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The main air handler, a hot/cold deck, supplied the air to constant volume mixing <br /> boxes. A pneumatic control system was used for equipment and temperature <br /> control. This system suffered from poor temperature control and poor static <br /> airflow. <br /> In 1994, the Public Safety Building underwent a seismic and mechanical retrofit. <br /> During this retrofit, the design of the air handling systems was changed to double <br /> duct variable air volume (VAV). The heating coil was removed from the main air <br /> handler and replaced by three hot water fan coils. A new heating /cooling air <br /> handler was installed for the jail and a new evaporative cooler with hot water <br /> heating for the gun firing range. The original constant volume mixing boxes <br /> where converted with static air control dampers and actuators for Direct Digital <br /> Control (DDC). The air handlers had variable frequency drives (VPD) and a full <br /> DDC system installed. This system continues to experience poor temperature <br /> control, poor static airflow, and poor air distribution. <br /> After the building was returned to service, the City obtained a survey (dated <br /> January 4, 1999) of the HVAC system in an attempt to find and correct the causes <br /> for the system deficiencies. The summary of this report shows that the plant has <br /> enough capacity to heat and cool the building, however, problems such as (but not <br /> limited to) the following were found: <br /> A. Large quantities of the ducting are uninsulated, and some main duct runs <br /> are undersized. There are a number of zones that do not achieve design <br /> airflow requirements. Sections of ducting have pressure drops as high as <br /> 2.0 "wg /100', and others are unsealed or have separated joints. <br /> B. The double duct boxes that where retrofitted are in very poor condition. <br /> C. The main air handling unit return fan and economizer are not in operation <br /> at this time due to the negative effect they have on pressure within the <br /> building. <br /> 3. GENERAL WORK TASKS <br /> 3.1 Investigation <br /> 3.1.1 Project initialization. Initial meeting with City staff. Present a preliminary <br /> project schedule, define and agree on expectations, communication norms <br /> and project roles, and create a project contacts list. <br /> 3.1.2 Cooling and heating load analysis. Perform a computerized cooling and <br /> heating load analysis for the building, based on accepted engineering <br /> standards and industry standards such as the ASHRAE weather data. The <br /> Exhibit A Page 2 of 5 <br /> 6/12/95 TAYLOR/Public Safely nuilding IIVAC System Rehab <br />