The cleanrooms are designed to the highest standards that most facility managers are conversant with. Measurements of airflow in changes per hour. Laser sensors used to monitor the counts of particles. The temperature is regulated to fractions of a degree. Dampness confined in narrow strips. But one thing always spoils all this planning, and that is the door systems that open cleanrooms to the rest of the world. Standard doors pose contamination risks, create pressure variations, and bring about expensive downtime which is hardly related to the actual cause.
Take the example of a normal pharmaceutical cleanroom on ISO Class 7 levels. Every time a manually operated door is opened slowly, a number of things occur at the same time. Conditioned air escapes, resulting in a decrease in air exchange rates. The less-clean corridor is entered by particles. Pressure differentials equalise, and it takes time to regain once the door is shut. These micro-events sum up to hours of unproductive time spent and a massive load to the filter within a single eight-hour shift, where personnel, materials, and waste removal had to make dozens of door openings. Because of these strict environmental requirements, many facilities rely on specialized commercial cleaning services to maintain contamination control and ensure cleanroom standards remain consistent. In semiconductor fabrication, the slightest loss of pressure can spoil a whole batch of wafers that would have cost hundreds of thousands of pounds.
The economic argument for cleanroom door system upgrades is strong. An incident of contamination in the production of medical devices is likely to cost more than 100,000 in product write-offs, line clearance, and time spent in investigations. In pharmaceutical filling, which is done in sterile environment, contamination can translate to a loss of millions of dollars of a batch. However, the majority of cleanroom operators still have standard industrial doors that were not intended to be used in controlled settings.
High-speed doors address the problem that the old-fashioned designs lack. Taking less than two seconds to open instead of ten to fifteen seconds for an average door, they reduce air exchange time by over eighty percent. They hold pressure differentials in that the door will not be open as long as pressure equalization will take. High-speed doors have been tested independently and have been found to reduce particle ingress by up to ninety percent, relative to ordinary doors. Human behavior is the biggest variable in cleanroom contamination that is eliminated using automated controls. No longer doors to keep open. Enough of lost seals. No longer have operators with a door opened as they fight with a cart.
The current roller doors for use in clean rooms are designed to suit the ISO environment as reflected in efaflex.co.uk. Surface smoothness does not allow the formation of particles. Sealed side guides are used to remove the openings where contamination may pass through the door. Fast cycle times are realized without slamming or vibration that may upset delicate processes. Certain models incorporate air-tight seals, safe passage vision panels and integration with facility management systems that record all openings to use in audit trails.
Facility managers that solely emphasize on HVAC upgrades or gowning procedures are not utilizing the weakest link in their contamination control plan. Even a cleanroom with the best air handling and the best gowning procedures could not achieve perfection as a slow door was left open and somebody moving a cart introduced contamination. The performance of doors is not a minor concern that is to be considered once the major systems are designed. It is a factual determinant of the cleanroom performance that must be stated at the same rigour as filtration and airflow.
It is common to find that the payback period of high-speed cleanroom doors is in a matter of months and not years. Fewer events of contamination will lead to fewer product write-offs and less cleaning validation downtime. Reduced energy is achieved through maintenance of pressure differentials and conditioned air. Automated doors will speed up the flow of materials since the operators do not need to halt and open the doors and push carts inside and close them. In clean room efficiency, any second that the door remains open is not only costly in terms of time. It is expensive in terms of product, energy and risk. The high-speed doors seal that divide – literally and monetarily.