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Energy Code Guide for Commercial Construction in Utah

2015 International Energy Conservation Code (IECC)

R401.2 Application

Commercial buildings shall comply with either:

  • ASHRAE 90.1-2013

OR

  • 2015 IECC

Shall use only one code option for the envelope, mechanical, and lighting compliance – no mixing of IECC and ASHRAE.

C103.2 – 103.3 Construction Documents

All thermal performance values and factors must be identical and included on:

  • Plans
  • Specifications
  • Energy Compliance Documents
  • HVAC Design Calculation

Utah Climate Zones by County

Utah climate zones by county

IECC Compliance Options

Prescriptive – Includes UA Trade-off

OR

Total Building Performance

2015 IECC Prescriptive & Trade-off Options

Comply with requirements of:

  • C402 – Envelope
  • C403 – Mechanical
  • C404 – Service Water Heating (SWH)
  • C405 – Lighting

AND

Pick 1 of 6 Additional Efficiency Options:

  • C406.2 – Increase HVAC efficiency
  • C406.3 – Reduced Lighting Power Density
  • C406.4 – Enhanced Lighting Controls
  • C406.5 – On-site Renewable Energy
  • C406.6 – Dedicated Ventilation Systems
  • C406.7 – High Efficiency SWH

ENVELOPE

C-402.2 – 402.4 Specific Envelope Requirements

  • Continuous insulation
  • Frame and Mass walls
  • Floor and Slab-on-grade floors
  • Roof reflectance – Climate Zone 3 only
  • 30% of gross wall area limit on fenestration
    • Increase to 40% with daylight responsive controls
  • Minimum skylight area for spaces > 2500 ft2
    • 3% of gross roof area limit on skylights
  • Increase to 5% with daylight responsive controls

2015 IECC Prescriptive Option

Opaque Thermal Envelope Requirements Comply with:

Table C402.1.3 – R-Value Method

OR

Table C402.1.4 – U-Factor Method

AND

Table C402.4 – Fenestration U-Factor and SHGC

Trade-Off Option (Prescriptive alternate)

  • C402.1.5 – Component performance alternative
  • Perform UA calculation with COMcheck
    OR
  • Equation 4-2

Mandatory Requirements

C402.5 Air Leakage-Thermal Envelope Comply with C402.5.1 through C402.5.8 OR test at 75Pa, to a leakage ≤ 0.40 cfm/ft2

  • Air Barriers – construction, materials, assemblies
  • Fenestration leakage
  • Rooms containing fuel burning appliances
  • Vestibules
  • Air intakes, exhaust openings, stairs & shafts

2015 IECC Performance Option

Comply with requirements of:

  • C407 – Total Building Performance
  • C402.5 – Air Leakage
  • C403.2 – Provisions applicable to all mechanical systems
  • C404 – SWH
  • C405.2, C405.3, C405.5 & C405.6 – Lighting
    AND
    C401.2(3)- Building Energy

MECHANICAL

Applies to all heating, cooling, ventilation, walk-in coolers & freezers & refrigerated warehouses

C403.2 Mandatory Requirements

  • Equipment sizing
  • Equipment performance – efficiency
  • Control requirements – set points
    • Snow melt
    • Zoning
    • Freeze protection
    • Economizer Fault Detection
    • Boiler reset
  • Ventilation
    • Demand Controlled ventilation
    • Enclosed parking ventilation
    • Energy Recover ventilation
    • Kitchen Exhaust
  • Duct Sealing & Insulation
  • Piping insulation
  • Fan motor horsepower & efficiency
  • Heating outside a building – controls
  • Comprehensive refrigeration/freezer requirements

C403.3 Economizers

  • Required for cooling system ≥ 54,000 Btu/hr
  • Controls and design dependent on use

C403.4 Hydronic and Multi-zone

VAV system places limits on reducing airflows to minimums, re-heat, & fan horsepower

C403.4.5 Heat Recovery for Service Water Heating

For buildings with high continuous water demand (example – hotel) > 6,000,000 BTU/hr, use A/C rejection heat

C404 Service Water Heating

  • Equipment performance
  • Higher efficiency where demand is high
  • Heat traps & piping insulation

C404.5 – Efficient piping size and length

C406.6 – Heated water re-circulation

  • Controls, temperature

C404.9 – Pools and Spas

  • Controls, pumps & covers

LIGHTING

C405.1 Controls & Maximum Lighting Power Density for Interior & Exterior Lighting

  • Occupancy sensors
  • Time switch controls
  • Lighting reduction controls
  • Daylight Responsive controls
    • Reduce artificial lighting automatically
  • Daylight zones – independent control in areas
    • Windows & skylights
  • Exterior lighting automatic operate per available natural light

C405.4 Interior Lighting Power

Total connected interior lighting power (TCLP)

  • Building area methodOR
  • Space by space method
  • Tables for both methods based on use of area or space
  • Additional allowances for specific lighting functions

C405.5 Exterior Lighting Power

  • Lighting power allowance based on space; parking, walkway, entry etc.
  • Trade-offs allowed between some space types
  • Total allowable lighting based on area
    1. Developed forest, park – rural
    2. Residential
    3. Other
    4. High activity commercial

C405.8 Electrical Motors

Nominal full load efficiency per table, based on horsepower

C405.9 Vertical Horizontal Transportation Systems & Equipment

  • Elevators, escalators and moving walks
  • Light limits elevators
  • Control to reduce speed when unoccupied
  • Regenerative drive down operation escalator

C408 System Commissioning

  • Must have commission plan at design stage
  • Air and water balance
  • Functional testing sequence of operation
  • Control calibration of mechanical, SWH and lighting
  • Final Commissioning Report

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