{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T14:07:11Z","timestamp":1777039631368,"version":"3.51.4"},"reference-count":33,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2019,8,20]],"date-time":"2019-08-20T00:00:00Z","timestamp":1566259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Building Research Institute (ITB)","award":["NZP-118\/2018"],"award-info":[{"award-number":["NZP-118\/2018"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A common method for investigating various fire- and smoke-related phenoma is a reduced-scale fire modelling that uses the conservation concept of Froude number as its primary similarity criterion. Smoke obscuration measurements were not commonly used in this approach. In this paper, we propose a new type of optical densitometer that allows for smoke obscuration density measurements on a reduced-scale. This device uses a set of mirrors to increase the optical path length, so that the device may follow the geometrical scale of the model, but that still measures smoke obscuration as if it were in full scale. The principle of operation is based on the Bougher-Lambert-Beer law, with modifications related to the Froude number-based scaling principles, to streamline the measurements. The proposed low-budget (&lt; $1000) device was built, calibrated with a set of the reference optical filters, and used in a series of full- (1:1) and reduced-scale (1:4) experiments with n-Heptane fires in a small compartment. The main limitation of this study is the assumption that there is similar soot production in full- and reduced-scale fires, which may not be true for many Froude-number scaling applications. Therefore, it must be investigated in a case-by-case basis. In our case, the results are promising. The measured obscuration in the reduced-scale had a 10% error versus averaged measurements in full-scale measurements. Moreover, there were well represented transient changes of the smoke layer optical density during the combustion and after the smoke layer settled.<\/jats:p>","DOI":"10.3390\/s19163628","type":"journal-article","created":{"date-parts":[[2019,8,21]],"date-time":"2019-08-21T11:19:06Z","timestamp":1566386346000},"page":"3628","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Smoke Obscuration Measurements in Reduced-Scale Fire Modelling Based on Froude Number Similarity"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7465-0212","authenticated-orcid":false,"given":"Wojciech","family":"W\u0119grzy\u0144ski","sequence":"first","affiliation":[{"name":"Fire Research Department, Building Research Institute (ITB), Filtrowa 1 St., 00-611 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9045-4687","authenticated-orcid":false,"given":"Piotr","family":"Antosiewicz","sequence":"additional","affiliation":[{"name":"Fire Research Department, Building Research Institute (ITB), Filtrowa 1 St., 00-611 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1225-5583","authenticated-orcid":false,"given":"Tomasz","family":"Burdzy","sequence":"additional","affiliation":[{"name":"Faculty of Mining and Geoengineering, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krak\u00f3w, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4466-7515","authenticated-orcid":false,"given":"Mateusz","family":"Zimny","sequence":"additional","affiliation":[{"name":"Faculty of Fire Safety Engineering, The Main School of Fire Service (SGSP), S\u0142owackiego 52\/54 St. Warsaw, 01-629 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9546-2336","authenticated-orcid":false,"given":"Adam","family":"Krasuski","sequence":"additional","affiliation":[{"name":"Faculty of Fire Safety Engineering, The Main School of Fire Service (SGSP), S\u0142owackiego 52\/54 St. Warsaw, 01-629 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,8,20]]},"reference":[{"key":"ref_1","first-page":"719","article-title":"The philosophy of fire safety engineering in the shaping of civil engineering development","volume":"64","author":"Sulik","year":"2016","journal-title":"Bull. Pol. Acad. Sci. Tech. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1016\/j.firesaf.2006.05.006","article-title":"Experimental behaviour of a steel structure under natural fire","volume":"41","author":"Wald","year":"2006","journal-title":"Fire Saf. J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.firesaf.2017.02.002","article-title":"An experimental study of full-scale open floor plan enclosure fires","volume":"89","author":"Hidalgo","year":"2017","journal-title":"Fire Saf. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.firesaf.2014.11.015","article-title":"Runehamar tunnel fire tests","volume":"71","author":"Ingason","year":"2015","journal-title":"Fire Saf. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.firesaf.2015.05.005","article-title":"Global analysis of multi-compartment full-scale fire tests (\u2019Rabot2012\u2019)","volume":"76","author":"Beji","year":"2015","journal-title":"Fire Saf. J."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Merci, B., and Beji, T. (2016). Fluid Mechanics Aspects of Fire and Smoke Dynamics in Enclosures, CRC Press\/Balkema.","DOI":"10.1201\/b21320"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/0379-7112(89)90045-3","article-title":"Scaling applications in fire research","volume":"15","author":"Quintiere","year":"1989","journal-title":"Fire Saf. J."},{"key":"ref_8","first-page":"1","article-title":"Visibility through Fire Smoke (I)","volume":"19","author":"Jin","year":"1970","journal-title":"Bull. Fire Prev. Soc."},{"key":"ref_9","first-page":"135","article-title":"Visibility through fire smoke","volume":"9","author":"Jin","year":"1978","journal-title":"J. Fire Flammabl."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/j.firesaf.2017.03.053","article-title":"Experimental and numerical evaluation of the influence of the soot yield on the visibility in smoke in CFD analysis","volume":"91","author":"Vigne","year":"2017","journal-title":"Fire Saf. J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1445","DOI":"10.1016\/S0082-0784(96)80365-1","article-title":"The effect of pool diameter on the properties of smoke produced by crude oil fires","volume":"26","author":"Mulholland","year":"1996","journal-title":"Symp. Combust."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2964","DOI":"10.1016\/j.combustflame.2013.06.020","article-title":"Pool fires\u2014An empirical correlation","volume":"160","author":"Ditch","year":"2013","journal-title":"Combust. Flame"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Khan, M.M., Tewarson, A., and Chaos, M. (2016). Combustion Characteristics of Materials and Generation of Fire Products. SFPE Handbook of Fire Protection Engineering, Springer.","DOI":"10.1007\/978-1-4939-2565-0_36"},{"key":"ref_14","unstructured":"Thomas, P.H., Hinkley, P.L., Theobald, C.R., and Simms, D.L. (1963). Investigations Into the Flow of Hot Gases in Roof Venting, Her Majesty\u2019s Stationary Office."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/0010-2180(75)90109-1","article-title":"Fire induced flow through an opening","volume":"25","author":"Prahl","year":"1975","journal-title":"Combust. Flame"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Quintiere, J.G. (2006). Fundamentals of Fire Phenomena, John Wiley & Sons Ltd.","DOI":"10.1002\/0470091150"},{"key":"ref_17","first-page":"1","article-title":"Scalling Mass Fires","volume":"Volume 11","author":"Williams","year":"1969","journal-title":"Fire Research Abstracts and Reviews"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"710","DOI":"10.1016\/S0016-0032(23)90146-8","article-title":"An instrument (densitometer) for the measurement of high photographic densities","volume":"195","author":"Jones","year":"1923","journal-title":"J. Franklin Inst."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1088\/0950-7671\/1\/11\/305","article-title":"A convenient photo-electric photometer and densitometer","volume":"1","author":"Baker","year":"1924","journal-title":"J. Sci. Instrum."},{"key":"ref_20","first-page":"17","article-title":"Visibility through Fire Smoke (II)","volume":"21","author":"Jin","year":"1971","journal-title":"Bull. Fire Prev. Soc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1002\/1099-1018(200009\/10)24:5<227::AID-FAM742>3.0.CO;2-9","article-title":"Specific extinction coefficient of flame generated smoke","volume":"24","author":"Mulholland","year":"2000","journal-title":"Fire Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1016\/0010-2180(94)90088-4","article-title":"Simultaneous optical measurement of soot volume fraction and temperature in premixed flames","volume":"99","author":"Choi","year":"1994","journal-title":"Combust. Flame"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Garc\u00e9s, H., Fuentes, A., Reszka, P., Carvajal, G., Garc\u00e9s, H.O., Fuentes, A., Reszka, P., and Carvajal, G. (2018). Analysis of Soot Propensity in Combustion Processes Using Optical Sensors and Video Magnification. Sensors, 18.","DOI":"10.3390\/s18051514"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Tang, R., Zhang, T., Wei, X., Zhou, Z., Tang, R., Zhang, T., Wei, X., and Zhou, Z. (2017). An Efficient Numerical Approach for Field Infrared Smoke Transmittance Based on Grayscale Images. Appl. Sci., 8.","DOI":"10.3390\/app8010040"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2299","DOI":"10.1080\/714923279","article-title":"Evaluation of the planck mean absorption coefficients for radiation transport through smoke","volume":"175","author":"Widmann","year":"2003","journal-title":"Combust. Sci. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1016\/j.jaerosci.2004.09.005","article-title":"Measurement of the optical extinction coefficient of combustion-generated aerosol","volume":"36","author":"Widmann","year":"2005","journal-title":"J. Aerosol Sci."},{"key":"ref_27","unstructured":"McGrattan, K., Hostikka, S., McDermott, R., Floyd, J., Weinschenk, C., and Overholt, K. (2017). Fire Dynamics Simulator User\u2019s Guide."},{"key":"ref_28","unstructured":"CEN (2019, August 20). EN 14604:2005+AC:2008 Smoke Alarm Devices. Available online: https:\/\/www.sis.se\/api\/document\/preview\/67895\/."},{"key":"ref_29","unstructured":"CEN (2019, August 20). EN 54-7:2018 Fire Detection and Fire Alarm Systems - Part 7: Smoke Detectors - Point Smoke Detectors That Operate Using Scattered Light, Transmitted Light or Ionization. Available online: https:\/\/standards.globalspec.com\/std\/13061688\/EN%2054-7."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Barsim, M.M., Bassily, M.A., El-Batsh, H.M., Rihan, Y.A., and Sherif, M.M. (2019). Froude scaling modeling in an Atrium Fire equipped with natural and transient forced ventilation. Int. J. Vent., 1\u201323.","DOI":"10.1080\/14733315.2019.1615220"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Park, J.H., Lee, S., Yun, S., Kim, H., Kim, W.T., Park, J.H., Lee, S., Yun, S., Kim, H., and Kim, W.T. (2019). Dependable Fire Detection System with Multifunctional Artificial Intelligence Framework. Sensors, 19.","DOI":"10.3390\/s19092025"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Li, Y., Wang, A., Yi, X., Li, Y., Wang, A., and Yi, X. (2019). Fire Control System Operation Status Assessment Based on Information Fusion: Case Study. Sensors, 19.","DOI":"10.3390\/s19102222"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Park, S., Park, S., Park, L., Park, S., Lee, S., Lee, T., Lee, S., Jang, H., Kim, S., and Chang, H. (2018). Design and Implementation of a Smart IoT Based Building and Town Disaster Management System in Smart City Infrastructure. Appl. Sci., 8.","DOI":"10.3390\/app8112239"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/16\/3628\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:12:33Z","timestamp":1760188353000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/16\/3628"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,8,20]]},"references-count":33,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2019,8]]}},"alternative-id":["s19163628"],"URL":"https:\/\/doi.org\/10.3390\/s19163628","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,8,20]]}}}