Thermal conditions in the Great Hall of the National Building Museum will be reasonably constant in both the vertical and horizontal dimensions.

The HOBO data collected on four floors of the National Building Museum, on both the south and north sides and the east and west quarters, show consistent temperatures over space and time in the Great Hall. These measurements were conducted during a roughly 2-hour period on Sunday, 22 April 2001. At the time of the measurements the outdoor air temperature was in the 80s and the Great Hall was not mechanically cooled, but ventilated with outdoor air through use of the HVAC system.

Temperature differentials both vertically and horizontally in the Great Hall did not exceed 5 degrees F during the period of measurement. Relative humidity showed less than a 10% difference between any of the points measured during the same time period. Team 2's primary hypothesis was proved valid. Temperature and humidity in the Great Hall were consistent from location to location.

It would be interesting to repeat this investigation during a time when the Hall was air-conditioned. Would the introduction of cool air at the fourth floor level increase the potential for stratification or would the substantial circulation of air developed by the air diffusers maintain an equitable temperatures distribution in the space?

It is suspected that the combination temperature/humidity HOBOs have a much greater time lag (with their internal sensors) than do the XT versions of the HOBO (with external sensors). In the case of this short-term investigation, even a five minute lag might make a difference and must be considered. Time coincidence of data must also be considered when launching multiple HOBOs over a several minutes period and then installing them in far-ranging positions. In the case of this investigation, alignment of data to coincident start times (using spreadsheet software) was important. Perhaps 30 minutes of initial data collection was not used while many of the sensors were still in the process of being installed.


It would be interesting to assist the lighting team with their measurements.

See the report of the "lighting" team for data related to illuminance levels in the Great Hall. There appeared to be more than adequate lighting in the Great Hall on the afternoon of Tool Day. In fact, the use of the many electric lamps located throughout the Hall seemed unnecessary and wasteful. The contacts Team 2 made with the building engineer allowed us to discover that many of the electric lamps in the Hall could not be switched off as they were connected to a programmed security system not under the easy control of the building operators. Ouch!

It would be interesting to take measurements of surface temperatures throughout the Great Hall.

Data collected in support of this sub-hypothesis lead to the conclusion that the Great Hall was being conditioned with mechanically delivered outdoor air on the Tool Day afternoon. This mode of operation was confirmed by the building engineer, who indicated that it was a typical way of operating the building on such days. The mass and volume of the building and an early start-up of the ventilation allowed the building to comfortably float through warm afternoon hours.

A differential in the temperature of supply air on the north and south sides of the building is the sort of interesting finding that often occurs in the course of a Vital Signs investigation. Ascertaining the reason for this differential could be a study in itself. Tentatively, the Team believes this differential might be due to micro-climate effects at the air intakes for the respective HVAC systems (north side versus south side intakes?). Lack of information as to the exact location of the outdoor air inlets prevented this sub-sub-hypothesis from being adequately addressed.

It would be interesting to see what the Great Hall looks like from the catwalks.

Evidence shows the view to be spectacular.

It would be interesting to ask the building engineer about the operation of the building.

As is usual, this hypothesis was proven to be true. A world of information was available for the asking.

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This page was last updated on 8 May 2001.