Designer House Plans – Environmental Standards Schedule

INTRODUCTION

• The Environmental Design Standards Schedule has
  • Grown like Topsy in Before The Architect’s Designer House Plans
  • Probably to grow some more
• An Environmental Design Schedule of some sort, is
  • A general requisite, albeit limited in scope, for higher-end designer house plan sets and
  • On rare occasion demanded in some categories as part of a designer house plan set submission by a building authority having jurisdiction
  • Commonly not nearly as comprehensive as that which follows, in this house designer’s opinion

• Latitude 38.68N, 77.76W
• Elevation: 498-640 linear feet
• Seismic: Zone = 1
• Exposure category: B
• Wind: Basic wind speed (3-second gust, 50-year mean recurrence) = 9 MPH; Monthly range = 6-9 MPH (1-1.5 MPH below U.S. average); Historical tornado activity: 15% above U.S. average; higher than Virginia average
• Precipitation
• Rainfall – At I2 (5-minute, 25-year recurrence) = 9 inches per hour; Monthly range = 2.-75-4.25 inches (1/2-3/4 inch above U.S. average);
• Snow – Ground snow load (50-year mean recurrence) = 30 pounds per square foot; Monthly range = 0-7 1/4 inches ( U.S. average, except ½-2 inches higher in Q1);
• Average annual, including rain, snow, and hail – 40.1-40.9 inches [depending on source]
• Temperature: Daily lo = 22-65F (Average); Daily hi = 42-85F (Average); Average range = 32-75F (Average); 24-hour average = 54.3F; Average minimum = 43.3F; Average maximum = 65.3F
• Humidity: Morning = 75-89% (Average); Afternoon = 49-59% (Average)
• Sunshine = 45-63% (2-8% points below U.S. average)
• Degree Days [variation depends on source’s average temperature peg]: Heating = 4200-4795 [former datum’s basis undisclosed, latter’s is 54F]; Cooling = 517-1548 [former datum’s basis undisclosed, latter’s is 54F]
• Insulation: Attic = R-49; Walls = R-18; Band = R-30; Basement = R-11, prefer R-18; Slab-on-grade = R-10; Heating Degree Days: 4200-4795 [depending on source]; Heating Degree Days: 517-966 [depending on source]
• Weathering Probability for Concrete: Severe
• Termite Infestation Probability: Moderate to Heavy
• Decay Probability: Slight to Moderate

• Latitude and longitude
  • Source: http://www.epodunk.com et al.
  • Use: Google Earth for direct observation; soffit and overhang depth gauge
• Elevation
  • Source: http://www.city-data.com et al.
  • Use: Wide variation inspires more specific jobsite locale; rain, snow, and temperature metrics can be elevation-dependent versus county averages
• Seismic zone
  • Source: International Residential Code map, if it’s an easy siting; often, local building departments in Zones 2B and up; scrounging around, otherwise
  • Use: At Zone 2B, this designer begins turning over some building design elements to engineering latitude, including but not limited to shearwalls, reentrant corner foundation structure, larger roof overhangs, as above porches, taller site walls, etc.; at Zone 3 and up, all structure from this shop must be reviewed with engineering latitude
• Exposure category
  • Source: International Residential Code
  • Use: To determine the extent to which natural elements, especially wind, shall be factored into design; to a lesser extent, at Exposure A and even B, natural light intrusion may be limited
• Wind
  • Basic wind speed (3-second gust, 50-year mean recurrence) in MPH
    • Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf
    • Use: Wide-ranging application to methods and materials of construction
  • Wind speed - Monthly range
    • Sources, variously: http://www.city-data.com
    • Use: Sense of wind variability; again to methods and materials for marginal judgments
  • Historic wind storm activity
    • Source: http://www.city-data.com et al. including local weather history news reports; clients’ awareness and alert
    • Use: Always spurs further investigation as to the generalized statement’s relevance – geographical relationship or topographical similarities to jobsite; tends to shade other wind metrics; can affect wall and roof structure, fenestration, roofing, etc.
• Precipitation
  • Rainfall rate (I2 = 5-minute, 25-year recurrence) in inches per hour (IPH)
    • Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf
    • Use: Watershed Schedule; footing drainpipe sizing; etc.
  • Rainfall - Monthly range
    • Source: http://www.city-data.com
    • Use: To gauge watershed variability, e.g., tighter range indicates steadier wetness; shading IPH
  • Snow – Ground snow load (50-year mean recurrence)
    • Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf except in some higher altitudes where data must be sourced from the local building authority having jurisdiction
    • Use: Primarily roof and deck structure; secondarily, certain design matters of functionality, particularly exterior mobility
  • Snow - Monthly range
    • Source: http://www.city-data.com
    • Use: Shade ground snow load metric
  • Average annual, including rain snow, and hail
    • Source: http://www.city-data.com
    • Use: Perspective
• Temperature (in lieu of the grossly generalized “Design Temperature")
  • Daily lo, daily hi, average range, 24-hour range, average minimum, average maximum, and comparison to national averages
    • Sources, variously: http://www.city-data.com & http://www.worldclimate.com
    • Use: Perspective on controlling daylighting; appropriate materials and methods for convenience of ventilation and heat transfer; materials durability, notably concrete; etc.
• Humidity - Morning and afternoon
  • Source: http://www.city-data.com
  • Use: Appropriate materials and methods for convenience of ventilation; materials durability
• Sunshine
  • Source: http://www.city-data.com
  • Use: Jointly with Temperature and Humidity, assessing extents of both in general and specific design aspects; impacts nature and character of fenestration; designing for daylighting and nightlighting
• Degree Days
  • Source: http://www.ornl.gov/~roofs/Zip/ZipHome.html or www.worldclimate.com
  • Use: HVAC prescription, including SEER (not less than 13 from this shop)
• Insulation
  • Source: http://www.ornl.gov/~roofs/Zip/ZipHome.html
  • Use: Definitive minimum R-values for ceiling, wall, floor, band, etc. based on zip code, structure; heating and cooling equipment design, etc. developed by DOE, Oak Ridge National Laboratory, Oak Ridge , TN
• Weathering Probability for Concrete
  • Source: International Residential Code
  • Use: To assess sufficiency of surface hardening, other amendments, etc.
• Termite Infestation Probability
  • Source: International Residential Code
  • Use: To assess need for termite shield design specifications
• Decay Probability
  • Source: International Residential Code
  • Use: To assess finish exterior clad durability, ventilating the building envelope, foundation height over finish grade, etc.

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