2923 -- Air Exchange Rate Measurements of the National Archives Building PDF

To aid in improving the performance of the heating, ventilating, and air-conditioning (HVAC) system of the National Archives Building so that it can better protect paper-based records of the United States, the National Bureau of Standards (NBS) measured air exchange rates under various combinations of temperature and wind speed. The average air exchange rate under normal operation of the HVAC system was 0.9 h^-1 for an average temperature difference of 20.3°F (11.3°C) and an average wind speed of 6.0 mph (2.7 m/s). This rate is approximately twice those for new General Services Administration (GSA) office buildings. No clear dependence of air exchange rate on temperature differences up to 30°F (17°C) or wind speeds up to 11 mph (5 m/s) was found.

With outdoor air dampers closed and fans operating, the average air exchange rate was 1.2 h^-1 for an average temperature difference of 14 .80F (8.20C) and an average wind speed of 3.8 mph (1.7 m/s). A test of interzone air movement showed that air migrates rapidly from nonstack to stack areas with fans operating normally.

The building could not be pressurized beyond an indoor-outdoor pressure difference of 0.06 in H₂O (14 Pa). At this pressure difference, the air exchange rate was 1.5 h^-1. As in the case of normal operation of the HVAC system, this rate is also approximately twice those for new GSA office buildings.

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