Tekniska system för uppskattning av personantal och personers placering i byggnader

Abstract

The aim was to identify technical systems potentially useful for estimating number of people and their location in buildings. Another aim was to investigate whether the information generated by the technical systems can have a positive effect on risk management. A number of technical systems were identified and evaluated. A more detailed evaluation of demand-controlled ventilation system with carbon dioxide measurement was performed. Through the detailed evaluation a method for estimating people with demand-controlled ventilation system was derived since this technical system was not originally intended for estimating the number of people. The evaluation showed that demand-controlled ventilation system have potential to be used for estimating number of people in buildings. The evaluation also showed that the ventilation conditions and generated carbon dioxide per person had the largest influence on the derived method and therefore needs further investigation. The evaluation of all identified technical systems showed that because of their different qualities there are systems that are better than others at estimating number of people in buildings. The evaluation also indicated that a combination of systems could improve the results of estimating number of people in buildings.

Popular Abstract

Estimating the number of people in buildings
with data from ventilation systems
Emma Ingmarsson1, Ida Pettersson1, Daniel Nilsson1, and David Purser2
1Department of Fire Safety Engineering, Lund University, Sweden
2Hartford Environmental Research, UK
The development of smart buildings is increasing and there are already many buildings around the
world with multifunctional technical systems [1-3]. In smart buildings, technical systems interact in
order to create new functions that are beneficial, e.g., improved cost, reduced environmental
impact, increased safety, etc [4]. Historically, technical systems in smart buildings have often had
energy and cost saving as their main purpose. However, some systems could potentially also be
used for other purposes, e.g., to facilitate evacuation.
It has been suggested that dynamic crowd management systems can potentially be used to improve
evacuation safety in future buildings [5]. The proposed dynamic system works according to an
iterative process where (1) the people in the building are located and counted, (2) people’s
movement patterns are simulated faster than real-time, (3) decisions about suitable evacuation
strategies are made, and (4) people are directed to the most appropriate exit by dynamic evacuation
systems, e.g., alarms and way-finding systems (see Fig.1). An essential part of the iterative process is
the estimation of the location and number of people in the building (see Fig.1), which might be
possible to achieve with existing systems in smart buildings. One possibility is to use ventilation
systems, which are often demand-controlled systems that adjust the ventilation conditions
depending on the actual building use.
The proposed paper will focus on the use of demand-controlled ventilation systems with carbon
dioxide measurement to estimate the number of people in buildings. At Lund University, many
teaching rooms have demand-controlled ventilation based on carbon dioxide measurement, and
two of these rooms were used to collect data (see Fig.2).
Fig.1 Dynamic crowd management system [3] Fig.2 A lecture room used in the study
An equation for calculating the flow of carbon dioxide from people (production rate) was first
derived (see Fig.3). The main assumptions in the derivation of the equation were that (1) people in
the room are the only source of generated carbon dioxide, (2) there are no leakages to or from the
room, and (3) the air is perfectly mixed in the room. The air is assumed to only enter and leave the
room via the ventilation system, and account is taken of the carbon dioxide concentration in the
ambient air.
The measured carbon dioxide concentration was inserted into the equation in order to calculate the
flow of generated carbon dioxide in the room. The calculated flow was then compared to a single
person’s carbon dioxide generation to estimate the number of people in the rooms. In order to
verify the estimate, comparisons with the observed number of people in the rooms were made.
Fig.3 A graphic representation of the assumptions made in the derivation of the equation
Results show that it is possible to get an indication of people’s movement in and out from rooms
(see Fig.4). The study also shows that the calculations (base-line case) systematically overestimate
the number of people compared to the visual observations (see Fig.4). A sensitivity analysis was
performed to investigate the influence of the input parameters on the results. This sensitivity
analysis showed that assumptions relating to the ventilation conditions and generated carbon
dioxide per person had the largest influence on the predictions. Based on these results, refined
calculations were made, which show closer agreement with the observations (see Fig.4).
Fig.4 Observed and predicted number of people in a lecture room
The study shows that it is possible to estimate the number of people in buildings with relatively
high accuracy using data from demand-controlled ventilation systems with carbon dioxide
measurement. However, the sensitivity analysis indicates that there are input parameters that need
further investigation, which can reduce the uncertainties of the method. The study shows that it is
possible to use technical systems for estimating the number of people even though they were not
originally intended for this purpose.
References
[1] Foster + Partners Ltd (2014) 7 More London Riverside, retrieved 22 Dec 2014 from
http://www.fosterandpartners.com/projects/7-more-london-riverside/?altTemplate=ProjectPDF.
[2] Deutsche Bank Corporate Real Estate & Services (2014) Greentowers – setting a New Global Standard,
retrieved 22 Dec 2014 from http://uli.org/wp-content/uploads/ULI-Documents/GP-Deutsche-
Bank.pdf.
[3] KFW IPEX-Bank (2014) We are CO2 neutral, retrieved 22 Dec 2014 from https://www.kfw-ipexbank.
de/International-financing/KfW-IPEX-Bank/About-KfW-IPEX-Bank/Gesellschaftliche-
Verantwortung/Betrieblicher-Umweltschutz/
[4] Chao, C. (2013). Smart Green Buildings of Tomorrow. Indoor & Built Environment, Vol 22 (4), 595-597.
[5] Nilsson, D. (2013) SMART Buildings: A way forward for evacuation safety? Presentation at the FPRF
symposium ”The Next Five Years in Fire and Electrical Safety”, November 13-14, AIA District
Architecture Center, Washington, DC.

• author: Ingmarsson, Emma and Pettersson, Ida
• supervisor: Daniel Nilsson
• organization: Division of Fire Safety Engineering
• course: VBRM10 20142
• year: 2015
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Occupancy, location of people, evacuation, ventilation system, carbon dioxide
• publication/series: LUTVDG/TVBB
• report number: 5487
• ISSN: 1402-3504
• language: Swedish
• id: 5050041
• date added to LUP: 2015-02-16 09:37:15
• date last changed: 2015-02-16 09:37:15