## 2018 Uniform Mechanical Code

#### Appendix G Example Calculation of Outdoor Air Rate

Heads up: There are no suggested sections in this chapter.
Heads up: There are no amended sections in this chapter.

# Appendix G Example Calculation of Outdoor Air Rate

The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

CALIFORNIA MECHANICAL CODE - MATRIX ADOPTION TABLE
APPENDIX G - EXAMPLE CALCULATION OF OUTDOOR AIR RATE
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-CG SFM HCD DSA OSHPD BSCC DPH AGR DWR CEC CA SL SLC
1 2 1-AC AC SS SS/CC 1 1R 2 3 4 5
amended (amended
sections listed below)
that are listed below
Chapter / Section
This state agency does not adopt sections identified with the following symbol:
The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

### G101.1 Example Calculation

Determine the outdoor air rate required for a single zone AC unit serving an interior 2000 square feet (185.81 m2) conference/meeting room with a design occupancy of 100 people. The system supplies and returns air from the ceiling. (See Chapter 4 of this code for guidelines)

Solution:

In accordance with Table 403.2.2, the zone air distribution effectiveness is 1.0 since the system supplies cooling only from the ceiling. Using the rates from Table 402.1 for a conference/meeting room, the minimum system outdoor air rate is calculated to be:

 Vot = (Equation G 101.1) = = 620 cubic feet per minute (ft3/min)

 Where: Az = zone floor area: the net occupiable floor area ofthe zone in square feet. Pz = zone population: The largest number of peopleexpected to occupy the zone during typical usage.Where the number of people expected to occupythe zone fluctuates, Pz shall be permitted to be estimatedbased on averaging approaches described inSection 403.6.1. Where Pz cannot be accuratelypredicted during design, it shall be estimated basedon the zone floor area and the default occupantdensity in accordance with Table 402.1. RP = outdoor airflow rate required per person in accordancewith Table 402.1. Ra = outdoor airflow rate required per unit area in accordancewith Table 402.1. Ez = zone air distribution effectiveness in accordancewith Table 403.2.2.
For SI units: 1 square foot = 0.0929 m2, 1 cubic foot per minute = 0.00047 m3/s
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