INTERNATIONAL ENERGY CONSERVATION CODE phần 7 pot

where:

F The measured leakage rate in cfm per 100

square feet of duct surface.

P The static pressure of the test.

Documentation shall be furnished by the designer

demonstrating that representative sections totaling at

from the building exterior or unconditioned or exempt

spaces by a minimum of R-8 insulation.

Exceptions:

1. When located within equipment.

2. When the design temperature difference between

the interior and exterior ofthe duct or plenum does

not exceed 15°F (8°C).

All ducts, air handlers and filter boxes shall be sealed.

Joints and seams shall comply with Section 603.9 of the

International Mechanical Code.

503.2.7.1 Duct construction. Ductwork shall be con￾structed and erected in accordance with the International

Mechanical Code.

503.2.7.1.1 Low-pressure duct systems. Alliongi￾tudinal and transverse joints, seams and connections

of supply and return ducts operating at a static pres￾sure less than or equal to 2 inches w.g. (500 Pa) shall

be securely fastened and sealed with welds, gaskets,

mastics (adhesives), mastic-plus-embedded-fabric

systems or tapes installed in accordance with the man￾ufacturer,s installation instructions. Pressure classifi￾cations specific to the duct system shall be clearly

indicated on the construction documents in accor￾dance with the International Mechanical Code.

Exception: Continuously welded and lock￾ing-type longitudinal joints and seams on ducts

operating at static pressures less than 2 inches w.g.

(500 Pa) pressure classification.

503.2.7.1.2 Medium-pressure duct systems. All

ducts and plenums designed to operate at a static pres￾sure greater than 2 inches w.g. (500 Pa) but less than 3

inches w.g. (750 Pa) shall be insulated and sealed in

accordance with Section 503.2.7. Pressure classifica￾tions specific to the duct system shall be clearly indi￾cated on the construction documents in accordance

with the International Mechanical Code.

503.2.7.1.3 High-pressure duct systems. Ducts

designed to operate at static pressures in excess of 3

inches w.g. (746 Pa) shall be insulated and sealed in

accordance with Section 503.2.7. In addition, ducts

and plenums shall be leak-tested in accordance with

the SMACNA HVAC Air Duct Leakage Test Manual

with the rate of air leakage (CL) less than or equal to

6.0 as determined in accordance with Equation 5-2.

COMMERCIAL ENERGY EFFICIENCY

4. Spaces where the supply airflow rate

minus any makeup or outgoing transfer

air requirement is less than 1,200 cfm

(600 Lis).

503.2.6 Energy recovery ventilation systems. Individual

fan systems that have both a design supply air capacity of

5,000 cfm (2.36 m3

/s) or greater and a minimum outside air

supply of 70 percent or greater of the design supply air

quantity shall have an energy recovery system that provides

a change in the enthalpy ofthe outdoor air supply of 50 per￾cent or more of the difference between the outdoor air and

return air at design conditions. Provision shall be made to

bypass or control the energy recovery system to permit

cooling with outdoor air where cooling with outdoor air is

required.

Exception: An energy recovery ventilation system shall

not be required in any of the following conditions:

1. Where energy recovery systems are prohibited by

the International Mechanical Code.

2. Laboratory fume hood systems that include at least

one of the following features:

2.1. Variable-air-volume hood exhaust and

room supply systems capable of reducing

exhaust and makeup air volume to 50 per￾cent or less of design values.

2.2. Direct makeup (auxiliary) air supply equal

to at least 75 percent of the exhaust rate,

heated no warmer than 2°F (1.I OC) below

room setpoint, cooled to no cooler than 3OF

(I.7°C) above room setpoint, no

humidification added, and no simulta￾neous heating and cooling used for

dehumidification control.

3. Systems serving spaces that are not cooled and are

heated to less than 60°F (I5.5°C).

4. Where more than 60 percent ofthe outdoor heating

energy is provided from site-recovered or site

solar energy.

5. Heating systems in climates with less than 3,600

HDD.

6. Cooling systems in climates with a I-percent cool￾ing design wet-bulb temperature less than 64°F

(18°C).

7. Systems requiring dehumidification that employ

series-style energy recovery coils wrapped around

the cooling coil.

503.2.7 Duct and plenum insulation and sealing. All sup￾ply and return air ducts and plenums shall be insulated with

a minimum of R-5 insulation when located in uncondi￾tioned spaces and a minimum of R-8 insulation when

located outside the building. When located within a building

envelope assembly, the duct or plenum shall be separated

CL= Fx pO.65 (Equation 5-2)

50 2009 INTERNATIONAL ENERGY CONSERVATION CODE®