Following Topics to be discussed in this article.
- Scope
- References
- General Requirements
- Test, Adjust and Balance objectives
- Quality Assurance
- Testing Organization
- Qualification of the Balancing Personnel
- Coordination & Project Communication
- Testing
- Submittals
- TAB instruments
- HVAC equipment preparation and testing
- Adjusting and balancing
- Testing and Balancing Report
- Recommendations and Conclusions
Testing, Adjusting and Balancing (TAB) of HVAC System
1. Scope
This article covers Test, Adjust And Balance procedure and report for HVAC systems.
2. References
Reference is made in this article to the following documents.
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
ASHRAE 70 Method of Testing for Rating the Performance of Air Outlets and Inlets
National Environmental Balancing Bureau (NEBB)
Procedural Standards for Testing, Adjusting and Balancing of Environmental Systems
Steel Metal and Air Conditioning Contractors’ National Association (SMACNA)
HVAC Systems Testing, Adjusting and Balancing
Fire, Smoke and Radiation Damper Installation Guide for HVAC Systems
3. General Requirements
3.1 Notwithstanding any pre-qualification carried out by Company, it is the CONTRACTOR responsibility to satisfy that HVAC system performance conforms to design documents.
3.2 Failure of contractor to comply with the requirements of this standard may result in system rejection without any responsibility on company.
3.3 Work under this section shall be accomplished using personnel thoroughly experienced and certified in the application of the established procedures and using instrumentation as recommended.
3.4 Work under this section shall be performed in accordance with established procedures contained in the reference standards.
4. Test, Adjust and Balance objectives
4.1 The following are main objectives of HVAC Test, Adjust and Balance (TAB) procedure:
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- Balancing air and water (if applicable) flow rates.
- Measuring electrical performance of HVAC equipment
- Verifying HVAC control system components operation
- Room/Building pressurization
- Room/Building Temperatrure & Relative Humidity Measurements f. Measuring sound and vibration levels
4.2 The above tests shall be accomplished by:
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- checking installations for conformity to design.
- measurement and establishment of the fluid flow rates.
- Recording and reporting the results.
4.3 HVAC systems shall not be deemed acceptable until the approval of TAB final result report. Corrective actions done to HVAC systems in order to correct the setting to acceptable limits and shall not be carryout on additional expense to COMPANY and/or delay in project completion schedule.
4.4 The contractor shall furnish all labor/agent necessary to run the TAB and obtain required information. Any test not considered satisfactory to COMPANY shall be performed again in the presence of COMPANY representative to ascertain compliance with this standard. Any adjustments, such as changing of sheaves, and belts to the equipment as called for in the standard shall be done without additional expense to COMPANY.
5. Quality Assurance
5.1 TAB shall be performed by independent agency either member in AABC or certified by NEBB.
5.2 HVAC equipment manufacturer or installation Contractor may not perform the TAB procedure or part of this procedure without approval from COMPANY.
5.3 TAB reports shall use standard formats of the AABC or NEBB and shall be approved by COMPANY prior to the TAB execution.
5.4 After the installations are complete, systems shall be operated in the presence of a COMPANY Representative to demonstrate satisfactory performance.
5.5 TAB works shall not proceed until work has been installed completely and system is in operation for at least 72 hours and there shall be no latent residual work still to be completed which can affect the TAB procedure or results.
5.6 Work scheduled for TAB shall not proceed until systems are clean and free from debris, dirt and discarded building materials.
6. Testing Organization
The Testing Adjusting and Balancing (TAB) work for HVAC installation shall be accomplished by a Balancing Contractor who has:
6.1 An organization/ firm that has met and maintains all the requirements of NEBB or AABC for firm certification for Testing Adjusting & Balancing and is currently certified. A certified firm shall employ at least one NEBB or AABC certified Supervisor/ Professional in full time management position.
6.2 An organization whose regular activities include testing, adjusting and balancing environmental systems;
6.3 An organization which utilized only regular employees experienced and trained specifically in the total balancing of environmental systems; and
6.4 An organization which has satisfactorily balanced at least five systems of comparable type and size.
6.5 An organization which is approved by COMPANY to perform TAB of HVAC systems.
7. Qualification of the Balancing Personnel
7.1 Qualified personnel regularly employed by the Independent Testing and Balancing Organisation who are experienced and trained specifically in the total balancing of environmental systems; and are supervised by a certified NEBB or AABC Supervisor/ Professional who is employed in full time management position by the organization.
7.2 Qualified personnel who have satisfactory balanced at least five (5) systems of comparable type and shape
7.3 In the event the Contractor fails to comply with the above provision, COMPANY Representative reserves the right to designate another professional testing agency at no additional cost to COMPANY.
8. Coordination & Project Communication
8.1 The Qualified Supervisor of TAB firm shall be responsible for directing technicians in performing the work.
8.2 The qualified supervisor of TAB firm shall report on progress made towards work completion as and when required by COMPANY, as well as report and address the problems encountered during work to provide sufficient inputs to the cause of the problem and recommend possible solutions.
9. Testing
9.1 Contractor shall submit its proposed Testing Adjusting and Balancing program for air and/or water balancing to COMPANY Representative at least two weeks prior to the scheduled test.
9.2 If the Testing Adjusting & Balancing program document suffices the project TAB requirements, COMPANY will issue it’s non-objection to the personnel and instrumentation required, and the scope of the TAB program.
9.3 All tests shall be conducted in the presence of COMPANY Representative unless he finds it acceptable not to do so. COMPANY representative shall be given two (2) days notice before any test is to be conducted.
10. Submittals
10.1 The TAB procedure submittal shall be prepared as specified in this section on NEBB or AABC forms prior to execution. The following shall be included but not limited to:
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- Complete copy of applicable NEBB or AABC forms and diagrams. b. TAB agency profile including official documents
- c. Copy of valid certifications or membership d. List of pervious jobs
- Technical staff qualification and certifications ..etc.
- f. List of tools and instrument supported with valid calibration certificate.
10.2 After executing the HVAC TAB a result report signed and stamped by TAB agency and by COMPANY witness or representative during the execution period shall be submitted for review and approval. Copy of approved design drawings shall be included as part of the submittal to show all published ratings or capacity data, air flow diagrams, performance data and other pertinent data to support the review of the report.
10.3 Re-submittal may be required whenever the report is not acceptable to COMPANY.
11. TAB instruments
11.1 Instrumentation type, quantity and accuracy shall be as defined in AABC national standards or NEBB procedural standard.
11.2 All instruments used in test, adjust and balance procedure shall be calibrated within last six months all certification shall be included in procedure submission. Calibration of all instrumentation requiring calibration shall be traceable to current National Institute of Standards and Technology standard or equivalent.
11.3 Equipment, instrumentation and materials necessary for cleaning, testing and balancing shall be provided with no additional cost to COMPANY.
11.4 Minimum Instrumentation: TAB firm certified supervisor shall provide appropriate TAB instruments that meet the minimum requirement as specified by the standards prepared by the technical societies and associations like AABC and NEBB with the approval of COMPANY.
11.5 Range and Accurancy: TAB firm shall possess instruments for each function and range as per standards prepared by the technical societies and associations of AABC and NEBB. Each instrument shall have been specifically designed to meet the minimum range and accuracy criterion as per the specified standards.
12. HVAC equipment preparation and testing
12.1 Equipment or appurtenances that may be damaged by the test pressure shall be bypassed. HVAC systems shall be tested and the air and water systems balanced.
12.2 Duct and piping systems shall be thoroughly cleaned before the various systems are covered or concealed.
12.3 Exterior walls, exterior doors, and windows shall be tested for air leak tightness. A pressurization test unit consisting of a package fan, manual dampers, and an air volume measuring device shall be used for determining the quantity of air leakage when area is required to meet the Purging and Pressurizing requirements. Exterior doors shall be closed during this test. If air leakage is found to exist, leakage shall be sealed in an approved manner and testing shall be repeated. Sealing methods shall be approved by COMPANY.
12.4 Ductwork leakage test shall be conducted to minimize the leakage as specified in Duct Design chapter of ASHRAE fundamental Handbook.
12.5 Chilled water piping shall be tested hydrostatically to a pressure of 860 kPag for four hours. Pressure loss shall not exceed 2 percent of the test pressure during the test period. Pressure pumps used to apply pressure shall be disconnected during the test duration.
13. Adjusting and balancing
13.1 Necessary steps shall be taken to adjust the fan pulley/sheaves (replacement with smaller size may be required) to provide the necessary air quantity as required for the balancing of the systems.
13.2 Air flow and hydronic piping (if applicable) systems shall be tested, adjusted and balanced to quantities indicated on the drawings or specified, and performance of equipment proven as to compliance with specified performance. Specified performance shall include delivered air quantities, pressures, speed, power input, vibration and sound generated or attenuated. Copies of final test data shall be kept at the job site and delivered to COMPANY at the time of final inspection.
13.3 Supply, return, and exhaust air ductwork shall be balanced in accordance with referenced documents and the following:
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- Total system air quantities shall be balanced by adjustment of fan speeds. Branch duct air quantities shall be adjusted by volume control dampers. Air terminal volume control devices shall be used to regulate air quantities of supply, return and exhaust only to the extent that adjustments do not create objectionable air turbulence and noise. Main air balancing by means of terminal volume control device shall not be acceptable.
- Air systems shall be adjusted so that each air outlet is within 10 percent of the indicated value on the plans, and each air handling unit and fan is within 5 percent of the figures scheduled on the plans. Belt drives shall be adjusted, replaced, or both, as necessary to provide the required air volumes. COMPANY shall be notified of adjusting and may elect to be present during the balancing operation.
- A certified report shall be submitted to COMPANY, outlining the procedure used to balance the systems, the types of measuring devices used, and a complete log indicating the quantity of air supplied by each diffuser, register, or grille and the quantity of air exhausted from each exhaust register or grille.
14. Testing and Balancing Report
14.1 The report shall be submitted in approved NEBB or ABCC forms and shall be submitted to COMPANY for approval. The data sample below are for guide only and approved forms shall be used.
14.2 Air Handling Units
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- Total Air Flow Rate – m3/s
- Outside Air Flow Rate – m3/s c. Return Air Flow Rate – m3/s d. Total Static Pressure – Pa
- Discharge Static Pressure – Pa
- f. Filter Static Pressure Differential – Pa Fan RPM
- Motor RPM
- i. Motor Operating Full Load Amps j. Motor Operating kW (HP)
- k. Outside Air Temperature – °C Dry Bulb (DB)/°C Wet Bulb (WB)
- l. Return Air Temperature – °C DB/°C WB m. Entering Air Temperature – °C DB/°C WB n. Leaving Air Temperature – °C DB/°C WB o. Refrigerant Suction Pressure – Pa
- Refrigerant Suction Temperature – °C
- Water Entering/Leaving Coil Temp. – °C
- r. Water Flow Rate – m3/s s. Coil Pressure Drop – Pa
14.3 Air-Cooled Condensing Unit
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- Saturated Suction Pressure/Temperature – Pag/°C
- Compressor Operating Amperes – each compressor c. Air Entering Condenser – °C DB
- Air Leaving Condenser – °C DB
- Total Air through Condenser – m3/s
- f. Condenser Fan Motor Operating Amperes – each fan g. Condensing Pressure/Temperature – Pag/°C
14.4 Air-Cooled Liquid Chiller
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- Saturated Suction Pressure/Temperature – Pag/°C
- Discharge Pressure/Temperature – Pag/°C
- c. Compressor Operating Amperes – each compressor
- Oil Pressure/Temperature – Pag/°C
- Air Entering Condenser – °C DB
- f. Air Leaving Condenser – °C DB
- Total Air Flow Through Condenser – m3/s
- Condenser Fan Motor Operating Amps – each fan i. Condensing Pressure/Temperature – Pag/°C
- j. Water Entering Evaporator Temperature – °C DB k. Water Leaving Evaporator Temperature – °C DB l. Total water flow – m3/s
- m. Water Pressure drop – Pa
14.5 Package A/C Units
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- Inlet Duct Static Pressure – Pa
- Outlet Duct Static Pressure – Pa
- c. Entering Air Temperature – °C DB/°C WB d. Leaving Air Temperature – °C DB/°C WB e. Suction Pressure – kPa
- f. Suction Temperature – °C
- Condenser Refrigerant Pressure – kPa
- Condenser Refrigerant Temperature – °C
- i. Oil Pressure – kPa
- j. Oil Temperature – °C
- k. Condenser Fan rpm
- l. Condenser Fan Air Flow – m3/s
14.6 Pumps
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- Total Water Flow – m3/s b. Static Head – kPa
- c. Pressure drop – Pa Motor RPM
- Impeller Size
- f. Motor Operating Amperes g. Motor Operating – kW
- % Efficiency (Minimum)
14.7 Fans
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- Total Air Flow – m3/s
- Total Static Pressure – Pa
- c. Discharge Static Pressure – Pa Suction Static Pressure – Pa
- Fan RPM
- f. Motor Operating Amperes g. Motor Operating – kW
14.8 Electric Duct Mounted Heating Coil a. Heat Output – kW
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- Air Flow Rate – m3/s
- c. Entering Air Temperature – °C
- Leaving Air Temperature – °C
15. Recommendations and Conclusions
Recommended correction actions by TAB agency shall be stated in the report for the CONTRACTOR to follow without delay. In case any conflict on the correction action between TAB agency and CONTRACTOR, COMPANY shall provide resolution and shall be implemented immediately.