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Crazy Quilt Project Management

crazy quilt pic

By: Ray Dodd, PE, CxA, LEED AP

In my 30+ year career as a mechanical engineer working with large commercial buildings, the one innovation that gives me chills is the “fast track” project delivery system.

Sure I get it – once the digging starts, money is flowing out but no money is flowing in. There is a rush to get the money moving in a positive direction. Old practices that delay the schedule needed to go and have been replaced by “fresh new ideas. Some are smart too – like starting the foundation work and structure while the rest of the design is being finished.

However, as the construction market has recovered the “fast track” project delivery system has evolved far beyond its original form. More and more we are experiencing normal conventions and smart construction sequencing thrown out in favor of going faster. Going faster often means things will occur out of order throwing a formally orderly process into chaos.

I remember years ago rural Montana had no speed limit. Out in those vast expanses of land you could drive as fast as your car would go. You got from one place to the next faster, sure, but the crashes were SPECTACULAR!

In a fast track world in order to shorten the project schedule we are often being asked to take our process and execute it piecemeal and out of order. This is what I like to call: Crazy Quilt Project Management.

We commission buildings – verifying the systems perform as designed. Commissioning is a process: “a series of actions or steps taken in order to achieve a particular end.” The key phrase in that definition is: in order. Making sure things work right requires that things happen sequentially. Our tests are written in a sequential manner, and you can only test something to make sure it works after all the elements of designing it and constructing it are complete.

But now when project nears substantial completion (when it is scheduled to be done) and the project isn’t going to be on time, many of those carefully thought-out processes have to go.

We are asked repeatedly – “Can’t you start testing the systems even though the contractors aren’t done?”

In my 30 years of experience I have witnessed time and time again that you can’t rush high quality craftsmanship. For example: Skilled pipe fitters will take within 10% the estimated number of hours to fabricate a big commercial or industrial fluid delivery system, no matter what. More construction workers on the job often doesn’t solve the problem. Despite what the scheduling computer model says, it always takes one woman 9 months to make a baby. You can’t get 9 women to make a baby in one month.

Our work – testing systems to verify function is a project management process reliant on dependencies.  A dependency is a relationship in which a task or milestone relies on other tasks to be performed (completely or partially) before it can be performed.

Crazy Quilt Project Management is simply this: Taking a carefully designed process with dependencies and bending reality so that those dependencies appear to have little or no importance.

I’m guessing that no matter what industry you are involved in you’ve experienced Crazy Quilt Project Management. In the short term it makes the people on the top of the pile look good. We finish on time, revenue is flowing and management is happy. However from the long view it looks much more like delusion. Behind the façade of “we’re finished”, the folks who become owners of the project/product experience layers of dysfunction upon layers of dysfunction and scramble to fix it.

Perhaps I’m old fashioned but I think Crazy Quilt Project Management is just what it implies. If you want something to work right, slow down, and do it right. Why? Because it’s always the smart thing to do.

Standby for Changes: Required Commissioning for Commercial Mechanical and Lighting Systems per the IECC 2012 Code

The 2012 International Energy Code is now being adopted by municipalities throughout the United States and contains new requirements for building systems commissioning.

Commissioning provides the building owner, designers and builders with risk mitigation by assuring that the systems function as designed. Commissioning also reduces RFIs, warranty issues, maintenance and construction issues as well as schedule creep due to lack of coordination by trades.

Until now, building commissioning has been prescribed for projects where non-conformance is an unacceptable risk, and for projects pursuing LEED (Leadership in Energy and Environmental Design) where building systems commissioning is a prerequisite for certification.

This new commissioning requirement is an important step to ensuring that buildings are designed, constructed and operate according to the owner’s needs, however, it’s a big change for owners and contractors if they aren’t aware of the new requirements and how they will affect projects with respect to cost, schedule, and participation.

With these new standards, the demand for commissioning in buildings will intensify. Significant changes in the code now require commissioning of the HVAC equipment, lighting controls, economizers and control systems of nearly all commercial projects with 40 tons of cooling or 50 tons of heating (680 MBTU of heating).

Requirements specific to the new 2012 code can be found in Section C408.1 of the IECC including commissioning of the building mechanical systems in Section C403 and lighting systems in Section C405. Some highlights include:

  • A detailed commissioning plan developed by a registered professional engineer that includes pieces of equipment; an operations and maintenance manual; and descriptions of systems adjusting and balancing.
  • HVAC systems require test and balance (TAB)
    • Air and water flow rates measured and adjusted to deliver final flow rates within tolerances in product specifications
    • Test and balance activities to include air system and hydronic system balancing
    • Each supply air outlet and zone terminal device equipped with means for air balancing per Chapter 6 of the IMC
    • Individual hydronic heating and cooling coils equipped with means for balancing and measuring flow
  • Functional performance testing to include all modes and sequence of operation, including full-load, part-load and emergency conditions.
  • HVAC control systems to be tested to document that control devices, components, equipment, and systems are calibrated, adjusted and operate in accordance with approved plans and specifications.
  • Sequences of operation to be functionally tested to document that they operate in accordance with approved plans and specifications.
  • Buildings or portions of buildings can’t pass final mechanical inspection until the code official has received a letter of transmittal from the building owner acknowledging the building owner has received the Preliminary Commissioning Report.

Is your Commissioning Authority and Firm certified?

Professional certifications and degrees are clear marks of competency in the architecture, engineering and constructions fields. However, when it comes to commissioning, an individual cannot obtain a degree in building commissioning and instead clients must depend on their commissioning agents to bring to the table a mix of job experience and industry recognized certifications. There are several certifications that clients seeking commissioning authorities can look to in order to ensure requisite knowledge and understanding of the building commissioning process.

Certified Commissioning Authority (CxA) from the AABC Commissioning Group

CxA certification is required for all government and military-related projects. Additionally, many industry clients, such as the healthcare sector, require certification.

This certification requires an examination not only an examination but the company must also be an independent certified commissioning firm. In addition to the examination, the commissioning authority must provide references and submit documentation on at least three projects. The certification is reviewed and renewed on annual basis to ensure the commissioning authority provides a quality-based service.

“The Certified Commissioning Authority designation allows clients everywhere to rely on professional credibility and dedication to providing the best in comprehensive services,” TBC Project Commissioning Authority Todd Watson,  LEED AP, CxA, QCxP, explains.

Accredited Qualified Commissioning Process Provider (QCxP) from The University of Wisconsin Madison

The QCxP provides a level of recognition for those who have acquired an understanding of the commissioning process through education and demonstrated a minimum level of understanding of the commissioning process through training and an examination.

Accredited Commissioning Process Technical Support Provider (CxTS) from The University of Wisconsin Madison

The CxTS highlights the skill and experience of individuals who have provided commissioning services primarily in select project stages, on small or limited scope projects, or who provide key technical support to commissioning activities. Applicants must provide documentation on two major or four smaller new construction or rehab projects or equivalent existing building projects, including letters of reference and pass the examination.

Owners and clients who seek out both commissioning expertise as well as industry recognized certifications from their certified commissioning professionals can rest assured that their high-performance, energy-efficient building will function as intended, every time.

Healthcare Commissioning Requirements for Certification

The popularity of building commissioning in the past ten years has increased dramatically largely due to the LEED (Leadership in Energy and Environmental Design) building certification program. The prescribed commissioning requirements for LEED were designed to validate that the energy consuming systems in the building–HVAC, lighting and domestic hot water–perform as designed. However, commissioning can deliver far more than an energy performance validation.

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

To Functionally Test or Not

There have been debates for years about what terms to use for the different commissioning tasks. One of those tasks is Functional Testing. There have been several suggestions for alternative terms. Below are my thoughts on some of the terms suggested to me. Read the rest of this entry »

Thinking Outside the Box

As commissioning authorities we are asked to think outside of the box, ask questions such as: what if? and why? to get people thinking and to try to avoid unforeseen problems. It’s like the graphic below, which I love. Can you connect 9 dots in a 3 x 3 square using only four lines and only going though each dot once?

Read the rest of this entry »

Presentation: Who Stole My High Performance Building?

I want to thank the Utah ASHRAE Chapter for inviting me to give my presentation called “Who Stole My High Performance Building?” on Friday December 3, 2010. It was a packed house with over 70 people in attendance. The audience participation and questions were great.  This presentation shares many of the lessons learned in the field and gives valuable feedback of how different designs are performing in the field. Read the rest of this entry »

Lessons Learned from a Building User

I received some feedback from a reader, Daryl,  the other day that was great and I’d like to share it with you.

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. Read the rest of this entry »

History of Commissioning

The Total Building Commissioning industry is relatively new and growing up as we speak.  It has been fun to be involved in the process and rub shoulders with many of the industry pioneers and experts.  A couple of years ago at a NCBC conference a “History of Commissioning” was presented as a display.  It was fascinating to see the information gathered together in one place.  PECI has posted this information on their website and kept it updated.

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. Read the rest of this entry »

Air Handler Supply Air Temperature Set Point (AH SAT StPt) Control Based on VAV Box Cooling Demand

In the Air Handler Supply Air Temperature Control post, we discussed a method of resetting the air handler supply air temperature set point based on the outside air temperature (OAT).  This post will discuss another method of resetting the air handler supply air temperature set point (AH SAT StPt) based on VAV box cooling demand.

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.

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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.

About TBC

As a leader in the building commissioning industry, Total Building Commissioning (TBC) is a facility consulting firm that specializes in the commissioning of mechanical, electrical, controls and all other major building systems as well as LEED™ certification consulting.

Contact TBC

info@tbcxinc.com

Phone: 801-401-8401
Toll Free: 877-822-9462

324 South State Street, Suite 400
Salt Lake City, Utah, 84111