Next Article in Journal
Integrating Geographic Information Systems and Augmented Reality for Mapping Underground Utilities
Previous Article in Journal
Review of Laser Scanning Technologies and Their Applications for Road and Railway Infrastructure Monitoring
Open AccessArticle

Visualizing Air Motion Involving Isolated Subsurface Structures: A Critical Tool for Understanding Ventilation Induced by Natural Forces

1
Northwest Occupational Health & Safety, North Vancouver, BC V7K1P3, Canada
2
Programa de Engenharia Ambiental, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
3
Escola Politécnica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
*
Author to whom correspondence should be addressed.
Infrastructures 2019, 4(4), 59; https://doi.org/10.3390/infrastructures4040059
Received: 5 June 2019 / Revised: 16 September 2019 / Accepted: 20 September 2019 / Published: 23 September 2019
Worldwide, infrastructure contains millions of isolated subsurface structures. Most, if not all, meet requirements for classification as confined spaces. Workers routinely enter and work in these structures. Ventilation of these spaces by air exchange induced by natural forces was documented first in 1936. The mechanism of the process remains to be discovered. This investigation utilized ‘smoke’ tubes to visualize air motion and video capture techniques to record the process. Air moved across the surface of the ground and unpredictably entered the airspace when a single opening in the manhole cover was present. The process is discrete and not continuous. Air moved downward linearly or in circular motion, and moved across the underside of the manhole cover in the direction opposite airflow and down the sidewall of the structure. This produced the rapid mixing in the airspace observed instrumentally. For two openings, entry was more aggressive and predictable. Separation between the openings influenced exchange. Closer spacing (center + circumference) produced better ventilation than wider spacing (circumferential openings opposite each other). Optimizing naturally induced ventilation of these structures has profound importance to minimize risk to passersby and workers who enter and work in them. View Full-Text
Keywords: visualization of near surface air motion; ‘smoke tubes’; isolated subsurface structure; natural forces; video recording visualization of near surface air motion; ‘smoke tubes’; isolated subsurface structure; natural forces; video recording
Show Figures

Graphical abstract

MDPI and ACS Style

McManus, T.N.; Haddad, A. Visualizing Air Motion Involving Isolated Subsurface Structures: A Critical Tool for Understanding Ventilation Induced by Natural Forces. Infrastructures 2019, 4, 59.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop