Commissioning provides the building owner, designers and builders with risk mitigation by reducing RFIs, warranty issues, maintenance and construction issues as well as schedule creep due to lack of coordination by trades. In specialized function facilities like state-of- the- art healthcare centers, the risk of critical systems failing to perform is unacceptable, thus commissioning is crucial to realizing the expected performance of the facility.

To that end, the Utah Department of Health Facilities Certification group has adopted, as of February 2012, the 2010 Guideline for Design and Construction of Health Care Facilities. In guideline section 1.2-8, commissioning is now required for the following systems:

• HVAC
• Electrical
• Emergency Power
• Nurse Call
• Med Gas
• Fire Protection/suppression
• Telecom
• Alarm/Security
• Pressure relationships for Infectious Control

Testing

There are several different tests used during the construction process and there are many different people who are responsible for each one. Testing is non-descript term and does not define anything. If you use this term, then everyone has to ask, “What testing are you talking about”. The commissioning authority would have to go into a painful contortion of trying to describe what they were talking about without actually giving a name to the term. Or  the CxA would end up giving their own name to the testing, thus adding to the confusion that already exists regarding the commissioning process. Can you imagine the following conversation of the CxA giving the contractor a copy of the Emergency Power Functional Test?

CxA:  Here is the copy of the Emergency Power System Test

Contractor:  What are you talking about?

CxA:  This is the Emergency Power System Test.  Are you ready for testing?

Contractor:  I already finished the testing.

CxA: No, I’m talking about my testing, are you ready for my testing?

Contractor: I did my testing already, I’m done.

CxA: OK good, but are you ready for my testing?

Contractor: It’s your testing, are you ready for it yourself?

CxA: No you don’t understand, you are responsible to do my testing, I just verify that you did it.

Contractor: Like $&#@, if it’s your testing, then you are responsible for it. I’ve done mine.

CxA: No, in the commissioning specifications it says that you are responsible to do the testing and I would verify it.

Contractor: Right, I did my testing, we sent you an e-mail that we were doing the testing and you didn’t show up.  That’s your problem.

CxA: What testing are you talking about?

Contractor: We have the grounding megger tests, the generator manufacturer technician did the system start-up and load bank tests. We sent you the reports.

CxA: Right, those are your tests. I need you to do my tests while I watch.

Contractor: What are you talking about?

CxA: You know, Functional Testing, my tests.

Contractor: There’s nothing in the specs about Functional Testing.

CxA: Yes there is, look in the commissioning section.

Contractor: Show me where it says Functional Testing in the spec.

CxA: Well it doesn’t say the words “Functional Testing,” but it describes that you need to do it.

Contractor: It says I am supposed to perform the “testing” and you would verify it. I did my testing, and you never showed up.

CxA: But the spec is talking about additional testing and you have to do it.

Contractor: What is testing called?

CxA: “Testing”.

Contractor: You know what, I’ve done my “testing”. All I’m required to do is what’s in the contract documents. And the way I read it, I did the “testing” just like it said. Now if you want to do your own testing, and you want me do it for you while you watch, then let me take this “test” paper and I’ll get back to you with a price.

This is not an argument that I want to get into, and a contractor will win an argument about ambiguity every time.

Functional Testing is a testing process separate from the contractor’s other tests and it should have its own name and be clearly defined in the contract documents.

Commissioning Testing

This term has some merit in that it at least gives a name to the testing and it is good that the term is associated with commissioning.  The downfalls of this term are that it propagates the fallacy that commissioning is only functional testing. One of the biggest battles of the commissioning industry has been to convince people that commissioning is a quality control process beginning at the planning phase and continuing through the life of the building. The “testing” done just before owner acceptance is just only one of the defined tasks of the commissioning process. The other negative about this term is that it implies that the CxA is responsible for all of the testing. There are many other people besides the CxA who need to be involved in the Functional Testing. This term would be a step back for the commissioning industry.

Acceptance Testing

This term is used by USGBC to describe the Functional Testing activity. This adds confusion to the commissioning industry because this term is also used for the testing done by special inspectors such as the Fire Marshall. It also is a problem in that the term implies that the Commissioning Authority’s role is to accept the system. The CxA’s role is to document the Functional Testing and then recommend to the owner that they accept the system.

Functional Testing

The merits of this term are familiarity and it also accurately describes the testing. People are familiar with the term which has been used in the commissioning industry since ASHRAE Guideline 1 was published in 1989. ASHRAE GL 1 used the term Functional Performance Testing. ASHRAE eventually dropped this term because they did not like the implications of performance in the term and eventually began using the term “testing” because they couldn’t agree on any other term. Functional Testing is a shortened version of FPT. Some of the reasons for shortening the term to just Functional Testing is because “performance” is somewhat redundant in meaning with “functional” but it also implies that the testing will verify performance. This is not the case. The Functional Testing process verifies that the system operates according to the sequence of controls, which should be congruent with the OPR. Functional testing does not verify equipment performance such as BTUh output, heat transfer capacity, etc. The term “Functional Testing” addresses the concerns that the ASHRAE  Commissioning standards committee had and also keeps an accurate familiar industry term.

One of the arguments against the term Functional Testing, is that it is a whole building process and we are not just testing HVAC systems. The argument continues to say that the term does not apply to Building envelope testing. I disagree with this argument. Every test that I have looked at for building envelope is verifying the functionality of either a system or a system sub-component in the same way as HVAC system functional testing. All of the building envelope components have a functionality or they would not put it into the building; air movement control, moisture transfer control, temperature transfer control, sound transfer control, etc. All of the ASTM Functional Tests that I have worked with, either directly or indirectly test the functionality of one or more of the building envelope systems or subsystems. Building pressure Functional Testing tests the air barrier system as well as construction quality in general. Adhesive pull tests verify attachment of the vapor barrier which is an indirect measurement of the proper installation and effectiveness (functionality) of the vapor barrier. Thermographic imaging does not directly test any systems but with proper interpretation can give tremendous information about the functionality of the building envelope and it’s subsystems.

In short, Functional Testing is a familiar industry term that accurately describes the commissioning process activity that the commissioning team uses prior to turning the building over to the owner, and it is a more appropriate term to use than any of the other terms proposed so far.

Integrated System Testing

This is a term that has seemed to come from the data center building sector. It describes testing the systems together, introducing multiple points of change, or failure into different systems and seeing how the system responds and recovers. It is always done after the Functional Testing. Unfortunately, there is a misunderstanding among many Cx providers of what Functional Testing should entail, because IST should be the last step of the FT process. The FT process should begin with components, then move to subsystems, then to systems, and then finally to testing all of the building systems together. Testing all of the building systems together is the definition of the IST. The IST term should not replace Functional Testing, but rather it should be understood that it is the last step of FT.

In summary, my strong opinion is that the BCA should properly define Functional Testing and use this term in the Best Practices of New Construction. Doing otherwise would make this standard different from all of the other BCA documents as well as inconsistent with the rest of the commissioning industry. The only exception may be the new ASHRAE Guideline 0. I believe that if no one else goes along with ASHRAE, they will eventually recognize their mistake and begin using the term Functional Testing in future guideline additions, especially if the BCA properly defines the term and uses it in their standards.

The other night I caught a plane after work so that I could be to a meeting the next morning on the other side of the country. When we landed it was about 11:3o pm cold, rainy and dark…the pilot made us sit in our seats for about 20 minutes until the ground crew was ready for us to get off the plane. It turns out that because of the storm, the electricity was out on our side of the airport.  They couldn’t maneuver the jetway up to the plane door so they had to use portable stairs to get us out of the plane onto the tarmack, then we had to climb back up another set of portable stairs to get into the jetway. TSA personnel were stationed about every 15 to 20 feet on the tarmack and inside the jetway with flashlights because it was pitch black.  The jetway was not connected to emergency power! Once we exited the jetway into the terminal there were emergency lights so we could find our way to baggage claim and out of the terminal.

As a commissioning authority my mind went crazy with questions. Did this get commissioned? What if someone would have asked the right questions such as: What if the power goes out? Will you be able to use the jetway? Will there be emergency lighting outside or inside the jetway?

It makes you wonder  how many more times are they going to go through this again before somebody decides to come up with the bucks to fix this, or will it be a code official that gets wind of it and tells them they have to fix it?

The rhetorical question that went through my head was, Would I have missed this if it had been my project? Who knows, but we can all avoid the mistake if we will learn from someone else’s mistake.

I’ve taken the experience and stored it in the back of my mind to remind me to ask more “what if” questions. Hopefully it will for you as well.

So did you figure out the puzzle before reading this post, or are you still thinking about it? Here’s the answer if you haven’t already figured it out or Googled it already.

Now, what is the fewest number of continuous arcs needed to pass through a 4 x 4 grid of points?

A special thank you to all those who contributed to ASHRAE’s food drive for the Utah Food bank.

I received several requests for a copy of the presentation. You can download it from the link below in this blog. I have added some commentary slides to help clarify the graphics and answer some of the audience questions from both during and after the presentation. I invite you to send any comments you have.

Now click on the link to download the presentation. Who Stole My High-Performance Building 2010-12-03 Utah Chapter 

Thanks again to all those that attended the presentation and for your kind words and feedback.

From Daryl…

I would like to talk about HVAC air flow engineering with you some just for fun. I have some text book errors to share with you.

I am an end user in the science field but with a strong mechanical background in a new California College with 4 small labs and a hall which is used as a prep area that divides the four rooms.

I disagree with using diversity in an educational setting. Maybe in a research lab but not in an educational setting. Why? Because we have a 3yr old lab in which diversity was used and we have rooms that are stuffy and fume hoods that do not work because the engineer figured only some of the fume hoods would be used only some of the time. Now the exhaust fans are undersized along and the air handler is too small.

Check this out. I was looking above the ceiling tiles and noticed that each room has its own exhaust fan to serve the fume hoods in that room which is good. Here is the bad part. They installed a smoke fire damper in each fume hood exhaust system which is a major mechanical code violation the Nation over correct? If students ever make smoke in one of the fume hood the system will see this as a fire and slam the damper shut.  Then the room will have to be evacuated for sure and the ducting on the other side of damper could collapse due to extreme and excessive exhaust fan static pressure.

Here is another short cut I do not like to see in building HVAC engineering. Using the space above the ceiling tiles as the return plenum. Yes it saves $$$$ by not having to duct return air, but the removal of heat is very poor and because of the tremendous static pressure it takes to try to pull the return air back to air handler.

Here is one more winner that I see. The air handler on the science building was not specified as a 100% outside air make up unit. Thus every winter the complete filter bank freezes up solid. As you know science buildings are special, air cannot ever be recycled or returned.

Thanks for sharing Daryl.

Feedback from building users, such as Daryl,  is invaluable and we can improve our delivery to our clients if we will just sit down and talk with them. Sometimes it takes knowing the right questions to ask to get them going, but once they get going…sit down, be quiet and write as fast as you can.

Lessons learned from somebody else’s experience, like Daryl’s,  is a lot less painful than learning it on our own. I really appreciate the people that have shared their words of wisdom with me so that I can improve what I am doing without having to take the hard knocks myself.

I will be sharing a few lessons learned (Dec. 2010) with the Utah ASHRAE Chapter when I give a presentation called “Who Stole My High-Performance Building”.  It will be a fun and informative presentation, and I will share parts of it in the future on this blog.

Todd Rindlisbaker, P.E., QCxP, LEED AP, HBDP, CCP, has been in the HVAC/plumbing design and commissioning business since 1993. He has extensive experience in project management, HVAC design, and energy studies and specializes in hydronic heating and cooling systems, controls optimization for comfort and energy efficiency and in commissioning. He has been involved in the design, installation, and commissioning of mechanical, plumbing, and building management systems throughout the United States and internationally.

You never know if a website link will go bad someday so I will copy the information below (giving full credit to PECI).  I will also add a couple of things to the list which I have put in bold and italics.

I hope you enjoy looking back at and seeing just how far the commissioning industry has come.

2010

• 18th NCBC: Hosted by ComEd

What does the future hold from here?

• BCA is scheduled to publish “Best Practices in Commissioning for New Construction”
• ASHRAE forms committee to write standard for a systems manual

2011

• What will you be doing for the commissioning industry?

Todd Rindlisbaker, P.E., QCxP, LEED AP, HBDP, CCP, has been in the HVAC/plumbing design and commissioning business since 1993. He has extensive experience in project management, HVAC design, and energy studies and specializes in hydronic heating and cooling systems, controls optimization for comfort and energy efficiency and in commissioning. He has been involved in the design, installation, and commissioning of mechanical, plumbing, and building management systems throughout the United States and internationally.  Todd also serves on the BCA committee for the “Best Practices in Commissioning for New Construction”

The advantage of resetting the AH SAT StPt based on VAV box cooling demand is that the supply air temperature set point would actually track the building demand.  It sounds pretty simple on the surface, but there are some things that can derail this strategy and make it fail.

__________________________________________________________________________

Keys to making this strategy work:

1. All zones must be able to be cooled most of the time by higher supply air temperatures.
   • A good rule of thumb is that the full cooling supply air flow delivered at the upper SAT reset limit should cool 50% of the design load.
   • Zones that are scheduled to turn off during unoccupied periods should be separated from zones that have a 24/7 cooling load.  This is often done by providing dedicated air conditioning units for the 24/7 rooms such as data closets, or grouping these zones together and serving them from separate air handlers.
   • Accurate, properly placed and calibrated temperature sensors are also key to making any control strategy work.

Conditions that will kill any supply air temperature reset strategy:

1. One or more zones has a constant high cooling demand and always requires supply air temperatures near the lower end of the SAT reset range.  Typical applications are data and telecom rooms or any place that has equipment running.
2. Failure to communicate how the reset control strategy works and the conditions necessary for it to work.  This is important to describe in the Basis of Design.

These items listed above point out good design practices that all designers know, but the designer needs to make some adjustments to the standard design in order to optimize any SAT reset strategy.

After determining each zone’s peak heating and cooling loads, the designer needs to then identify all of the zones that have high cooling demands that do not back off during non-peak conditions.  If there are cases where high cooling demand zones cannot be separated from intermittently occupied zones, the designer can design these high cooling demand zones for a higher supply air temperature.  This will increase the cooling airflow which will increase the size of the VAV box serving these zones.  For instance, a zone supplied by 55 degree air with 75 degree return air requiring 1000 CFM to cool the space would required 2000 CFM to cool the space with a 65 degree supply air temperature.  This will cost a little more up front for a larger VAV box and supply ductwork in this zone, but it will save significant amounts of reheat energy and increase comfort in the other system zones.  The argument could successfully be made that the air handler airflow would not need to be increased because during the cooling design load conditions the air handler SAT would be 55 degrees and so this zone would only require 1,000 CFM to cool this room.  The CFM would only increase during the periods of low cooling demand in the other zones.  As long as this is explained in the Basis of Design other people can quickly understand that the system has diversity and that the sum of the VAV box CFMs will be more than the air handler CFMs.

A real-world example of this strategy is the project that is located in Salt Lake City where the summer dry bulb design temperature is 97 degrees F.  The system resets the supply air temperature between 55 and 68 degrees.  The strategy has eliminated almost all of the reheating and reduces the overall system airflow and fan energy.  This was easy to see why, because before the reset strategy was implemented, 50 to 75% of the VAV boxes would be in reheat mode while about 2 – 5% of the VAV boxes would be in cooling mode when the outside air temperature was 70 degrees F.  By resetting the supply air temperature, the supply airflow is increased to the high cooling load zones while the other boxes that were in reheat are now operating at the minimum airflow set point which is significantly less than the heating airflow set points.

With that said, here is a Supply Air Temperature Reset Control sequence based on VAV box demand that could have been used in the project from the previous post.

1. SUPPLY AIR TEMPERATURE SET POINT RESET CONTROL:

Reset the air handler SAT StPt of each air handler based on the VAV box cooling demand.  If the air handler enters a cooling mode that involves the evaporative cooling (Stage 3), then the SAT StPt shall be set to the evaporative cooling mode set point. Each air handler will have its own reset schedule as follows:

1. If the maximum VAV cooling demand is below 85% for 5 minutes then the supply air temperature set point shall be raised by 0.5 degrees.
2. If the maximum VAV cooling demand is above 100% for 5 minutes then the supply air temperature set point shall be lowered by 0.5 degrees.
3. The initial supply air temperature shall be 60°F.
4. If the air handler enters a cooling mode that involves the evaporative cooling (Stage 3), then the SAT StPt shall be set to the evaporative cooling mode set point.

Air Handler SAT Reset Based on VAV Box Cooling Demand

It should pointed out that this strategy is called “Trim and Respond” because the set point is “trimmed”, and then the system responds and is allowed to settle out before trimming again.  The reason for using this type of strategy instead of a PID loop is that there would be interactions with other PID loops and it would be very difficult to keep them stable.  When you change the supply air temperature, then the VAV box PID loop will respond by increasing or decreasing the cooling demand signal.  This is fed back to the SAT StPt control loop.  By using a trim and respond sequence with a significant time delay, the SAT StPt control will be stable.

As it is noted in this post that there are many details that need to be addressed to make the VAV box cooling demand reset method work, I believe that the extra effort is worth it and can pay huge dividends in energy savings and occupant comfort.

Sequence Notes: A safety in this sequence was to make sure that whenever the evaporative cooling mode was operating that the SAT StPt would be 55°F or below.  Graphic design was also addressed to provide the operators simple and intuitive access to monitor system operations and adjusting system settings.

Todd Rindlisbaker

Todd Rindlisbaker, P.E., QCxP, LEED AP, HBDP, CCP, has been in the HVAC/plumbing design and commissioning business since 1993. He has extensive experience in project management, HVAC design, and energy studies and specializes in hydronic heating and cooling systems, controls optimization for comfort and energy efficiency and in commissioning. He has been involved in the design, installation, and commissioning of mechanical, plumbing, and building management systems throughout the United States and internationally.

Signed into law and effective January 1, 2011, California has adopted the California High Performance Green Standards Building Code. What is significant about this is that ASHRAE, USGBC, IES and ICC have developed an almost identical document published this year–ASHRAE Standard 189, Design of High Performance Green Buildings.

What is ASHRAE 189? Simply put, it is an ANSI standard developed in model code language designed to provide code-enforceable mandatory minimum requirements for high-performance green buildings.

“Applicable to new commercial buildings and major renovation projects, it will address energy efficiency, a building’s impact on the atmosphere, sustainable sites, water use efficiency, materials and resources and indoor environmental quality. Standard 189P will become the benchmark for all sustainable green buildings in the United States because it is being developed for inclusion into building codes,” said ASHRAE President Terry Townsend.

The groups developing this standard–USGBC, ASHRAE, ICC, ICBO, BOCA and others–intend that this standard become an integral part of the next version of building codes published in the United States. Of course adoption of these codes in whole (or in part) is the prerogative of each municipality, yet the tenets of ASHRAE 189 will significantly impact the design and construction industry in the years to come.

Some highlights:

Many of the LEED components familiar to constructors and designers of commercial buildings will become code.

Comprehensive commissioning for buildings over 5,000 SF is required by code.
• All water-consuming elements must be commissioned including irrigation.
• The commissioning authority will verify all IAQ requirements through the construction process.
• Envelope commissioning is mandatory. Building envelope systems, components and assemblies to verify air tightness, thermal and moisture integrity.
• Measurement devices with remote communication capability shall be provided to collect energy consumption data. This requires that buildings be circuited segregating HVAC, lighting and process electrical loads so that energy can be monitored and projected energy performance can be verified.

Of course there are many other important elements to ASHRAE Standard 189 that affect all members of the design-build team. To learn more go to: www.ashrae.org/greenstandard

Raymond A. Dodd, P.E., CxA, LEED AP possesses a wide breadth of experience, totaling more than 25 years, in the mechanical facilities field with extensive knowledge of commercial, industrial, institutional and high-technology mechanical facilities systems. He is a skilled project manager proficient at handling the logistic, technical and communications challenges required in the commissioning, construction, design and sales process. He has been the owner of an HVAC service company, which has given him hands-on experience and provided him with additional insight into constructability of his designs as well as the issues faced by owners and facilities personnel throughout the commissioning process. He has worked as a consulting engineer and directed the engineering group for a large national mechanical design/build company and served as a LEED™ commissioning engineer.

rad@tbcxinc.com

On a recent project, the Variable-Air-Volume (VAV) air handler controls sequence did not have supply air temperature reset control.  This is acceptable according to the local energy code (ASHRAE 90.1-2007) which only requires supply air temperature reset for constant volume air handler systems, but it uses additional energy. These air handlers are VAV-type systems with four stages of cooling; outside air economizer dampers (OA Econ), in-direct condenser water cooling coil (ICC), direct evaporative cooling (Evap), and a chilled water coil (CHW).  This system is commonly called an IDEC (In-Direct, Evaporative Cooling) system.  The cooling sequence is as follows;

At first glance, someone would look at this and be thinking that these are expensive air handlers, and they would be right that it does cost more to add the in-direct and direct evaporative sections to a regular air handling unit. So it is important to note that this project is located in Salt Lake City, UT which is a high mountain desert.  The design conditions are 97°F DB and 63°F.  If you do a BIN data plot on a psychometric chart,  it is fairly easy to see that this system will operate on mechanical cooling between 100-200 hours a year verses about 2000 hours a year on a traditional mechanical cooling only air handler.  The following BIN data plot shows the number of hours that the system will operate at each outdoor air condition throughout the year (based on a five-day work week).  The number of hours that the cooling will be reduced are the hours between the first and second lines.

Hourly BIN Plot on Psychrometric Chart - Salt Lake City, UT (created by TBC using Greenheck HDPsyChart)

An IDEC type cooling system requires the supply air temperature to be 55°F or lower whenever the evaporative cooling stage is on.  This constraint is meant to ensure that the indoor humidity will not rise above 40%. The engineer specified that the supply air temperature set point be set at 53°F.

Even though a constant supply air temperature set point is acceptable for a VAV system based on the local energy code (ASHRAE 90.1-2007) it was causing the system to use large amounts of reheat energy most of time, even when the outside air temperature is as high as 80°F.  It was also causing many occupant comfort complaints especially when the outside air temperature was cold or moderate.

There are multiple methods to provide Supply Air Temperature Set Point  (SAT StPt) Reset Control.  Two of the most common methods are based on Outside Air Temperature and on the maximum VAV box cooling signal.

Each reset method has its advantages and disadvantages:

Outside Air Temperature Reset Method

Advantages:

• Relatively simple to program
• Better than nothing

Disadvantages:

• It is “open loop” control.  Open loop control does not provide feedback into the control loop and therefore does not adjust based on system response.  Open loop control is highly discouraged because of this.  An example of open loop control in your car would be speed control based on the type of street driven on.  This method would press down the accelerator a certain percentage based on the street type.  This control would not give any feedback to how fast the car was going, what the traffic was like, whether you were traveling downhill or uphill, or even, the actual speed limit.  It is easy to see how this would be very inaccurate and undesirable.
• No very accurate.  A building operator has to watch the system over a year of two and try to adjust the reset parameters to get it to match the building characteristics.  Even when this is done right, it will only be a fair estimation.

VAV Box Cooling Demand Method

Advantages:

• The system responds directly to the building load and is able to use less energy by using the highest supply air temperature as possible.

Disadvantages:

• It is more complicated to program.

This particular project’s building owner operates well over 100 buildings and has a very knowledgeable, full-time control system engineer who monitors the buildings and can deal with building control issues as needed.  Based on this, the owner chose to use the outside air temperature reset control method, with the understanding that the controls engineer would need to monitor the building over the next one to two years and tweak the set points to get the supply air temperature set point (SAT StPt) reset adjusted for this building.

The following Supply Air Temperature Reset Control sequence was used for this project:

Reset the air handler SAT StPt of each air handler based on the outside air temperature.  If the air handler enters a cooling mode that involves the evaporative cooling (Stage 3), then the SAT StPt shall be set to the evaporative cooling mode set point. Each air handler will have its own reset schedule as follows:

Air Handler SAT Reset based on OAT

End of Sequence

Sequence notes: A safety in this sequence was to make sure that whenever the evaporative cooling mode was operating that the SAT StPt would be 55°F or below.  Another item addressed in this sequence was graphic design that would provide simple and intuitive access to the operators for monitoring system operations and adjusting system settings.

In my next post I will provide an example of the SAT StPt reset control based on VAV box cooling demand. Later blog posts will explore control system graphics design.

Todd Rindlisbaker

Todd Rindlisbaker, P.E., QCxP, LEED AP, HBDP, CCP, has been in the HVAC/plumbing design and commissioning business since 1993. He has extensive experience in project management, HVAC design, and energy studies and specializes in hydronic heating and cooling systems, controls optimization for comfort and energy efficiency and in commissioning. He has been involved in the design, installation, and commissioning of mechanical, plumbing, and building management systems throughout the United States and internationally.

So how do you budget for commissioning? Can you just plug in a $/sq. ft. number and move on? Maybe or maybe not.
Is the project LEED™? If so, LEED™ views commissioning as a prerequisite with prescribed tasks covering the HVAC, lighting control, domestic hot water and renewable systems beginning at the construction phase of the project. LEED™ also offers an enhanced point for commissioning that brings the commissioning authority on during the design phase of the project with additional tasks (and an increased budget).

If the LEED™ measurement and verification point (M&V) is attempted, commissioning takes an additional role to verify the energy usage which begins in the design development of the project.

Another factor is the size and complexity of the building. Because some commissioning tasks are uniform for all projects,  smaller buildings have a higher cost per square foot.

Finally, what does the building require? In an office building,  HVAC, lighting control and domestic hot water commissioning may suffice. However, a clean room with tight control of humidification will require envelope commissioning. In a data center, commissioning of the electrical systems is critical.

Below are a few ranges for commissioning costs but as this article suggests, have a commissioning  professional budget the project based on building type, operational requirements, size and complexity so that your cost estimates for commission have you covered.

Note: In general, the cost of commissioning a new building ranges from 0.5 to 1.5 percent of the total construction cost, as shown in the table. For an existing building, never before commissioned, the cost of retro-commissioning can range from 3 to 5 percent of the total operating cost.

• Entire building (HVAC, controls, electrical, mechanical): 0.5-1.5 percent of total construction cost

• HVAC and automated control system: 1.5-2.5 percent of mechanical system cost

• Electrical systems: 1.0-1.5 percent of electrical system cost

Raymond A. Dodd, P.E., CxA, LEED AP possesses a wide breadth of experience, totaling more than 25 years, in the mechanical facilities field with extensive knowledge of commercial, industrial, institutional and high-technology mechanical facilities systems. He is a skilled project manager proficient at handling the logistic, technical and communications challenges required in the commissioning, construction, design and sales process. He has been the owner of an HVAC service company, which has given him hands-on experience and provided him with additional insight into constructability of his designs as well as the issues faced by owners and facilities personnel throughout the commissioning process. He has worked as a consulting engineer and directed the engineering group for a large national mechanical design/build company and served as a LEED™ commissioning engineer.

rad@tbcxinc.com