| Cleanliness Classification | Airborne particle concentration | ISO Class 5, 6, 7, or 8 according to ISO 14644-1 | Determines filtration efficiency, air-change strategy, room layout, pressure relationships, and validation scope. | High |
| Particle Control | Particle size to be controlled | Commonly measured at particle sizes of 0.1, 0.2, 0.3, 0.5, and 5.0 micrometres | Defines the monitoring instruments, sampling plan, and performance criteria required during qualification. | High |
| Temperature | Operating temperature range | Often 18–24°C, subject to process and personnel requirements | Supports product stability, equipment performance, operator comfort, and environmental consistency. | High |
| Relative Humidity | Humidity control range | Often 40–60% RH, subject to material and process sensitivity | Helps control static electricity, condensation, corrosion, material behavior, and product quality. | High |
| Pressure Control | Pressure differential between adjacent areas | Commonly about 5–15 Pa between rooms with different cleanliness levels | Controls the direction of air movement and reduces the risk of contamination entering cleaner areas. | High |
| Airflow Pattern | Unidirectional or non-unidirectional airflow | Unidirectional airflow for critical zones; mixed airflow for many controlled background areas | Influences ceiling coverage, return-air positioning, equipment placement, and cleanroom energy demand. | High |
| Air Changes | Air-change rate | Project-specific; commonly higher for cleaner classifications and greater contamination loads | Must be calculated from room classification, occupancy, equipment heat load, process emissions, and recovery requirements. | High |
| Room Size | Usable cleanroom area and clear height | Based on process equipment, maintenance access, personnel flow, material flow, and future expansion | Prevents overcrowding and ensures that airflow, cleaning, maintenance, and safety requirements can be achieved. | High |
| Process Flow | Personnel and material movement | Separate or controlled routes with defined entry, exit, gowning, staging, and waste-removal points | Reduces cross-contamination risk and determines the number and arrangement of airlocks, pass-throughs, and support rooms. | High |
| Gowning Strategy | Gowning sequence and personnel capacity | Defined step-by-step sequence with capacity based on peak occupancy | Ensures that personnel preparation is compatible with the required cleanliness level and production schedule. | High |
| Material Transfer | Pass-through cabinet or material airlock requirements | Interlocked doors, cleanable surfaces, and transfer procedures appropriate to the contamination-control plan | Supports controlled transfer of components, tools, samples, and waste without compromising room classification. | High |
| Surface Finishes | Wall, ceiling, and floor construction | Non-shedding, smooth, sealed, cleanable, and resistant to chemicals used in the process | Reduces particle accumulation and allows effective cleaning, disinfection, inspection, and long-term maintenance. | High |
| Utilities | Electrical power, process gases, water, drainage, and data connections | Capacity and connection points defined by the equipment list and utility-load schedule | Allows the turnkey provider to coordinate mechanical, electrical, process, and automation interfaces before installation. | High |
| HVAC Capacity | Cooling, heating, filtration, and ventilation load | Calculated from airflow volume, heat generation, occupancy, outdoor-air requirements, and local climate | Prevents unstable environmental conditions, excessive energy consumption, and insufficient system capacity. | High |
| Monitoring | Environmental and differential-pressure monitoring | Continuous or periodic monitoring based on risk assessment and regulatory expectations | Provides evidence that critical conditions remain within limits and enables faster response to deviations. | Medium |
| Validation | Qualification and acceptance testing | Design, installation, operational, and performance qualification as applicable | Confirms that the completed facility meets defined requirements for airflow, particles, pressure, temperature, humidity, and recovery. | High |
| Safety | Fire protection, emergency access, alarms, and occupational safety | Designed in accordance with applicable local building, fire, electrical, and workplace-safety requirements | Protects personnel and assets while ensuring that safety systems do not compromise contamination control. | High |
| Energy Efficiency | Operating energy demand and heat-recovery opportunities | Evaluate fan energy, filtration pressure drop, airflow reduction strategies, controls, and heat recovery | Cleanrooms can consume significant energy; early optimization lowers operating costs without reducing required performance. | Medium |
| Maintainability | Filter access, equipment service space, cleaning access, and spare-parts strategy | Maintenance routes and service clearances defined before construction | Reduces downtime and allows maintenance work to be performed without unnecessary disruption or contamination risk. | Medium |
| Future Expansion | Scalability of room capacity and building services | Reserve space, electrical capacity, HVAC capacity, and connection points where practical | Allows production growth or process changes without requiring a complete redesign of the cleanroom facility. | Low |
| Project Delivery | Scope boundaries, schedule, budget, and documentation | Clearly defined design deliverables, procurement responsibilities, construction milestones, testing, training, and handover records | Prevents gaps between contractors and provides a single coordinated path from requirement definition to operational readiness. | High |
