BUILDING SYSTEMS:
AN INTRODUCTION

2008 Fred Tepfer
1380 Bailey Avenue Eugene, OR 97402
non-commercial use freely granted
 

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Why Building Systems Matter

You've read the headlines: Two identical office towers with very different utility bills. Brand new schools who use much more energy per student than 70 year old schools. Buildings that have to be completely abandoned due to problems with leaks, or mold, or failing foundations, or asbestos. All of these failures stem from poor understanding of building systems. This is where the building details are, where the facilities rubber hits the road.

But wait a minute. As an educator, don't you just hire a professional, an architect or an engineer, to take care of this for you? Well, in every case cited above, they did hire a professional. The best places are created by the talented professionals working with committed, informed owners and users, which is you, at some time in your future. In particular, if you care about the long-term ownership costs of your buildings, then you really care about the selection and maintenance of building systems, because that's where the money is. Or if your interest is environmental impacts of building construction and operatiion, that's also largely about building systems.

Understanding certain conceptual models about buildings is a good starting point for becoming competent in facilities. Two of these models are particularly useful.

Model 1

The first model is to conceive of building systems as analogous to animal systems:

BUILDING SYSTEM ANIMAL SYSTEM
structural frame (beams, columns, etc.) skeleton (holds up body)
exterior skin ( exterior doors, windows, and roof) skin (protects from environment)
heating/cooling/ventilating systems blood circulation system (moves energy)
electrical system (also includes computer & phone networks) nervous system


Model 2

The second model is more sophisticated and more meaningful, and appears in Stewart Brand's How Buildings Learn , a book highly recommended to anyone who is planning, designing, building, or otherwise participating in building-related processes. Brand organizes the building elements as shown in the diagram below. He suggests that buildings with appropriate separation of systems are much better to own and inhabit, and will have longer and more useful lives because they allow the layers to be maintained and replaced at different times. For example, if the plumbing pipes are entirely buried in the concrete structure, it is very difficult to work on them. Similarly, if all of the internal walls are of solid concrete, the interior layout of the building can't adapt to changing needs, so it cannot evolve and may be doomed to a premature death (see Commonwealth Bridge case study).

It is important to keep in mind that all of this exists to support and enhance the human activities in the building: the learning, the teaching, the preparation, the interactions, and so forth.

Elaborations on what these mean:

Skin is the stuff that keeps out the elements, including roofing, siding, windows, exterior doors, gutters, caulk in cracks and joints, and so forth. Most people put thermal insulation here also.

Structure holds up the building. Separation of structure from space dividing systems is important because it allows for future addition or removal of interior walls and doors as program needs change. Starting from the top, the roof has rafters or joists or trusses, and beams, and possibly girders (beams that hold up beams). The exterior walls may hold up the roof or the roof may be supported by columns (posts). The floor may sit directly on the ground (a concrete slab-on-grade) or may be built of concrete, steel, or wood with a basement or crawlspace underneath. There are also elements that brace the building against lateral (sideways) forces such as wind and earthquakes.

Systems (or Services) provide comfort and communications to the users of the building. Proper separation of systems and allowance for future system expansion and replacement are essential to good building design. Heating, cooling, plumbing (for kitchens and restrooms and to carry away stormwater), electric power, fire alarm and fire supression (sprinkler) systems, phone and data communications (including computer networks, television cable) are all building systems. Building systems, especially heating/cooling systems, are responsible for a high proportion of building operating costs.

Space dividers are walls, doors, and so forth. Flexibility for future change is probably as important as the original layout, as most buildings are re-configured during their lives. Keeping major system elements (main pipes, main electrical runs, main duct runs, etc.) out of the way of future changes to interior walls is an important part of this. Some of the building finish materials on space dividing systems are responsible for a high proportion of building operating costs, in particular floors, restrooms, and doors.

Stuff is what we use in our daily lives, the furniture, books, chalk, table lamps, and so forth, as well as the people who occupy the space.

Site is where the building is and is largely immutable. School sites evolve over time with changing needs for outdoor education and recreation, but these changes are largely superficial and respect the original site characteristics and placement of the buildings. Large buildings are very rarely moved to a new site.

Skin and systems (or services) are the two areas that have the largest long-term impacts, as does site to a smaller extent. Mechanical systems (fans, pumps, controls) have many moving parts, complex systems, and are often poorly designed, poorly maintained, and have high long-term costs for schools. Electrical systems' long-term impacts are mostly concentrated in lighting systems which use a high percentage of the building energy, require relamping and cleaning, and may have complex control systems. Building skin relates to energy use, daylighting, and also, after an initial honeymoon period, a high percentage of maintance dollars. A cursory understanding of mechanical systems, building skin issues, and lighting systems is essential in smart decision making for the long-term health of your district. Here are some specific examples of why this can matter:

Example #1:

There is a common assumption that new buildings are less expensive to operate than older buildings. While this is often true, it's surprising how often the newest buildings in a district have the highest energy cost (measured on a per student basis). When the systems are at least twenty years old and past their "honeymoon" period, there are many cases where all costs exceed those of older schools. Why is this so? New schools often are air-conditioned, which uses a lot of energy, heated and cooled with fans instead of radiators, which uses more energy. New schools often have very complex heating/cooling control systems that districts can't afford to maintain, especially when the $125 per hour technician comes from two or three hours away. This results in systems operating out of balance, simultaneously heating and cooling air at tremendous financial and environmental cost. A surprising number of modern buildings run heating during the xummer

Example #2:

Lighting systems installed before the mid-1990s are quite possibly very inefficient. They may use systems that are inefficient (older fluorescent tubes and ballasts, inefficient fixtures) and/or provide more light than is needed. A project to replace the fixtures, or to relamp/reballast them, can be paid for in part with utility incentives and pass-through tax credits, and result in quick savings.

In new or older buildings, schools can effectively use daylight to replace electric light, but such an approach must be designed and implemented. One approach is to put the lighting near the windows on light sensors that turn off or turn down the fixtures near the window. If the room is well designed for daylight, it has well-distributed daylight and the electric light can be turned off entirely. Quite a few classrooms designed before 1970 incorporated advanced daylighting approaches, but no automatic controls.

 

 

 

The following articles in this section provide additional information about building systems, especially as they relate to the ownership and design of schools.

  1. Green Buidlng Systems
  2. Heating, Ventilation, and Air Conditioning
  3. Finishes
  4. Roofing
  5. Acoustics

updated 1/08

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