| Applicable Cleanroom Classification | ISO 14644-1 classification from ISO Class 8 to ISO Class 5, depending on process sensitivity. | The required class determines airflow, filtration, energy demand, validation scope, and operating cost. | Require a documented particle-risk assessment showing why the proposed ISO class is suitable for each room and process step. |
| Maximum Particle Limits | At 0.5 µm, ISO 5 allows up to 3,520 particles/m³; ISO 6 allows 35,200; ISO 7 allows 352,000; ISO 8 allows 3,520,000. | Particle limits provide an objective basis for comparing design proposals and qualification results. | Ask for classification calculations, sampling locations, test conditions, and the proposed at-rest or operational state. |
| Airflow Strategy | Non-unidirectional airflow is commonly used for ISO Classes 7–8; unidirectional airflow is commonly used for critical ISO Class 5 zones. | Airflow design affects particle recovery, operator protection, heat removal, and energy consumption. | Require airflow visualization, recovery testing, velocity or air-change calculations, and a clear explanation of turbulence-control measures. |
| Typical Air-Change Planning Range | Common early-stage planning ranges are approximately 5–20 air changes/hour for ISO 8 and 30–60 air changes/hour for ISO 7. ISO 6 may require approximately 60–150 air changes/hour, depending on the design. | Higher air-change rates can improve recovery but may increase fan power, filtration load, and operating cost. | Reject proposals based only on a generic air-change number; require performance calculations tied to room volume, heat load, occupancy, and process emissions. |
| Pressure Cascade | A common design target between adjacent cleanliness zones is approximately 5–15 Pa, subject to door operation and process requirements. | Stable pressure relationships help control infiltration and prevent contamination migration. | Request a pressure-cascade diagram, alarm limits, door-interlock logic, and evidence that the cascade remains stable during normal operation. |
| HEPA Filtration | Under EN 1822 classification, H13 filters have a minimum integral efficiency of 99.95% at the most penetrating particle size, while H14 has 99.995%. | Filter efficiency, sealing, installation quality, and replacement access are as important as the nominal filter grade. | Require filter certificates, in-situ leak-test procedures, gasket or gel-seal details, pressure-drop data, and replacement clearances. |
| Temperature and Relative Humidity | Many manufacturing environments specify approximately 18–24 °C and 40–60% RH, but product and process requirements take priority. | Tighter environmental control can increase capital cost, energy use, and validation complexity. | Compare setpoints, allowable operating bands, seasonal performance, humidity-control method, sensor locations, and alarm response procedures. |
| Material and Surface Design | Preferred features include smooth, non-shedding, cleanable, corrosion-resistant surfaces; flush joints and coved transitions reduce contamination traps. | Durable surfaces reduce cleaning time, maintenance interruptions, and long-term contamination risk. | Review panel construction, coating chemical resistance, joint details, impact resistance, cleanability, repair method, and spare-material availability. |
| Monitoring and Data Integrity | A suitable system may monitor particles, pressure differential, temperature, humidity, alarms, access status, and equipment operating conditions. | Continuous or scheduled monitoring supports faster deviation detection and more defensible compliance records. | Confirm audit trails, user access controls, time synchronization, backup policy, alarm history, data export, and retention requirements. |
| Qualification and Commissioning | A complete package commonly includes design review, installation verification, airflow testing, HEPA leak testing, particle classification, recovery testing, and environmental verification. | Turnkey responsibility should extend beyond construction to documented proof that the system performs as specified. | Request a commissioning matrix with acceptance criteria, calibrated instruments, test methods, deviations, corrective actions, and final approval records. |
| Regulatory Alignment | Common reference frameworks include ISO 14644 series, applicable good manufacturing practice requirements, and occupational health and safety regulations. | The correct compliance pathway depends on the product, process, market, and risk profile. | Require a compliance matrix mapping every project requirement to a drawing, specification, test, document, or operating procedure. |
| Energy Efficiency | Energy demand is strongly influenced by airflow volume, fan efficiency, filtration pressure drop, outdoor-air treatment, temperature control, and operating hours. | Optimizing airflow and controls can reduce lifecycle cost without lowering the required cleanliness performance. | Compare annual energy simulations, variable-speed drives, demand-based control, heat recovery where appropriate, standby modes, and filter pressure-drop assumptions. |
| Delivery and Installation Planning | A realistic turnkey schedule should separately identify design approval, procurement, fabrication, site preparation, installation, testing, qualification, and operator training. | Separating these milestones exposes long-lead equipment, site dependencies, and commissioning risks before contract award. | Require a critical-path schedule, procurement assumptions, factory acceptance tests, site acceptance tests, contingency time, and responsibility boundaries. |
| Total Cost of Ownership | Evaluate capital cost together with energy, filter replacement, calibration, cleaning, maintenance, validation, consumables, downtime, and future expansion. | The lowest initial quotation may create higher operating and compliance costs over the facility life. | Request a 10-year or 15-year lifecycle-cost model with stated assumptions, escalation rates, maintenance intervals, and replacement costs. |
| Maintainability and Expansion | Key provisions include service access, filter replacement space, accessible sensors, isolation capability, spare capacity, and modular room or HVAC layouts. | Facilities often need capacity changes, new equipment, or revised workflows during their operating life. | Evaluate maintenance access, shutdown zones, future utility loads, ceiling loading, spare electrical capacity, and expansion interfaces. |
| Training and Operational Handover | Handover should include operating procedures, cleaning methods, alarm response, maintenance instructions, as-built drawings, certificates, and training records. | Correct operation is essential for maintaining room performance after the installation team leaves. | Make final payment dependent on complete documentation, trained operators, accepted punch-list closure, and a defined post-handover support period. |