7 Sustainability Ideas for Modular Classrooms in the Education Industry (guest post)

mobile classroomToday, a guest post on sustainable modular classrooms from Kathy Werder, a freelance architect by profession and a researcher by nature.   According to Kathy, most of her research papers focus on promoting integration that leads to sustainable and lean design and construction practices. Kathy is obsessed with the latest rage in the construction industry – modular building solutions. She is also an avid writer, and loves blogging about green buildings and portable construction units. Welcome, Kathy!

According to Wikipedia, a sustainable building refers to “ a structure and using process that is environmentally responsible and resource-efficient throughout a building’s life-cycle from sitting, to design, construction, operation, maintenance, renovation, and demolition.”

So if we accept this definition to be true, in order to make an actual sustainable building we have to consider the entire process of building right from the blueprint stage all the way to demolition, and ensure that at every step of the way there is minimal or no negative impact on the environment, especially in terms of resource efficiency.

School buildings require a lot of energy to function. However, there are a great many things that can be easily done to make a sustainable school building. Of course, you would have to opt for modular buildings for schools since they are known to be constructed in a resource and energy efficient way. [Editor’s note: I’m not sure that sustainability would *require* the use of a modular building, but they do have known, quantifiable built-in sustainable features.]

Whether you get your building from a vendor or directly from a manufacturer, here are a few things you can do to your modular classroom buildings in order to make them more sustainable.

Recyclable Materials

The first and most obvious step is to make sure your modular school building is built out of recyclable materials as far as possible. This would include recycled steel, wood and glass as well as recyclable pipelines, window frames, etc.

Approximately 10-20% more lumber is used to construct mobile buildings than in convention construction (to add structural integrity); therefore, using recycled wood can pay dividends.

Recycled steel is robust, not combustible, and mold-resistant, and it is useful for framing.

Carpet tiles made of 100% recyclable materials can be used by most builders. For instance, Mobile Modular Management Corporation uses glueless, 100% recycled carpet tiles that do not release volatile organic compounds (VOC).

There are cost advantages to using recyclable materials and in many cases, there is an associated lowering of installation labor costs.

Indoor Air Quality

Before installing a central air system, first see if it is possible to maximize on natural ventilation by designing classrooms in the style of atriums or by installing large, strategically placed windows that allow for sufficient cross ventilation.

Should you choose to install a central air system anyway, bear in mind that HVAC systems are the main energy consumers in any type of building, especially in schools. New, energy efficient 2-stage HVAC systems should be used that require less energy to function and consume significantly less electricity. They also use refrigerants that do not harm the ozone layer.

In addition to this, some modular construction companies use radiant heat barrier and increase the R-value of all insulation to reduce HVAC load and maintenance costs.

Geo Exchange Systems

Geo exchange systems make use of the energy (or temperature) stored in the earth to perform a large number of functions. It can heat and cool an entire school building, it can provide refrigeration and it can also be used to heat water.  If there it is possible to install a geo exchange system, it is the next best solution to natural ventilation.


Most schools function during the day and so essentially there should be no need to use much artificial lighting. Modular or portable classrooms can be constructed specifically to maximize natural daylight. Large windows with energy efficient glass will ensure that there is plenty of daylight coming into the room while still being able to retain a comfortable temperature that is not affected by external conditions. Sun tunnels can be used to maximize natural lighting as well.

Solar Power

Solar power is the most incredible gift that we have in terms of an energy resource today. Furthermore, with the advanced technology that we have at our disposal today, there are numerous ways in which we can harness solar energy:

    • Solar powered water heating is perhaps the most common way in which solar energy is used.
    • Solar powered light bulbs are another great invention that should definitely be used
    • Solar plugs are also another incredible invention that a school should definitely take advantage of. Instead of using electricity to power laptops and computers, solar plugs can be used wherever possible.

Room Acoustics

Maximizing good room acoustics is another way to save electricity, especially in auditoriums. Since you have the luxury of having your school built to your exact specifications, it would be fairly easy to ensure that your auditorium has good acoustics, wherein you will very rarely require microphones.

Regular Maintenance

As with any other building, school buildings need regular maintenance, and this is especially true if they are modular. All the various energy efficient systems that have been put in place need to be checked and serviced regularly in order to ensure smooth functioning and optimal efficiency. Neglecting to maintain the systems regularly will render all your initial efforts futile and will in fact begin to prove counterproductive.

Thanks Kathy for your article.  Now it is your turn.  Have you designed for a green or LEED school facility?  Considered modular construction as part of your design?  Share your thoughts below.

Turning Manure into megawatts (Swine Farm Biogas Renewable Energy Project)

As I noted in my last post, Withers & Ravenel’s Swine Farm Biogas Renewable Energy Project, located in Bladensboro, North Carolina, is one of this year’s ACEC Excellence in Engineering Award winners.

I asked the folks at Withers & Ravenel to give share more about their project, how it was conceived, and how it was designed.

Why Swine Farms? What was the genesis of this Project?pig outline

North Carolina is “pork proud”, with approximately 9 million hogs on farms scattered throughout the eastern part of the State. These farms rely on open pit lagoons and land application for the treatment and disposal of animal waste.   However, open-air treatment lagoons have a poor reputation among some lawmakers, residents and environmentalists. They are accused of creating sickening odors, allowing methane to escape into the atmosphere, and contaminating groundwater and streams.

Because of environmental concerns, the State temporarily suspended permitting the construction and operation on any new swine farms utilizing lagoon treatment systems in 1997, and required new farms to meet “environmentally superior technology” (EST) standards.  Since the enactment of the suspension, there have been no new hog farms introduced in North Carolina.

Tax Credits, Legislation, and Funding

In 2007, the State passed Senate Bill 3, which pushes the use and development of renewable energy standards, the State took a big step toward encouraging innovative treatment technologies for swine waste by mandating utilities to purchase Renewable Energy Credits (REC) generated from swine waste. The Bill also provides a 35% State tax credit in addition to the Federal 30% tax credit.

Spurred by the availability of the NC Green Business Fund grants from the 2009 American Resource Recovery Act, Withers & Ravenel conceived the 600kW renewable energy project and assembled the project team, which included developer AgPower Partners LLC, Withers & Ravenel engineers, and Barnhill General Contractors.

The project was able to receive over $2 million dollars in grants and tax credits, including a $500,000 grant from the NC Department of Energy and $1.5 million grant from the US Treasury. The Owner, Billy Storms, was able to finance the balance of the project cost through a loan with the Cape Fear Farm Credit Association.

Storms Farm Digester Site

Storms Farm Digester Site

Engineering a Plan for the System

In North Carolina, swine farms flush the houses with water in a closed system with a lagoon providing storage and treatment of waste which is then applied to crops. With this process, the waste is diluted to around 1-2% solids.  However, in order to reduce the water content for more efficient temperature control of the anaerobic digestion, the waste needs to be between 5-10% solids.

With the implementation of scraper technology, swine waste volume was significantly reduced by eliminating the added liquid from the flushing system.  This made the Storms Farm much less reliant on the volume required in the existing lagoons, reduced the required size of the anaerobic digester, providing benefits to both the waste handling concerns and to energy production.  The scraper system also reduced the amount of ammonia gas in the barns, which is beneficial to animal and human worker health.

Most digester systems for swine manure in North Carolina have relied on ambient covered lagoons. However, at Storms Farm, with the scale of a 600 acre farm and swine houses separated by as much as a mile, it was not cost-effective to build and cover a new lagoon to treat the waste using anaerobic digestion.  The distance between the 23 barn complex made it problematic to pump waste because of build-up in the pipe known to cause maintenance and failure problems.

After review of viable technologies, Withers & Ravenel recommended DVO Anaerobic Digesters to supply the digester technology for Storms Farm. DVO has an extensive tract record using their patented mixed plug-flow digester technology on dairy farms, but there was no comparable swine waste facilities using mesophilic digestion in the US.   Europe has a substantial number of facilities that use swine manure mixed with other substrates, but there was no reliable source of data for the gas yield using solely swine waste substrate.

As a result, Withers & Ravenel took multiple manure samples from local farms and had them tested to help estimate the biogas yield. Even with this data, there was very little information to collaborate the projected biogas yield. After all alternatives were evaluated, the most cost-effective, efficient option was to construct a heated mesophilic digester system with cogeneration and to convert the barns to scraper manure removal systems.

Receiving Pit and Generator Building

Receiving Pit and Generator Building

Construction Issues

Geotechnical borings were done and revealed the need to raise the digester above grade due to a high ground water table. This required sloping the backfill around the tank as insulation to maintain the needed 95 degree temperature in the mesophilic process.  The report also revealed the need to pre-load the site to avoid potential settling of the digester and cogeneration building.  This additional grading and site work was necessary from the original conceptual site plan.

The Digester Operation

The scraper system scraps the waste to a gravity collection system and storage tanks behind each barn. Two vacuum trucks and drivers empty each of the 23 tanks daily to collect the manure collected from each of the barns, drive to the digester facility and empty the manure into the influent pump station.

Manure is pumped into the  1.1 million gallon in-ground concrete digester where the temperatures are maintained above 95 degrees (mesophilic) and the natural occurring anaerobic bacteria destroy the volatile solids, produce the bio-gas containing 65% methane, kill pathogens, and produce a high quality inorganic waste product virtually pathogen and odor free for storage and, eventually, land application as fertilizer. At Storms Farms, about 60,000 gallons of swine waste is processed each day. The biogas is “scrubbed” of corrosive components and combusted in an 845 HP gas driven engine/generator integrated system provided by Martin Machinery, from Latham, Missouri.

The digester produces wastewater that is free of pathogens and odors and removes 90% of the phosphorus and 75%  of ammonia nitrogen.  The electricity – enough to power over 300 homes – is sold to North Carolina Electric Membership Corp.’s grid network.

Through this design, Withers & Ravenel was able to develop Storms Farm into the largest swine biogas renewable facility in North Carolina, generating 600kW of power with an operating capacity of 95%.

Generator Room

Generator Room

The volume reduction due to the implementation of the scraper system and digestion process has allowed the treated effluent to be returned to one of the existing lagoons, reducing the dependence on the original six lagoons on the site.

Future projects to remove the inorganic solids remaining in the effluent by dewatering and to treat for additional phosphorous and ammonia nitrogen removal are in the planning stages in order to meet the additional requirements of an EST standard farm.

What was the Owner’s involvement?

Billy Storms, owner of Storms Farms was instrumental in getting the Project off the ground, through financing the project, through the willingness to change the method of manure management and by accepting the technological challenge of running what is, essentially, a small wastewater treatment and power plant. He was a true partner in the project and was directly responsible for the selection and installation of the manure scraper system in all of the barns, implementing the operations of the truck collection system, the digester and generator systems as part of the farm operations.

Storms Swine Waste Ribbon Cutting

Billy Storms cuts ribbon at Opening Ceremony; team members look on

What can we learn from this project?

This project demonstrates a method to economically build new swine farms without total dependence on the historical open air lagoon treatment system, and flushing system collection methods, a conversion that is necessary to meet the State EST standards. The system also develops renewable energy meeting the goals in Senate Bill 3 requiring swine waste to be utilized in a percent of the production of renewable energy.

However, because of the cost, risk, and complexity of the project, its applicability may be limited to a handful of existing farms in North Carolina.  Larger farms, preferably more than 50,000 animals, are required in order to have the scale to produce the amount of energy to have an economical rate of return on investment.

Thanks, Withers & Ravenel, for the detailed project description. Your turn: Thoughts? Comments? Questions for the team?  Shoot me an email or post in the comments below.

Photos (c) Withers & Ravenel; Pig outline courtesy Pixabay.

Of Bridges, Biofuels, and Buildings (Engineering Excellence Awards)

As I noted earlier this week, the ACEC of North Carolina’s Engineering Excellence Awards gala was held last month. 13 amazing projects were awarded recognition, including projects involving environmental and coastal issues, higher education facilities, and government projects.

Each project was important, unique, or challenging in some manner. In my next post, I will highlight one of the most unusual– the Swine Farm Biogas project by Withers & Ravenel.  In the meantime, here are all of the winners, which I’ve loosely sorted into categories:

Mingo Creek Trail Bridge

Mingo Creek Trail Bridge

Coastal & Environmental projects

The Karen Beasley Sea Turtle Rescue and Rehabilitation Center, Surf City, NC (Cavanaugh & Associates)

Sea Bright to Manasquan Profile Survey, NJ (McKim & Creed)

American Tobacco Trail Pedestrian Bridge, Durham, NC (Parsons Brinckerhoff)

Mingo Creek Trail, Knightdale, NC (Stewart)

Town of Hillsborough Riverwalk, Hillsborough, NC (Summit Design and Engineering Services)

Swine Farms Biogas Renewable Energy Project, Bladenboro, NC (Withers & Ravenel)


Marsico Hall at UNC

Marsico Hall at UNC

Campus & Higher Education projects

South Halls Renovation, Penn State, University Park, PA (Clark Nexsen)

Science & Technology Building, Fayetteville State University, Fayetteville, NC (McKim & Creed)

Marsico Hall, University of North Carolina, Chapel Hill, NC (Mulkey Engineers & Consultants)

Military, Municipal, & Highway projects

Infantry Squad Battle Course, Marine Corps Base Camp Lejeune, Jacksonville, NC (Catlin Engineers and Scientists)

Carolina Field of Honor War Memorial, Kernersville, NC (Woolpert)

Broad Avenue Bus Terminal, High Point, NC (Mulkey Engineers & Consultants)

NC DOT Land Application of Concrete Byproducts, NC (S&ME)

The diversity of the award-winning projects was very clear, as even a cursory review of the projects demonstrates.  I recommend you follow the links to the specific projects to see some great photos and hear more about the projects in detail.

In the meantime, tell me what project you would have given the “best in show” award to if you were the judge.  Or, was a project left out of the awards that you thought superior to some of these?  Share your thoughts about both these projects, and any others that you think should have made the cut, in the comments section.

Photo credits:  Mingo Creek Bridge by James Willamor; Marsico Hall by Bbfd

Bats, Water, Soil, and Bridges- an Engineer’s dream

Want to know how bats may effect your engineering plans?  Want to hear about cool new bridges?  Read on.

Over the past month, I’ve had the pleasure of attending two events hosted by the North Carolina Chapter of the ACEC (American Council of Engineering Companies).  The first of these was the Joint Transportation Conference, held in conjunction with the NC DOT.  The second was the annual ACEC Engineering Excellence Awards.  At both events, I learned interesting information that engineers should know. Today, I will discuss the Transportation Conference, including some new regulations and unusual design methods.  I will save the highlights from the Excellence Awards for later this week.

Northern Long-eared Bat

Northern Long-Eared Bat

  1.   It’s a cave, it’s a bat, it’s bats, man!     Did you know that your future bridge project may be effected by the Northern Long-Eared Bat?  It’s true.  Right now, the federal government is considering listing the bat on the Endangered Species List, due to the 98-99% mortality rate the bats are experiencing due to “white nose syndrome”. Over 1,700 projects in North Carolina could be impacted, including work on bridges, culverts, abandoned buildings, and guardrails–essentially, any activity involving tree clearing, structure demolition/removal, or structure maintenance. On November 26th, 2014, the US Fish and Wildlife Service extended the comment period to discuss the implications of listing the bat on the endangered species list. If the bat is listed, there is no grandfathering of projects.  All projects will immediately be required to engage in protective activities. Stay tuned, but be aware that your transportation projects could be effected starting sometime next year.


2.  Is that a pirate on your map or is it worse–soil contamination? 

known and possible soil contamination

known and possible soil contamination

At the conference, we also heard from the GeoEnvironmental Section of NC DOT on their geologic symbols for known or potential contamination. Known contamination consists of soil or ground water samples that have been analyzed; or by evidence of such contamination as cracked transformers, battery casings, unusual odors while excavating, or new anecdotal information about past use. Potential contamination, in contrast, is for areas where there is no data, but historical maps or photos which indicate current or assumed past uses of possible contamination, such as gas stations, dry cleaner facilities, auto body facilities, chemical manufacturers, landfills, and manufacturing plants. Both known and potential contamination sites are important for designers, as they consider:

  • large cuts, drainage, utilities, or stream relocations in contaminated areas
  • selecting chemical resistant construction materials
  • additional costs for materials, remediation
  • other unanticipated costs or complications


highway stormwater program     3.  Water, water everywhere!  We also heard what’s new with the Highway Stormwater Program, including the updated Post-Construction Stormwater Program and the companion Stormwater BMP Toolbox manual. To learn more about these programs, check out:

  • The NCDOT Stormwater website, which contains useful links; and
  • The Highway Stormwater youtube chancel of training videos, which is still in development but will include environmental sensitivity maps, nutrient load accounting tools, and stormwater management plans.


Dragon Bridge

Dragon Bridge

4.  Cool, cool bridges  One of the highlights of the conference was hearing about some truly unique bridge designs, including:

  • The Tappan Zee Hudson River Crossing, in New York, featuring twin-tower cable stayed structures and all electronic toll collection
  • Vietnam’s Dragon Bridge, a truly working piece of art; and
  • The Milton-Madison Bridge Slide, (Indiana/Kentucky) the longest bridge slide in North America.  The Milton-Madison Bridge Slide was  a feat of engineering design.  Using “truss sliding” a new 2,427 foot long truss was moved along steel rails and plates and “slid” into place atop the existing, rehabilitated, bridge piers.


What about you?  Did you attend the conference?  If so, what insight did you take away?  Share in the comments, below.


Photo credits:  Bats ; soil marks from NCDOT presentation; Dragon Bridge

Modernist Houses Galore! [visual candy for architects]

candyDo you like modern architecture?  Is Frank Lloyd Wright someone you wish you could have met?

If so, then you’ll want to check out the new “Masters Gallery” of the North Carolina Modernist Houses (NCMH) group.  With changes and additions announced this week, it’s Gallery is America’s largest open digital archive of Modernist houses, as well as the internationally known Modernist architects who designed them.

Currently, the Gallery showcases over 30 architects with extensive house histories and over 10,000 photos.  The Gallery is extensive and searchable and includes, among many other notables, Frank Gehry and, of course, Frank Lloyd Wright.

To view the NCMH Masters Gallery, go to http://www.ncmodernist.org/ and click on “Masters Gallery” under the Archives listing.   Be careful, though, because NCMH founder and director George Smart, you can spend many addictive hours looking around.  Hey, at least this addiction doesn’t require a trip to the gym afterwords!

 Photo courtesy WikiMedia Commons.

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