• The story of Commissioning in Greece. Our office has a lot of experience since 2002, year of "Olympic Games" Facilities Construction.

  • Static Completion?

  • Planning: When?

  • HVAC Optimization: How?

  • Tunning a HVAC system?

  • Fault detection: How?

  • ISO 50001 EnMS: How?

  • Building Automation and Control Systems PM Time allocation.

Copyright 2019 - NICHOLAS A. CHAZAPIS

 BAS DEMONSTRATION AND ACCEPTANCE

   1. Prior to acceptance, the control system BAS will undergo a series of performance tests, to verify operation and compliance with this specification.

   2. These tests will occur after the Contractor has completed the installation, started up the system, and performed systems TAB.

   3. The tests described to be performed in addition to the tests that the contractor performs as a necessary part of the installation, start-up, and debugging process and as specified in the “Control System BAS Checkout and Testing”. The engineer will be present to observe and review these tests. The engineer will be notified at least 10 days in advance of the start of the testing procedures.

   4. The approved checklists and forms will be completed for all systems as part of the demonstration.

   5. The contractor will provide at least two persons and will demonstrate actual field operation of each control and point for all modes of operation including day, night, occupied, unoccupied, fire/smoke alarm, seasonal changeover, and power failure modes. The is to demonstrate the calibration, response, and action of every point and system. Any test equipment required to prove the proper operation will be by and operated by the contractor.

   6. As each control input and output is checked, a log will be completed showing the date, Technician’s initials and any corrective action taken or needed.

   7. Demonstrate compliance with sequences of operation through all modes of operation.

   8. Demonstrate complete operation of operator interface and work station client / server PC's.

2. CX stamp


 DETAILED PERFORMANCE PRESENTATION

The following items to be demonstrated:

a. DDC / BAS loop response. The contractor will supply trend data output in a graphical form showing the step response of each DDC / BAS loop. The test will show the loop’s response to a change in set point, which represents a change of actuator position of at least 25% of its full range. The sampling rate of the trend will be from 10 seconds to 3 minutes, depending on the speed of the loop. The trend data will show for each sample the set point, actuator position, and controlled variable values. Any loop that yields unreasonably under-damped or over-damped control will require further tuning by the Contractor.

b. Demand limiting. The contractor will supply a trend data output showing the action of the demand limiting algorithm. The data will document the action on a minute-by-minute basis over at least a 30-minute period. Included in the trend will be building kW, demand limiting set point, and the status of sheddable equipment outputs.

c. Optimum start/stop. The contractor will supply a trend data output showing the capability of the algorithm. The change-of-value or change-of-state trends will include the output status of all optimally started and stopped equipment, as well as temperature sensor inputs of affected areas.Interface to the building fire alarm system.

d. Operational logs for each system that indicate all set points, operating points, valve positions, mode, and equipment status will be submitted to the architect/engineer. These logs will cover three 48-hour periods and have a sample frequency of not more than 10minutes. The logs will be provided in both printed and disk formats.

Any tests that fail to demonstrate the operation of the system BAS, will be repeated at a later date.

The contractor will be responsible for any necessary repairs or revisions to the hardware or software to successfully complete all tests.


 Acceptance

 1. All tests described above, will have been performed to the satisfaction of the engineer and owner, prior to the acceptance of the automatic control system (BAS), as meeting the requirements of completion stage. Any tests that cannot be performed due to circumstances beyond the control of the contractor, may be exempt  from the completion requirements if stated as such, in writing by the engineer. Such tests will then be performed as part of the warranty.

2. The BAS system will not be accepted until all forms and checklists are completed as part of the Demonstration and submitted.

 

 cx process3


 Demand Limiting:

 

a. Most BAS have a demand limiting algorithm, which can help to maintain the maximum power demand for a building below a set target. This feature helps to minimize maximum demand charges paid to utility companies.

b. Typical demand limiting feature, which predicts the future power demand based on the actual rate of increase of building demand and switches off (sheds) loads to ensure that the set demand limit is not exceeded. Similarly, the feature also normally allows the switching on (restoring) of loads when the demand drops.

c. In general, the demand limiting algorithm calculates the amount of load to be shed or restored and then sheds loads up to the cumulative load required to be shed. If there is an option to shed more than one load, the algorithm will shed loads based on set priority, where loads with lower priority will be shed before shedding loads with higher priority.

d. If there are multiple loads with the same priority, the load that has been shed the least amount of time will be shed first. In this feature, other parameters, such as maximum and minimum off-time for each load, can be set based on operational requirements.


 Optimal start-stop:

 

a. The optimal start-stop algorithm available on most building automation systems (BAS) can predict how long a building or space will take to reach the desired temperature based on the variables that affect it, such as outdoor air temperature, indoor space temperature, and building thermal characteristics.

b. This algorithm can be used to start the AHUs (and chillers/boilers) at the latest possible time to achieve the required space conditions before the space is occupied.

c. Similarly, at the end of the day, the algorithm can help to shut down the cooling or heating plant at the earliest possible time.


Operating Trend Logs:

 

a. Trend logging is a feature that allows recording of selected parameters at preset intervals of time. The feature can be used to log the value of parameters such as temperatures, flow rates, electrical power, and cooling demand. The recording interval can be set from one minute to about two hours.

b. The trend data can be used for various functions, ranging from trouble shooting to identifying energy saving opportunities.

c. An example of the usefulness of the trend logging feature in BAS when it shows the trend data for chilled water supply temperature, which indicates that it exceeds the set point temperature after 12:00 noon, while another trend shows that the condenser water supply temperature exceeds the maximum design value after 11 a.m. indicating that the high condenser water temperature may be the cause of the chillers not being able to meet the chilled water temperature set point.

d. The trend logging feature can also be used for trouble shooting by trending multiple parameters. For example, if a chiller frequently trips, trending of related operating parameters, such as condenser water and chilled water flows and temperatures, may help to identify the cause as low flow or high condenser water temperature.


 Connected building Commissioning (CBCx) - Smart Commissioning

 

a. An automated whole building diagnostics tool (CBCx), a software program that takes a top-down approach to diagnostics to detect excess energy consumption of the whole building and its major system.

b. Smart Commissioning describes a specific application of building data analytics, referred to as connected building commis­sioning, that is significantly enhancing the construction-phase commissioning process and showing improved outcomes for the building owner and occupants. Onsite walk-throughs, systems checklists, and equipment-by-equipment testing are being augmented with high-resolu­tion, real-time data monitoring, automated performance testing, and fault detection analytics that programmatically test and characterize equipment and systems failures.

c. These new processes have allowed for rapid, thorough, and repeatable testing of building systems and for more transparent and reliable testing results. Discussed here is the integration of these new processes into the exist­ing new construction commissioning framework with California Institute of Technology. CBCx specifically targets both the pre-functional and functional testing period, where the greatest opportunities for improve­ment and largest payoffs in terms of budget, time, and added quality assurance reside.

d. CBCx tools offer a greatly enhanced pre-functional test period. The alternative to the documentation-heavy approach of traditional pre-functional testing is to inte­grate analytics software to all equipment that is being controlled by the building’s central automation system (or other networked systems when possible, e.g., light­ing, fire and life safety). In this way, every setpoint, sensor and command point for all equipment can be trended, monitored, and analyzed as a system. Having this data available upfront, immediately after equipment startup, allows the commission­ing engineer to validate whether systems are online, and at least nominally operational.

2. CX stamp 

iaq chaz upd

  

iaq chaz Wolf

 

iaq chaz Wolf2

 

iaq chaz2

 

iaq chaz3

 

 

 

 

 

 

 

 

20.7.2016 MBCx

Commissioning the BAS

 

Commissioning of building systems is a process that verifies whether the operational building, that is delivered not only meets the requirements of the building owner, but also the intent of the design.

Successfully demonstrating that a building’s Building Automation System (BAS) is operating correctly is a key component of the process led by the commissioning authority (CxA) in the functional performance testing phase.

However, in order for testing to be successful, a number of activities must be performed with specific processes followed, verifying that all elements are in place and are working together to support a successful demonstration.

During the construction phase, these activities and processes can include a review of in-progress equipment installation, verification that adequate air and water flows meet the required heating and cooling capacities, and documentation of complete equipment installation including all trades before final confirmation that the HVAC system and related controls are performing according to owner requirements and design intent.

The HVAC system, like many other building systems, is operated by a BAS that functions according to a combination of automatic and manual inputs. The BAS is responsible for controlling a number of individual elements so that they work in concert and function as a system. Modern controls systems are highly sophisticated and complex even if the intent of this complexity is internal—so that the net result to the operator is simplicity. The complexity is due to the hardware that makes up the components of the automation, the controls theory, the logic that monitors current conditions and predicts the most appropriate response, and the sequences of operation that are defined by the specifying engineer to provide functionality, comfort, and efficiency of design. The BAS is therefore a critical part of the building systems commissioning process.

The BAS affects the commissioning of many other building systems and is a system that, in itself, requires commissioning for successful operation. As noted, demonstration of successful operation is just one of the later stages of the commissioning process.

To maximize the benefits of the commissioning process and have the highest positive impact on a building throughout its lifecycle, commissioning must be performed early on as well as throughout construction and design—even during the planning phases of a building project.


 

 

Owner’s project requirements

As mentioned, one of the first steps in the commissioning process is review of the OPR. The OPR includes project goals and the owner’s measurable performance criteria. However, because the owner may not know the right questions to ask or understand specific technical requirements that will be important to the project, the owner will often require assistance from the design team or the CxA to help develop this information. Owners of multiple buildings, such as university campuses, will usually have a better collection of information on which to develop the OPR than an owner of a single building.

Factors to consider in this process on the user side are the experience and training of the current staff, and any planned investment in future facility staff additions or training. Using this information, the specified BAS should match the ability of the future user in terms of: navigating the graphical interface of the BAS, drilling down into individual components of the HVAC system, changing setpoints, modifying the sequences of operation, and setting up and downloading historical BAS trend data to analyze the operation.

3. OPR

 


 

 

Basis of design

The basis of design (BOD) is the design team’s response to the OPR. It is critical that the BAS have a well-developed BOD. It should present the environmental assumptions, such as climate data used to size the HVAC system, as well as summarize how the elements in the design meet the OPR. The BOD should be broken down by system for easy reference.

Specifics to include in the BOD, with regard to controls, include the specified manufacturer, the other building systems to be integrated into the BAS, capabilities for remote connectivity, communication protocol such as BACnet or LON, integration requirements, type of sensors included in the design (as well as the required accuracy), trending capability, and other criteria for selection of various control components. Requirements for remote alarming may also be specified, including the details of who should be given remote access and if connection by mobile devices is desirable.

 

 2. Basis of Design


 

 

Design review

Once the OPR and BOD have been documented and the design progresses, the CxA will perform a design review against the OPR and BOD to verify that the progression of the design is consistent with this information.

Toward the end of the design phase, controls diagrams are developed and will be subject to focused review by the CxA to confirm not only that the specified components are adequate to meet the OPR and BOD, but also that the controls points necessary to successfully and efficiently operate the building are provided and integrated into the BAS.

Review will also include sequences of operation and alarm inputs. Many of the problems encountered by the design engineer, owner, and integrator that cause many of the shortcomings after installation, even though it conforms to original design intent, can be eliminated during the design process.

 

1. design review


 

 

Specifications

Specifications are critical components of the documents that will be included in the design review.

The controls section of the specifications will be reviewed along with the sequences of operation for consistency with the OPR and BOD. Issues to be identified throughout the review of BAS specifications include adequate capacity for control points, memory and appropriate timeframes and frequency for storing trends, and any desired remote access interface for the owner or any consultants the owner may wish to provide access to (including the CxA).

Server performance is also an area that will certainly impact the performance of the BAS. In addition, any issues regarding integration and protocol for various control components and subsystems that will be required to work in tandem will be identified.

5. Specs


 

Submittal review

The submittal review phase is a necessary part of any commissioning scope.

The automatic temperature controls (ATC) submittal is, in many cases, reviewed at a higher level of detail than any other by the design engineer and CxA. The submittal process allows the design engineer to verify that any substitutions are at least equal to that specified.

The CxA does not review with this specifically in mind, because the CxA’s scope with regard to design review is typically to conduct an assessment against the OPR and BOD. The ATC submittal is highly relevant to the CxA because many controls-related details aren’t fully developed until the submittal phase. Design specifications may provide an overview of how the system is intended to function, but it is the ATC submittal that fully develops the sequence of operation to be programmed into the BAS, and provides all of the necessary specific hardware components.

The final approved submittals are also the basis for developing the commissioning prefunctional checklists (PFC) and functional performance test (FPT) plans. Other control elements, such as control valves, will receive focused review during the submittal process from the CxA. For instance, a valve working at above rated pressure might function for a short period of time, but will fail prematurely. Too high of a pressure drop for control valves is often ignored as long as the flow is reached. Cavitation will be an issue with upper limit pressure drops across the valve.

 

4. Submittals


 

 

Commissioning meetings

A difficult characteristic about BAS commissioning is that this system is one of the last systems to be installed and finalized. This means that progress occurs slowly, if at all, early in construction and rapidly toward the end, when all other systems and the building as a whole is preparing for turnover. It is, therefore, very important that an elevated level of communication occurs between the controls contractor, CxA, and the entire construction team.

 

11. Meetings


 

 

Pre-functional checklists

PFCs are a fundamental component of the commissioning process and its documentation. All equipment in the commissioning scope is required to have an associated PFC. The PFC verifies that the equipment has been fully installed by all trades. Once the PFC is complete, the component is ready for final verification testing. Each PFC with a controls component will have controls items on the checklists. And the BAS itself may have a dedicated PFC, documenting that head-end graphics are complete, applicable systems being controlled are fully integrated, and trends have been enabled.

Point-to-point verification is a critical task to be completed and verified. Control points include the conversion from volts, amps, or pressure measurements into other variables used by the BAS. There is, of course, opportunity for error in these conversions and formulas and they must be verified so that the actual temperature, pressure, position, etc., matches the conversion as recognized at the BAS.

 

6. pfc


 

 

Functional performance testing

FPTs are the most demanding part of the commissioning effort. FPT plans are developed by the CxA based upon design documents, submittals, the OPR, and the BOD. FPTs are then executed by the contractor and witnessed by the CxA for acceptance. Like PFCs, FPTs will have strong controls components for most equipment and systems. The FPT generally includes a demonstration of the expected sequence of operation as specified, alarms and safeties, schedules, and setpoints for variables to be maintained such as temperature, flow, and pressure.

Final FPTs are performed through the BAS with complete graphics. It is essential that all work, including balancing of air and water systems, is complete before final FPTs are performed. The CxA also should determine a list of points to be trended. The trends should be made available before any functional performance testing occurs. Any anomalies observed should be resolved before testing.

 

7. FPT


 

 

Issues log

The commissioning issues log is maintained through design, construction, acceptance, and even the post-occupancy period.

Controls-related issues, which are likely identified during acceptance and post-occupancy, often include installation work not being complete, an operational sequence not occurring as expected, or graphical representations not matching what is physically occurring in the controlled system. As with other items on the commissioning issues log, items are tracked until resolution.

10. issues


 

 

O&M training

Operations and maintenance (O&M) Training on the BAS is a major effort that must be scheduled prior to turnover for the operator to effectively control the building.

The training should include a demonstration of the system through the BAS, but also allow the operator being trained to take control and navigate the system in order to validate the capability for operation after the contractor and CxA have completed their scope.

A comprehensive agenda should be developed for training, and it is not intended to be an open question and answer session.

9. O M


 

 

Post-occupancy, seasonal testing and warranty

While the goal is that all issues be resolved before project turnover, often problems are identified only after a building has been occupied for a period of time, and when the seasonal environment has altered the load on the building.

Post-occupancy commissioning activities include monitoring the building operation, occupant and operator interview, and analysis of short-term trend data that is available through the BAS.

This analysis of trends, created during the acceptance phase, is especially useful during the first heating and cooling seasons when the HVAC system is first tested with the full force of the natural environment.

Any issues that arise can typically be addressed under the system warranty, and should be back-checked prior to the commissioning end-of-warranty review.

 

8. POE

CX

 

 

logo8