Equipment location common operation

Most of the chemical fume hoods considered here consist of a cabinet or enclosure set at waist level (above a table or storage cabinet) that is connected to a blower located above the hood or external to the hood through a duct system. The cabinet has an open side (or sides) to 2illow a user to perform work within. A movable transparent sash separates the user from the work. Most chemical fume hoods have a sill that functions as an airfoil at the work surface below the sash. The connection to the blower might be by use of a v-belt, or it may be direct drive. This allows provision of a smooth flow of air with minimal turbulence. In some installations, axially mounted blowers are used, especially if multiple hoods are ducted into a common blower. Baffles located in the rear of the cabinet provide control of the air flow patterns, and can usually be adjusted to provide the best air flow around the experiment or procedure being performed. Many chemical fume hoods are equipped with air flow indicators, low flow monitors and alarms, and differenti2d pressure sensors to allow the user to operate safely. The major types of chemical fume hoods include the standard/conventional, W2dk-in, bypass, variable air volume, auxiliary air, or ductless types. Additional types include snorkels and canopies that are portable. Each type must be understood to be operated most efficiently within specifications (see the section below on safe operation). 

Thermocouples and wire leads require constant maintenance due to wire breaks and malfunctioning thermocouples. In most cases, the root cause of the problem is easy to determine. When a thermocouple loses continuity the instrument panel typically reports either an open circuit or a very negative temperature. A more difficult but also common problem occurs when the control thermocouple is not located close to the heating element on the control system. In this case, it is possible for the thermocouple to be influenced by another heated control zone while allowing its control zone to operate at temperatures that can be either very hot or very cold. Such cold conditions can cause the polymer to solidify in the transfer line while a hot condition can cause the resin to degrade. During the installation and startup of new equipment, it is important that the thermocouples are matched with the proper controller and control zone. 

Level 1 changes consist of site changes within a single facility where the same equipment, standard operating procedures (SOPs), environmental conditions (e.g., temperature and humidity) and controls, and personnel common to both manufacturing sites are used and where no changes are made to the executed batch records, except for administrative information and the location of the facility. 

Aseptic Assembly. The first interventions performed are those that prepare the equipment for the aseptic process. This entails the removal of sterilized materials and equipment items from the autoclave and transfer to the location where the aseptic processing activities will be performed. This is ordinarily followed by the assembly/preparation of the equipment for the process. Aseptic assembly in which sterilized parts are removed from protective materials, installed and adjusted in preparation for the aseptic process are perhaps the most potentially invasive of all of the activities which must be performed. The operator must be meticulous in their execution of these tasks to prevent the inadvertent contamination of product contact surfaces. Strict adherence to the principles of aseptic technique described earlier is essential. These interventions are a necessary part of every aseptic activity, and it is common to identify the first containers filled as they may be more indicative of potential problems with the aseptic assembly. For this reason, the validation program should include process simulations that include containers filled immediately after the set-up of the equipment. 

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