By Michael Bruce, Filtration group, HVAC
“Making prudent operational and financial
decisions while considering a variety of variables
can be challenging – but it doesn’t have to be.”
Most experts agree that cleanroom design, operation and maintenance is complicated. If your design doesn’t support your processes, you will likely experience lower than expected uptime. When problems don’t surface until after the room is in operation, they are more difficult and costlier to correct. Understanding best practices for meeting the specific requirements for a cleanroom application goes well beyond complying with ISO standards.
Making prudent operational and financial decisions while considering a variety of variables can be challenging – but it doesn’t have to be. Breaking down the steps and learning “cleanroom language” are good places to start. Working with filtration solution experts who can help you consider your Total Cost of Ownership (TCO) can have a positive impact on your bottom line.
Cleanroom technology became relevant in the early 1960s, with aerospace innovations. The first cleanroom standardization occurred in 1963 and were not heavily regulated. Today, an increasing number of industries rely on cleanroom technology and adhere to requirements and standards set in place by the institute of environmental sciences and technology.
Innovations are constantly evolving, and national and international standards help companies regulate practices – an integral part of effective, and consistent, cleanroom technology.
The challenge is to operate cleanrooms that achieve the particulate concentration goals without breaking the bank. When asked to explain their successful cleanroom operations, experts point to TCO. Deciphering the terminology the international Standards Organization (ISO) provides classifications for cleanroom standards. Nine ISO classes help discern the levels of cleanliness which equate to the number of contaminants in the room. The most common classifications of cleanrooms are ISO 7 and Iso 8, which generally require between 5 and 150 changeouts per hour [as a point of reference, a conventional HVAC system makes 2 to 4 changeouts per hour.]
In general, a cleanroom will require the same number of low air returns and HEPA filters. however, just like HEPA filters, air return models differ. It is important to be aware of the quality of the filter to determine its functionality – the number of air returns can be higher or lower than the number of HEPA filters, based on filter capacity. Another important consideration is laminar air flow, commonly referred to as unidirectional. This refers to air that flows in an unimpeded trajectory with a steady velocity. When airflow is not unidirectional, a mixed flow, the movement of air is turbulent, the velocity fluctuates and will result in possible contamination in critical environments such as pharmaceutical manufacturing and medical testing, or lower yields in electronics manufacturing. Cleanrooms come in every conceivable configuration and there are multiple variables to consider. Ultimately, each variable will influence your bottom line. By taking a holistic approach of all costs associated with meeting cleanroom standards it is possible to better balance the Total Cost of Ownership and short and long-term financial goals of the operation. What may appear to be a cost-prohibitive Fan Filter unit (FFu), could end up paying for itself within a few years and sometimes within months.
Calculating TCO leads to the optimization of cleanrooms and helps to optimize operational costs and maximize profits. It also gives you the ability to see the big picture by combining the costs of filtration solutions, installation labor, energy consumption and disposal. Accounting for all costs is the best method for designing cleanrooms and selecting filtration equipment.
TCO = Labor + Filter Solutions + Energy Consumption + Disposal
Deciding which filtration solution is best requires proficiency, data and a command of tco. When it comes to filters, an upgrade in quality will typically increase upfront costs, yet the savings in lower energy consumption will result in greater dollar savings.
Considerations for proper product selection of a fan filter unit and accompanying filter is often driven by the lowest upfront price, but that decision unknowingly costs significantly more money over time. To ensure the proper balance of upfront and long term costs, four primary factors need to be considered when selecting an FFU for a cleanroom. These factors include the cost of energy, the required air changeouts per hour, the available percentage of ceiling space for proper installation, and the height of the cleanroom.
Cost of energy in the united states, energy costs vary greatly depending on the region. For example, energy in the northeast and on the West Coast can cost up to three times that of the midwest. To optimize costs, cleanrooms that operate in locations with high energy costs must include an FFU and filter that are energy efficient, such as the Flowstar VS250 FFU. Compared to its sister products, the Sentinel and the VS100, the VS250 uses 50-67 percent less energy at 90 fpm air velocity.
For FFU installation sometimes, there are physical obstructions above the ceiling of a cleanroom such as the HVAC, electrical, and building structures that do not allow for FFUs to be installed. The lower the available amount of ceiling space for FFUs, a higher flow rate performance is needed from the installed FFUs . FFUs with built-in lighting options like the Flowstar VS100 and VS250 can help manage the ceiling space as well – as higher-end ISO class cleanrooms can require 100 percent of the ceiling to be covered with FFUs.
The higher the ceiling of a cleanroom, the harder the FFUs have to work. Let’s target a 100 air changeout per hour rate in two separate 1,000 sq.ft. rooms, one with an 8-foot ceiling and another with a 12-foot ceiling. Because of the added volume in the second room, to achieve the same air changeout rate you would have to install 50 percent more FFUs or run the same amount of FFUs 50 percent harder, which is even more expensive and will not produce laminar air flow – a critical component in ISO classes 1-5. Air changeouts per hour as you move from ISO Class 8 to ISO Class 1, a higher air changeout rate is needed to achieve the particulate concentrations required. this requires higher flowrates from the selected FFU, or more FFUs altogether.
The list of obstacles and challenges to maintaining a well-operated cleanroom can be lengthy. Inefficient placement of workstations, limitations to space and ceiling height, temperature and climate fluctuations, ventilation issues and financial hesitation all play a role in just how complex it can be. By organizing needs, partnering with quality filtration solution experts, and understanding the up-front costs compared to the payoff over time are essential to operating a successful cleanroom.
Focusing on quality and value will guide decisions regarding the products that are best-suited for cleanroom needs. ultimately, experts agree – understanding TCO is paramount to long-term operational and financial success. Working with filtration solution experts who can help optimize TCO will have a positive impact on the bottom line.