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3. CALIFORNIA HERS RA3.9.4.1.2 FOR WHF AIRFLOW MEASUREMENT
IMPORTANT:
Read this before equipment setup!
IMPORTANT:
For proper usage as a powered flow hood for testing airflow, please refer to
Reference Appendices RA3.9.4.1.2. This device is designed to be compliant with that protocol.
The WHF-PFH is approved to be used with the Retrotec 5000/6000 series blower door fans,
and TEC Model 3 110V series blower door.
NOTE: Retrotec 5000 series will only work with the WHF-PFH to measure up to 4500 CFM
The WHF airflow measurement shall be performed using the following procedures:
1. Open the window(s) that are typically opened during WHF operation.
2. Turn on all WHFs required to meet the dwelling unit WHF airflow rate. Adjust multiple or
variable speed WHFs to operate at an airflow rate that will be greater than or equal to the
rate required for compliance.
3. Adjust the dwelling unit window openings to bring the dwelling unit to the WHF-OP of
negative 10 Pa
±
5 Pa WRT outside.
4. Measure the airflow rate(s) at the inlet grille(s) with a calibrated powered flow hood to
determine the total WHF airflow for the dwelling unit.
No part of the WHF intake shall be blocked or masked off to accommodate an undersized hood.
Operation of the powered flow hood shall conform to the specifications in the manufacturer’s
product documentation.
