# E 605.1.3 Dwelling-Unit Ventilation

*Q*) shall be as specified in Table E 605.1.3.1 or, alternatively, calculated in accordance with Equation E 605.1.3.1.

_{tot}**TABLE E 605.1.3.1 VENTILATION AIR REQUIREMENTS, (cubic foot per minute)[ASHRAE 62.2:TABLE 4.1a]**

FLOOR AREA (ft^{2}) | BEDROOMS | ||||
---|---|---|---|---|---|

1 | 2 | 3 | 4 | 5 | |

<500 | 30 | 38 | 45 | 53 | 60 |

501-1000 | 45 | 53 | 60 | 68 | 75 |

1001-1500 | 60 | 68 | 75 | 83 | 90 |

1501-2000 | 75 | 83 | 90 | 98 | 105 |

2001-2500 | 90 | 98 | 105 | 113 | 120 |

2501-3000 | 105 | 113 | 120 | 128 | 135 |

3001-3500 | 120 | 128 | 135 | 143 | 150 |

3501-4000 | 135 | 143 | 150 | 158 | 165 |

4001-4500 | 150 | 158 | 165 | 173 | 180 |

4501-5000 | 165 | 173 | 180 | 188 | 195 |

For SI units: 1 square foot = 0.0929 m^{2}, 1 cubic foot per minute = 0.00047 m^{3}/s

(Equation E 605.1.3.1)

*Q _{tot}* = 0.03A

*+ 7.5(*

_{floor}*N*+ 1)

_{br}Where:

Q_{tot} | = | total required ventilation rate, cubic feet per minute (ft^{3}/min) |

A_{floor} | = | dwelling unit square foot (ft^{2}) |

N_{br} | = | number of bedrooms; not to be less than one |

For SI units: 1 cubic foot per minute = 0.00047 m^{3}/s, 1 square foot = 0.0929 m^{2}

**Exceptions:** Dwelling-unit mechanical ventilation systems shall not be required where the Authority Having Jurisdiction determines that window operation is a locally permissible method of providing ventilation and provided one or more of the following conditions is met:

*Q*) shall be calculated using Equation E 605.1.3.2:

_{inf}[Equation 605.1.3.2]

*Q _{inf}*(cfm) = (

*NL*×

*wsf*×

*A*/ (7.3)*

_{floor})Where:

NL | = | normalized leakage |

wsf | = | weather and shielding factor from ASHRAE 62.2. |

A_{floor} | = | floor area of residence, ft^{2} (m^{2}) |

* Replace 7.3 with 1.44 for metric units. [ASHRAE 62.2:4.1.2(e)]

*Q*) shall be calculated using Equation E 605.1.3.3:

_{fan}[Equation 605.1.3.3]

*Q _{fan}* =

*Q*— (

_{tot}*Q*×

_{inf}*A*)

_{ext}Where:

Q_{fan} | = | required mechanical ventilation rate, cfm (L/s) |

Q_{tot} | = | total required ventilation rate, cfm (L/s) |

Q_{inf} | = | may be not greater than ^{2}/_{3} × Q_{tot} |

(see ASHRAE 62.2 for exceptions for existing buildings)

A_{ext} | = | 1 for single-family detached homes, or the ratio of exterior envelope surface area that is not attached to garages or other dwelling units to total envelope surface area for single-family attached homes. [ASHRAE 62.2:4.1.2(f)] |

^{3}/min (0.003 m

^{3}/s) for each additional person. Where approved by the Authority Having Jurisdiction, lower occupant densities shall be permitted to be used. [ASHRAE 62.2:4.1.3]

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