Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-11C - State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial › Section 51-11C-40376 - Section C403.7.6-Energy recovery ventilation systems

Current through Register Vol. 24-14, July 15, 2024
C403.7.6
Energy
			 recovery ventilation systems.
Energy recovery ventilation systems shall
			 be provided as specified in Sections C403.7.6.1 and C403.7.6.2.
C403.7.6.1
Ventilation for Group R-2
			 occupancy.
For all Group R-2 dwelling and sleeping units, a balanced
			 ventilation system with heat recovery system with minimum 60 percent sensible
			 recovery effectiveness shall provide outdoor air directly to each habitable
			 space in accordance with the
International Mechanical Code
.
			 The ventilation system shall allow for the design flow rates to be tested and
			 verified at each habitable space as part of the commissioning process in
			 accordance with Section C408.2.2. The return/exhaust air stream temperature for
			 heat recovery device selection shall be 70°F (21°C), or as calculated
			 by the
registered design professional
.
C403.7.6.2
Spaces other than Group R-2
			 dwelling units.
Any system serving a space other than a Group R-2
			 dwelling or sleeping unit with minimum outside air requirements at design
			 conditions greater than 5,000 cfm or any system where the system's supply
			 airflow rate exceeds the value listed in Tables C403.7.6(1) and C403.7.6(2),
			 based on the climate zone and percentage of outdoor airflow rate at design
			 conditions, shall include an energy recovery system. Table C403.7.6(1) shall be
			 used for all ventilation systems that operate less than 8,000 hours per year,
			 and Table C403.7.6(2) shall be used for all ventilation systems that operate
			 8,000 hours or more per year. The energy recovery system shall provide a 68
			 percent minimum sensible recovery effectiveness or have an
enthalpy
			 recovery ratio
of not less than 60 percent at design conditions. Where
			 an air economizer is required, the energy recovery system shall include a
			 bypass of the energy recovery media for both the outdoor air and exhaust air or
			 return air dampers and controls which permit operation of the air economizer as
			 required by Section C403.5. Where a single room or space is supplied by
			 multiple units, the aggregate ventilation (cfm) of those units shall be used in
			 applying this requirement. The return/exhaust air stream temperature for heat
			 recovery device selection shall be 70°F (21°C) at 30 percent relative
			 humidity, or as calculated by the registered design professional.
EXCEPTION:
An energy recovery ventilation system shall not be
						  required in any of the following conditions:
1. Where energy recovery systems are restricted per
						  Section 514 of the
International Mechanical Code
to sensible
						  energy, recovery shall comply with one of the following:
1.1. Kitchen exhaust systems where they comply with
						  Section C403.7.7.1.
1.2. Laboratory fume hood systems where they comply
						  with Exception 2 of Section C403.7.6.
1.3. Other sensible energy recovery systems with the
						  capability to provide a change in dry-bulb temperature of the outdoor air
						  supply of not less than 50 percent of the difference between the outdoor air
						  and the return air dry-bulb temperatures, at design conditions.
2. Laboratory fume hood systems that include at least
						  one of the following features and also comply with Section C403.7.7.2:
2.1. Variable-air-volume hood exhaust and room supply
						  systems configured to reduce exhaust and makeup air volume to 50 percent 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 (1.1°C)
						  above room setpoint, cooled to no cooler than 3°F (1.7°C) below room
						  setpoint, no humidification added, and no simultaneous heating and cooling used
						  for dehumidification control.
3. Systems serving spaces that are heated to less than
						  60°F (15.5°C) and are not cooled.
4. Where more than 60 percent of the outdoor air
						  heating energy is provided from site-recovered energy.
5. Systems exhausting toxic, flammable, paint or
						  corrosive fumes or dust.
6. Cooling energy recovery.
7. Systems requiring dehumidification that employ
						  energy recovery in series with the cooling coil.
8. Multiple-zone systems where the supply airflow rate
						  is less than the values specified in Tables C403.7.6 (1) and (2), for the
						  corresponding percent of outdoor air. Where a value of NR is listed, energy
						  recovery shall not be required.
9. Equipment which meets the requirements of Section
						  C403.9.2.4.
10. Systems serving Group R-1 dwelling or sleeping
						  units where the largest source of air exhausted at a single location at the
						  building exterior is less than 25 percent of the design outdoor air flow
						  rate.
Table C403.7.6(1) Energy Recovery Requirement
				(Ventilation systems operating less than 8,000 hours per year)
Percent (%) Outdoor Air at Full
						  Design Airflow Rate
Climate zone
[GREATER THAN EQUAL TO] 10% and [LESS THAN ] 20%
[GREATER THAN EQUAL TO] 20% and [LESS THAN ] 30%
[GREATER THAN EQUAL TO] 30% and [LESS THAN ] 40%
[GREATER THAN EQUAL TO] 40% and [LESS THAN ] 50%
[GREATER THAN EQUAL TO] 50% and [LESS THAN ] 60%
[GREATER THAN EQUAL TO] 60% and [LESS THAN ] 70%
[GREATER THAN EQUAL TO] 70% and [LESS THAN ] 80%
[GREATER THAN EQUAL TO] 80%
Design Supply Fan Airflow Rate
						  (cfm)
4C, 5B
NR
NR
NR
NR
NR
NR
[GREATER THAN EQUAL TO] 5000
[GREATER THAN EQUAL TO] 5000
NR = Not required.
Table C403.7.6(2) Energy Recovery Requirement
				(Ventilation systems operating not less than 8,000 hours per
				year)
Percent (%) Outdoor Air at Full
						  Design Airflow Rate
Climate zone
[GREATER THAN EQUAL TO] 10% and [LESS THAN ] 20%
[GREATER THAN EQUAL TO] 20% and [LESS THAN ] 30%
[GREATER THAN EQUAL TO] 30% and [LESS THAN ] 40%
[GREATER THAN EQUAL TO] 40% and [LESS THAN ] 50%
[GREATER THAN EQUAL TO] 50% and [LESS THAN ] 60%
[GREATER THAN EQUAL TO] 60% and [LESS THAN ] 70%
[GREATER THAN EQUAL TO] 70% and [LESS THAN ] 80%
[GREATER THAN EQUAL TO] 80%
Design Supply Fan Airflow Rate
						  (cfm)
4C
NR
[GREATER THAN EQUAL TO] 19500
[GREATER THAN EQUAL TO] 9000
[GREATER THAN EQUAL TO] 5000
[GREATER THAN EQUAL TO] 4000
[GREATER THAN EQUAL TO] 3000
[GREATER THAN EQUAL TO] 1500
[GREATER THAN EQUAL TO] 120
5B
[GREATER THAN EQUAL TO] 2500
[GREATER THAN EQUAL TO] 2000
[GREATER THAN EQUAL TO] 1000
[GREATER THAN EQUAL TO] 500
[GREATER THAN EQUAL TO] 140
[GREATER THAN EQUAL TO] 120
[GREATER THAN EQUAL TO] 100
[GREATER THAN EQUAL TO] 80
NR = Not required.