HVAC system requirements

The HVAC systems require chilled water as a cooling medium to satisfy the ambient air temperature requirements for the plant. The central chilled water system (VWS) supplies chilled water to the HVAC systems and is functional during reactor fiill-power and shutdown operation. 

The elements of a PM plan include periodic inspection, cleaning, and service as warranted, adjustment and calibration of control system components, maintenance equipment and replacement parts that are of good quality and properly selected for the intended function. Critical HVAC system components that require PM in order to maintain comfort and deliver adequate ventilation air include a outdoor air intake opening, damper controls, air filters, drip pans, cooling and heating coils, fan belts, humidification equipment and controls, distribution systems, exhaust fans. 

If the hypothesis or model does not seem to be a good predictor of what is happening in the building, you probably need to collect more information about the occupants, HVAC system, pollutant pathways, or contaminant sources. Under some circumstances, detailed or sophisticated measurements of pollutant concentrations or ventilation quantities may be required. Outside assistance may be needed if repeated efforts fail to produce a successful hypothesis or if the information required calls for instruments and procedures that are not available in-house. Analysis of the information collected during the LAQ investigation could produce any of the following results ... 

An evaluation of the HVAC system may include limited measurements of temperature, humidity, air flow, as well as smoke tube observations. Complex investigations may require more extensive or sophisticated measurements of the same variables (e.g., repeated COj measurements taken at the same location under different operating conditions, continuous temperature and relative humidity measurements recorded with a data logger). 

In the current review, the term effectiveness of air distribution will be used to describe the ratio of the occupied zone area (where thermal comfort and contaminant concentration are within ranges required by standards and codes) to the total occupied zone area. This hygienic criterion allows one to judge how well the HVAC system fulfills its main task—creating thermal comfort conditions and controlling contaminants in the occupied zone. 

The actual noise levels produced by HVAC systems can var) considerably, and it is not possible to generalize the problems that may be encountered. From a safety point of view, it is advisable to start hearing conservation programs for workers. Permanent hearing damage will result when the noise levels exceed 80 dB(A) for a given time period. Whenever possible, it is desirable to control noise pressure levels to meet the requirements of speech communication in this case noise should not exceed 65-70 dB(A). 

Commissioning The process of setting to work an HVAC system in order to meet the operating design requirements. 

To save energy, many HVAC systems employ a mechanism for regulating the flow of outdoor air called an economizer cycle. An economizer cycle takes advantage of milder outdoor conditions to increase the outside air intake and in the process reduces the cooling load on the system. Controlling the rate of flow of outdoor air appears simple, in theory, but often works poorly m practice. The small pressure drop required to control the flow rate of outdoor air is rarely controlled and monitored. Quite often, the damper system used to regulate the airflow is nonfunctional, disconnected from the damper actuators, or casually adjusted by building operators (Institute of Medicine, 2000). 

To provide the guideline for validation of the HVAC system to meet the design qualification requirement and to be capable of operating within established limits and tolerances... 

The following checks may be performed to assure that the HVAC system meets the requirements specified in the contract. 

The mechanical contractor is usually also responsible for providing adequate pressurized water supply, drainage (with special provisions for low-level areas of the closed-loop water system), bypasses, an electrical supply (typically 110 V, 1 phase, but also 3 phase where temporary pumps are required), HVAC system air purge vents, as well as other facilities, such as site access, toilets, security, and equipment handling systems. 

Features of the HVAC system that affect product quality (sterility) and therefore require qualification include... 

Exhaust to nonproduction areas Recirculation of production/laboratory air into nonproduction ( clean ) areas prohibited. Dedicated HVAC systems are required. Air flow away from breathing zone... 

In situations where it is not feasible to depend only on physical barriers, an isolation suite can be designed for working with these materials. Air locks and rooms that have negative differential pressure to the main hall ways are required, as well as HEPA-filtered inlet air and double-HEPA-filtered exhaust air. An uninterrupted power supply should be connected to the exhaust air handler to maintain a negative differential pressure if the suite is in operation during a power outage. If the exhaust air handler fails, all plant air handlers should be programmed to automatically turn off to minimize the potential for a positive differential pressure to develop. Each isolation suite may require a dedicated HVAC system.P l... 

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