How to Plan a Cleanroom Design & Build Project

• All elements of the cleanroom project typically developed by project designer
• Plan should define the design & construction related requirements for products and processes specified by user and facility management
• Cleanroom project team- establish goals, objectives, needs of the project, project scope, technical performance requirements, outline schedule & budget, identify project responsibility
• List of staff-building, environmental, safety, code regulations, good manufacturer practice guidelines
• Consider cost of impact, schedule of design process, milestones
• Risks need to be identified & mitigations planned

Cleanroom Contamination Control Considerations

• All equipment & processes used in cleanroom should be in a matrix listing requirement
• Additional issues that affect the building design and construct ability
• Hierarchy of cleanliness should be specified & contamination control concept should be developed
• Contaminant movement & mitigation need to be analyzed

Cleanroom Site Selection & Services Requirement

• Ground load-bearing capacity
• Ground water and soil toxicity
• Ambient air quality & airborne pollutants
• Availability of utility and services at site versus the required utility and services to determine if additional services or remote connections from adjacent facilities
• Environmental issues
• Site ambient vibration & noise levels determination of their acceptability for the process with or without special treatments
• Ambient electromagnetic fields
• Local zoning ordinances & regulation

Cleanroom Critical Flow Arrangements

• Operations, maintenances and quality personnel need to be consulted throughout the design
• Efficient operation- a systemic design effort to determine functional interdependences adjacencies & efficient flow to minimize the migration of contaminants and to optimize process flow
• Design of personnel flow in and out of cleanroom
• Equipment and materials entering cleanroom must be precleaned and moved through either an airlock or a pass through
• Exposed room surface finish materials must be compatible with the processes in the cleanroom

Cleanroom Facility Design Considerations

• Standard-ISO 14644-1
• The class of airborne particle concentration is specified
• Levels of other cleanliness attributes
• Facility Planning- externally -> environment & community
• Climate, geology, topography, building codes, height, color
• Architectural Planning- internally driven -> engineer requirements, user requirements, quality requirements, corporate standards
• Predesign & Design Activities
• Project profile development
• Expandability
• Flexibility
• Adequacy of space
• Minimization of classified environments
• Impacts to site/environment/community
• Cleaning methods & materials
• Cleanability and accessibility
• Construction Methods
• Standard construction
• Prefabricated construction
• Cleanroom construction materials
• More monolithic, nonporous, non-shedding, easily clean
• Pressurization-door seals->direction of swing
• Vibration-internal/external
• Constructability

General Indoor Design Conditions & Considerations

• Temperature
• Personnel considerations
• Process-related conditions
• Construction materials and temperature specification
• Monitor and control
• Humidity
• Process equipment can add moisture
• Exhaust
• Replacement air should be conditioned before entering the cleanroom
• The greater amount of outdoor air introduced, the higher the cost of conditioning
• Airborne Molecular Contamination
• Makeup Air
• Air handling units (AHU) requires series of filters to remove particles from ambient air
• Filters protect the coils & extend life of HEPA/ULPA filters
• Process Exhaust
• Filtration System-HEPA/ULPA filters typically mounted to ceiling

Indoor Environmental Quality

• Air temperatures, humidity, supply air distribution speed

Outdoor Emission Control & Outdoor Air Intake

• Release of particles, chemical fumes, or microbes

Design for Safety Concerns

• Physical barriers & zone separation to reduce the impact of sudden dispersion
• Zone-or room-based air purge system
• Storage of toxic/flammable material
• Proper egress path design to reduce the exit distance
• Isolation of hazardous materials
• Code requirements
• Security & Access Control- Protect against unauthorized personnel
• Building Codes & Standards- Authority having jurisdiction, international codes, national local codes/standards, OSHA, ADA, EPA, NEC

Cleanroom Testing Terminology

• Airborne Molecular Contamination-AMC
• Coincidence-presence of 2 or more particles
• Colony-forming unit (CFU)
• Condensation nucleus Counter (CNC)
• Diluter
• Functional requirement specification (FRS)
• Macroparticle
• Master plan
• National Metrology Institute (NMI)
• Particle Size Cutoff Device
• Polydisperse Aerosol
• Ultrafire Particle
• Viable Particle

Cleanrooms in Semiconductor & Electronic Facilities

• Facilities need to be flexible, environmentally benign, extendable, reliable and cost-effective
• Wafer & chip are terms used to describe the base manufacturing units
• Wafer-refers to mono-crystalline silicone dishes used to produce integrated circuit devices
• Wafers & chips are produced in a fabrication facility or “wafer fab” or “fab”

HVAC Configuration Cleanroom

• Meet heating & cooling needs- satisfies space air cleanliness requirements with that same system
• Traditionally accomplished air cleanliness- by using high airflow rates
• Challenge is to configure system when airflow rate required by dilution is higher than required heating & cooling load
• A cleaner class cleanroom requires higher airflow rate
• ACH= air changes per hour
• Engineers first calculate airflow rate required to meet heating/cooling load
• Then calculate airflow rate to achieve air cleanliness
• Then use flow ratio to determine best practices
• Airflow streams can either be mixed, diverted or both

HVAC Design for Various types of Pharma Facilities

• Primary means of protection from cross-contamination
• Pharma products in two categories:
• Nonsterile Products-tablets, capsules, liquids, creams & ointments & medical devices noninvasive
• Sterile Products-injected into blood stream by syringe or intravenous catheter, medical devices that are inserted into body
• Two Basic Ingredients:
• Inactive ingredients
• Active ingredients

Clean Design

• Interior surfaces & fitted air delivery systems have some impact on air cleanliness
• For better HVAC
• Corrosion-resistant interior surfaces
• Direct-drive instead of belt-driven fan motors
• Sealed bearings for motors
• Ultraviolet (UV) lights for cooling coils
• Antimicrobial coating on cooling coil drain pans

Design for Redundancy & Reliability

• Redundancy should be provided at level matches process requirements
• Addressed at a component level, multiple fans operating in tandem (fan wall), or at system level with multiple air handlers in parallel operation

Cleanroom Airflow Rate

• Cleanroom height can impact air change rate and air velocity

Cost-Effective Options for Lowering Cleanroom Air Change Rates

• More options are available than using a high air change rate
• Some measures can be used to lower the air change rate requirement
• Selecting equipment, machinery, furniture, and room construction materials with lower particle generation levels
• Pick lowest particle generation as possible
• Isolate and remove High-Concentration Particles generated in the cleanroom
• Enhance surface cleaning protocols to prevent surface particles from turning into airborne particles
• Control particle entry through supply air
• Design return and exhaust air systems effectively for particle exit
• Maintain proper pressurization/no depressurization