Below is the best method statement that covers closed control units installation testing and commissioning on a project site.
The mechanical site engineer / site supervisor will give necessary instructions to tradesmen (pipe fitters & duct installers) and provide necessary approved construction/shop drawings of latest revision along with coordinated layouts for ccu installation works.
Following tools shall be required before starting the CCU installation work:
- Pipe cutting & threading machines
- Standard mechanical Tool Box
- Mobile scaffolding
- Measuring Equipment’s
- Spirit Levels
- Applicable PPE including Safety Harness
- Cutting tool for cutting the insulation
- Appropriate brush for applying the adhesive
- Tools for painting
- Lifting equipment’s like winches, hoists
General CCU Installation Requirements
All workers to attend safety induction conducted by main contractor and given specific training on the safe installation methods.
Install Closed Control Units and Accessories as indicated on the approved shop drawing and as per site requirements.
The Site Supervisor/Foremen will also check that proper tools and equipment are available to carry out the work and are in compliance with contract specification.
Site Supervisor also explains the tradesmen regarding safety precautions to be observed during the installation of closed control unit.
Installation Procedure for Closed Control Units
Approved materials for closed control units, will be installed as per approved installation details, approved shop drawings, project specifications, site conditions, manufacturer’s recommendations and approved mockup.
The CCU will be transferred from the stores to the work area, taking into account the make, model, and capacity & labeling/tag #.
This will ensure the correct CCU is installed at the correct location.
Cut loose all banding (if applicable) from skid but do not remove the skids until the unit is shifted to the exact installation location/area.
The supervisor / foreman will ensure the subject areas are ready to receive the CCU. The base, concrete plinths & rubber pads etc. must be completed prior to the installation of the CCU.
Arrange the installation of any CCU according to the approved drawing, making sure of the units’ correct location and orientation, having access for the fan & motor, filter, and valve package (where applicable accordingly) with sufficient access space for operation & maintenance purposes.
Anti vibration isolators/ neoprene pads will be installed as required to support the Close Control Units as per manufacturer’s recommendations and the project specifications.
Check the level of the unit using spirit level & firmly tighten the anchor bolts.
Depending on accessibility and site conditions, some CCU’S may be required to be shifted in sections, these sections must be aligned & jointed firmly, ensuring proper gasket in-between sections is used.
Ensure nuts & bolts are tightened properly.
Electrical & Mechanical Connections & Supports
Condensate drains piping are directly connected to the nearest drain pipe or waste pipes (floor drains), that shall be provided by respectively 1:100 slopes or as per approved shop drawings and have proper insulation to avoid any damage of condensation drip that may occur.
At every change of direction of the condensate drain pipes, clean outs will be provided.
The supports will be installed as per the approved shop layout drawings and approved support details and specifications of the project.
Make sure that no parts of CCU will be obstructed by pipes and valves, locations and elevations of these accessories will be as per approved layout drawings.
Connect ductwork to the unit cabinet using flexible connections of full size of the equipment & ductwork connections to avoid the transfer of vibration as indicated on the approved drawings.
Make sure that competent electrician installs the field wiring, controls & earthing of the equipment.
Ensure the tightness of all connections & terminals to the recommended torque levels.
Attach & fix the identification labels (including air and water flow directions), safety & warning signs at the location shown on the approved drawings ensuring compliance with specification requirements.
Ensure calibration certificates shall be provided for all instruments used.
CCU power wiring connections will be done by competent electricians as per approved shop drawing and manufacturer recommendations.
Control wiring will also be done as per the manufacturer’s recommendations and controls which are applicable and as directed by the control philosophy/sequence of operation.
Care will be taken to provide bypass piping connections to the closed control units and other HVAC equipment’s that needs to be isolated during Water Flushing & Chemical Treatment (WF&CT) of the whole chilled water piping system. Back washing of the coils shall be done as per WF&CT method statement, which shall be submitted separately.
After successful installation, closed control units will be cleaned and covered by polythene plastic for protection as per approved IAQ plan and prior commencement of CCU testing & commissioning.
Closed Control Units Testing and Commissioning Method Statement
The purpose of this hvac testing and commissioning method statement is to define the step by step method to implement the correct practices for the pre-commissioning & commissioning of Close Control Units through the guidelines contained herein so as to ensure that the testing job execution complies with the project requirements and serves the intended function to satisfactory level of the client.
Tools Required
- Digital Multimeter
- Clamp Meter
- Tachometer
- Anemometer
- Flow Hood Kit
- Digital Thermometer
- Psychrometer
Quality Control at Site
In general, it shall be ensured by site mechanical engineer that product manufacturer’s recommendations are followed all the time, main contractor shall further oversee the CCU precommissioning and commissioning activity as per the approved method statement for startup and commissioning of closed control units.
Closed control units shall be tested and commissioned by manufacturer or supplier representatives while respective contractor shall monitor the work progress.
CCU Commissioning Procedures
Mechanical checks:
Carefully inspect the unit and check the installation is complete and approved.
Check and ensure the shipping bolts / clamps are removed.
Also check tightness of all nuts / bolts, screws, fasteners, rubber vibration isolators etc. as applicable
Check all the chilled water/refrigerant piping is completed, pressure tested and approved.
Also make sure that duct work connections are complete and approved as per approved shop drawings / details.
Ensure the cooling coil and all interiors of CCUs are clean and free from foreign materials.
Check the fan rotates freely by hand and the direction of rotation on initial startup.
Ensure the provision of cleanout as per the drawings.
Make sues correct slope of the drain tray in the direction of drain pipe connection.
Perform the drain water flow test to ensure the water is draining out completely to nearest drain point.
Electrical Checks:
Ensure the connected cables have been tested and verify the test reports.
Check all terminations are complete and tightened as required.
Make sure that the cabling / wiring including grounding is complete and dressed neatly, including thermostat connections.
Ensure all electrical identification and labeling is complete.
Check the isolator is fixed close to the closed control units for emergency power shutdown purpose.
Closed Control Unit Start Up and Testing
Check the line voltage before energizing the power.
Switch ON the power.
Verify for the proper operation of the closed control units motor.
Measure the current drawn (amperage) by closed control units and record the same on provided forms.
Verify proper operation of the thermostat, supply air temperature and humidity sensor.
Check for any abnormal noise and vibration on startup. Rectify as / if required.
After about an hour’s operation, check that all nuts / bolts, screws, clamps etc. are tight and secure.
Measure the total airflow delivered by the Closed Control Unit check against the design flow and record the same in the approved format.
Record the CCU data in the commissioning formats.
Ensure compliance to the manufacturer’s instructions as applicable.
Conduct the CCU performance test in the presence of consultant/client and get approvals on prescribed formats.
Health and Safety Requirements
Safety precautions shall be followed as per the established Project Safety Plan.
Only experienced and skilled technicians shall be engaged for carrying out startup and commissioning of closed control units.
Safety guards shall be in place and secured prior to starting up the units.
Cable test reports shall be verified prior to energization.
Appropriate warning signs and warning tapes shall be placed during start up and commissioning as required.
All PPE shall be worn as appropriate according to the nature of the job.