The Secrets of Contamination Control in Mission Critical Facilities
Let's talk about contamination control in mission & cleanliness critical facilities.
Biyat Energy & Environment Ltd are specialists in holistic cleanroom strategy development for advanced industrial & manufacturing facilities throughout the Design | Build | Launch project stages. Here's a few pointers from our experience of what's needed.
Design Phase
The building design and cleanliness strategy will affect the OpEx of the site for its given lifetime. Bear in mind energy costs associated with HVAC. Optimising cleanroom area layouts, contamination control coverage (m2) and ceiling heights during the design phase are important to minimise such costs.
When designing your cleanroom space, attention to the required ISO cleanliness classification is a must, I.e. ISO-8. This is usually driven by the industry standard and warranty clauses of certain critical components i.e. fuel injector assembly. The classification will also set the HVAC requirements (I.e. air changes per hour / filtration type).
Positive pressurisation of your cleanroom space is another method of ensuring dust, debris and other unwanted nasties are held at bay.
Segregation between cleanliness critical areas and non-critical areas. I.e. Manufacturing halls (comparatively 'dirty') and assembly halls (clean). In the case where a certain process is deemed critical, a modular self-contained cleanroom can be built around the process itself or an independent cleanroom designed for areas such as laboratories and metrology / quality measurement facilities. For temporary cleanroom requirements, inflatable 'softwall' cleanrooms offer a nice alternative rather than building a structure.
The incorporation of vestibules for material transport into the building design is a crucial factor for success. Examples include logistics access points between clean and dirty areas such as 'incoming hold areas' which store components arriving to the site, 'manufactured product hold areas' that feed into clean assembly halls and 'final assembly and finished product logistics areas' ready for outbound logistics off-site.
Forklift and tow trucks serving such areas are typically segregated also. I.e. Separate units serving clean and dirty areas. In the instance where vehicular movement is required between these zones, the vestibule systems as mentioned above can be fitted out with vehicular contamination control systems to facilitate dirt removal during transit. Tangible results can be seen and for the purpose of staff awareness / behavioural change initiatives - the dirt collected from under the grates can be bagged up, measured & presented on a notice board comparing week on week results to validate the system effectiveness.
Another key factor when considering logistics movement, between areas as mentioned above (particularly when coming from outside) - is the use of rapid roller shutter doors - important for minimising contamination ingress as well as for keeping your building warm. Be sure to maintain and monitor them (visually or via the BMS), there is a tendency for operators to tamper with the controls to leave them open so awareness as to their purpose is required.
For external facing logistics bay openings, heated 'air curtains' can be coupled with the rapid roller shutter doors to further prevent potential contamination ingress.
Construction Phase
Long-term thinking is required from the outset when building an advanced industrial facility. During construction once the building shell and floor is complete, temporary measures such as multi-station boot cleaners, heavy duty carpets and temporary 'wipeable' contamination control mats can be implemented coupled with adequate pest control, 'butcher style' strip curtains, zipwall systems, aperture sealing and regular floor scrubbing to minimise the clean-up operation later on.
Prior to building completion, a 'builders deep clean' is required including difficult to reach areas at height, i.e. above duct work, pipes, wall bracing etc. It is then highly advisable to follow this up with a subsequent 'professional deep clean' prior to equipment installation - as once fit out commences, accessibility will be hindered. Floor scrubbing and mopping should continue throughout the installation phase. Subsequent cleaning operations, including 'white glove' cleaning may also be required prior to energisation of critical equipment i.e. switchgear in the case installation work occurred in, around and above them during room readiness activities.
Installation Phase
Once various installation contractors arrive on scene, they should be briefed on the cleanliness expectations. 'Non-slip' overshoe provision, the requirement for hoovers during dust producing activities i.e. when drilling into the floor, clear eating and drinking rules etc. should be monitored and enforced. It is also beneficial to have a dedicated contractor entrance point via a temporary vestibule system - kitted out with a floor mounted contamination control system designed for larger debris, followed up with a subsequent control mat designed to capture finer debris. It's important to have such mats laid in the direction of foot travel as a number of steps may be required to adequately remove particles.
For enhanced contractor awareness, regular briefings on cleanliness and clear posters encouraging mantras such as 'a clean site is a safe site' is welcome. Particle monitors (0.5, 5, 10-micron measurements) can also be situated around the cleanroom area during installation to illustrate the impact of installation activities. Such monitors can form part of a permanent set-up during operations and linked to an alarm system.
A note on welfare facilities during construction and installation. Keep them clean, well-stocked and in order. If the respective teams don't feel valued, this will soon manifest itself in the quality of work and respect given to the building.
Polished, sealed concrete floors provide the necessary protection for mission critical spaces and mitigate the risk of airborne concrete dust throughout the lifetime of the facility.
Non-marking tyres on MEWPs coupled with tyre covers (socks) can also be implemented to prevent vehicular dirt ingress via installation vehicles. Waste sacks can also be fitted to scissor lifts to maintain a good cleanliness culture from the outset. MEWP maintenance can be performed externally.
Operational Launch & Ramp-Up Phase
Bringing people into the equation - there are a few considerations once launch & ramp-up operations begin. Firstly, pedestrian contamination control matting can be placed at high footfall access points into your clean areas, i.e. when entering from comparatively 'dirty' areas such as manufacturing halls, internal canteens / rest areas and when entering from outside via changing rooms.
Important note: It is crucial to survey any doors that open outwards onto these kinds of mats to ensure they don't impede opening or closing. Particularly an issue for fire doors.
The above can be combined with 'non-slip' overshoe stations for visitors entering cleanroom areas (don't forget to put a chair). Automatic overshoe machines are available for large numbers of personnel. Custom waste receptacles can also be provided with clear graphics for used overshoes. Again, staff awareness is required to ensure the benefits are understood as there is a temptation to take the overshoes for lunch and back again defeating their purpose. As a novelty, hotel style shoe polishing machines can also be fitted to make someone's day a little brighter :)
'Captive' footwear systems can be employed for full-time operators to avoid cross-contamination between areas and contribute to a higher overall cleanliness standard in your cleanroom area. Also, a specialist laundry service can be provided so operative workwear is managed on site.
During routine cleaning activities, cleaning equipment i.e. brushes, mops, etc. specifically designed for cleanrooms should be employed plus the use of lint-free materials i.e. wipes.
In terms of waste management, bin receptacles towed out and in of the facility ideally use a dedicated access point so not to interfere with production logistics. In addition to the vehicular contamination control systems as mentioned - the bins can be weather protected via a custom towable apron and wiped down if necessary, prior to returning inside the building.
We hope you found this article useful!
If you are looking for professional cleanroom engineering support relating to your next industrial mega-facility design & build project...please reach out to us!
Contact — Biyat Energy & Environment Ltd (biyatenergyenvironment.com)
This article was written by Luay Zayed, Founder' of Biyat Energy & Environment Ltd. A global energy and environmental consultancy specializing in turnkey engineering solutions that protect the environment and improve energy efficiency in the manufacturing & industrial sectors.
