The time that it takes an occupant population to reach safety when descending a stair during building evacuations is typically estimated by measurable engineering variables such as stair geometry, speed, stair density, and pre-observation delay. In turn, engineering models of building evacuation use these variables to predict the performance of egress systems for building design, emergency planning, or event reconstruction. As part of a program to better understand occupant movement and behavior during building emergencies, the Engineering Laboratory at the National Institute of Standards and Technology (NIST) has been collecting stair movement data during fire drill evacuations of office and residential buildings. These data collections are intended to provide a better understanding of this principal building egress feature and develop a technical foundation for future codes and standards requirements. NIST has collected fire drill evacuation data in 14 buildings (11 office buildings and 3 residential buildings) ranging from six to 62 stories in height that have included a range of stair widths and occupant densities. A total of more than 22000 individual measurements are included in the data set. A summary of the data is shown below.
While mean movement speeds in the current study of 0.44 m/s ± 0.19 m/s are observed to be quite similar to the range of values in previous studies, mean local movement speeds as occupants traverse down the stairs are seen to vary widely within a given stair, ranging from 0.10 m/s ± 0.008 m/s to 1.7 m/s ± 0.13 m/s. These data provide confirmation of the adequacy of existing literature values typically used for occupant movement speeds and provide updated data for use in egress modeling or other engineering calculations.
The report available below provides details of the data collected, an analysis of the data, and examples of the use of the data.
The data contained in the spreadsheets include the following.
Data taken for each occupant:
Column A: The code that indicates type of data in the current row of the spreadsheet: C for column headings, F for distances from floor to exit, and E for data collected for each evacuee.
Column B: The unique number assigned to each evacuee. Numbered from 1 to the number of unique evacuees identified from the original video record.
Column C: This column indicates the gender of the occupant. "M" is used for male, "F" for female, and a "?" may be included if the gender is not clear from original video record.
Column D: This column indicates, by an "x" in the spreadsheet, whether the evacuee was carrying anything during evacuation.
Column E: This column indicates, by an "M" in the spreadsheet for occupants that occupy significantly more than half the stair width during evacuation and by an "L" in the spreadsheet for occupants that occupy significantly less than half the stair width during evacuation. This may identify a possible obstruction to flow of other evacuees if the evacuee slows or stops during evacuation.
Column F: This column indicates, by an "x" in the spreadsheet, whether the evacuee was carrying an overcoat/jacket during evacuation.
Column G: The column indicates whether the evacuee was traveling with other evacuees throughout the evacuation. If the occupant was traveling with other evacuees, the others' occupant number is listed in the spreadsheet.
Column H: This column indicates, by an "x" in the spreadsheet, whether the evacuee was assisting or being assisted by another evacuee during the evacuation.
Column I: This column indicates the highest floor in the stair where the evacuee was first observed on the original video record.
Column J: This column indicates the floor in the stair where the evacuee was began their evacuation, if known.
Column K: This column provides the occupant's description, including hair color, clothing, and any items the evacuee carried during evacuation. This column is used to uniquely identify the evacuees during data collection. "LH/RH" labels are used to identify an occupant carrying something in the left hand or right hand and "LA/RA" labels are used to identify an occupant carrying something on the left arm or right arm.
Data taken for each occupant at each camera location (Columns L through R are repeated for each camera location in the stair.):
Column L: This column indicates whether the evacuee descended the stair near the inside handrail, the outside handrail, or in the middle of the staircase.
Column M: This column indicates handrail usage by the evacuee. "I" indicates the use of the inside handrail, "O" indicates the use of the outside handrail, "B" indicates the use of both handrails, and "A" indicates alternating handrail use. If this column is blank, this may indicate either that the occupant did not use the handrail or that the handrail use could not be seen in the original video record.
Column N: This column indicates the spacing to the previous evacuee: 1 for one or fewer open treads, 2 for two open treads, 3 for three open treads, . for four or more open treads.
Columns O and P: The time (from beginning of original video record) that the evacuee first entered the camera view on the current floor in minutes and seconds.
Columns Q and R: The time (from beginning of original video record) that the evacuee left the camera view on the current floor in minutes and seconds.