The Construction Phase

Now that you have hired your architect, discussed all the attributes of your building project (including all the sustainable issues and more discussed in the blog), you are ready to build your project. This will be the longest and most intensive phase of the project. You will be working not only with the architect and their staff, but also the contractor, city inspectors, your materials testing firm, possibly the state department of transportation if you front a highway, the county health department and others. The first step is to have the architect issue a 'Notice to Proceed'. Usually you have a pre-construction meeting with all the subcontractors and general contractor to go over the parameters of the project, discussing who is the contact person for each entity, shop drawing submittals and pay application submittals and the timing of each. The Notice to Proceed is critical because it sets the date that the project construction officially starts. All parties agree on this date at the pre-construction meeting. Unless you have a starting date, there is no way to prove the ending date, which sometimes can be controversial. The pay applications are the monthly requests from the contractor for the work in place and any materials that are stored on site. The architect reviews the monthly pay apps and approves the work, or has the contractor make revisions if there are discrepancies. Notice that you are paying for materials that are stored on the project site. We do not recommend that you pay for materials stored off site unless they are in a bonded and insured warehouse. Even then, we usually limit the amount of materials stored off site to special occurrences that cannot be avoided. The pay applications will show the amount of work completed and the amount in retainage. The normal amount of retainage is 5% of the total amount of the contract. This amount is withheld each pay period and held to the end of the project to insure that all the work has been completed to everyone's satisfaction. As the work progresses, the contractor will have questions that will arise. These are put forth to the architect in an 'RFI', or Request For Information. It is critical that the architect respond to these RFI's in a timely fashion so that the construction of the project in not impacted. Weekly on site job progress meetings should review all outstanding RFI's and their progress. The weekly meetings should also discuss and review the construction schedule. If progress has been impeded by any issue, it is critical for the contractor to show you how they intend to make up for the lost time. If the delay is weather related, it rained or it is too muddy to work, then the contractor must log that occurrence and request and extension of time to the architect. This of course depends on how the contract is written, if you are allowing weather related days to extend the contract time or not. My next blog will discuss the change order process and how to close out a project.

Fluorescent vs. LED Lights

As school budgets and energy consumption continue to be hot topics; and the IgCC (see The Future of Building Green) is requiring both dimmable light fixtures and occupancy sensors, selecting the proper lamps for your school should be an important topic of discussion. The two biggest players in the game are Fluorescent and LED – both viable options, depending on your district’s goals.

Important characteristics that will apply to both lamp types are as follows:

Lumens – the amount of light emitted per second (light output)

Efficacy – is the factor of lumens per watt consumed

Color Rendering Index (CRI) – The measure of the ability of a light source to reproduce the colors of an object as compared to a natural light source; expressed on a scale of 0-100 with 100 being daylight. The available range is relatively the same (50-90) in both fluorescent & LED lamps so I won't compare them, but it's important to speak with your architect and electrical engineer about your expectations.

Color Temperature (CCT) – The numerical measurement of a light source’s color appearance, measured in degrees Kelvin. Think about fire, as it begins to burn, the flames are red & orange, but as it gets hotter, the flames turn blue & white. Lamps are the same, cooler temperatures are warmer in color and warmer temperatures are cooler in color. Similar to CRI, the available ranges are the same (2500K-6500K), you just need to discuss options and related costs with your architect.

Linear Fluorescent Lamps: The Contender

This is the MOST common lamp used in commercial and institutional buildings. This fact alone is what makes them so affordable - the technology is mature and the market stable. The basic construction of a linear fluorescent lamp is a glass tube coated on the inside with a phosphor, filled with a mixture of argon/krypton gases and a tiny amount of mercury. Light is produced when the phosphor coating is excited by the UV radiation from the electrode/mercury combination. It is very important to ensure lamps are disposed of properly because while the amount of mercury is small, as thousands of lamps end up in landfills the hazard increases. Please contact your city for proper hazardous waste disposal. Lamps are identified based on their shape and diameter – meaning if the Tube is 1” (8/8”), it is a T8. Standard sizes used in schools are T12s (although these are being phased out for inefficiency, older buildings may still have them), T8s and T5s. It is important to note that ALL fluorescent lamps require a ballast (a mini transformer) to provide voltage to start the lamp and regulate the electrical current during operation. T12s use electromagnetic ballasts and T8/T5s use electronic ballasts that are about 40% more efficient than electromagnetic. An energy conservation option for older buildings with tight budgets is to convert all T12 lamps to T8s; just be sure the fixtures and ballasts are compatible with the new lamps. An uncommonly known downfall of linear fluorescent lamps is their sensitivity to temperatures. Fluorescent lamps will not light up in extreme cold or hot temperatures because the mercury vapor pressure is dependent on the ambient operating temperature of the lamp (not room temperature, but the temp around the lamp itself in the fixture). The lamp life can also be affected by how often the light is turned on & off. Lamp life is based on a three-hour burn cycle, three-hours on and 20-minutes off. Operating lamps at a longer than three-hour burn cycle will increase lamp life (up to 36,000 hours); conversely, operating lamps on shorter burn cycles will reduce lamp life.



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Image courtesy of US Dept. of Energy

Advantages:
Mature Technology = Low Cost
Low Cost per Lumen
Extensive Fixture Options

High Efficacy (30-110 lumens/watt)

Long Life (7,000-24,000 hours)

Disadvantages:

Requires a ballast

Added cost for dimmable ballast

Temperature Sensitivity
Lamp life affected by how often it's turned on/off
Must be disposed of properly (mercury & gas)

Delayed turn on - flicker

LED Lamps: The Challenger

Light Emitting Diodes (LEDs), also known as Solid State Lighting (SSLs), are highly sought-after for their reduced energy consumption. Multiple LEDs can easily put out the same amount of light as fluorescent tube for a fraction of the wattage. An additional cost savings that we stumbled upon in a recent project was that while one electrical panel can typically support 25 linear fluorescent troffers (the 2x4 fixtures), the same panel could support 75 LED fixtures – that’s a significant initial savings in electrical equipment. That’s right, I said it: initial savings. Every time someone brings up LED lights their first reaction is, “I know they’re more energy efficient, but it costs SO much initially.” Initial costs are dropping slowly and there are some factors that are making the competition a little closer. I mentioned fewer electrical panels for the same # of fixtures. If you’re familiar with the new energy code (IECC), it has defined that any lights within daylight zones must have dimmable controls that are independent of the general area lighting. In order to make a fluorescent lamp dimmable, there is a major change in the ballast that increases the cost – almost equal to that of an LED which is inherently dimmable. Another thing people are concerned about is the color of LEDs. Long gone are the days of blue-tinted light, unless that’s what you want. In fact, LEDs are available in saturated colors (Red, Green, Blue, etc.) and various temperatures of white light – some achieving CRIs of 90+. The final benefit I’m going to discuss is the heat emitted from LED lamps. A typical linear fluorescent emits about 30 btu’s/hr while an LED only emits 3.4 btu’s/hr. This could translate into a minor adjustment to the cooling load for the building – something to discuss with your mechanical engineer.

Advantages

Image courtesy of US Dept. of Energy



High Efficacy (25-100 lumens/watt)

Long Life (35,000-50,000 hours)

Inherently dimmable

Reduced energy consumption (~1/2)

Mercury-Free

Less Heat Build-up (~ 1/10^th)

Immediate On

 

Disadvantages

High initial cost

Directional nature – requires more lamps to get ambient light effect

Limited fixture options (troffers)

Resources:

U.S. Department of Energy - http://www1.eere.energy.gov/manufacturing/utilities/fluorescent.html                                           http://www1.eere.energy.gov/manufacturing/utilities/solidstateled.html

Eartheasy - http://eartheasy.com/live_energyeff_lighting.htm#1c

Comparison Chart: http://www.designrecycleinc.com/led%20comp%20chart.html

Window Design

We all know how hot it can get during these summer months. While I sit here next to a window in my cubicle, it got me thinking about proper window design. Many of us spend most of our day inside buildings that do not have efficient windows. You can definitely feel the difference when you walk into a room with windows facing south and/or west. Improper glazing can negatively affect the building’s energy consumption, appropriate levels of day lighting, and the occupants’ visual and thermal comfort.

When it comes to window design, there are several variables to consider. A few come to mind such as the current climate condition, where the building is located, the building size and type of windows, and the building’s primary function.

The orientation of the building plays a big part on how it can maximize solar access. Taking full advantage of day lighting can help reduce the need for electrical lighting as well as heating and cooling loads. One best practice on proper building orientation is with the long axis of the building oriented east-west to maximize southern exposure and northern indirect lighting which can contribute to less heat gain and glare.

The window size and placement on the building, according to the regional climate, also play a part in climate control. Colder climates perform differently than warmer climates. In colder climates, it’s best to take full advantage of the sun by placing larger windows on the south side, which can provide greater opportunity for passive solar heating. Here, the sun rises farther south of east and also sets farther south of west. In warmer climates, it’s difficult to control solar heat gain and glare when placing windows on the east and west sides of the building. The sun rises north of east and sets north of west. Therefore, windows on the east and west sides will get direct sunlight for several hours each day. This will also bring in more heat when it is not needed. One solution to help control this in the warmer climates is to provide window shades, fins and/or overhangs. However, north and south facing windows should be significantly larger to provide better daylight and views.

The type of glass also plays a part in the aesthetics, energy consumption, and glare within the building. Different types of glazing vary in their abilities to let light through and to prevent heat loss. Glazing is rated by several factors such as:
1. U factor: This is a measurement of the rate of heat transferred through the glass. The lower the U factor, the less heat that actually enters the building.
2. Solar Heat Gain Coefficient or SHGC: This is the fraction of the solar energy that is transferred through the glass of a window. In cold climates, a higher SHGC is ideal to collect heat from the sun. In warm climates, a lower SHGC is desired to block heat from the sun from entering the building.
3. Visible Transmittance or VT: This is how much light is transmitted through the glass. The higher the percentage, the more light that comes through the window.

All of these factors can be obtained by window manufacturers.

http://www.efficientwindows.org/ToolsForSchools.pdf

The Future of Building Green

Third party ratings systems for green design have been around for some time now, but it’s possible that rating systems may eventually go away. Perhaps green supporters are finding ways to ensure that green design sticks around for good.

The U.S. Green Building Council (USGBC) , American Institute of Architects (AIA), and several other key organizations joined forces with the International Code Council (ICC) to develop the future of building green as code; thus, requiring the reduction of energy usage and environmental impact in commercial construction (new and existing).

The International Green Construction Code (IgCC) is the first of its kind for state and local government to adopt as of March 2012. The IgCC is intended as an overlay code to the existing set of International Building Codes, and as a complement to voluntary third party rating systems such as LEED. As an overlay code it allows green design practices to be integrated without conflicting with International Building Codes.

The IgCC is setup by chapters and addresses areas including: Site Development, Material Resource, Energy and Water Conservation and Efficiency, Indoor Environmental Quality and Comfort, Building Operation and Maintenance; in addition to Project Electives. The Project Electives are opportunities for building designs to exceed minimum requirements. The total number of electives which a building owner must comply is set by the jurisdiction; however, the building owner can then select which of those electives is appropriate for their project.

The IgCC is utilizing best practices within the code to deliver opportunities for building owners to have a high performance building. Criteria under “Building Operation, Maintenance and Owner Education, “such as periodic re-commissioning helps ensure that a building is performing as designed. Commissioning offers owners the opportunity to correct or improve building systems that affect the operations and maintenance cost over the lifetime of the building.

Most notable is that the IgCC is not required to be adopted in full. It allows jurisdictions to select from baseline provisions and also provides flexibility through provision options that can be customized to meet local needs. The IgCC is written in a mandatory and explicit language; however, the code can be adopted as mandatory or non-mandatory.

Because the code can be customized by the jurisdiction; it gives the public an opportunity to influence which parts of the code are adopted. Several cities and organizations have assembled task force groups to evaluate the development of the IgCC and offer recommendations on what to adopt and when, since this gives tate and local jurisdiction the authority to enforce green building practices as code.

The next round of changes to the IgCC is scheduled for 2014. Like any new code it will likely take several years for mainstream adoption. However, early adopters such as the state of Oregon, Rhode Island, Maryland, North Carolina, and Florida; as well as the cities of Richland (Washington), Keene (New Hampshire), Scottsdale, Phoenix and Kayenta (Arizona) and Boyton Beach (Florida); put this green code on its way to becoming the future of building green.

For more information on the International Green Construction Code visit: www.iccsafe.org