Orange County NC Website
Browse       Search
DocuSign Envelope ID: B94F2D40-3B3C-47A7-86C2-6F1 B4F92C62C <br /> Orange County Emergency Services Building Construction Documents <br /> 2. CL is duct leakage class in cfm/100 sq. ft. at 1-inch w.c., which shall be <br /> a. "6"for rectangular sheetmetal, rectangular fibrous ducts, and round flexible ducts. <br /> b. "Y for round/flat oval sheetmetal or fibrous glass ducts. <br /> 3. P is test pressure, equal to the design duct pressure class rating in inches w.c. <br /> F. Duct Air Leakage Testing (DALT): <br /> 1. Installed ductwork shall be tested prior to installation of access doors, take-offs etc. <br /> 2. All testing shall be witnessed by the engineer or owner's representative. Contractor shall give <br /> the engineer or owner's representative 72 hours' notice prior to testing. <br /> 3. The testing shall be performed as follows: <br /> a. Perform testing in accordance with SMACNA HVAC Air Duct Leakage Test Manual. <br /> b. Use a certified orifice tube for measuring the leakage. <br /> c. Define section of system to be tested and blank off. <br /> d. Determine the percentage of the system being tested. <br /> e. Using that percentage, determine the allowable leakage (CFM)for that section being <br /> used. <br /> f. Pressurize to operating pressure and repair any significant or audible leaks. <br /> g. Re-pressurize and measure leakage. <br /> h. Repeat steps 6 and 7 until the leakage is less than the allowable defined in step 5. <br /> 3.08 DEMONSTRATION <br /> A. Training <br /> 1. Train the Owner's maintenance personnel on troubleshooting procedures and testing, <br /> adjusting, and balancing procedures. Provide four(8) hours on site training. Review with the <br /> Owner's personnel the information contained in the Operating and Maintenance Data <br /> specified in Division 1 and Section 23 01 00. <br /> 2. Schedule training with the Owner through the Engineer with at least 7 days prior notice. <br /> 3.09 COMMISSIONING <br /> A. Perform prerequisites prior to starting commissioning activities. <br /> B. Fill out Prefunctional Checklists for: <br /> 1. Air side systems. <br /> C. Furnish to the Commissioning Authority, upon request, any data gathered but not shown in the final <br /> TAB report. <br /> D. Re-check minimum outdoor air intake flows and maximum and intermediate total airflow rates for <br /> 50 percent of the air handlers plus a random sample equivalent to 50 percent of the final TAB <br /> report data as directed by Commissioning Authority. <br /> 1. Original TAB agency shall execute the re-checks, witnessed by the Commissioning Authority. <br /> 2. Use the same test instruments as used in the original TAB work. <br /> 3. Failure of more than 25 of the re-checked items of a given system shall result in the rejection <br /> of the system TAB report; rebalance the system, provide a new system TAB report, and <br /> repeat random re-checks. <br /> 4. For purposes of re-check, failure is defined as follows: <br /> a. Air Flow of Supply and Return: Deviation of more than 10 percent of instrument reading. <br /> b. Minimum Outside Air Flow: Deviation of more than 20 percent of instrument reading; for <br /> inlet vane or VFD OSA compensation system using linear proportional control, deviation <br /> of more than 30 percent at intermediate supply flow. <br /> c. Temperatures: Deviation of more than one degree F. <br /> d. Air Pressures: Deviation of more than 10 percent of full scale of test instrument reading. <br /> e. Sound Pressures: Deviation of more than 3 decibels, with consideration for variations in <br /> background noise. <br /> 5. For purposes of re-check, a whole system is defined as one in which inaccuracies will have <br /> little or no impact on connected systems; for example, the air distribution system served by <br /> one air handler or the hydronic chilled water supply system served by a chiller or the <br /> condenser water system. <br /> E. In the presence of the Commissioning Authority, verify that: <br /> PDC Project 18102 TESTING, ADJUSTING, AND 23 05 93- 5 <br /> 12/17/2018 BALANCING FOR HVAC <br />