Areas of application
Cleanrooms, Food Technology, Pharmaceutical and Semiconductor Technology
Objective
Modern production methods place increasingly stringent demands on the production environment, including air quality. Concepts and measurements developed by ILK Dresden ensure that these requirements are met, verifiably and in a documented manner
Description
To verify qualification and acceptance during the commissioning of HVAC systems in cleanroom and service areas, qualification and acceptance measurements are typically performed for air temperature, relative air humidity, air velocity, sound pressure level, illuminance, differential pressure relative to the cleanroom reference pressure, flow visualization, filter leak test, cleanliness class, recovery time, and turbulence level. Conducting these measurements requires precise preparation and planning as early as the construction and installation phase. The qualification and acceptance of the HVAC systems with respect to the aforementioned measurement parameters, as well as of the cleanrooms and adjacent service areas, is carried out in accordance with the guidelines DIN EN ISO 14644-1 and VDI 2083-3. To verify the intended function of the ventilation system, measurements of supply air velocities for the terminal filters in accordance with VDI 2083-3 are also necessary. Calibrated measuring instruments compliant with the DaKKS standard are used for these measurements.
The leak test on supply air filters is performed by scanning the filter surfaces, seals, and edges at a scan speed to be determined in advance. A leak is detected if the permissible limit particle concentration is exceeded beneath the respective measurement point as the probe moves. In cleanrooms and return air areas, particle measurements are performed to verify the specified cleanroom classes ISO 4 to 7 (corresponding to FED Standard 10, 100, 1000, 10000) under normal operating conditions of the HVAC system without production equipment or personnel. The measurement points for determining the particle counts in the room air are calculated based on the square root of the area in accordance with DIN EN ISO 14644-1, with multiple measurement points arranged diagonally throughout the room and in critical areas, such as near doors. The recovery time 100:1, also known as the cleaning efficiency, is determined from the change in particle concentration over time using the indirect method for the required number of measurement points.
