EEBA Criteria
The Energy and Environmental Building Association
(EEBA) has developed these goals,
objectives and criteria for energy and resource efficient buildings. They
provide guidance for design, construction and comprehensive rehabilitation
(gut-rehab) of low-rise residential and small commercial buildings less
than 20,000 square feet (1,900 m2) floor area.
Goals for Energy and Resource Efficient Building
Energy Efficiency
To promote building practices that result
in a substantial reduction in energy use for space conditioning, water
heating, lighting and appliance operation.
Improved energy efficiency can reduce
the environmental impact of the built environment, improve economic well
being and promote global stability.
Occupant Safety
To promote building practices that result
in an improvement in fire and structural safety.
Improved construction practices can
reduce the risk from earthquakes, hurricanes, floods and fires.
Occupant Health
To promote building practices that result
in an improvement in the indoor environment.
Improved construction practices can
reduce the risk from building related illness and sick building
syndrome.
Durability
To promote building practices that prolong
the useful service life of buildings, reduce maintenance and promote
serviceability.
Rehabilitation and replacement of damaged
components and structures results in the inefficient use of resources.
Improper moisture control can lead to premature failure of building
components and can contribute to poor environmental conditions for
occupants.
Occupant Comfort
To promote building practices that improve
thermal comfort, daylighting, lighting, humidity control, odor control,
noise control and vibration control.
Providing comfort for building occupants
is one of the fundamental requirements of shelter.
Environmental Impact
To promote building practices that reduce
the impact on the local and global environment.
The impacts of the built environment on
the planetary environment make it necessary to make informed,
environmentally responsible choices during the construction process.
Objectives for Energy and Resource Efficient Building
Energy Efficiency
Energy
efficient and resource efficient construction should address the following
objectives for design, construction, commissioning, operation and
maintenance.
A. Building Structure
Thermal transmission through heat loss
and heat gains should be reduced by the specification and installation,
with proper attention to detail and quality assurance, of increased
levels of thermal insulation. Insulation systems should be installed
such that they reduce convective, conductive and radiative heat losses
and gains. Thermal anomalies such as thermal bridges should be
minimized.
Moisture gain resulting in decreased
thermal and structural performance should be controlled. Air flow
retarder systems and vapor diffusion retarders should be used to protect
the building envelope from uncontrolled air and moisture flow.
Thermal transmission through convective
heat loss and gain driven by "wind-washing" should be reduced
by the specification and installation, with proper attention to detail
and quality assurance, of an external air barrier system or external
"weather barrier."
Fenestration systems should be selected
according to climate, building orientation, interior comfort,
daylighting, ventilation, furnishing durability and egress requirements.
B. Mechanical Systems
Indoor air quality should be facilitated
by the installation of a controlled mechanical ventilation system. Heat
recovery is recommended in severe heating climate zones.
Only sealed combustion or power vented
direct combustion appliances should be installed in occupied spaces. Gas
cook tops and gas ovens should only be installed in conjunction with
exhaust fans.
Thermal and peak load reductions derived
from improving levels of insulation, airtightness and fenestration
performance of the building envelope should be evaluated in the sizing
of equipment.
The domestic hot water system should meet
high efficiency standards. Options for reducing water consumption are
recommended. Solar energy for hot water heating should be considered.
Efficient illumination design and
lighting systems should be used. Natural lighting of spaces should be
considered prior to specifying electric illumination systems. Lighting
designs and controls should consider the availability of natural light.
Occupancy sensors should be considered for foyers, utility room,
basements, garages and other spaces. Hard wired general area lighting
should employ fluorescent fixtures. Other lighting fixtures should use
compact fluorescent lamps.
Major appliances should meet high energy
efficiency standards using current appliance ratings.
C. Occupant Considerations
A comprehensive operations manual should
be provided to occupants which includes necessary operating, maintenance
and repair information so that the performance of the building can be
maximized.
Occupant Safety
In no case should the application of energy
efficient or resource efficient design or construction strategies,
materials, equipment or appliances violate safety codes and standards.
A. Building Structure
Recognized structural design shall be
employed to resist live, static and wind loads.
B. Mechanical Systems
Mechanical systems shall be designed and
constructed to facilitate occupant safety.
C. Occupant Considerations
Information relating to the safe
operation of the building and mechanical systems shall be provided to
occupants. Information relating to safe maintenance of installed
mechanical systems shall also be provided.
Occupant Health
Energy efficient and resource efficient
construction should provide a healthy living and working environment.
A. Building Structure
Selection of construction materials that
have low emission rates of toxic materials; foundations designed to
exclude entry of soil gas; and implementation of moisture control
measures are recommended.
B. Mechanical Systems
A controlled mechanical ventilation
system should be provided to facilitate occupant health.
C. Occupant Considerations
Information relating to the healthy
operation of the building and its mechanical systems should be provided
to the occupants.
Durability
Energy efficient and resource efficient
construction should include the following moisture control measures in
order to provide long term performance and durability.
A. Building Structure
The building envelope should provide
mechanisms to control the migration of moisture in the liquid and vapor
form.
Building materials and components should
be protected from rain, snow and other moisture sources during storage
on site, construction and commissioning of the building.
B. Mechanical Systems
Controlled ventilation, mechanical
cooling or dehumidification systems should be provided to maintain
acceptable indoor relative humidity. Such systems and their controls
should maintain humidity in the range of 25 to 60 percent. Source
control of moisture should be used where possible.
C. Occupant Considerations
Instructions for the proper use and
maintenance of moisture control systems should be provided to occupants.
Occupant Comfort
Energy efficient and resource efficient
construction should provide a comfortable living and working environment.
A. Building Structure
The building envelope should facilitate
the comfort of occupants.
B. Mechanical Systems
The mechanical systems should facilitate
the comfort of occupants.
C. Occupant Considerations
Information relating to the comfortable
operation of the building and its mechanical systems should be provided
to the occupants.
Environmental Impact
Energy efficient and resource efficient
construction should minimize the impact on the environment. Design and
construction strategies which account for full life-cycle energy
consumption and resource utilization—including the reuse, recycling and
reconfiguration of materials and practices—should be used.
A. Building Structure
The building envelope should be deployed
on its site and in its local environment in an environmentally sensitive
fashion.
Use of virgin materials or materials with
low recycled content should be minimized.
On-site reuse of surplus construction
materials should be provided. Recycling of materials should be
maximized.
B. Mechanical Systems
The energy efficiency of mechanical
conditioning systems should be maximized.
C. Occupant Considerations
Information relating to the resource
efficient operation and performance of the building should be provided
to the occupants. Measures facilitating the recycling of consumer waste
should be utilized.
Criteria for Energy and Resource Efficient Building
The
following criteria are recommended for the design and construction of
energy and resource efficient buildings.
Component Criteria
A. Building Structure
Overall energy consumption for heating,
cooling and water heating should meet Energy Star requirements (30%
improvement over a standard reference home based on the envelope and
equipment requirements of the 1993 Model Energy Code) as determined by
an accredited home energy rating system procedure.
Air leakage of buildings (determined by
pressurization testing) should be less than 2.5 square inches/100 square
feet leakage ratio (CGSB, calculated at a 10 Pa pressure differential);
or, 1.25 square inches/100 square feet leakage ratio (ASTM, calculated
at a 4 Pa pressure differential); or, 0.25 cfm/square foot of building
envelope surface area @ 50 Pa.
B. Mechanical Systems
Controlled mechanical ventilation at a
minimum base rate of 20 cfm per master bedroom and 10 cfm for each
additional bedroom will be provided when the building is occupied.
A capability to increase the base rate
ventilation on an intermittent basis to 0.05 cfm per square foot of
conditioned areas will also be provided.
Intermittent spot ventilation of 100 cfm
will be provided for each kitchen. Intermittent spot ventilation of 50
cfm or continuous ventilation of 20 cfm when the building is occupied
will be provided for each washroom/bathroom.
Positive indication of shut-down or
improper system operation for the base rate ventilation will be provided
to occupants.
Mechanical ventilation shall use less
than 0.5 watt/cfm for ventilation systems without heat recovery or less
than 1.0 watt/cfm for ventilation systems with heat recovery.
Mechanical ventilation system airflow
should be tested during commissioning of the building.
Heat recovery on controlled mechanical
ventilation is recommended in severe heating climate zones. Heat
recovery rates of heat recovery ventilators should be greater than 65
percent, including effectiveness of distribution.
Total ductwork leakage for ducts
distributing conditioned air should be limited to 10.0 percent of the
total air handling system rated air flow at high speed determined by
pressurization testing at 25 Pa.
Ductwork leakage to the exterior for
ducts distributing conditioned air should be limited to 5.0 percent of
the total air handling system rated air flow at high speed determined by
pressurization testing at 25 Pa.
Only sealed combustion or power vented
direct combustion appliances should be installed in occupied spaces.
These appliances must be rated to vent properly at largest expected
negative pressure. Gas cooktops and gas ovens should only be installed
in conjunction with exhaust fans.
Major appliances should meet high energy
efficiency standards using current appliance ratings. Select only those
appliances in the top one-third of the DOE Energy Guide rating scale.
Lighting power density should not exceed
1.0 Watts per square foot.
C. Occupant Considerations
Systems that provide control over space
conditioning, hot water or lighting energy use should be clearly marked.
Information relating to the operation and maintenance of such systems
should be provided to occupants.
The designer and general contractor
should provide comprehensive information to occupants relating to the
safe, healthy, comfortable operation of the building and mechanical
systems.
Indoor Environment
Criteria
Energy efficient and resource efficient
construction should provide comfortable indoor conditions as defined by
ASHRAE Standard 55-1989 (Addendum 55a-1994).
A. Building Structure
The building and site should provide
effective drainage measures to control rainfall runoff and to prevent
entry into the building.
The building foundation should be
designed and constructed to prevent the entry of moisture and other soil
gases.
Building assemblies should be designed
and constructed to permit drying of interstitial spaces.
Building assemblies should be designed
and constructed to prevent airflow into insulation systems from both the
interior and exterior.
Radon resistant construction practices as
referenced in the ASTM Standard E-1465-90 "Radon Resistant Design
and Construction of New Low Rise Residential Buildings" should be
utilized.
Materials, adhesives and finishes with
tested low emission rates should be selected.
B. Mechanical Systems
Controlled mechanical ventilation systems
shall be installed.
Where combustion appliances are used,
only sealed direct combustion or power vented systems should be
installed in habitable spaces. Gas cooktops and gas ovens should only be
installed in conjunction with exhaust fans.
Forced air systems should be designed to
provide balanced airflow to all conditioned spaces and zones. Interzonal
air pressure differences should be limited to 3 Pa.
Filtration systems should be provided for
forced air systems which provide a minimum atmospheric dust spot
efficiency of 30 percent (derived from ASHRAE Standard 52.1-1992).
Indoor humidity should be maintained in
the range of 25 to 60 percent by controlled mechanical ventilation,
mechanical cooling or dehumidification.
C. Occupant Considerations
Occupants should be provided with an
operator’s manual containing specific operating instructions on how to
maintain a healthy indoor environment.
Control systems should include advisory
display or indicative modes to alert occupants to "trouble" or
"failure" conditions.
Environmental Impact
Criteria
Energy efficient and resource efficient
construction should be designed, constructed and operated to reduce
overall life-cycle impact on the environment considering energy
consumption, resource use and labor inputs in the fabrication, erection,
modernization, operation and disassembly of the building, components and
systems.
The design and construction of buildings
should use recycled materials, or new materials with a high recycled
content. Minimization of scrap on site and design for disassembly should
be provided.
Discussion Relating to
Criteria
The
Criteria are for the most part self-explanatory. However, two concepts
require explanation: air leakage coefficients and ductwork leakage. The
following discussion relates to these two concepts.
In selecting the approach to
measure/evaluate energy use the following factors were considered:
- A single airtightness value was selected
as it has become clear that it is as important to build a tight
building envelope in the hot, humid south as in the cold north.
Similarly, mixed, humid climates and hot, dry climates also require
tight building envelopes. The importance of tight construction goes
far beyond energy conservation. Health and durability are the
principle concerns with respect to this issue.
- The airtightness value is based on the
surface area of the building envelope not the volume. Air change per
hour at 50 Pascals was rejected as a basis for measurement because it
confuses the issue. We are dealing with leakage through the building
envelope. Holes, holes, holes. Of course, ach @ 50 Pa is a popular,
albeit misguided, criteria. The requirements have been translated for
information purposes only. Based on ach @ 50 Pa, values are between
3.2 and 2.8 for 1,500 to 2,500 square foot houses with basements (not
including the basements in these square footage determinations). The
airtightness value is roughly double the Canadian R-2000 tightness
requirement of 1.5 ach @ 50 Pa although it is roughly twice as tight
as conventional construction.
Air Leakage -- Determining
Leakage Ratios and Coefficients
Using a blower door, measure the flow rate
necessary to depressurize the building 50 Pascals. This flow rate is
defined as CFM50. Alternatively, determine the Equivalent Leakage Area (EqLA)
in square inches at 10 Pascals using the procedure outlined by the
Canadian General Standards Board (or alternatively, determine the ELA
using the ASTM procedure calculated at 4 Pascals). When determining these
values, intentional openings (design openings) should be closed or
blocked. These openings include fireplace dampers and fireplace glass
doors, dryer vents, bathroom fans, exhaust fans, HRV’s, wood stove
flues, water heat flues, furnace flues and combustion air openings.
Calculate the leakage ratio or the leakage
coefficient using the entire surface area of the building envelope. When
determining the surface area of the building envelope, below grade surface
areas such a basement perimeter walls and basement floor slabs are
included.
For example, a 2,550 square foot house
constructed in Grayslake, IL has a building envelope surface area of 6,732
square feet and a conditioned space volume of 33,750 cubic feet (including
the basement). The measured Equivalent Leakage Area (EqLA) using a blower
door is 128 square inches. This also corresponds to a blower door measured
CFM50 value of 1,320 cfm and a blower door measured 2.3 airchanges per
hour at 50 Pascals.
|
Surface
Area |
EqLA |
CFM50 |
ach
@ 50 Pa |
Volume |
| 6,723 ft2 |
128in2 |
1,320 cfm |
2.3 |
33,750 ft3 |
To determine the Leakage Ratio, divide the
surface area of the building envelope by 100 square feet and take this
interim value and divide it into the EqLA.
6,732 ft2 » 100
ft2 = 67.32
128 in2 » 67.32
= 1.9 in2/100 ft2
(Leakage Ratio)
To determine the Leakage Coefficient,
divide the CFM50 value by the surface area of the building envelope.
1,320 CFM50 » 6,732 ft2
= 0.20 cfm/ft2
(Leakage Coefficient)
Many airtightness measurements are recorded
as air changes per hour at a pressure differential of 50 Pascals (ach @ 50
Pa). To convert ach @ 50 Pa to CFM50 multiply the volume of the building
envelope (including the basement) by the ach @ 50 Pa and divide by 60
min/hour.
For example, 2.3 ach @ 50 Pa across a
building envelope of volume 33,750 ft3 is equivalent to a CFM50 value of
1,320 cfm.
33,750 ft3 x 2.3
ach @ 50 Pa » 60 min/hr = 1,320 CFM50
Ductwork Leakage
To determine the allowable limit for
ductwork leakage, determine the rated air flow rate of the air handler,
furnace, air conditioner, etc. at high speed from the manufacturer’s
literature. For example, a typical heat pump system may have a high speed
flow rate of 1,200 cfm across the blower according to literature supplied
with the unit. Ten percent of this value is 120 cfm. This 10 percent value
becomes the total ductwork leakage limit when the total air handling
system is depressurized to 25 Pascals with a pressurization test of the
distribution system.
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