The Activity Center
An Exercise in Energy
THE ACTIVITY CENTER: AN EXERCISE IN ENERGY MERIDIAN OFFICE PARK DOUGLAS COUNTY, COLORADO
AN ARCHITECTURAL MASTERS THESIS SUBMITTED TO THE THESIS COMMITTEE COLLEGE OF ENVIRONMENTAL DESIGN UNIVERSITY OF COLORADO AT DENVER
DAVID SAMUEL MILLER, JR. SPRING SEMESTER 1932
"You will at once admit that any businessman approached several years ago with a view of purchasing stock in a flying machine company would have feared the sanity of the proposer. After it has been shown conclusively that it can be done, there is now no difficulty in securing all the money which is wanted, and very rapid progress in aviation is from now on insured. We will have to go through this same course."
Solar Entrepreneur 1906
"Facilities for recreation have come to play an ever more significant part in the leisure activities of Americans of all ages. And the use of such facilities has come to be ever more a part of daily life rather than a departure from it. The lunch-hour or after-work swim or tennis game, the family bowling, skiing or boating outing have become quite ordinary in contemporary life; and more and more facilities are being designed to accommodate them."
Jeanne M. Davern Places for People 1976
Project Description and Objectives Advisors Background Evolution
Current Precedents Site Analysis
Location and Context
Climatic Analysis and Building Recommendations
Topography and Soils
Codes and Zoning
Uniform Building Code Colorado Energy Code Handicapped Law Douglas County Zoning Energy Sources
Photovoltaic Cells Thermoelectric and Thermionic Cells Solar Steam Wind
Geothermal Hydro-electric Tidal-electric Storage
Energy Center Lobby Reception Pro Shop Starter
Business Manager Accounts
Athletic Department Secretary Computer Area
Systems Synthesis Appendices
A: Wind System Data B: Photovoltaic Manufacturers Bibliography
Not since the period of the Roman Empire, has the emphasis of energy and activity been evident in society. Americans are increasingly conscious of their health, often to the point of obsession. And with the Arab Oil Embargo in 1973, energy awareness has also been an obsession. This is the image that H.O.H. Developers are proposing for the Meridian Office Park in suburban Denver. The concept provides facilities for healthy leisure activity, while expressing energy efficiency in structure.
In this thesis report, I plan to go one step further: to develop an architectural design for a recreational center that is completely energy self-sustaining. This will not only include heating, but it will also incorporate electrical power generation for this approximately 45,000 sq. ft. facility. A thorough investigation of the various energy alternatives will be shown, as an example for small communities, agriculture, industry, and administrative uses.
The activity center will provide:
22 handball/racquetball courts 2 squash courts
indoor lap pool and outdoor recreation pool
full gymnasium for basketball, volleyball, badminton and free exercise indoor and outdoor jogging track outdoor sand volleyball
Nautilus weight lifting equipment for "circuit training" locker facilities for both men and women
sauna, steam, whirpool, hot tubs, cold plunge and massage â€”
lounge with full bar pro shop
golf starting house
The energy center will provide:
electrical power generation sources back-up storage capabilities control room with monitoring equipment climatilogical data collection public information and tours
Advisors and Acknowledgements
Elizabeth Wright Ingraham Architect
Architect, Design Professor at the University of Colorado at Denver
T. David Lee
Associate; Barker, Rinker, Seacat and Associates, Architects Jeff Gilberti
Sales Director, The Denver Sporting Club
Architect, Design Professor at the University of Colorado at Denver G.K. Vetter
Architect, Design Professor at the University of Colorado at Denver Gary Long
Systems Synthesis, Mechanical D.C. Holder
Systems Synthesis, Structural
Historically, organized activities and self-improvement programs were originated by the Greeks 2500 years ago. Olympic spirit and greatness became routine in Greece. Intellectual, spiritual and physical improvement was instilled in all Greek citizens, as evidenced by the various physical elements such as the temples, stadiums, and amphitheatres.
Also, the Greeks were involved with the warming properties of the sun. The sun was thought of as a means for good health. Therefore, access to sunlight became a priority parameter in Greek design. Another consideration for the development of passive solar technology in Greece was due to the scarcity of wood and coal for heating fuel. Importation of these fuels became expensive and time consuming, and so solar heating and cooling principles were developed. Among these principles were building and room orientation, porticos facing south, overhangs for sun control and thick adobe walls for insulation.
Three Greek cities exemplified this solar attitude. Olynthus, a solar planned city of 2500 residents built in the Fifth Century B.C., Priene, a city of 4000 residents on the south slope of Mount Mycale, and Delos, built in the rocky terrain of the Aegean. Each city had streets which ran on an east-west axis for maximum southern exposure and , therefore, permitted all citizens to receive the opportunity of solar radiation.
In Rome around the Third Century B.C. the greatest parallel in history to this particular project developed. Fossil fuels were depleted, and transportation costs for these fuels were exorbinant. Solar energy principles were therefore implemented by Vitruvius, the master of Roman architecture, to alleviate the situation. Vitruvius borrowed the principles already established_by the Greeks. These concepts plus the new use of glass and mica, increased the Roman's ability to capture solar heat.
Roman society also placed great importance on leisure. The government built large baths for its citizens to relax arid play. Self-improvement activities were undertaken in warm, comfortable solar heated environments.
As with the Greeks, the sun was again thought of as therapeutic.
The best example of this combined thinking for leisure activity in a solar environment, would be the Baths of Caracalla. Caracalla was constructed to serve 2000 people. Incorporated in the design were saunas, swimming pools, baths and exercise areas for weightlifting and other strenuous activities. The plan was oriented on an east-west axis to maximize solar gain. Use of maximum fenestration on the south, with little or no fenestration on the north kept the structure as warm as possible. Pools and tile masses were utilized for heat storage.
The ancient city of Priene
The ruins of the Baths of Caracalla in Rome.
Cross-section of the caldarium in the public bath
This leisure attitude led to the eventual downfall of the Roman Empire. They bacame lazy and non-productive.
The government was financing leisure activities, which absorbed men from the military. Taxes and food prices were raised to support this diminishing military force, which in turn led to economic and military collapse.
Centuries past, and the impetus on leisure along with the concern over fossil fuel shortages diminished. Work and culture were emphasized, and the dangers related to the reliance on fossil fuels were forgotten.
During the middle of the Industrial Revolution, scientists were again becoming concerned with the extensive use of fossil fuels. Two American engineers by the names of Willsie and Boyle developed the first solar power plant between 1892 and 1909. A total of four plants were constructed to produce power from the sun. The designs involved low temperature flat plate plate collectors and either pumped well water or provided refrigeration. Solar electrical generation was also developed as an economical alternative. Costs for solar power were approximately $1.00/kwhr cheaper than conventional coal power plants.
The most notable of the four plants by Willsie and Boyle was the one constructed in Needles, California. Here, a thousand feet of collector area produced constant water temperatures of up to 180Â° F. Hot water then went to a boiler, heating liquid sulfur dioxide to power the main engine. The Needles plant was also able to achieve something that no other mechanical system had done before, store solar energy. Willsie and Boyle had taken some of the daily hot water from the solar collectors and stored it in an insulated tank. When the sun went down, or it became cloudy, the stored hot water was then run over pipes containing liquid sulfur dioxide, which in turn drove the plant's engine. Thus solar power could be used night and day.
During this same period advances were being made with hydroelectric, wind and geothermal power plants. But probably the one significant advance deals with Frank Shuman's solar power plant in Meadi, Egypt in 1912. Instead of using flat plate collectors, Shuman, along with C.V. Boys, utilized parabolic reflectors with a suspended pipe in the middle. This increased solar collection capabilities 4% to 1. Water was heated to 200Â° F. then converted to low-pressure steam capable of powering an engine. Shuman's collectors were mounted on gearing so they could track the path of the sun. Hot water storage, like that of Willsie and Boyle's, kept the Meadi Plant running night and day. Frank Shuman's plant was the first to incorporate tracking, storage and solar collection into the same sophisticated facility.
Extreme emphasis on leisure again developed during the 1970's in the United States. The leisure movement has recently materialized to engulf the masses. Everyone seems to be involved in a leisure activity of some sort or another.
In the preceding decades before this renewed leisure upsurge, activities were limited to exclusive clubs, schools and YMCA's. The populace was not aware of physical fitness. Beautiful bodies were to belong to movie stars and athletes. But with the increase in heart and lung disease, doctors cried out for people to be concerned with exercise and their bodies. Then in the 1970's fitness and appearance became an obsession.
Unlike the Romans, where leisure activities were financed by the government, the new recreation revolution i entrenched in the free enterprise system. The following figures bear this out: 30 million confirmed runners are purchasing running shoes at $40-$50 a pair, thus amounting to $1.5 billion; 5000 health clubs were built within the recent decade with 300 million square feet of mirrors installed for people to admire their bodies obvious rippling effects through the construction field and manufacturing industry resulted. All told, the leisure industry is a $150 billion business and growing.
Businessmen and women think of leisure in terms of production and profit. Founded in the high technological industries of Japan, recreation and fitness periods for employees have become commonplace. Instead of having a two martini lunch, workers are exercising during their lunch periods. Many major businesses are involved with leisure periods. Among these companies is Xerox, with its own corporate fitness center in Stamford, Connecticut. In the Denver Metropolitan Area such corporations as Johns-Manville, Martin Marietta, IBM and Coors all encourage leisure time periods. Along with the facilities and the time to exercise, classes and clubs for fitness are provided. The total effect is to provide "wellness." Wellness is a term used to describe physical, mental and emotional health. By furnishing an employee with the opportunity for wellness, which reduces stress, an employer gets increased production from an individual. And if employees maximize their productivity, larger profit margins will result for the company. Also, reduced payments for company medical care are a major contributor in the movement for corporate leisure attitude, along with reduced insurance premiums for the individual.
As the saying goes, if you look good, you feel good.
Though there are many facilities for recreation in the Denver Metro Area and across the nation, two stand out as exceptional in their field, and they are the models for the Activity Center at Meridian Office Park. These facilities are The Denver Sporting Clubs in Cherry Creek and the Denver Technological Center. Each of these facilities are heavily used by the paying clientele, and provide luxurious accommodations for the user.
The atmosphere of healthy exercise is combined with privacy, relaxation and social activities for fitness to become a pleasure, not a burden. Fitness through athletics is emphasized, as evidenced by the numerous racquet-ball courts, running track and extensively equipped weight room. Relaxation is considered to be as important as exercise, with such amenities as whirlpools, hot tubs, sun decks, sleeping rooms, saunas and a restaurant/ lounge which have been provided for this purpose.
Cut pile carpeting is furnished throughout, along with fabric wall coverings. Used for luxury and low maintenance the facility looks like a club, not a high school. Mirrors are utilized extensively in the weight room, and both mens and womens locker rooms. Stylish contemporary wood lockers appoint the dressing areas along with the spacious cosmetic areas.
Racquetball courts are constructed of concrete with a white resilient plastic wall covering to provide an even ball bounce and visual clarity of the black racquetball. It costs $5000 per year to paint one court. Sturdy, clear plexiglass is preferred, like that used in championship courts. Artificial lighting is necessary for bright, even illumination. The courts are open on the top for ventilation and viewing access for referees during matches. Airlocks on the upper levels are provided to eliminate court noise for the public and relaxation areas.
The indoor lap pool is of standard Olympic size specifications, and non-slip surfaces are furnished on the pool decks. A tartan surface is utilized for the indoor running track to reduce the wear and tear on an individual's knees, and offices are provided for the management and staff of the club.
The total package of amenities is designed in a way to furnish fitness and safety in a comfortable, luxurious environment for patrons and employees.
Location and Context
The Activity Center is located in the central portion of the Meridian Office Park, south of Denver. It is bordered on the south by a 5 story, 300 room hotel, on the west by the main office park drive, on the north by the 1st tee box to the golf course and to the east by the 9th green. Across the drive to the west are the 10th tee and the 18th green of the golf course designed by Jack Nicklaus and Associates. The highest point of the entire complex is to the east of the building site and slopes down towards the west.
Access to and from the site is off of the drive to the west, with the main flow of traffic coming from and going to the south. This is the location for the main entrance to the office park, and is noted to be a secondary road. West Parker Road borders the main entrance to the office park, and is the link between 1-25 and the site itself. This will be almost the exclusive route of all traffic to enter the site.
Surroundings and Context
Besides the golf course and hotel, the immediate surroundings will include office buildings and light industrial plants. The atmosphere is that of a high technology, college setting.
Currently the site and vicinity are kept in agriculture, but future planning has projected this general area for continued office park development with additional residential communities scattered in between.
No building context is set due to the absence of buildings, but a correlation could be drawn from the Inverness Office Park to the north of the Meridian complex. Various low level office structures of a variety of materials are to be found. Cab Childress' Geary Operating Company building stands alone as a good example, with its horizontal low rise form, earth berms and brutal concrete aesthetic. Richard Crowther's Hotsy Corporation building sets a tone with its rounded block forms and brown stuccoed appearance.
At the north end of the complex is the Arapahoe County Airport. The ACA caters to small single engine aircraft, and small executive jets (Learjets). Noise becomes a primary concern here. The Activity Center site is currently outside of the non-buildable noise contour of 65 Ldn, and in the 55 Ldn zone (SA. 1). An Ldn depicts the
A - Activity Center Iâ€”I - Hotel CD - Office I - Lt. Industrial C - Commercial
Meridian Office Park
Geary Operating Company Cab Childress
Arapahoe County Airport
day/night average sound level, which incorporates the number of take offs and landings, the time of day, and the runway used. A sound level above 65 Ldn can damage human hearing. The Meridian Office Park is considered to be of compatible land use, and the Activity Center is classified as a "non-sensitive" building type to noise.
Take offs and landings of jets per day are currently at 25, and this number is expected to double by the year 2000. The 65 Ldn noise contour will enlarge, but still not converge into the Activity Center site (SA. 2).
In all, sound buffering through early berming, vegetation screens and building construction must be incorporated into the design.
The location and characteristics of the site give the opportunity for various panoramic views. Foremost would be the view to the west of the picturesque Rocky Mountains. Here peaks such as Mt. Evans and Longs Peak can easily be spotted. Also to the west, there will be a scenic view of the 10th and the 18th holes of the golf course as it meanders down the western slope of the site.
To the east looms the large ridge, which cuts off any visual access to the eastern plains. But visual interest from the activity on the 1st and 9th^ holes of the golf course will justify consideration in design.
Views to the south will be blocked by the hotel, but gaps to the southeast and southwest allow visual access to the man-made lake and southern plateaus respectively.
To the north, views are limited, but the mountains creep into the northwest view. Cars zipping past the complex on 1-25 can easily see the Activity Center from the road.
Electric power is supplied by the Intermountain Rural Electric Association. Sewer and water will be supplied in the Meridian complex itself. The sewage treatment facilities are on the northern border of the office park, and a large water tank for water supply is directly east of the Activity Center on the ridge.
r SA. 2
View to Northwest
View to South
View to Northeast
Climatic Analysis and Building Recommendations
The Metropolitan Denver region (Latitude 39Â°45â€˜N, Longitude 104Â°52'W), lying on the western edge of the Great Plains, near the foothills of the Rocky Mountains, is an area of transition from the climate of the plains to the climate of the foothills. The region has a high-elevation continental climate that has been characterized as semi-arid, Steppe-type clime.
Temperatures are generally moderate, with a mean annual temperature of 11.3Â°C. (52.3Â°F.). Ranges in extremes have been recorded from -34Â°C. (-30Â°F.) to 40Â°C. (105Â°F.). The average monthly temperature varies from 30.4Â°F. in January to 73.3Â°F. in July. See Temp. Chart C.l.
Monthly precipitation data for Denver are shown in Chart C.3. Generalized precipitation patterns for the Denver region and surrounding areas are shown in Chart C.4. Precipitation is relatively light (average annual depth:
31 cm (12 in.), with a large proportion of the rain falling during the growing season from April to September. Much of this summer precipitation occurs as a result of thunderstorm activity. Heavy thunderstorms in the eastern foothills and plains area occasionally cause damaging flash floods. The generally low relative humidity is a major factor in the areal potential evapotranspiration rate of 610 mm (24 in.) per year. This amount is twice the average precipitation and is an indication of the aridity of the area.
Snowfall is generally not heavy, with most snow occuring between November and April. Mean monthly snowfall data for Denver are shown in Chart C.3. Extensive flooding caused by snowmelt in the mountains occurs only at times when there has been either a heavy accumulation of snow or a sudden increase in high-elevation temperatures.
The growing season is- approximately five to six months long, from April to September, when the temperature does not fall below freezing.
Relative Humidity Temp
Temperatures C. 1
J FMAMJ JASOND
average daily maximum average
average daily minimum minimum
â– 4 am 10 pm 10 am 4 pm
Humidity C. 2
Moisture C inches]
0->IUUftUIO)Nia) id o 3 iu
1 .... â€¢ SELECTED REPORTING WEATHER STATION
-- ISOHYET, mm (inches)
SC'JRCE WA7E= OLâ€™AL'TY ViAiGEMENT ~.i\ =Â£ = 0 = 1
General Precipitation Pattern Denver Region C.A
The prevailing cooling winds come from the south-southwest at 39 mph, while the harsh winter winds approach the site from the north and northwest. Chinook winds periodically blow from the mountains to the west with great turbulence and occur once or twice a year. Air quality is usually good, thanks to the prevailing winds. But an occasional wind shift from the north brings the pollution cloud from Denver. On the whole, the site is considered to be low wind effected.
Charts C.6 to C.13 show that the Denver area receives a large amount of sunshine during a majority of the year. Clear skies increase the effect of solar radiation, which therefore helps to moderate the climate. Summer solstice is 73.5Â° while the winter solstice is 26.5Â°.
The bioclimatic chart shows that the climate of the plains and plateaus is mainly too cool or too cold for comfort due to a large diurnal swing. Keeping out the cold while capturing the sun to heat up the building in winter is the primary concern. Protect the building from the cold north and northwest winds to minimize infiltration and convective losses. Landscaping and earth berms can be useful here. Use of vestibule entry spaces to prevent sweeping air exchanges with the outside, and place auxiliary spaces against the cold north and west walls. Special attention is paid to keeping the heat in and the cold temperatures out. Insulate the building and use massive, heavy building materials, such as stone, brick or concrete, to store internal heat gain and temper outside temperature extremes. During the few hot months, for natural ventilation and evaporative cooling relief, place bodies of water or plants in the path of the prevailing southerly winds. In addition, exclude the summer sun but let in the winter sun by positioning the building in the shade of trees and other buildings and adding well-designed shading devices.
All in all, flexible design is very important here since sun and wind can be both a liability and an asset. Therefore, a building which can open and shut to different climate forces at different times of the year will be most energy conserving and comfortable.
North 100 400 GOO
Annual Wind Rose C. 5
13 - IB IS - 84 25-38 39*
Degree Days C. B
Heat Needed Heat Needed
Heatinq Degree Days Base 65 Â°F
Coolinq Degree Days Base VO Â°F
J FMAMJ JASOND
Days In a Month Â°/o Sunshine
Â°/o Possible Sunshine C. ~7 Average '72Â°/o
Days Cloud Cover C. 8 126 Days
J FMAMJ J A SOND
Daily Direct Solar Radiation C. 9 _L to Sun
J FMAMJ J ASOND
Daily Total Horiz. Radiation C. 10
J FMAMJ JASOND
Hourly Total Normal Solar Radiation C. 12
J FMAMJ J ASOND Sunrise to Surset
Kwhr / Sq. M / Day on
Bioclimatic Chart C.1-4
45. Bioclimotic Chert, for U.S. moderate zone inhabitonti.
Topography and Soils
The Metropolitan Denver region is located along the western periphery of the high plains of Colorado, which slope gently upward for almost 300 km (186 miles) from the eastern border of the state to the base of the foothills of the Rocky Mountains. The relief can be characterized as rolling prairie, with some hills and ridges intersected by nearly flat floodplains along watercourses. Much of the land currently under cultivation, mostly to the east and northeast of Denver, is nearly flat and level.
Site and Geologic Conditions
As stated previously, Meridian Office Park is situated in the north end of Douglas County, immediately south of Arapahoe County. Arapahoe County Airport is located directly north of the northeast leg of the property. Interstate 25 borders the west side of the southern section and West Parker Road constitutes the southern border. Cultivated farmland surrounds the northwest, northeast and southeast perimeters of the site. To the south the area is primarily uncultivated rangeland.
Topographically, Meridian Office Park is comprised mostly of rolling hillslopes and gently sloping ephemeral drainages. Cottonwood Creek, an intermittent drainage, crosses through the western portion of the site.
Land use throughout the site has been predominantly farming. At the time of our investigation, the fields were being planted with winter wheat. Some portions_pf the site, mainly steeper slopes, are not cultivated and are supporting native grasses, plants and some cottonwood trees along Cottonwood Creek. An old earthfill embankment occurs in the southeastern portion of the site. This embankment forms a small pond area which collects runoff during periods of precipitation. However, this pond was dry at the time of our investigation. Several unimproved farming access roads occur throughout the property.
The site lies on the west flank of the Denver Basin, a doubly plunging syncline. Bedding of the bedrock dips very gently to the east towards the axis of the basin.
The uppermost bedrock formation which occurs at the site is the Paleocene-age Dawson Arkose named after prominent arkosic sandstone beds, but also containing many claystone and quartzose beds (facies). Outcrops within the project area and bedrock encountered by the exploratory holes consist predominately of claystone with some mudstone (siltstone-claystone) and sandstone. The Dawson Arkose is underlain by about 12,000 feet of older sedimentary rocks. Tertiary and Upper Cretaceous-age formations which underlie the Dawson Arkose in descending order are:
the Denver, Arapahoe, Laramie Formations, the Fox Hills Sandstone and the Pierre Shale. Some of these formations are referred to later.
Overlying the bedrock over the majority of the site are surficial deposits. These deposits consist of small remnants of Slocum Alluvium; residual, colluvial and eolian soils (loess); and recently deposited alluvium.
Slocum Alluvium, deposited during the Pleistocene, have mostly been removed from the site by erosion. Remnant or localized deposits were found in a road cut and evidenced by boulders and cobbles which had been cleared from fields. Retransported boulders and cobbles were also observed along the flood plain in Cottonwood Creek. Where observed in a road cut on the southern boundary of the site, the alluvium consisted of coarse grained sand and fine and coarse grained gravel. Boulders as large as 3 feet in maximum dimension were observed in retransported deposits.
Recent alluvium, Piney Creek Alluvium and Post-Piney Creek Alluvium are present in the bottom of Cottonwood Creek. The alluvium consists of medium and coarse grained sand and fine gravel. Our field mapping indicates these deposits are limited to the bottom of the channel; however, mapping by Maberry and Lindvall indicates that alluvium is present in other tributary drainages on the site. Deposition of alluvium in the majority of these tributary drainages is obscure if present. Also, any alluvium in these drainages probably consists primarily of clayey sand and sandy clay derived from the adjacent hillslopes.
The most predominant soil deposits'at the site consists of residual soils, colluvium and eolian soils. These soils are found on the tops and side slopes of the rolling hills across the site as well as in the majority of the lesser developed drainages. The materials are quite intermixed and would be difficult to distinguish for mapping purposes. However, these soils do have dissimilar engineering properties as later discussed. The overburden soil depths vary from 2 to 14 feet in the exploratory holes. The grphic logs of the exploratory holes are presented on the attached figure.
Additional geologic data is included in our preliminary geotechnical investigation, Job N. 22, 147, dated May 18, 1981.
To explore the subsurface conditions, three test holes were drilled at the approximate locations shown on Fig. 18. Two test holes are located at the booster pump station and one test hole at the irrigation station. The subsoils encountered consisted predominately of sandy clay overlying claystone and sandstone bedrock.
Swell-consolidation tests indicate that the sandy clay exhibits a low to moderate swell potential under low loads when wetted. Swel1-consolidation tests on the claystone bedrock also indicate that it exhibits a nil to moderate swell potential under low loads when wetted. Results of the swell-consolidation tests are shown on the attached Figs.
No free water was encountered in our test holes at the time of drilling or when measured 7 days after the completion of drilling.
Based on the data obtained during the field and laboratory investigation, we believe straight-shaft piers drilled into the bedrock should be utilized to support the proposed pumping facilities.
Buildings founded on shallow foundations placed on swelling soils and bedrock, similar to those encountered at this site, can experience structural deformation, if the soil and bedrock are subjected to changes in moisture content. The drilled pier foundation will place the bottom of the piers near soils of relatively stable moisture content and make it possible to load the piers sufficiently to resist uplift movements.
'The following design and construction details should be observed for straight-shaft pier foundation systems:
1. Piers should be esigned for a maximum end bearing pressure of 30,000 psf and a skin friction of 3,000 psf for that portion of the pier in bedrock.
2. Piers should be designed for a minimum dead load pressure of 10,000 psf, based on pier end area only. If the minimum dead load requirement cannot be achieved, the pier length should be extended beyond the minimum penetration to make up the dead load deficit. This can be accomplished by assuming 1/2 of the skin friction given above acts in the direction to resist uplift.
3. Piers should have a minimum length of at least 12 feet.
4. Piers should be designed to resist lateral loads assuming the modulus of horizontal subgrade reaction in the clay soils of 40 tcf and a modulus of horizontal subgrade reaction of 200 tcf in the bedrock.
5. Piers should be reinforced their full length to resist tension created by swelling soils.
6. A 4-inch void should be provided beneath grade beams to prevent the swelling soils and bedrock from exerting uplift forces on the grade beams and to concentrate the pier loadings.
7. Pier holes should be properly cleaned prior to the placement of concrete.
8. The absence of water in the exploratory test holes indicates the use of casing will probably not be re-
quired to reduce water infiltration into the holes. However, if water does occur, the requirements for casing can sometimes be reduced by placing concrete immediately upon cleaning and observing the pier holes. In no case should concrete be placed in more than 3 inches of water.
9. Care should be taken to prevent the forming of mushrooms at the top of thepiers since this can increase uplift pressures in the piers.
10. A representative of the soil engineer should observe the pier drilling operations.
Floor slabs present the greatest problem where swelling materials are present at floor slab elevation because sufficient dead load cannot be imposed upon them to resist uplift pressures generated when the materials are wetted and expand. Based on the proposed construction and the moisture-volume change characteristics of the materials encountered at these sites, we recommend that the floor slab consist of a structural floor system above a well-vented crawl space. The floor should be supported on grade beams and piers, the same as the main structure.
Slab-on-grade construction may be considered as an alternate to floor slabs, provided the increased risk resulting from floor slab movement is recognized and precautions are taken to reduce the effects of the movement.
If slab-on-grade construction is chosen, the following measures should be taken to reduce movements should the underslab materials be subjected to moisture changes:
1. Floor slabs should be placed on at least 3 feet of nonexpansive fill. Fill placed beneath slabs should be a material approved by the soil engineer and should be placed compacted to at least 95% of the maximum standard Proctor density, within 2% of the optimum moisture content.
2. Floor slabs should be separated from all bearing walls and columns with an expansion joint which allows unrestricted vertical movement.
3. Conduits and utilities entering or exiting the building walls and resting on the floor slabs should be provided with slip joints which allow at least 2 inches of vertical movement.
4. Floor slabs should be provided with control joints to reduce damage due to shrinkage cracking and should be adequately reinforced. We suggest that the joints be provided on the order of 15 feet on centers.
5. A minimum 4-inch free-draining gravel layer should be placed beneath the slabs. The gravel should have a maximum size of 1-1/2 inches and contain no more than 5% passing the #200 sieve.
6. All plumbing lines should be carefully tested before operation. Where plumbing lines enter through the floor, positive bond breaks should be provided. Flexible connections should be provided for slab bearing mechanical equipment.
The precautions and recommendations itemized above will not prevent the movement of the floor slabs if the
underlying expansive materials are subjected to alternate wetting and drying cycles. However, the precautions will reduce the damage if such movement occurs.
Imported granular material should be used to backfill the foundation walls within 3 feet of the ground surface. The granular soils behind foundation walls should be sloped from the base of the wall at an angle of at least 45Â° from the vertical. The upper 3 feet of the wall backfill should be a relatively impervious on-site clay soil to prevent surface water infiltration of the backfill. Backfill should be carefully placed in uniform lifts and compacted to between 85% and 95% of the maximum standard Proctor density. Care should be taken not to overcompact the materials since this could cause excessive lateral pressure on the walls.
Foundation walls which are laterally supported and can be expected to undergo only a moderate amount of deflection may be designed for a lateral earth pressure utilizing an equivalent fluid pressure of 40 pcf per foot for horizontal backfill placed as discussed above. In addition, all foundation walls should be designed for appropriate surcharge pressures.
Water Soluble Sulfates
The concentration of water soluble sulfates measured in samples obtained from the exploratory test holes ranges from less than 0.004 to 0.023. This concentration of water soluble sulfates represents a negligible degree of sulfate attack on the concrete exposed to these materials. The degree of attack is based on a range of negligible, positive, considerable and severe, as presented in the U.S. Bureau of Reclamation Concrete Manual.
Based on this information, we do not believe special sulfate resistant cement will be required for concrete exposed to the on-site soils and bedrock.
We assume that the lower level building excavation, wet well and pipe excavations will be constructed by overexcavating slopes to a stable configuration rather than utilizing a temporary retaining wall system.
We suggest temporary excavation slopes be constructed no steeper than 2 horizontal to 1 vertical. Temporary slopes in the bedrock may be excavated at 1 horizontal to 1 vertical. Some minor sloughing may occur adjacent to the slope faces at these angles; however, large slope failures are unlikely. We should be no-'-^tified to observe excavation as it proceeds.
In our opinion, excavation of the bedrock and overburden soils should be possible with heavy duty conventional excavation equipment. Difficult excavations may be encountered and light controlled blasint may be required in confined excavations at the subject sites. Some blasting will probably be required where thick beds or lenses of sandstone bedrock are encountered.
1. The general subsurface conditions at the project site consist of stiff to very stiff sandy clays over-lying medium to very hard claystone, sandstone and siltstone bedrock. The roadway pavement sections for the project should consist of full depth asphalt pavement or Portland cement concrete pavement placed on lime stabilized subgrade. Design pavement sections and construction details are outlined in the report. The proposed L.W.P.M.D. building should be supported on straight-shaft piers and the maintenance facility should be supported on spread footings with design and construction requirements as outlined.
The water reservoir structure should be supported on stright-shaft piers drilled into bedrock with design and construction details as discussed.
The detention pond and earth reservoirs should be graded on 4 horizontal to 1 vertical slopes with design and construction details as discussed.
The wastewater treatment facility should be constructed with permanent interior cut and fill slopes on 4 horizontal to 1 vertical and permanent exterior cut and fill slopes on 3 horizontal to 1 vertical. The retaining walls and filtration buildings should be supported on foundations as outlined.
Depending on the final floor elevations of the lift stations, the foundation systems should be supported on either spread footings or straight-shaft piers as outlined.
2. The proposed activity center should be supported on straight-shaft piers drilled into bedrock with design and construction details as discussed. A spread footing alternate has also been presented in the report.
The Metropolitan Denver region is part of the high plains area that extends from the Great Plains to the foothills of the Rocky Mountains. The elevation of the study area ranges from 1,400 m to 1,800 m (4,600 ft. to 6,000 ft.), placing it within the Upper Sonoran life zone. This zone begins at the Transition zone of the foothills of the Rocky Mountains and extends beyond the eastern border of Colorado. The growth and distrib-tion of vegetation is largely dependent upon climate, relief, substrate, fire and the occurrence of human activities such as grazing and agriculture. With an average annual precipitation rate of only 30 to 40 cm (12 to 16 in.), water availability is the chief limiting factor leading to the low growth of grasses and forbs on the plains.
Prior to settlement, the plains supported a mixed prairie which was made up primarily of perennial bunch-grasses. Short grasses such as blue grama and buffalo grass dominated on drier sites, and taller grasses (western wheatgrass and little bluestem) occurred on sites with higher moisture, such as along eastern stream courses and toward the mountains to the west. Prior to settlement, a very complex mosaic of steppe communities existed in the Denver area in response to the numerous soils. Under natural conditions, the three major plant communities probably were (1) upland prairie or short-grass plains, (2) meadow and (3) cottonwood-willow. The plains did not support tree growth except along the watercourses, which were fringed . with cottonwoods and willows. Dense thickets of wild plum and chokecherry, with scattered clumps of hack-berry and box elder, occurred sometimesMn gulches and arroyos. The original distribution of natural vegetation in the Denver region is shown in Figure B.l.
The Activity Center biotic community can be classified as a cultivated land unit, since this land has been previuosly held in agriculture.
Cultivated vegetation includes sod farms, irrigated farms and dry farms. Thousands of hectares of the plains are devoted to irrigated farming along the South Platte River, and to dryland farming on adjoining uplands.
In some areas, such as in Arapahoe County, irrigated farmland has decreased significantly in the past 30 years because of community development and the diversion of water from the South Platte River for domestic purposes. No large vegetation mass is found on the site.
1- GRASSLANDS OF THE PLAINS-Blue gramma Is the dominant
2- CRASSLANDS OF THE PLAINS-Blue grama, sand dropseed,three-
awn, sand reed, bluestem, sldeoats grama, and yucca,
3- GRASSLANDS OF THE PLAINS-San reed, bluestem, sand drop-
seed and sand sage on sandhills.
4- GRASSLANDS OF THE FOOTHILLS-Wheatgrass, needlegrass, sand
reed, bluestem, and blue grama mixed with areas of shrub and occasional ponderosa pine.
5- WOODLANDS OF THE LOWER MOUNTAINS-With stands of ponder-
osa pine (and often Gambel Oak) with Douglas-flr, blue spruce, white fir and occasional aspln mixed with fescue, muhly, bluegrass, shrubs and forbs.
6- WOODLANDS AND GRASSLANDS OF SUBALPINE AREAS-With stands
of spruce and fir or lodgepole pine, or aspen.
Thurber's fescue grassland parks Intermingle with timbered areas.
7- GRASSLANDS AND MEADOWS OF ALPINE REGIONS ABOVE TIMBERLINE
With sedges, grass, willow, birch and forbs.
Agricultural lands are typically cultivated as monoculture units. The allocation of large parcels of land to only a few plant species leads to a simplified environment with low animal diversity. Animal populations are generally characterized by numerous small burrowing rodents, seed-eating birds and a few wide-ranging predator species. Although a monoculture yields little variety in habitat, the crops provide an important food source for wildlife. This is particularly significant in migratory bird wintering areas near Riparian-Aquatic habitats. The stubble, fence rows and unharvested remains are often vital to wildlife for sustenance and cover during the winter months.
Wildlife in the region of the Activity Center includes various fowl and other creatures. Characteristic birds include Brewer's Blackbird, Western Vesper Sparrow, Ring-Necked Pheasant, Western Meadowlark, Lark Bunting, Barn Swallow, Say's Phoeve, Housefinch Bank Swallow and King Fisher. Characteristic animals include Meadow Vole, Pocket Gopher, Ground Squirrel, Harvest Mouse, Western Jumping Mouse, Weasel, Bull Snake, Garter Snake, House Mouse, Raccoon, Feral Cat, Spadefoot Toad and Fence Lizard.
Rare and Endangered Species
The Federal Register for rare or endangered plant species was reviewed, for the State of Colorado. No plant species were considered to be threatened in the Denver Region.
The Nongame and Endangered Species Conservation Act (Reference 35) for the State of Colorado is consistent with Title 50, Part 17 of the U.S. Conservation of Endangered Species Act. The Colorado Division of Wildlife further protects several wildlife species not covered by the Federal Conservation Act. The Wildlife Division has recognized the stress on wildlife caused by a growing population and changing land use, and endeavors to protect wildlife habitat as well as endangered wildlife species. Animals protected by State and Federal regulations that may occur within the study area include the black-footed ferret, peregrine falcon, white pelican and river otter.
The black-footed ferret (Mustela nigripe) occurs within shortgrass prairies. Its historic range coincides closely with that of its prey species, the prairie dog. The population has been drastically reduced and its range decreased due to changing land uses and programs to control, or eliminate prairie dogs. Scattered reports of the black-footed ferret indicate nearly statewide distribution, with tendencies toward the eastern
grasslands. The lands within the study area are largely cultivated or grazed and probably represent a marginal habitat for the black-footed ferret.
Colorado has two recognized subspecies of the peregrine falcon: a winter nesting resident, the American peregrine (Falco peregrinus anatum), and the arctic peregrine (Falco p. tundrius), a migratory visitor during the spring and fall. The resident subspecies is of greater concern within the Rocky Mounatin area. Human activities such as road-building, forest and sagebrush clearing, game hunting and outdoor recreation have deteriorated the quality of the environment for this species. The peregrine falcon requires high cliffs for nesting sites and a food supply of small birds. Accurate information about breeding pairs has been difficult to obtain. However, the plains area may still have some value as a feeding range for this species.
The white pelican (Pelicanus erythrorhynchos) is common in portions of the United States and is not considered endangered on a national basis. Within Colorado, it is presently considered endangered as a nesting summer resident. White pelicans may be found at several reservoirs along the South Platte River drainage; however, they nest and rear young only at Riverside Reservoir, outside of the study area.
The river otter (Lutra canadensis) formerly ranged over many of the rivers and lakes of North America. Due to hunting and human encroachment, otters have been eliminated or their numbers reduced over much of their range. However, the river otter is not considered endangered on a national basis. The otter has probably always been rare in Colorado . Scattered sightings have been reported in the South Platte River drainage in Weld County, and it is unlikely that a breeding population is present. Because this species is usually limited to wilderness areas, it is unlikely that it could ever exist in any numbers in the study area. Most of the streams and lakes are influenced by adjacent homes, industry or other incompatible human developments.
Codes and Zoning
Uniform Building Code
Building Code Review
Topic Code Location
Occupancy Group Section 601 Section 701
Occupancy Separation Table 5B
Building Type Section 602 Section 508
Location on Property Section 603
Group A Division 3 Group H Division 1
Type V - 1 Hour
Fire Resistive Substitution: Where one hour fire-resistive construction throughout is required, an approved automatic fire extinguishing system may be substituted, provided such system is not otherwise required. Exceptions: (See Section)
A.3 to front or have access to public street of 20 feet minimum width.
A.3 to have 20 feet wide unobstructed access to main street. A.3 fire resistance of exterior walls to be:
2 hours less than five feet 1 hour elsewhere
A.3 openings in exterior walls to be:
Not permitted less than five feet Protected less than ten feet
H.l 60 ft. from property lines including property lines adjacent to public ways.
A.3 = 10,500 S.F./Floor H.l = 4,400 S.F./Floor
Allowable Floor Areas
(b) Areas of Building Over One Story
The total floor area of all floors shall not exceed twice the area allowed for one-story buildings. No single floor shall exceed that permitted for one-story buildings.
(c) Basements and Cellars
Need not be included in allowable area provided does not qualify as a story nor exceed permitted one floor area.
(d) Area Separation Walls (See Section)
(a) 3. Separation on all sides: Where public space more than 20 feet in width extend on all sides of the building and adjoin the entire perimeter, floor areas may be increased at a rate of five percent for each foot by which the minimum width exceeds 20 feet, (c) Automatic Fire-Extinguishing Systems: â€”
The area may be tripled in one-story buildings and doubled in buildings more than one story.
A.3 - 2 Stories
H. l - 1 Story
Above height limitations may be increased by one story if the building is provided with an automatic fire-extinguishing system throughout except if system is provided for:
I. Area increase (Section 506 (c))
2. Substitution for one hour fire-resistive construction (Section 508)
Towers, spires and steeples, erected as a part of a building and not used for habitation or storage, are limited as to height only by structural design f completely of non-combustible materials, or may extend not to exceed 20 feet above the height limit in Table No. 5.D if of combustible materials.
Section 3301 (d) Determination of Occupant Load
Exceptions: (As pertaining to A.3)
1. The occupant load of an area having fixed seats shall be determined by the number of fixed seats installed.
2. The occupant load permitted in a building or a portion thereof may be increased above that specified if the necessary exits are provided.
3. Accessory use areas which ordinarily hre used only by persons who occupy the main areas of an occupancy shall be provided with exits as though they were completely occupied, but their occupant load need not be included in computing the total number of occupants for the building.
4. Locker rooms two exits per 30 occupants, 50 S.F./person.
Table 33-A Storage (Warehouse) (See Exception 3 above)
300 square feet per occupant Mechanical Equipment Room 300 square feet per occupant
(g) Mixed Occupancies
The capacity of a building containing mixed occupancies shall be determined by adding the number of occupants of the various portions.
(b) When located in basement or above first story to be of not less than one hour fire resistive construction. When occupant load is 50 or more and occupancy is located over usable space, occupancy shall be separated from such space by not less than one hour fire-resistive construction.
H.l Light, Ventilation and Sanitation (See Section)
Usable Space Under Floors:
Usable space under the first story shall be enclosed with one hour fire-resistive construction. Doors shall be self-closing, of noncombustible construction or solid wood core, not less than 1-3/4" thick.
Roof covering shall be fire-retardant
Fire Resistive Requirements-for Building Elements:
Exterior Bearing Walls Interior Bearing Walls Exterior Nonbearing Walls Structural Frame Partitions - Permanent Shaft Enclosures
- One Hour
- One Hour
- One Hour
- One Hour
- One Hour
- One Hour
(See Section 1706)
- One Hour
- One Hour
Exterior Doors and Windows - Section 2203
Detailed Construction Requirements (cont.) Section 1705 Exceptions: (b) Fixed Partitions Partitions dividing portions of offices occupied by one tenant only, and do not establish a corridor serving an occupant load of 30 or more may be constructed of: 1. Noncombustible materials 2. Fire-retardant treated wood 3. One hour fire-resistive construction 4. Light construction or panels up to three-fourths the height of the room in which placed; when more than three-fourths the height of the room, such partitions shall have not less than the upper one-fourth of the partition constructed of glass. (c) Folding, Portable or Moveable Partitions Approved folding, portable or moveable partitions need not have fire-resistive rating provided: 1. They do not block required exits and do not establish an exit corridor. 2. Their location is restricted by means of permanent tracks, guides or other approved means. 3. Flamability shall be limited to materials having a flame-spread classification as set forth in Table No. 42-B for rooms or areas. (d) Walls Fronting on Streets or Yards (See Section) (e) Trim May be combustible in restricted applications (See Section) (f) Loading Platforms Exterior shall be noncombustible construction or heavy timber with wood floors not less than 2" nominal thickness.
Detailed Construction Requirements (cont.)
(g) Insulating Boards
Combustible insulating boards may be used under finished flooring.
Section 1706 Shaft Enclosures
(a) Openings extending vertically through floors shall be enclosed in a shaft of one hour fire-resistive construction.
1. An enclosure will not be required for openings which serve only one adjacent floor.
2. Chutes with a cross-sectional area of not more than nine square feet may be unenclosed if lined on the inside with gypsum wall-board and covered with 26 GA. galvinized sheet metal. All openings into such enclosure shall be protected.
(b) Protection of Openings
Every opening into a shaft enclosure shall be protected by a selfclosing fire assembly.
1. Opening^ to exterior.
2. Openings produced by air ducts may be fire-dampered.
(c) Termination of Rubbish Chutes
Shall be in room of one hour separation from remainder of building.
(d) Elevator Shafts
Shafts housing elevators and extending through more than two stories shall be vented to the outside.
Section 1707 Weather Protection
(a) Weather Resistive Barriers
All weather exposed surfaces shall have a weather resistive barrier to protect the interior wall covering.
(b) Flashing and Counterflashing
Exterior openings exposed to the weather shall be flashed in such a manner as to make them weatherproof.
Detailed Construction Requi rements (cont.)
Section 1708 Members Carrying Masonry or Concrete
All members carrying masonry or concrete walls in buildings over one story in height shall be fire protected with not less than one hour fire protection.
Fire protection may be omitted from the bottom flange of of lintels spanning not more than six feet when not part of a structural frame.
Section 1709 Parapets
(a) Parapets shall be provided on all exterior walls of buildings.
1. Walls which are not required to be of fire-resistive con-struction.
2. Walls which terminate at roofs of not less than two hour fire-resistive construction or roofs constructed entirely of noncombustible materials.
3. Walls where, due to location on property, unprotected openings are permitted.
Parapets shall have the same degree of fire resistance required for the wall upon which they are erected. The height shall not be less than thirty inches.
(c) Waterproofing Weather Exposed Areas
Surfaces exposed to the weather and sealed underneath shall be waterproofed.
Detailed Construction Requirements (cont.)
Section 1710 Projections
Projections may be of combustible or noncombustible construction. Combustible projections shall be of one hour fire-resistive consruction when on walls where protections of openings are required.
Section 1711 Water Closet Compartments and Showers
(a) Floors and walls to be of smooth, hard, non-absorbant surface.
(b) Toilet facilities
Clear space thirty inches wide with twenty-four inches in front of stool.
Appendix C Water Closets
Uniform Fixtures Persons
Plumbing 1 1-15
6 1 additional for each 40 Lavatories 111-150
1 additional for each 40
Drinking Fountains 1 per 100
Detailed Construction Requi rements (cont.)
Whenever urinals are provided, one water closet less the number specified may be provided for each installed except the number of water closets shall not be reduced to less than two-thirds of the minimum specified.
Handicapped Toilet Facilities:
1. Clear space of 44 inches at doors.
2. Clear space within toilet room to accommodate a 60 inch diameter.
3. Clear space of 42 inches wide 48 inches long in front of at least one water closet stool.
4. Grab bars at each side or back and one side.
5. At least one lavatory with a clear unobstructed space 26 inches in width, 27 inches in height and 12 inches in depth.
6. At least one mirror with bottom within 40 inches of the floor.
7. Hand drying within 40 inches of the floor.
Section 1712 Water Fountains
Where water fountains are provided, at least one shall have a spout within 33 inches of the floor and shall have up-front, hand-operated controls. If placed in an alcove, the alcove T
shall not be less than 32 inches wide.
Section 1716 Guardrails
Guardrails required at enclosed floor and roof openings more than 30 inches above grade. Guardrails shall not be less than 42 inches in height. 9 inch sphere penetration.
Section 1717 Foam Plastics
1. Foam plastics may be used in the following locations:
A. Within the cavity of a masonry or concrete wall.
B. On the room side of conforming walls or ceilings provided the foam plastic is protected from the interior by h" gypsum board.
C. Within wall cavities (See Section)
Section 3302 Exits Required
(a) Number of Exits (See Table 33-A)
1. Floors above first story shall have two or more exits.
2. Mezzanines over 2,000 square feet or 60 feet in any direction to have two or more stairways.
3. Number of exits required from any story determined by occupant load of that story plus fifty percent of the occupant load in the first adjacent story above (and the first adjacent story below, when applicable).
4. The maximum number of exits required for any story shall be maintained until egress is provided.
1. The total width of exits in feet shall not be less than the total occupant load served divided by 50.
2. The total exit width required from any story of a building shall be determined by using the occupant load in the first adjacent story above (and below, when applicable).
3. The maximum width of any story shall be maintained.
(c) Arrangement of Exits
With only two exits^jthey must be placed equal to not less than one-half of the length of the maximum diagonal of the building.
(d) Distance to Exits
Maximum to exterior door or enclosed stairway in building to be 150 feet or 200 feet with sprinklers.
(e) Exits Through Adjoining or Accessory Areas
Permitted when through adjoining room that is accessory and provides direct means of egress to corridor, etc.
Table 33.A (F) Entrances to Buildings
Main entrances must be accessible by means of wheelchair and be on the same level as elevator access.
Section 3303 Doors
Exits doors serving occupant load of more than 50 shall swing in direction of travel.
Exit doors shall be openable from interior without use of key.
(e) Width and Height
Required exit doorway shall be minimum of 3 feet wide and 6 feet 8 inches high. Maximum 4 foot wide.
Section 3304 Corridors and Exterior Exit Balconies
Minimum 44 inches.
(c) Height Minimum 7 feet.
(e) Access to Exits
Possible to go in either direction from any point in the corridor to a separate exit, except for dead ends of maximum 20 foot.
(f) Changes in Elevation
By means of a ramp when corridor serves an elevator.
(g) Construction One hour.
Doors to one hour corridors to be not less than 20 minute selfclosing, and must be labelled.
Section 3305 Stairways
Occupant load more than 50: 44 inches wide. Occupant load 50 or less: 36 inches.
(c) Rise and Run
Rise to be 4" to 7", Run to be 10 inches or more.
Dimension to measured in the direction of travel equal to the width.
(h) Basement Stairs
Approved barrier to prohibit persons continuing into basement.
(i) Distance Between Landings 12 foot maximum, vertically.
Both sides 30-34 inches above nosing.
6'-6" vertically from parallel and tangent to tread nosing.
Ramps (See Section)
(b) Width (See Stairs)
1 in 12 maximum.
Applies to all interior stairways and ramps (See Section)
Exit Signs and Illumination
(b) At every required exit doorway in Group A.3 and B.2 above 100 occupants.
Aisles (b) Width
3'0" if serving one side, 3'6" if serving two sides, increase in width 1h inches for each five foot of length from furthest point.
Exit Requirements (cont.) (c) Distance to Nearest Exit 150 feet through aisles to exit door is maximum, plus 200 feet if approved automatic sprinkler system is installed. (d) Aisle Spacing Maximum of six intervening seats between any one seat and the aisle. (g) Slope Not to exceed one foot in eight.
Section 3314 Seat Spacing 1. Standard - 12" between back and front edge. 2. Continental - 18" for rows of 18 or less. - 20" for rows of 35 or less. (See Section)
Section 3316 Group A Division 3 Occupancies - Exit Requirements (See Section)
Note: See 1979 U.B.C. for detailed Code Requirements.
Colorado Energy Code
Energy Code Review
The Colorado Energy Code for non-residential buildings, which became effective July 1, 1978, has the following effect on this project:
Exterior Design Conditions Winter: 3 Degrees F. D. B.
Summer: 90 Degrees F. D. B.
Heating Degree Days: 6016
Degrees North Latitude: 39 Degrees 45'
Interior Design Conditions:
Interior design temperature shall be 72 F. for heating and 78 F. for cooling. Other design temperatures may be used for equipment selection if they result in lower energy usage.
Standard RS-3 (ASHRAE 62-73, Standards for Natural and Mechanical Ventilation). For general office space, this states that there will be e minimum of 15 CFM of outdoor air per person based on 10 people per 1000 SF.
Building Envelope Requirements:
All buildings that are heated or mechanically cooled shall be constructed so as to provide the required thermal performance of the various components. A building that is designed to be both heated and cooled shall meet the more stringent of the heating or cooling requirements as provided in the Code when requirements of the exterior envelope differ. Exterior joints around windows and door frames; openings between walls and foundations, between walls and roof/ceilings and between wall panels; openings at penetrations of utility service through walls, floors and roofs, and all such other openings in the building envelope shall be caulked, gasketed, or otherwise sealed in an approved manner.
Heating and Cooling Calculations:
Heating and cooling design loads for the purpose of sizing HVAC systems shall be determined in accordance with 1972 ASHRAE Handbook of Fundamentals or an equivalent computation procedure.
Design of Mechanical Systems:
Consideration shall be given to the use of recovery systems which will conserve energy provided the amount expended is less than the amount recovered when the energy transfers potential and the operating hours are considered.
Each HVAC system shall be provided with at least one thermostat for the regulation of temperature. Each thermostat shall be limited as follows:
- Where used to control heating only, a maximum temperature of 75 F.
- Where used to control cooling only, a minimum temperature of 75 F.
Where used to control both heating and cooling, it shall have a maximum high temperature setting of 85 F. and a minimum of low temperature setting of 55 F. and shall be capable of operating the
system heating and cooling in sequence. It shall be adjustable to provide a temperature range of
up to 10 F. between full heating and full cooling.
Zoning for Temperature Control in Nonresidential Buildings:
Each separate HVAC System.
Each separate zone. As a minimum each floor of a building shall be considered as a separate zone. In a multi-story building where the perimeter system offsets only the transmission losses of the exterior wall, an entire side of uniform exposure may be zoned separately. A readily accessible manual or automatic means shall be provided to partially restrict or shut off the heating and/or cooling input to each floor.
Control Setback and Shut-Off in Nonresidential Buildings:
Each HVAC system shall be equipped with a readily accessible means of shutting off or reducing the energy used for HVAC during periods of non-use or alternate uses of the building spaces or zones served by the system.
The HVAC system design shall provide means for balancing the air and water systems including, but not limited to, dampers, temperature and pressure test connections and balancing valves.
Energy for Air Delivery:
The air transport factor for each all-air HVAC system shall not be less than 4.0 The factor shall be based on design system air flow for constant volume systems. The factor for variable air volume systems may be based on average conditions of operation.
Each mechanical supply and exhaust ventilation system shall be equipped with a readily accessible means for either shut-off or volume reduction and shut-off when ventilation is not required.
Cooling with Outdoor Air (Economizer Cycle):
Each fan system shall be designed to use up to and including 100 percent of the fan system capacity for cooling with outdoor air automatically whenever its use will result in lower usage of new energy.
Simultaneous Heating and Cooling:
Concurrent operation of independent heating and cooling systems serving common spaces and requiring the use of new energy for heating and cooling shall be minimized by one or both of the followings
By providing sequential temperature control of both heating and cooling capacity in each zone.
By limiting the heating energy input through automatic reset control of the heating medium temperature (or energy input rate) to only that necessary to offset heat loss due to transmission and infiltration and, where applicable, to heat the ventilation air supply to the space.
Combustion Heating Equipment:
All gas and oil fired comfort heating equipment shall show a minimum combustion efficiency of 75 percent at maximum rated output.
Electrically Operated Systems Components, Cooling Mode:
HVAC system components, whose energy input is entirely electric, shall show a Coefficient of Performance (COP) Cooling not less than the values shown in the energy tables for the specific components.
Insulation of HVAC Systems:
Air Handling Duct Systems.
All ducts, plenums and enclosures installed in or on buildings shall be thermally insulated as required in the Code.
Standard insulation. All piping installed to service buildings and within buildings shall be thermally insulated in accordance with the Code.
Duct Construction. All duct work shall be constructed and erected in accordance with ASHRAE and SMACNA Standards.
Service Water Heating. Hot water for domestic purposes shall be generated and delivered in a manner conducive to saving heat energy. ,
Conservation of Hot Water. Showers used for other than safety reasons shall be equipped with flow control devices to limit total flow to a maximum of 3 gpm per shower head.
Lavatories in restrooms shall be equipped with:
- Outlet devices which limit the flow of hot water to a maximum of 0.5 gpm.
- Devices which limit the outlet temperature to a max.imum of 110 F.
- Self closing valves that limit delivery to a maximum of 0.25 gallons of hot water.
Utilization equipment, rated greater than 1,000 W and lighting equipment greater than 15 W, with an inductive reactance load component, shall have a power factor of not less than 85 percent and shall be corrected to at least 90 percent under rated load conditions. Power factor corrective devices, installed to comply with this Code, shall be switched with the utilization equipment, except where this results in an unsafe condition or interferes with the intended operation of the equipment.
Where a choice of service voltages is available, a computation shall be made to determine which service would produce the least energy loss, and that voltage shall be selected.
In any building, the maximum total voltage drop shall not exceed 3 percent in branch circuits or or feeders, for a total of 5 percent to the furthest outlet based on steady state design load conditions.
Lighting Switching: ;â€”
Switching shall be provided for each lighting circuit, or for portions of each circuit, so that partial lighting required for custodial or for effective complementary use with natural lighting may be operated selectively.
Lighting Power Budget:
The lighting power budget for the building shall be the sum of the power limits computed for all lighted interior and exterior spaces. For purposes of establishing the iighting power budget, the following lighting levels are used.
- Task Lighting:
In most cases, the levels of illumination listed are for specific tasks. These levels are for the task areas defined in the Illumination Engineers Handbook Std RS-8 or, where not defined, at all usable portions of task surfaces. In some cases, the levels of illumination are listed for locations. These levels are to be considered as average levels.
In areas surrounding task locations, the average level of general lighting, for budget purposes only, shall be one-third of the level for the tasks performed in the area, but in no case less than 20 footcandles. Where more than one task level occurs in a space, the general level shall be one-third the weighted average of the specific task levels.
In circulation and seating areas where no specific visual tasks occur, the average level of illumination shall be one-third of the average general lighting in the adjacent task spaces, but in no case less than 10 footcandles.
Handicapped Code Review
In 1975 the Colorado Legislature passed a law which extended the application of the 1973 "Handicapped Law" to the construction of privately funded buildings. The law states in part, "The governmental unit responsible for the enforcement of this Article shall grant exceptions or modify any particular Standard of Specification when it is determined that it is impractical and would create an unusual hardship or would unreasonably complicate the construction, alteration or repair in question. Any such exception or modification of the provisions of this Article shall be made in writing as a matter of Public Record." It is the intent of the law to make all buildings accessible to and functional for the physically handicapped to, through, and within their doors without loss of function, space or facility where the general public is concerned.
Entrances At least one primary entrance to each building shall be useable by those in wheelchairs.
Public Walks 48" minimum width, 5% maximum slope, 5' x 5' level platform, extend 1' beyond each side of door.
Parking Spaces 12' minimum width.
Ramps Maximum slope of 1 in 12, level platform at 30' intervals minimum.
Handrail (at least one) Extend 18" beyond top and bottom steps, extend 12" beyond top and bottom of ramp.
Risers If possible not exceeding 7" in height.
Toilet Stalls One handicapped stall in each toilet room.
Lavatories Useable by individuals in wheel chairs.
Mi rrors Not over 40" above floor.
Urinals Appropriate number mounted 19" above floor or at floor.
Towel rack and Disposers Mounted no more than 40" above floor.
Water Fountains Accessible to the handicapped.
Telephones Accessible to the handicapped (wheelchairs). Appropriate number equipped for those with hearing disabilities.
Doors Minimum clear opening of 32", level floor 5' each side.
Elevators Opening on same level as entrance, accessible by disabled, identify control buttons.
Utility Switches Within reach of those in wheelchairs.
Graphics Raised letters and identifying devices mounted between 4'-6" and 5'-6" above floor; Minimum height of 7'-0" when suspended from ceilings.
Doors Not intended for use and potentially dangerous to the blind shall have knurled knobs.
Warning Systems Audible signals shall be accompanied by simultaneous visual signal. Visual signal shall be accompanied by simultaneous audible signal.
Douglas County Zoning
Intent: Areas for commercial, wholesale and service uses.
Uses Permitted By Right:
1. All uses permitted in the B - Business District
2. Commercial parks (rental or lease). A preliminary site plan shall be submitted with each rezoning request.
3. Commercial subdivisions (sales). Each subdivision shall be platted in accord with the requirements of the Douglas County Subdivision Regulations, except as modified by this Section.
4. Places for conducting any commercial, wholesale or service activities, not of an industrial nature, inclusive of, but not limited to the following uses:
Amusement and recreation facilities Automobile service stations Auto and truck repairs Bakeries
Carpentry, including woodworking
Car sales, new and used __
Car wash, automatic or coin-operated
Commercial storage areas; screened by a solid fence or wall or chain-link fence at least six (6) feet in height Contractors offices
Drive-in eating and drinking establishments Food lockers, fresh and frozen Machine shops
Motor vehicles and motorized equipment: sales, leasing, rental, servicing and repair as an accessory activity
Mini-warehouses, subject to site plan approval: N() storage of dangerous or flammable materials and NO selling of merchandise and other tangible goods or services from any unit Printing and publishing Raceways
Radio and television offices Shopping centers Sign Painting
Theatres, outdoor Tinsmith shops Tire repair shops Upholstery shops
5. Open space
Uses Permitted by Special Review:
1. Veternary clinics and hospitals
2. Commercial storage areas; screened by soild fence or wall at least six (6) feet in height
3. Caretaker residence
Minimum Area and Yard Requirements:
The Planning Commission and the Board of County Commissioners may require additional setbacks be provided.
1. Lot width 100 feet
2. Front yard 40 feet
3. Side yards 15 feet
4. Rear yards 25 feet
5. Building height 60 feet
All roof-mounted equipment shall be properly screened; solar collectors excepted.
Each site shall be landscaped in accord with an approved plan. The areas landscaped shall be inclusive of, but not limited to, the required front yard.
Permitted Lot Coverage:
That portion of any site outside of the required setbacks, landscaping, off-street parking and easements for public or private use.
LI - Light Industrial
Intent: Areas for research, warehousing, light assembly, processing, manufacturing and distribution facilities
Uses Permitted By Right:
1. Any non-residential uses permitted in B - Business, C - Commercial, or LI - Light Industrial Zone Districts No hotels, motels, schools, hospitals, nursing homes and extended care facilities shall be permitted in this zone district.
2. Light industrial parks (rental or lease). A preliminary site development plan shall be submitted with each rezoning request.
3. Light industrial subdivisions (sales). Each subdivision shall be platted in accord with the requirements of the Douglas County Subdivision Regulations, except as modified by this Section.
4. Assembling plants
5. Bottling plants
6. Compounding plants
7. Dairy processing plants
8. Distribution facilities
9. Food and beverage processing
10. Light manufacturing
11. Processing and treatment plants
12. Scientific research
13. Storage and warehousing
14. Underground electrical transmission and distribution lines, telegraph and telephone lines, telephone exchanges, electrical substations and gas regulator stations, inclusive of public offices and repair and storage facilities.
15. Accessory uses and buildings
16. Open space
The above uses and similar non-offensive Light Industrial uses are subject to the following conditions:
a. All permitted principal uses shall be operated within enclosed structures
b. Dust, fumes, odors, refuse, smoke, vapor, noise, lights and vibrations shall be confined to the site upon which the use is located
c. Parking, access and circulation on the site shall be surfaced with asphalt, concrete or equivalent surface
d. Outdoor storage and accessory operations may be concealed by a solid fence or wall or chained link fence at least six (6) feet in height
e. All uses shall be in accord with an approved site or final plat
Minimum Area and Yard Requirements:
The Planning Commission and the Board of County Commissioners may require additional setbacks be provided.
1. Lot width
2. Front yard
3. Side yards
4. Rear yards
5. Building height
100 feet 40 feet
No setback, except when adjoining a residential zone district or when use is on corner lot - 15 feet 25 feet 60 feet
All roof-mounted equipment shall be properly screened*, solar collectors excepted.
Each parcel or tract shall be landscaped in accord with an approved plan. The areas landscaped shall be inclusive of, but not limited to, the required front yard.
Permitted Lot Coverage:
That portion of any site outside of the required setbacks, landscaping, off-street parking and easements for public or private use.
Uses Permitted by Special Review:
1. Hotels, motels, conference/convention facilities
2. Caretaker residence
Off-Street Parking Standards
Intent: Off-street parking areas shall be required in all districts as an accessory use to buildings and uses newly constructed, enlarged or restored. Except as provided in other sections of this Resolution, off-street parking areas shall be according to the following requirements.
Residential Dwelling Units:
Required off-street parking for non-residential land uses shall be based on the total gross floor area of the principal structure (all floors); requirements shall not be based on the foot print of the principal structure.
Schools and Institutions of Higher Education:
Other Business and Commercial Uses: One (1) off-street parking space per two hundred and fifty (250) square feet of gross floor area, or as required by the Board of County Commissioners.
1. Each off-street parking space shall be a minimum size of eight (8) feet by twenty (20) feet, except on a curve when the length shall be at least twenty-two (22) feet in length. Whenever possible, the parking space shall be arranged in such a manner so that a vehicle will not back directly from a required off-street parking space into public right-of-way.
2. Each required off-street parking space shall have adequate access to a public street or other thoroughfare.
Alleys, where they are utilized, shall only be used as secondary means of access to a lot or parcel.
3. Each required off-street parking space, in all zoning districts, shall be properly graded and drained.
4. Each off-street parking area which is accesssory to any principal use other than a single-family dwelling located on a lot in excess of 10,000 square feet in size shall be surfaced with asphalt or concrete, or other method approved by the Board of County Commissioners.
5. Each off-street parking area accessory to a principal use in C, GI or PD District shall be located in the
same zone district as the principal use and within 500 feet of the principal use.
6. Each off-street parking area accessory to a principal use in A-I, A-II, RR, ER, SR, MF, MH, B or LI District shall be located on the same lot as the principal use, or within a common parking area within five hundred (500) feet of the specific use(s).
7. No off-street parking area required for any use for the purpose of complying with the provisions of this Resolution shall be included as part of an off-street parking area similarily required for another use.
8. Required off-street parking in any zone district shall be located not closer than fifteen (15) feet back of the required property line and not closer than ten (10) feet back from the required side property line abutting a public street.
9. Each off-street parking area containing parking spaces for 50 or more vehicles shall provide a landscaped
area or areas dispersed within the parking area which shall be a portion of the overall site landscaping
requirement and shown in appropriate landscaping plan. The area may include storm water detention areas.
-j_J0. Required off-street parking area(s) may phased in with proposed phased development. Areas not improved shall be reserved for this purpose.
Photovoltaics. The process by which sunlight is converted directly into electricity. No mechanical processes are involved. Efficiencies are therefore increased. This wonder of technology was known only to research scientists until the advent of the national space program, when this energy generation source was envisioned for everyday use.
The photovoltaic principle was first discovered by French physicist Edmund Bequerel in 1839. This discovery was made while Bequerel was experimenting with different electrolytic cells. He observed that by shining light on these materials, a jump in electrical current was produced. Bequerel further established that different wavelengths generated more electricity than others.
Research declined until American physicist Charles Fritts built the first solar cell of selenium. The size of this cell was comparable to that of a quarter. Fritts was also credited as the first scientist to describe the photovoltaic process.
Again research of photovoltaics fell off until 1954. During the years previous to 1954, a physicist at the A.T.&T. Bell labs by the name of Daryl Chapins was working on photovoltaics. A colleague of Chapins, Gordon Pearson, accidentally found that silicon generated a substantial amount of electricity when it was exposed to light. Aware of Chapins troublesome experiments, Pearson informed him of this phenomenon and the two collaborated to design the first silicon cell. This cell had an initial efficiency of 6%, but was projected to reach an efficiency of 15%.
As described earlier, the photovoltaic effect converts light into electricity. But to understand this phenomenon, the knowledge of light, which drives the photovoltaic cell must first be perceived. Light is comprised of bundles of energy known as photons. These photons characteristically travel in wave patterns at very high speed, thus they act like bullets from a gun. Some photon have higher amounts of energy than others. The shorter wavelengths contain these maximum energies. This variation in energies is the reason that not all sunlight can be converted into electricity. Only certain photons have the proper quantity of energy to power a photovoltaic cell. Table Ph. 1 delineates the reasons for solar energy loss.
Photons of light, at the proper wavelength, bombard the silicon atoms. The photons interact with electrons and are then absorbed into the atom. This extra energy forces one of the outer silicon electrons off, thus creating an electrical current.
The most common photovoltaic cells are comprised of two types of silicon. A phosphorous-doped silicon, called n-silicon, is placed on top of a boron-doped silicon, p-silicon. This arrangement of silicon increases the flow of electrons, thus creating a greater electrical current. Electrical current then flows from a copper wire attached to the n-silicon.
As stated previously, electricity generated by photovoltaics is in the form of direct current. So for application in a majority of uses, a power conditioner must be employed to convert direct current to alternating current.
Silicon is not the only material qualified for use in photovoltaic cells. There are up to six other elements which can be used. They are the following:
% of Sunlight
Cadmium Sulfide lfL_
Cadmium Telluride 25
Indium Phosphide 26
Cadmium Arsenide 27
Aluminum Antimonide 27
Though there are other elements which provide a higher efficiency than silicon, silicon is the easiest and cheapest of these materials to manufacture. Costs of silicon photovoltaic cells are currently between $1-10 per watt. For photovoltaics to become cost effective, the price must come down to between $.50-1.00/watt. It is projected by photovoltaic experts Paul Maycock and Edward Stirewalt, that this cost reduction will occur in the mid to late 1980's.
Photovoltaics are similar to batteries in that they have a limited life span. With current technology, they have a 20-30 year life span. This reinvestment of capital is incorporated into the cost figures mentioned previuosly.
Dim-*-----Intensity of light-â–ºBright
Few-.----Number of photons--â–ºMany
High ------------------Photon Energy Â» Low
Short ------------------Wavelength------------------â–º Long
Solar spectrum PH. 1
Schematic design of single crystal silicon solar cell
Though photovoltaic cells are sealed units, and provide one of the cleanest form of energy known to man, they do have some drawbacks. Thermal hotspots occur from the absorbtion of solar heat and the reflection of that heat, similar to the effect of a mirror. Also, reflective glare is produced, thus restricting vision for individuals in the immediate vicinity. Increases in the temperature of the micro-climate result.
Since photovoltaic cells use polymers in their manufacturing process, toxic fumes could be released if the cell's seal is broken. Therefore it is imperative that these cells be located away from areas which have high accident ratios, i.e. golf courses. Also, lightning rods are required to avoid breakage caused by lightning strikes.
Short circuits, sparks and resulting fires could be of concern, but with the proper electrical insulation, this situation becomes highly unlikely.
The amount of shading area produced from the size of the photovoltaic arrays will again create adverse and abnormal micro-climatic conditions for vegetation and ground covers. Therefore, siting of these arrays and selection of ground cover materials becomes important.
Long range considerations involve the disposal of :the photovoltaic cells after their life has expired. Where and at what cost will these cells be disposed of ? Obvious environmental problems in the realm of toxic and solid waste crop up.
Despite these questions of performance, photovoltaics efficiency of providing clean energy overcomes these drawbacks. Compared to coal or oil fired electric plants, photovoltaics come out way ahead as a non-polluting energy source. (Fig. Ph.2)
2,366 modules (97,000 cells)
20-year cost (1980 dollars):
Capital investment $600,000
60-kilowatt diesel-electric generator Lifetime: 20 yearsâ€”131,400 kWh/yr Diesel replacements: 10 (tx $16,000 each Fuel: 9,000 bbl (1,039 tons)
20-year cost (1980 dollars):
Capital investment $160,000
Fuel Â«& $3/gal) $1,134,000
(operation and maintenance extra)
Comparison of photovoltaics with diesel-electric for power generation. PH.
Thermoelectric and Thermionic Cells
While other scientists were working with mirrors and steam boilers to generate thermal electricity from the sun, a new avenue was pursued by E. Weston in 1888. He proposed a device which he called the "thermocouple". Solar energy, which is focused on the device, develops a voltage between the hot junction and a cold junction. Each junction is comprised of a connected pair of wires of dissimilar materials. Weston used nickel and iron. In 1897, H.C. Reagan, Jr. proposed a thermojunction device in which the cool junction was kept at a low temperature by blowing air on it from a windmill. Others developed "thermo piles", "thermoelectric generators", etc. But all were onto the subject of thermoelectricity, which unfortunately stayed in the laboratory due to the high system's costs. The only applications invloved the space program.
A thermoelectric cell is one in which a current is generated as the result of the voltage appearing at the junctions between two dissimilar metals. This occurs only when one set of junctions is maintained at a different temperature than the other.
Like silicon photovoltaic cells, thermoelectric cells contain no moving parts. Therefore, efficiencies in energy conversion are higher than mechanical means. A major difference between thermoelectric cells and photovoltaic cells is the extremely high temperature needed for electrical generation. To achieve this high temperature, focusing collectors must be added to the flat plates. The voltage generated by the thermoelectric cell is linearly proportional to the temperature difference between the hot and cold junctions. Higher temperatures are therefore desirable. Electricity is pulled from the cold junction. Several materials can obtain the high temperature range of 200-600Â° F. With the difference of temperatures, different expansion and contraction rates can rip apart a thermoelectric cell. But Russian scientists have developed alloys which seal the elements without effecting the cell's performance.
Another problem develops due to the high temperature differential. The difference in temperatures must be maintained and the elements must be in close proximity to each other. Water is utilized to cool the one junction, but it plays havoc with the cell's seal due to the temperature differential.
Thermionic solar cells follow the same principle as the thermoelectric cells, except that the thermionic cell relies on a vacuum to generate electricity. When a metal surface is heated in a vacuum enclosure, it will emit electrons, forming a space charge about the heated surface. The device is shown in Figure T.2.
SUNLIGHT FROM CONCENTRATOR
While thermionic cells appear to be another alternative energy device, the need for extremely high temperatures seems to cancel out the advantages. The temperatures needed for electron emission range between 2000-2700Â° C. for pure metals and above 1200Â° C. when easily ionized atoms such as cesium are added to the vacuum.
These high temperatures lead to high radiation losses and evaporation of the cathode material.
Due to the need for high temperatures in a thermionic cell, there is a need for high precision collectors.
High costs result, therefore thermionics are only feasible for space applications.
Thermoelectric cells, as with photovoltaics, create thermal hotspots and large amounts of shaded areas. Chemical contamination of the soils and air could occur if the seal is broken. Again, as with photovoltaics, breakage can be avoided by locating the cells in protected areas along with the installation of lightning rods.
Theroelectric cells are a one step electrical conversion, but due to the need for focusing collectors, additional costs result. Thus they are not as attractive as other alternative energy sources.
A less complicated approach to electrical power generation entails the production of steam, which has been heated by the sun. This steam acts on a turbine to create electricity.
In the 1800's the Industrial Revolution was running rampant. Man was continually searching for ways in which machines could do inexpensive work. The most prevalent example was Robert Fulton and his steam engine, which could do the work of several horses.
In Europe these ideas also flourished. A French scientist by the name of Augustin Mouchot found that solar heat could accomplish the same results as wood for the production of steam. In 1860, Mouchot's first solar collector followed closely the hot box concept, which contains one heat absorbing box inside of another.
Mouchot utilized two copper cauldrons instead of boxes in this case.
Mouchot's first attempt was not very successful, so he continued to refine his design. To increase solar heat collection, Mouchot wrapped a glass cover around the cauldrons. This design could, as Mouchot notes, "capture practically all the rays falling upon the exterior bell." This concept of increased and intensified exposure-inspired Mouchot to produce his most efficient solar engine.
After initial experiments, Mouchot finished the Tours Solar Machine in 1874. The Tours expanded the capabilities of the double cauldron apparatus by constructing a conical mirror, which surrounds the boiler. The mirror was feet in diameter with 56 square feet of reflective surface. The mirror concentrated the sun's rays on the boiler, thus creating higher temperatures to produce steam, which fired the machine piston. The Tours drove a h horsepower engine at 80 strokes per minute. A maximum pressure was developed to 75 psi.
With this design, Mouchot realized that an extremely large amount of space would be needed for solar engine power. Improvements in design were obviously necessary.
In 1879, Mouchot devised a method for storing solar power. This involved the separation of water into hydrogen and oxygen by electrolysis, and then reintroduce them to produce steam (See Storage-Electrlytic Fuel Cells).
In 1880, Mouchot went back to his mathematical studies, and his assistant, Abel Pifre, resumed these solar experiments. Pifre's advancement of solar power was futile. The consensus of opinion in Europe during this period found no feasibility for solar power due to the cold and cloudy climate. Thus research was stymied.
Across the Atlantic during the same period, an American engineer by the name of John Ericsson was performing similar experiments. In 1870, Ericsson built a solar powered steam engine, claiming it was the world's first. When questioned as to the claim in regard to Mouchot's achievements, Ericsson dismissed them as mere toys. Ericsson also developed a solar hot-air engine two years later.
To reduce the cost and maintainance of the reflector, Ericsson developed the first parabolic solar reflector in 1884. Here Ericsson increased the amount of boiler area exposed to the sun, thus providing a higher efficiency. But with Ericsson's experiences with patent thieves, the plans and specifications for the "perfect solar motor" went with him to his grave in 1888.
With this setback, scientists and engineers had to reinvent the wheel. Among those dedicated individuals was Aubrey Eneas. Eneas developed solar motors such as Ericsson's around the turn of the century, but found that adequate boiler temperatures could not be achieved with parabolic collectors. So Eneas went back to a conical reflector. Eneas' conical reflector was able to track the sun as it passed through the sky. He tested this motor in Denver in 1899.
These motors were used to pump irrigation water for farmers and worked well. But the goal of 1000Â° F. boiler temperature with solar heat seemed impossible. So the search was on for liquids that would produce steam at a low temperature. Charles Tellier, known as the father of refrigeration, was familiar with low temperature liquids such as ammonia hydrate and sulphur dioxide, each having a boiling point of -28Â° F. and +14Â° F. respectively. He applied his knowledge to solar motors. Steam was produced by flowing ammonia hydrate through flat plate collectors on the roof of his shop near Paris, France. This discovery led to power plants like the ones built by Willsie and Boyle, and Frank Shuman.
Due to the low cost and suspected abundance of fossil fuels, solar power generation faded away in the middle of the 1900's. But with the current energy shortage, solar power generation has once again appeared on the scene.
The Tours solar engine, 1874
Eneas' sun motor
Basic technology for generating electricity through solar heat has not changed drastically in the sixty years since the 50 horsepower steam engine in Egypt. Aside from these early developments, solar steam generation has not discovered very many new principles. Most improvements are based on refinements of equipment and systems. One of these new principles deals with steam generation on a large scale. Parabolic "Frenzel" mirrors track the sun and focus it on a huge boiler tower. This system is able to achieve the long awaited goal of 1000Â° F+.
In the Pyrenees, The French have a 105 square yard array of mirrors, which can generate temperatures of up to 5400Â° F. A plant of this sort by the University of Houston and McDonnell-Douglas requires a square mile of collectors and a 1500 foot high tower to produce 500 megawatts of power. Of course these systems mentioned above are for a larger scale than that of an activity center. But the technology used in creating better heat absorbing surfaces, lower temperature chemicals and mirror construction can now be applied to parabolic, conical and flat plate collectors.
There are two attractive avenues of development. The first is to devote the solar steam generation plants solely to the generation of power. The second is to reap a combined harvest of electricity and heat.
In the first instance, less than one third of the energy in sunlight is put to use in solar steam generation, the remainder is discarded. The second approach, the "total energy" concept, is based on the eminently practical philosophy that if we are going to all the trouble collecting sunlight, we should use as much of it as we can. One way gives simple power to plants optimized for the generation of electricity, the other uses sunlight more effectively. Both have their advantages.
Sunlight is diffuse heat, so solar devices have to be large to capture a useful amount of it. Furthermore, the highest temperature concentrations come from directional collectors and they must fo.llow the sun from sunrise to sunset. But the tilting of acres of solar collectors is not so simple and some engineers opt for simple flat plate collectors with selective coatings. Also, flat plate collectors, because they aren't directional, continue to work reasonably well on hazy or cloudy days. Selective coatings absorb and retain sunlight, creating a kind of greenhouse effect in a thin surface layer.
By trapping solar energy in this manner, flat plates with low concentration ratios can heat a working fluid to about 400Â° F. One of the main disadvantages of flat plate collectors is that no ready made turbine technology exists for such low temperatures. Water, as stated previously, is not a good working fluid in that temperature range. Organics, such as freon and toluene, have superior properties, but have limited operating experience in power generating equipment.
To achieve higher temperatures, about 600Â° F., we can bend flat plates into parabolic collectors, like those at Meidi, Egypt. The 600Â° F. is still lower than steam temperatures in fossil fuel plants, but comparable to those in nuclear plants using pressurized water reactors.
So steam turbines and associated machinery already exist for this operational range. Parabolic collectors prove to be at an advantageous scale for the Activity Center. As an example, The University of Minnesota and Honeywell are developing parabolic collectors four feet across and eight feet long to focus sunlight on a water heat pipe covered with a selective coating of aluminum oxide.
Conical reflectors have recently been developed to achieve the elusive 1000 F. temperature needed to power conventional steam generators. Two collectors were developed for the DOE and Jet Propulsion Laboratory research project in 1979 by General Electric and Ford Aerospace. The General Electric power system utilizes an 8 meter (26.2 feet) diameter collector which focuses incident solar radiation on a spherical shaped heat pipe receiver boiler. To protect the highly sensitive mirrors from dust and damage, a pneumatic transparent enclosure is placed over the entire concentrator, but only 86% of total sunlight comes through. The reduction in maintainance cost outweighs this inefficiency. The boiler produces a superheated steam of 950Â° F. and 1200 psi to drive a central generator. Each collector generates approximately 6.7 kw.
The Ford Aerospace concentrator is two times larger than the GE collector, 16 meters (52.5 feet) in diameter. Each concentrator has- its own power conversion unit, consisting of a reciprocating Stirling cycle heat engine and alternator to produce 50 kw of electricity. The conversion device is mounted in the same fashion as conventional parabolic dish antenna. Both systems have simple azimuth and altitude tracing devices.
As with photovoltaics and thermoelectric cells, solar steam generation has the same effects upon the environment.
General Electric Proposed Collector Receiver/Boller Assembly
Ford Aeronutronlcs Power Module
Due to the use of mirrors and other reflective materials, thermal hotspots and glare will result. Also, the shaded area beneath the collectors will create abnormal micro-climatic conditions.
Low temperature liquids will contaminate soils and ground waters if released from the steam generation device. Therefore, careful construction and maintenance of piping is essential. The possibility of this condition occuring is remote if all systems are maintained well.
Wind is probably the oldest and most widely used source of power in the world. First used by the Egyptians around 2800 B.C. to fill the sails of their slaving ships, now wind is utilized as an alternative energy source for electrical power generation.
Around 700 A.D. the Persians utilized a vertical shaft wind machine, a panamone, to grind grain. The panamone was mounted between two vertical masonry walls, with the opening facing directly into the prevailing winds. This design increased the average wind speed, so the panamone could be used during long periods of constant wind. A unique architectural solution results.
The popular connotation of wind power was developed by the Dutch during the medieval years. Windmills were huge structures with four bladed horizontal shaft propellers. Gearing furnished the Dutch with greater power to grind grain, pump water or apply to sawmill uses.
In the following years, pivots and tails were added to guide the propellers into the wind, thus providing a greater chance for constant wind power. In 1850 Daniel Halliday applied these principles, along with an in- -creased number of blades, to create the American Farm Windmill. Water pumping for livestock was its main purpose.
By 1900 the Danes had applied wind power to electricity. The gearing and shaft were tied into turbines, which in turn generated electricity. In the 1940's Smith-Putnam attained 1250 kw with their gigantic wind machine on Grandpa's Knob in Vermont. High winds snapped the 8-ton blades, and the Smith-Putnam was never rebuilt.
Wind power has come to the forefront as one of the least expensive and efficient facilities in North Carolina Hawaii and at the Rocky Flats Nuclear Weapons Plant in Jefferson County, Colorado. Here, manufacturers bring their machines to be tested and receive recommendations for refinement. Also, consumer information is publish ed and tours are given regularly.