Building concentrations shall be estimated based on the following parameters and criteria:
a.Laboratory-measured volatile organic compound (VOC) emission factors and actual surface area of all materials as described in (b) below.
c.The actual building parameters for volume, average weekly minimum ventilation rate, and ventilated volume fraction for the building being modeled shall be used.
d.Standard building scenarios or modeling from similar buildings shall not be allowed.
e.Average weekly minimum air change rates shall be calculated based on the minimum outdoor airflow and hours of operation for the specific building being modeled.
f.Steady-state conditions with respect to emission rates and building ventilation may be assumed.
g.Zero outdoor air concentrations, perfect mixing within the building, and no net losses of VOCs from air due to other effects such as irreversible or net sorption on surfaces (i.e., net sink effects) and chemical reactions may be assumed.
h.All assumptions shall be clearly stated in the design documents.
i.The estimated building concentration, CBi (µg/m3), of each target VOC shall be calculated using Equation 2 of CDPH/EHLB/Standard Method V1.1 (commonly referred to as California Section 01350), as shown below. Estimated building concentrations of individual target VOCs with multiple sources shall be added to establish a single total estimated building concentration for individual target VOCs.
|EFAi||=||area specific emission rate or emission factor at 96 hours after placing a test specimen in the chamber (14 days total exposure time), µg/m2·h|
|AB||=||exposed surface area of the installed material in the building, m2|
|VB||=||building volume, m3|
|aB||=||average weekly minimum air change rate, 1/h|