to be sent off-site for calibration without impacting operations. There will be an initial outlay of expense with purchasing a second unit, but the benefit of keeping the facility operating should outweigh the initial cost of purchasing and maintaining spare equipment.
- Using a local calibrations service will prevent additional delays in downtime. Transit of the equipment and delays in customs can take up a large time that equipment is off-site, so by carrying out calibration in the UK the impact of equipment being off-site and therefore potentially resulting in downtime is minimised. The risk of damage to potentially expensive equipment is also minimised.
- If possible, using a loan piece of equivalent equipment provided by the company that is calibrating the equipment may be the best option to prevent downtime. There would be no requirement for purchasing additional equipment, and if the loan equipment is delivered before shipping the equipment for calibration, there should be no impact on operations.
In-house or independent testing?
The use of a combination of third-party and in-house validation and testing can combine to produce counter-measures to site downtime. By using in-house testing and monitoring, swift responses to any problems that may have occurred can be logged and actioned. Staff who regularly work in these areas are likely to spot potential deviations early on, and with an efficient system to capture these faults, they may be fixed before any room downtime is required.
The use of third-party validation and testing will provide a more independent and thorough test of the facility than can be achieved through in-house testing. Requalification of a cleanroom at regular intervals, whether determined by regulatory bodies or internal risk assessments, will assure that the cleanroom is operating within the expected acceptance criteria, and if any failures are observed, investigation and remedial work can be carried out by trained staff to reduce the impact on routine operations.
Through a holistic and proactive approach to monitoring and maintenance, you not only gain better visibility of the operations of your facility, but you can raise productivity and cut back on costly downtime.