cleanroom
[Image courtesy of SERVICOR]
There are over500,000 detectable earthquakes each year, with major earthquakes—those with a magnitude of 7.0 or higher— occurring monthly, often causing severe damage and even casualties. Global industries are becoming increasingly reliant on cleanroom environments, with an expected5.9% demand increase expected by 2030. To maintain strict control over air quality, temperature, and humidity, the challenge of ensuring that these environments stay undisturbed during natural disasters, like earthquakes, is critical. With their potential to disrupt structural integrity, airflow, and equipment, earthquakes can quickly compromise the very essence of what makes a cleanroom effective: cleanliness and contamination control.
Seismic-rated cleanrooms are becoming increasingly important, and sometimes required, particularly in earthquake-prone regions such as California, Oregon, and Washington. In this article, we highlight the six considerations cleanroom professionals need to keep in mind when building a seismic-rated cleanroom and why these precautions are vital for both operational safety and regulatory compliance.
The challenges of maintaining a controlled environment
The purpose of a cleanroom is to minimize particle contamination, creating a controlled environment that factors in everything from temperature regulation to air filtration. Earthquakes bring significant vulnerabilities to cleanroom systems including air filtration, HVAC, and structural integrity. When any, or all of these, aspects are compromised, the delicate, controlled environment can quickly become contaminated, jeopardizing both operations and the safety of those working within it.
Nearly75% of the U.S. population lives—and works—in regions that are susceptible to potentially damaging earthquakes including southern Alaska, California, Hawaii, and parts of the Mississippi Valley. “One of the largest challenges in building a seismic-rated cleanroom is accounting for the impact of a seismic force and a shifting foundation, while maintaining the precise environment required for cleanroom operations,” said Mark Zabala, senior sales manager atSERVICOR byNortek Air Solutions. “Designing a cleanroom to survive seismic forces isn’t enough. Cleanrooms in these areas need to be designed to survive and maintain their cleanroom classification level in order to remain operable.”
The importance of seismic standards
Seismic standards are put in place to ensure that buildings and structures can withstand the forces of an earthquake. During an earthquake, not only is the structural integrity of the building at risk, but so is the safety of employees, as well as the quality of the processes occurring within the cleanroom.
In areas with frequent seismic activity, such as California, the risk of earthquake-related damage is significant, and the potential consequences of structural failure are severe. “California sits in a seismic zone 4 and experiences about two to three major earthquakes each year,” said Zabala. “SERVICOR was designed in 1983 and our cleanrooms have been through at least 90 major earthquakes in California alone.”
From the destruction of expensive equipment to contamination risks, or even the injury of personnel, a poorly designed cleanroom could expose an organization to catastrophic losses. The seismic rating of a cleanroom ensures that both the building and its contents are secure in case of an earthquake.
Understanding the key components of a seismic-rated cleanroom
A seismic-rated cleanroom considers not just the structure itself, but the elements inside the cleanroom that could pose a danger if shifted around in a seismic event. “The frame of the cleanroom is only one consideration,” explained Zabala. “Fan filter units (FFUs) and air handling units (AHUs) are critical to ensuring cleanrooms operate at the required class level but they add significant weight to a cleanroom. While that extra weight is housed and accounted for through the ceiling grid, the addition of hundreds—potentially thousands of pounds—shifting above employees and critical processes poses a significant danger.
“In 2013, a 7.0 earthquake hit a customer’s 6,000 square foot ISO 7 SERVICOR Hardwall Cleanroom in Mexicali, Mexico,” explained Zabala. “Their cleanroom sustained zero damage to the cleanroom itself or the process inside of it. Since that event, the customer has purchased over 100,000 square feet of additional SERVICOR cleanrooms because they know the system will help protect their operations.”
Key considerations when designing and constructing a seismic-rated cleanroom
Cleanroom operators must consider the potential impact of earthquakes and ensure that they are partnering with cleanroom experts with experience building and maintaining seismic-rated cleanrooms. Here are six key considerations cleanroom owners should consider before constructing:
1. Seismic zone requirements
Before designing a cleanroom, it’s crucial to understand the seismic requirements specific to its future location. In the U.S., there are four seismic zones based on the level of seismic activity, with zone 4 attributed to the highest risk zone.
Pacific coast states California, Oregon, and Washington are in high seismic zones, requiring their cleanroom structures to be built to withstand earthquakes of considerable size. Specifically, California requires all cleanrooms to meet seismic zone 4 standards. With the likelihood of a magnitude 8 or larger earthquake hitting California in the next 30 years rising from4.7% to 7.0%, designing for seismic activity continues to be more important than ever.
2. Load distribution and structural integrity
Weight load distribution is critical in seismic-rated cleanrooms. Each piece of equipment should be appropriately anchored to ensure that it does not shift, tip, or fall during seismic activity. “When we design a cleanroom with steel ceilings, likeSERVICOR Modular Cleanrooms, we eliminate the need for hangers, which allows us to design a self-supporting cleanroom and ultimately achieve a seismic rating,” said Zabala. The welded ceiling grid modules cradle the often heavy ceiling components including lights, ceiling tiles, and FFUs. These features create the sturdy structure, while minimizing additional load and strain to the existing structure.
“One of the reasons that modular cleanrooms are so popular is because they allow for so much flexibility,” said Zabala. “Flexibility allows for cleanroom owners to change the footprint of the cleanroom in the future. With a seismic-rated cleanroom, we are building a self-supported cleanroom. We’ve leveraged welded steel in our SERVICOR frames and ceiling system to retain all the benefits and features that customers need in a modular system, while ensuring that the room is self-supported to achieve a seismic rating.
A self-supporting cleanroom system does not rely on support from the building’s structure and is designed with floor anchors to ensure stability, minimizing the risk of a cleanroom being damaged or collapsing during an earthquake. This approach prevents unnecessary load on the building’s existing infrastructure and reduces the potential for cascading failures.
3. Design requirements by seismic zone
The four U.S. seismic zones have different design requirements so understanding where the cleanroom will live and how it will function is important. For instance:
Seismic zone 4is the highest level of seismic activity and includes California and certain parts of Oregon and Washington. It has the strictest requirements including reinforced structures, with adequate load-bearing capabilities for ceiling-mounted equipment, walls, and partitions.
Seismic zone 3is attributed to areas with moderate seismic activity and requires adequate earthquake-resistant design measures.
Seismic zone 2is designated to areas with low to moderate seismic activity, meaning that while fewer design requirements may exist, they can ensure operational safety for employees.
“One of the major advantages to using a modular cleanroom, like SERVICOR, is the flexibility to change the size and location of the cleanroom,” explained Zabala. “With some cleanrooms, if you were to move it across seismic zones, you would need to adjust the design and structure of the cleanroom to meet the seismic zone requirements. Connecting with your cleanroom manufacturer to understand if their cleanrooms are engineered to perform anywhere, or if future retrofitting is needed, will ensure that you have the flexibility your business needs in the future.”
4. Structural engineering and certification
One of the key steps when building a seismic-rated cleanroom is collaborating with licensed structural engineers to perform thorough calculations and provide certification. Structural engineers are critical in evaluating the seismic impact on cleanroom systems and ensuring that the design meets local codes and regulations.
Engineers will conduct detailed analyses to ensure that the cleanroom’s materials and systems are designed to absorb and distribute seismic forces evenly, reducing the risk of structural failure. “Once the drawing process is complete, plans are sent to a structural engineer to confirm compliance,” explained Zabala. “If any modifications are required, they’ll be submitted for customer approval and proceed with manufacturing.”
5. Safety protocols and training
Developing a seismic-rated cleanroom is the first step but the impact of people within the cleanroom also needs to be accounted for. Ample safety protocols and employee training is important to ensure that anyone in the cleanroom understands the unique risks that earthquakes can present, as well as proper protocols of keeping contaminants out of the cleanroom.
6. Proper maintenance and inspections
Maintenance and inspections are standard requirements to ensure that a cleanroom is operating at the required class level/ISO level. Cleanrooms are dynamic environments with equipment that needs continual monitoring, in fact the lack of appropriate monitoringand documentationis one of the most common pitfalls cleanroom operators have. With modular cleanrooms providing ultimate flexibility, any future upgrades or reconfigurations need to adhere to seismic rating standards.
“A seismic-rated cleanroom isn’t just about surviving an earthquake,” concludes Zabala. “It’s ensuring that operations can continue as smoothly as possible. With the right partner, materials, systems, and planning, you can create a space that is as resilient as it is clean.”
With an increase in cleanroom demand, designing for structural resilience and maintaining the integrity of cleanroom systems, even during a power outage, are important to minimizing contamination within a cleanroom. With experienced cleanroom partners and proper planning, cleanrooms can withstand seismic eventsandmaintain required cleanliness levels.
About Mark Zabala
With 19 years of experience in the cleanroom industry, Mark Zabala’s comprehensive skill-set spans field installations, site coordination, cleanroom design, and engineering. Mark has been involved with IEST as a voting/contributing member in several working groups, as well as an active member of ISPE, ASHRAE, and SEMI. His extensive background enables him to gather critical insights in his role as senior sales manager at Nortek Air Solutions CleanSpace that lead to the successful implementation of cleanroom systems for customers and partners alike.