ISO Class 7 Cleanroom Standards | Particulate, ACH, Requirements
01 February 2025

ISO Class 7 Cleanroom Standards | Particulate, ACH, Requirements

In accordance with the ISO 14644 standards, ISO Class 7 cleanrooms represent a highly controlled environment that is engineered to maintain specific cleanliness values. The enclosed system encompasses ceiling-mounted fan filter units (FFUs) that generate a continuous supply of HEPA or ULPA-filtered air. In this article, we'll cover top-level considerations and standards for ISO 7 cleanroom design and construction. Additionally, we'll explore general principles for ISO 7 standards including particulate levels, ACH requirements, and equipment-based considerations among several unique applications.

ISO 7 Cleanroom Standards | ISO 14644
ISO 14644 is a set of international standards developed by the International Organization for Standardization, governing various aspects of cleanroom operations such as design, construction, and performance.

ISO 14644-1 delineates air cleanliness in terms of the number of airborne particles per cubic meter at a designated particle size, which for an ISO 7 cleanroom is fewer than 352,000 particles sized 0.5 μm or larger per cubic meter of air.

ISO 14644-2 addresses the monitoring requirements to provide ongoing compliance, which is essential for quality assurance in critical processes carried out in the cleanroom environment.

ISO 14644-3, provides methodologies for testing and verifying that the cleanroom meets ISO 7 parameters. Tests encompass airflow, filter leakage, pressure difference, and containment leak tests, among others.

In addition, ISO 14644-4 outlines design and construction attributes, which must be adhered to for ISO 7 cleanrooms. This includes specifications for HVAC systems, pressure differentials, and materials that comply with the need for low particulate shedding. Lastly, ISO 14644-5 stipulates the operational protocols required to maintain ISO 7 classification, including personnel behavior and training, cleaning procedures, and documentation.

ISO 7 Cleanroom Definition
ISO 7 is a classification within the ISO 14644-1 framework that delineates air cleanliness in terms of the number of airborne particles per cubic meter at a designated particle size. For ISO Class 7 cleanroom certification, particle counts must maintain allowable particle counts for each per cubic meter of air:iso 6

  • ≥ 0.5 µm particles, maximum count is 352,000
  • ≥ 1.0 µm particles, maximum count is 83,200
  • ≥ 5.0 µm particles, maximum count is 2,930

ISO 7 Cleanroom Air Changes
Air changes per hour (ACH) serve as a fundamental metric to quantify the efficacy of cleanroom HVAC systems in removing dirty air and replacing it with fresh, HEPA-filtered air. renewing the cleanroom air, thereby minimizing particulate and microbial contamination.

Typical ISO 7 cleanroom air handling systems may require anywhere from 60 - 90 air changes per hour. Most cleanroom builds will fall toward the lower threshold of this range.

ISO 7 Gowning Room Design
ISO 7 cleanroom designs will usually include an independent gowning room partition for donning and doffing cleanroom garments. Designated gowning spaces simplify the execution of gowning procedures and help to reduce operator-born contamination that could otherwise enter the clean room via hands, feet, clothing, or equipment.

Gowning rooms are typically specified at one ISO class higher than the primary production rooms. Therefore, most ISO class 7 cleanrooms will request a gowning room with ISO class 8 air quality, but this is not always the case.

In facilities that fall under USP chapters 797/800 standards, cleanroom requirements are specifically described for ante-rooms, buffer rooms, and primary engineering controls (PECs). Buffer rooms must meet at least ISO Class 7 air quality. Ante-rooms providing access to positive pressure buffer rooms must meet at least ISO Class 8 classification.

ISO 7 Cleanroom Pass-Throughs & Gowning Equipment
Cleanroom pass-through systems allow for equipment and supplies to pass in and out of the cleanroom from adjacent areas.

Pass-through chambers feature interlocking doors to ensure that the chamber can only be opened and accessed by one operator at a time. This interlock mechanism disables access to the other side of the chamber while the other door is open, and prevents uncontrolled airflow between rooms of divergent pressure.

Pass-Through Chambers feature internal architecture with obstruction-free, featuring lipless edges and radius corners. These design elements not only facilitate easier cleaning but also minimize areas where contaminants may accumulate.

We offers end-to-end solutions for cleanroom-specialized equipment including tables, chairs, workstations, garment racks, and storage solutions to facilitate compliance and ease during the gowning process. For projects of any size, Terra specialists can help you design, configure, and outfit your gowning room based on your specific facility layout and cleanliness requirements.