Sunday, January 31, 2010

METHOD STATEMENT FOR TESTING, ADJUSTING AND BALANCING OF HVAC SYSTEM..


TABLE OF CONTENTS


1.       Scope of Work .
2.      Definitions and Abbreviations 
3.      References  
4.       Responsibilities .
5.       Safety   
6.       Procedure   
7.       Procedure for Testing and Balancing  
8.       Equipment 
9.       Instruments & Calibration for Testing 
10      Attachments document's details
           
            * SATIP-K-001-12
            * SAIC-K-4041
            * SAIC-K-4042
            * SAIC-K-4043
            * SATR-K-4006


1.               Scope

·         The scope of this document is to define the method to be applied for testing, adjusting & balancing of HVAC Air systems, sub-systems, related equipments and their allied components.

2.           Definition & Abbreviations

 2a. Definition

                      i.        Adjust: To regulate fluid flow rate and air patterns at the terminal equipment, such as to reduce fan speed or adjust a damper.
                     ii.        Balance: To proportion flows within the distribution system, including sub mains, branches, and terminals, according to indicated quantities.
                    iii.        Barrier or Boundary: Construction, either vertical or horizontal, such as walls, floors, and ceilings that are designed and constructed to restrict the movement of airflow, smoke, odors, and other pollutants.
                   iv.        Draft: A current of air, when referring to localized effects caused by one or more factors of high air velocity, low ambient temperature, or direction of airflow, whereby more heat is withdrawn from a person's skin than is normally dissipated.
                    v.        NC: Noise criteria.
                   vi.        Procedure: An approach to and execution of a sequence of work operations to yield repeatable results.
                  vii.        RC: Room criteria.
                 viii.        Report Forms: Test data sheets for recording test data in logical order.
                   ix.        Static Head: The pressure due to the weight of the fluid above the point of measurement. In a closed system, static head is equal on both sides of the pump.
                    x.        Suction Head: The height of fluid surface above the centerline of the pump on the suction side.
                   xi.        System Effect: A phenomenon that can create undesired or unpredicted conditions that cause reduced capacities in all or parts of a system.
                  xii.        System Effect Factors: Allowances used to calculate a reduction of the performance ratings of a fan when installed under conditions different from those presented when the fan was performance tested.
                 xiii.        TAB: Testing, adjusting, and balancing.
                 xiv.        Terminal: A point where the controlled medium, such as fluid or energy, enters or leaves the distribution system.
                  xv.        Test: A procedure to determine quantitative performance of systems or equipment.
                 xvi.        Testing, Adjusting, and Balancing (TAB) Firm: The entity responsible for performing and reporting TAB procedures.
2b. Abbreviations

1.         Clients : Saudi Aramco / Samsung Saudi Arabia
2.         Sub Contractor : Construction and Installation Contractor
3.         TAB Contractor : Commissioning Contractor; 3rd Party of Testing, Adjusting and Balancing (TAB Contractor).
4.         Vendor : HVAC Equipments Manufacturer
5.         CA : Commissioning Authority
6.         CX  : Commissioning
7.         MC : Mechanical Contractor
8.         EC  : Mechanical Conctractor
9.         CC  : Controls Contractor
10.      GC  : General Contractor
11.      CPI : Commissioning,Pre-Inspection Checklist
12.      RFA : Request for Assessment
13.      OMS : Operations &  Maintenance Staff
14.      NEBB : National Environmental Balancing  Bureau
15.         TQ : Technical Queries         

3.            References

    
·         ASHRAE Commissioning Guidelines
·         ASHRAE Standards
·         National Environmental Balancing Bureau Procedural Standards (NEBB)


4.            Responsibilities


·         Installation contractor to confirm the complete operational readiness of the HVAC system to allow the pre-commissioning task and checklist to be performed.

·         Installation contractor shall verify the installation conformity to the  design drawings in accordance with the specifications and approved Technical Query.
·         Installation contractor to provide operation and maintenance manuals. Manual contents are defined as  the manufacturer’s data on  the HVAC equipment installed and must include the following:
1)      The  manufacturer’s method for Pre-Commissioning, TAB and performance Testing of the HVAC equipment, systems, subsystems and its components  for correct operation under actual load conditions.
2)      The manufacturer’s recommended tolerance for  maximum and minimum operating conditions; Flow, RPM, etc.; proper locations; and  unit at design flow rate.
3)      The  recommended correction to allow adjustment of air terminals.
4)      A list of spare parts, identification numbers and diagrams of their pressure drops for air systems.
·         Commissioning contractor to inspect the system after site readiness notification to determine that  the system is actually complete and ready to be started for  TAB activities.
·         TAB contractor to field verify A & K factors for applicable air terminals, if required.
·         TAB contractor to test & adjust the minimum and maximum air flows as required for the project.
·         TAB contractor ensures all devices must be calibrated and provided with test certificate reports which shall be submitted to QC prior to start the TAB activities.
·         TAB Contractor ensures that all equipments shall be delivered as per Design & Specification.
·         TAB contractor to make all field adjustments required for balancing and  prepares certified report.
·         TAB contractor to prepare a final TAB report and documentation of final system & component  balance conditions.
·         Commissioning contractor to document any deficiencies prior to performance  testing, which prevent the system  from being properly verified and any conditions caused by a deficiency and give them the responsible representative for correction.

5.          Safety
 
·               Every TAB team member has a responsibility to work in a safe manner, not to interfere with anything provided for their safety and to report any hazardous situation without delay to their immediate supervisor on the project site.
·               Safety is everybody’s responsibility. Each has a duty to the other to maintain a working environment that is, so far as is practicable, free from hazards and  risk of  injury to personnel. The elimination of  injury to employees and a reduction in  the amount of  damage or loss of the equipment or materials must be of utmost concern to all agencies involves in  the TAB process for HVAC system.
·               Where it is impossible to provide a hazard-free environment, TAB contractor accepts the responsibility to provide protection, advice and  information that will help combat particular  hazards.

6.        Procedures

6.1 Equipment Start Up

·         After pre-inspection is complete, equipment shall be systematically started up according to the approved start up forms procedures by Luberef.
·         Representatives of equipment  vendors shall be present to observe  and to assist in the start up process.
·         Start up of all HVAC air side equipment and systems shall be done as per manufacturer’s recommendations.

6.2 Preparation
A.  Prepare a TAB plan that includes strategies and step-by-step procedures.
B. Complete system readiness checklists and prepare system readiness reports. Verify the     following:
                      I.    Permanent electrical power wiring is complete.
                    II.    Automatic temperature-control systems are operational.
                   III.    Equipment and duct access doors are securely closed.
                  IV.    Balance Damper, Fire Damper, Combination smoke fire dampers are opened.
                    V.    Isolating and balancing valves are open and control valves are operational.
                  VI.    Ceilings are installed in critical areas where air-pattern adjustments are required and access to balancing devices is provided.
                 VII.    Windows and doors should be closed so indicated conditions for system operations can be met.

6.3  Testing & Balancing

Testing and  Balancing shall be conducted after start up check by TAB agency/contractor and shall be conducted as per the following:
·         Latest version of NEBB procedural standards and the project specification with approved TQs if applicable.
·         Instruments used by the TAB for taking measurements shall comply with  the specifications  listed in table enclosed with this document.

7.       Procedure of Testing, Adjusting and  Balancing

TAB shall be done as per latest NEBB procedural standards:

·         In  order to achieve the purpose of Testing, Adjusting and Balancing of HVAC system the above referred method shall be applied.
·         To ensure that the basic procedures are followed in TAB processes, the following  general procedures are described.


7.1. General Testing Procedures for Air Systems

These procedures shall be applied to all measurements encompassed in TAB to complete the report forms applicable as per the attachments.
1.        Perform testing, Adjusting and balancing procedures for each system according to the procedures contained in Air Conditioning Systems "NEBB's Procedural Standards for Testing, Adjusting and Balancing of Environmental Systems".
2.        Cut insulation, ducts, pipes, and equipment cabinets for installation of the test probes to the minimum extent necessary to allow adequate performance of procedures. After Testing, Adjusting and Balancing, close probe holes and patch insulation with new materials identical to those removed. Restore vapor barrier and finish according to insulation Specifications for this Project.
3.        Prepare test reports for both fans and air outlets. Obtain  manufacturer’s outlet  factors and recommended testing procedures. Cross check the summation of required outlet  volumes with required fan  volumes.
4.        Determine the best locations in main and branch ducts for accurate duct-air flow  measurements.
5.        Check air flow patterns from the outdoor-air louvers and dampers and the return and exhaust air dampers through the supply-fan discharge and mixing dampers.
6.        Locate start–stop and disconnect switches, electrical interlocks, and motor starters.
7.        Verify that motor starters are equipped with  properly sized thermal protection.
8.        Check dampers for proper position to achieve desired airflow path working condition
(open and close).
9.        Check for airflow blockages (Filters).
10.      Check condensate drains for proper connections and functioning.
11.      Check for proper sealing of air-handling-unit components.
12.      Mark equipment and balancing device settings with paint or other suitable,  permanent identification material, including damper-control positions, valve position indicators, fan-speed-control levers, and similar controls and devices, to show final settings.
13.      Report deficiencies discovered before and during performance of TAB  procedures. Observe and record system reactions to changes in conditions. Record default set points if different from the indicated values.

7.2. Procedures for Constant-Volume Air System

1.    Adjust fans to deliver total indicated airflows within the maximum allowable fan speed  listed by fan  manufacturer.
2.    Where sufficient space in ducts is unavailable for Pitot-tube traverse measurements, measure airflow at terminal outlets and inlets and calculate the total airflow.
3.    Measure outlet static pressure as far downstream from the fan as practical and upstream from restrictions in ducts such as elbows and transitions.
4.    Measure static pressure directly at the fan outlet or through the flexible connection.
5.    Measure inlet static pressure of single-inlet fans in the inlet duct as near the fan as possible, upstream from the flexible connection and downstream from duct restrictions.
6.    Measure inlet static pressure of a double-inlet fans through the wall of the plenum that houses the fan.
7.    Measure static pressure across each component that makes up an air handling unit, rooftop unit and other air handling and  treating equipment.
8.    Report the cleanliness status of filters and the time static pressures are measured.
9.    Measure static pressures entering and leaving other devices, such as sound traps, heat-recovery equipment and air washers under final balanced conditions.
10.  Do not make fan-speed adjustments that result in motor overload. Consult equipment manufacturer’s about fan speed, safety factors. Modulate dampers and measure fan motor amperage to ensure that no overload will occur. Measured amperage in full cooling, full heating, economizer and any other operating mode to determine the maximum required brake horsepower.
11.  Adjust volume dampers for main duct, sub main ducts and major branch ducts to  indicate airflows within specified tolerances.
12.  Where sufficient space in sub main and branch ducts is unavailable for Pitot-tube traverse  measurements, measure airflow at terminal outlets/ inlets and calculate the total airflow for that zone.
13.   Measure static pressure at a point downstream from the balancing damper and adjust volume dampers until proper static pressure is achieved.
14.  Remeasure each sub-main and branch duct after all have been adjusted. Continue to adjust sub-main and main branch ducts to indicate  airflows within specified tolerances.
15.  Measure terminal outlets using direct-reading hood or outlet manufacturer’s written instructions and calculating factors.
16.  Adjust air outlets and inlets for each space to  indicate airflows within  specified tolerances of the indicated values. Make adjustments using branch volume dampers rather than collar dampers.
17.  Adjust each outlet in the same room or space to within specified tolerances of indicated quantities without generating noise levels above the limitations prescribed by the Contract Documents.





7.3. Flow Measurements Procedure

7.3a Procedure for Pitot Tube Traverse and Air Flow Hood

To accomplish repeatable traverse measurements, take the measurements in a specific measured pattern. There are two acceptable methods.

i.      The equal area method.
ii.     The log/Tehebycheff method.
iii.    Locate a traverse position in a straight section of duct.
iv.   Duct size must not change in a traversed section.
v.    Face the Pitot tube into the air stream and parallel to the air stream before taking measurements. Convert velocity pressure to FPM velocity before averaging. Take traverse measurements in actual conditions and actual cubic feet per minute (ACFM). Correct ACFM to standard CFM (SCFM) when specified. Verify that the velocity measurements are acceptable. AMCA Publication 203-N 90 states that a  traverse plane is suitable for flow measurements if  more than 75% of the velocity pressure readings are  greater  than 1/10 of the maximum  velocity measurements.
vi.   Airflow Hood is a multipurpose electronic air balancing instrument primarily used for efficiently taking direct air volume readings at diffusers and grilles. Designed to fit over standard sized grilles and diffusers, this digital Balometer feature is a 24” x 24” hood opening. The hood channels air flow through the base to directly measure air volume in cubic feet per minute. Weighing less than eight pounds, the Balometer allows single operator use and reduces user fatigue. It features a detachable micro manometer for increased flexibility in multiple measurement applications. Offering durable operation, this lightweight, ergonomically designed Airflow capture hood kit saves time and money by combining multiple measurement tools into one package. A professional tool for airflow commissioning and balancing with quick and simple hood changes. Measuring range from 50 to 3500 m3/h / -2500 Pa to 2500 Pa, handles integrated in the measuring unit. Calculation of average airflow with easy-access button, display of data sets, recording and downloading of datasets on PC, via LPCF / DATALOGGER software. 


7.3b. Procedure for Electric Power  Measurenent

Electrical data measurements  include the  following:

i.      Amperage readings on each phase.
ii.     Voltage readings on each phase.
iii.    Balanced and unbalanced KW readings, when applicable
iv.   Power factor, when applicable.
v.    As additional data as required to verify performance.
vi.   Take motor KW measurements to verify horsepower before recommending the changing of  motors.
vii.  Comply with proper safety procedures, including the use of electrical gloves when taking power readings on approved forms that correspond to the equipment being tested.

7.3c. Procedure for Rotational Speed Measurements

i.      Verify that the vibration Isolators are properly installed.
ii.     Select the type of appropriate instrument required for the test.
iii.    Remove the  belt guards on each unit with  the unit off.
iv.   Verify that the drive alignment is correct.
v.    Verify that belt tension is correct.
vi.   Turn  the unit on and with adequate clearance, measure RPM
vii.  Take final RPM measurements with the unit at balanced conditions.
viii. Measure RPM at each speed mode operation.
ix.   Take motor RPM measurements to verify the motor load. RPM changes with load on  the  motor, which affects the fan RPM.
x.    Reinstall the belt guard with the unit off.
xi.   Comply with proper safety procedures, including preventing the loose clothing or hair from being caught in the rotating components.
xii.  Record all rotational test measurements on approved forms that correspond with the equipment tested.
xiii. Use a photo tachometer or strobe when access will not allow a direct reading tachometer to be used.
       
7.3d. Procedure for Static Pressure Measurements

i.      Take the fan suction pressure in the eye of the fan wheel inlet or fan inlet plenum. Do not include inlet vanes.
ii.     Take the fan discharge pressure at the discharge of the fan outlet. If the fan has an  outlet damper as part of the fan, do not include the damper. Fan pressure data, along with the fan RPM, motor brake horsepower, and fan curve can be used to determine the fan performance and system effect.
iii.    Measure the external static pressure in the unit supply outlet duct and unit return air inlet duct. The  external unit pressure equals the supply outlet duct pressure minus the return inlet duct pressure.
iv.   Measure the pressure losses across each related device in the unit, i.e., filters, heating coils, cooling coils, damper section, etc.
v.    For static controlled systems, measure and record the static pressure at the control static pressure sensor location.
vi.   Compare and review static pressure measurements against the manufacturer’s submittal data for differences that could affect the system performance.

7.3e. Procedure for Basic Temperature Measurements

i.      Use thermometers with  current calibration records and compare them to each other for a matched set at the time of the test.
ii.     Psychrometer/Digital Thermometer to the point required for accurate measurements according to the manufacturer’s directions.
iii.    The test location for a single point measurement should be at the average fluid temperature (air or water). If the  average temperature cannot taken at one location, then take multiple points in a traverse fashion and record the average. Test wells in pipes,  must protrude into the pipe to allow for accurate measurement (approximately 50% of the pipe diameter). Add heat  transfer fluid to wells for accurate temperature measurements.
iv.   Avoid effects of radiation, i.e., avoid measuring  next to an electric heating coil element.
v.    Allow time for the thermometer to reach equilibrium with the fluid (air or water)  being measured. Take periodic readings without removing the thermometer from the  fluid  until the  temperature remains essentially constant more than a 30 second time period. When using a 0.1” F thermometer and conducting a field performance or witness test, once the thermometer has reached equilibrium, record three readings at five second intervals and use the average as the station reading.
vi.   In HVAC applications, avoid surface temperature measurements unless no other method is available. The surface temperature will not be the true fluid temperature, and this  method has a great deal of error. If a surface temperature is used, give great care to cleaning the pipe so there is good contact with the thermometer and the pipe. Insulate over the thermometer and pipe to reduce the ambient air effect on the temperature readings. This method is best suited to determine the temperature drop between a supply pipe and a return pipe on coils or fin  tube radiation.
vii.  Take the wet bulb temperatures in airstreams and in ambient air using an appropriate thermometer with a cotton wick installed over the sensing portion of the thermometer. The wick should have extra length to help retain moisture during the measurement period, and  may be extended to a water reservoir for a prolonged measurement. The wick should be wetted with distilled water for performance or witness testing. Clean, fresh water is adequate for more field testing as the error, if any, is  not  significant. The airflow over the wick shall be approximately 1,000fpm for wet bulb  testing.

7.3f  Procedure for Vibration Measure Measurements.

                i.        Perform vibration measurements when other building and outdoor vibration sources are at a minimum level and will not influence the Measurements of equipment being tested.
               ii.        Turn off equipment in the building that might interfere with testing.
              iii.        To Restrict people from occupying areas where human activity may affect accuracy of measurements.
             iv.        Exterior vibration sources; i.e. trains, roadway traffic, adjacent construction activities, etc.
              v.        Attach and secure the vibration transducer in accordance with the latest edition of the NEBB Procedural Standards for Measurement of Sound and Vibration.
             vi.        Measure and record, on all pumps and fans over 3 HP, and all chillers and compressors over 5 HP, at discrete frequencies or in 1/3 octave bands as follows:
a.    Discrete vibration levels from 1 to 200 Hz in 1 Hz increments, or
b.    In each 1/3 octave band from 12.5 Hz to 200 Hz.
            vii.        Measure and record equipment vibration, bearing vibration, equipment base vibration, and on building structure adjacent to equipment. Record velocity and displacement readings in the radial vertical, radial horizontal and axial planes, where measurements can be performed safely.

7.3g  Procedure for Sound Level Measurements.

i.      Close windows and doors to the space.
ii.      Perform measurements when the space is not occupied, or when the occupant noise levels from other spaces in the building and outside are at a minimum, or do not affect Sound readings.
iii.    Clear the space of temporary sound sources so unrelated disturbances will not be
      Measured. Turn off all sound sources (personal computers, printers, fax machines, etc.) in the space that may affect sound readings.
iv.    Positional sound level instrument during measurements to achieve a direct line-of-sight between the sound source and the sound-level meter.
v.    Take sound measurements at a height approximately 48 inches above the floor and at least 36 inches from a wall, column, or any other large surface capable of altering the measurements.
vi.   Take sound measurements in dB (linear or flat), with the slow time constant, in the octave bands from 31.5 to 8000 Hz.
vii.   Take sound measurements with the HVAC systems off to establish the background  levels and take sound measurements with the HVAC systems operating. Calculate the difference between measurements. Apply a correction factor depending on the difference and adjust the measurements.
viii. Sound testing in all occupied space horizontally and vertically adjacent to all.
ix.    Perform sound testing at 10% of locations on the project for each type of the following spaces. For each space type tested, select a measurement location that has the greatest anticipated sound level. If testing multiple locations for each space type, select at least one location that is near and at least one location that is remote from the predominant sound source.
1.    Private office.
2.    Open office area.
3.    Conference room.
4.    Auditorium/large meeting room/lecture hall.
5.    Classroom/training room.
6.    Patient room/exam room.
7.    Sound or vibration sensitive laboratory.
8.    Hotel room/apartment.
9.    Library open space.
10.  Public areas (such as lobbies, hallways, break rooms).
x.    Perform sound testing in all spaces with a design criterion of NC or RC 25 or  as per Client  Specification.

8.           Equipment Testing


8.1. Air conditioning units {Air Cooled Condensing Unit (ACCU), Air Handling Unit(AHU), Package Unit(PU), Split Unit(SU), Fan Coil Unit(FCU), Chemical Filtration Unit(CFU) and Exhaust Fan (EF) } : As per the application forms in latest NEBB Procedural standard.
8.2 Air Outlet: As per the applicable forms in  latest NEBB Procedural standard.


9.           Instruments & Calibration for Testing

·         TAB instrumentation shall comply with the specification of Table-4 Section 4 of NEBB Procedural Standards, Seventh Edition and Quantity, Accuracy, and Calibration.
·         In case of any conflict between the above measurements and NEBB standards, precedence shall be given to the NEBB Procedural Standards.

10.         Attach following documents

·         SATIP-K-001-12  (Testing, Adjusting and Balancing (TAB) of HVAC System)
·         SAIC-K-4041   (Review of HVAC System Testing Organization Qualifications                                    Including TAB Personel/Technician)
·         SAIC-K-4042   (Review of HVAC System Testing, Adjusting and Balancing Procedures       including Test Equipment and Certificates)
·         SAIC-K-4043   (Final Inspection of HVAC System)
·         SATR-K-4005  (Laboratory Hood Test)
·         SATR-K-4006  (Conduct HVAC System Testing, Adjusting and Balancing)
                           (HVAC System Testing, Adjusting and Balancing Report)

·         Job Safety Analysis (JSA) Or Job Hazard Analysis (JHA).       

Prepared by M.Ajmal Khan.