Q: We are developing a post-occupancy evaluation for our clients and are struggling with how to ask the users, who don't know much about green buildings, about the qualities of their green building. Do you have any suggestions for resources or examples of occupant surveys?
A: Post-occupancy evaluations (POEs) are useful for evaluating the success of any building design, but are particularly useful in evaluating green buildings. It is the only opportunity architects and designers have to learn if their buildings actually work. Think of it as a report card to assess what is good about a building and what is not.
The goals of a green POE are to document and measure the indoor environmental quality, energy performance, occupant satisfaction and the other green factors you incorporated. This information will help architects design better green buildings.
Using interviews, behavioral maps, user surveys, visitor questionnaires and observational walkthroughs, POE reports typically contain nine items (sorted by priority):
Top Priority: Health, Safety, Security
Mid Priority: Function, Efficiency, Work Flow
Last Priority: Psychological, Social, Cultural
Some examples:
1. The University of Minnesota's Center for Sustainable Building Research (CSBR) (http://www.csbr.umn.edu/evaluation.html) has conducted POEs of the sustainable design efforts of several state agencies.
Their researchers discovered when more daylight was incorporated into green buildings, too little thought was given to shading and light control. Excessive glare from the natural light, especially at computers, was lowering productivity.
Occupants had invented "unique" strategies to minimize the glare, from hanging blinds to covering windows with cardboard or using umbrellas over their desks. Normally, architects would be unaware of the repercussions of such measures. A POE reveals new design opportunities.
2. The Probe studies in the UK (http://www.usablebuildings.co.uk) were a unique collaboration between researchers, designers, government and publishers to undertake POE studies of sixteen commercial and institutional buildings. They addressed the efficient operation of buildings, generating valuable information about the success of a variety of green building strategies.
3. Keen Engineering (http://www.stantec.com) carried out POE surveys of seven green buildings in the Pacific Northwest using a web-based Occupancy Satisfaction Survey developed by the Center for the Built Environment at the University of California-Berkeley (www.cbe.berkeley.edu).
Despite the valuable information gained from a POE, they are rarely undertaken. Green and high-performance buildings are particularly good candidates for POEs, since they provide a way to learn about the performance or unexpected side effects of new products, technologies and techniques.
POEs may also help to evaluate whether LEED-certified and other green buildings deliver on their promises, and they can provide the hard evidence that green building advocates need to make their case.
Some suggestions for fully benefiting from Post-Occupancy Evaluations:
-
Include POEs in your proposal to ensure you get paid for your work.
-
Remember the old business adage: If it gets measured, it gets managed.
-
Publish your findings in-house to the other teams so everyone may learn from past projects.
-
Use the findings from one POE to benefit current and future projects. You will be able to say with great accuracy how much energy a particular design can produce and how happy occupants are with a particular amount of natural light.
-
Share your findings with your client and offer staff trainings as part of a possible additional service.
FURTHER READING:
Improving Building Performance
by Wolfgang Preiser, PhD
www.ncarb.org
Post-occupancy Evaluation
by Larry Lord and Margaret Serrato
http://www.aia.org
California Department of General Services
Quick-Response Studies guide
http://www.documents.dgs.ca.gov/POE/Reports/FINAL_QRS_Protocol_Guide_2-28-03_e.doc
RELATED LINKS:
Facility performance evaluation (FPE)
Whole Building Design Guide
http://www.wbdg.org/design/fpe.php
BetterBricks
http://www.betterbricks.com
MORE INFORMATION:
Building Research Establishment (BRE)
http://www.bre.co.uk
Usable Buildings Trust
http://www.usablebuildings.co.uk/
Center for the Built Environment
www.cbe.berkeley.edu
University of Minnesota Center for Sustainable Building Research
www.csbr.umn.edu
GreenClips
http://www.greenclips.com
California Department of General Services
http://www.poe.dgs.ca.gov/
AIA Center for Building Performance
http://www.aia.org/bp_confreports
--------------------------------------------
Q: What is fly ash? What are the positive and negative affects of using it in concrete.
A: Let's take your question in parts. First, WHAT IS FLY ASH?
Fly ash is the fine residue powder byproduct from coal-fired electric generating plants. Since the burning of coal provides up to 85 percent of our electricity (depending on where you live), a great deal of this powder is produced. Some sixty-three million tons of fly ash were produced in 2002, resulting in sixty-three tons of mercury byproduct.
Currently, the fly ash is released into the air, buried in a landfill, or illegally dumped into our oceans. Fly ash contains approximately one part per million of mercury (NOTE: The maximum level of mercury in drinking water permitted by the EPA is two parts per billion.) The mercury seeps into our groundwater and contaminates our fish. Humans eat the fish, and the mercury accumulates in our bodies.
Mercury has been linked to numerous health problems, including autism in newborns, endocrine disruption, and cardiovascular disease. Since 1990, there has been a 10-fold increase in the incidence of autism. One can quickly see a need for an alternate use of this fly ash.
NOTE: It only takes 1/70th of a teaspoon of mercury to contaminate a 20-acre body of water and make all fish within it toxic to humans. This is about the amount of mercury in a typical medical thermometer.
WHAT IS CONCRETE?
Concrete is a mixture of sand, water, stone and Portland Cement. The cement is the key ingredient in concrete, comprising about 12 percent of the mix weight, acting as the binding agent that holds sand and other aggregates together in a hard, stone-like mass.
Energy consumption is the biggest environmental concern with Portland Cement, requiring a great deal of energy to mine out of the earth, grind up, heat in a kiln and process into the final product. Cement production is one of the most energy intensive of all industrial manufacturing processes. One can also see a need to find an alternative for cement.
HOW TO OFFSET THESE ENVIRONMENTAL EFFECTS:
Depending upon the use of the concrete, fly ash can be substituted for 20 to 50 percent of the Portland Cement in the concrete mix. There have been reports of some people using as high as 70 percent fly ash substitution.
By taking a waste byproduct that was previously releasing mercury in our environment, we are also reducing the amount and impact of cement, therefore killing two birds with one stone (no pun intended).
The use of fly ash in concrete already saves about forty-four trillion Btus of energy annually in the United States. Increasing the rate of fly ash substitution from the current 9 percent to a conservative 25 percent would save an additional seventy-five trillion Btus.
OTHER BENEFITS OF USING FLY ASH IN CONCRETE:
Fly ash also offers numerous other advantages. It improves the performance and quality of the concrete. Fly ash affects the plasticity of concrete, improving workability and reducing the amount of water needed. In addition, fly ash will increase strength, reduce permeability, reduce corrosion of reinforcing steel, increase sulphate resistance, and reduce alkali-aggregate reaction.
In terms of costs, fly ash is actually less expensive than concrete, giving you no reason not to use it on every project.
DRAWBACKS OF USING FLY ASH IN CONCRETE:
Since a concrete mix is essentially a big chemical reaction, adding fly ash slows the curing of the concrete. This can be an issue in situations where the concrete must reach a certain percentage of its maximum strength in a certain time.
In addition, if you are using a spray-on concrete (shot-crete) type of installation, you may have problems with adding fly ash and the consistency of the mixture.
Otherwise, no other features of adding fly ash would be seen as a drawback.
HOW TO SPECIFY FLY ASH IN YOUR CONCRETE:
There are at least a dozen companies providing fly ash to concrete producers. Talk to your contractor or concrete supplier and find out if they are willing to add fly ash to the mix. Your structural engineer should be consulted before changing the structural concrete mixture.
FLY ASH USE IN OTHER BUILDING PRODUCTS:
Faswall is a fiber-cement block Insulated Concrete Form (ICF). These ICF's are made of cement with fly ash content to reduce the amount of cement used.
www.faswall.com
Syndecrete is a precast lightweight concrete containing fly ash and recycled waste from carpet manufacturing. The product is more resistant to chipping and cracking than conventional concrete, tile, or stone making it a great choice for countertops, table tops, fireplace surrounds and sinks.
www.syndesisinc.com
SOURCES:
Headwaters Resources
http://www.flyash.com
Environmental Building News
http://www.buildinggreen.com/auth/article.cfm?filename=020201b.xml (SUBSCRIPTION REQUIRED)
Berkeley Energy Office
http://www.ci.berkeley.ca.us/sustainable/residents/TrueCosts/100Watt.html