The LWF Blog
Fire Safety Engineering for Design – Smoke Ventilation – Part 190
July 1, 2024 10:33 amLWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 189, LWF discussed pressure differentials and smoke ventilation. In part 190, we look at the tenability criteria for smoke ventilation system design, beginning with smoke hazards.
Smoke from a fire is a hazardous substance. It contains both irritants and narcotic components which can cause significant ill-effects on people and animals. The effects range from disorientation, through vision issues and can even result in death. The effects are dependent upon how prolonged and concentrated the exposure is.
The main irritants are organic smoke products and acid gases, e.g. hydrogen chloride (HCI). Dependent upon the concentration this can cause pain in the eyes, leading to compromised vision and tearing, and lung problems leading to difficulty breathing.
The main narcotic component of smoke is carbon monoxide. Hydrogen cyanide is also an issue in the case of pre-flashover fires. Inhalation of these gases in sufficient concentrations and over time can cause narcotic effects, leading to disorientation and collapse.
The temperature of smoke is also a significant hazard. Smoke may cause burns to exposed skin and lungs by convection and radiation. Hyperthermia may also be a risk if long exposure is experienced.
Smoke particles and irritants can compromise the vision of those people looking to evacuate a building. In this way, while the irritation to the eyes is not life-threatening or the cause of long-term health problems, it can delay or prevent escape and present a significant hazard, as those affected may be overcome by smoke.
Smoke inhalation is the leading cause of death in fires and aside from the very significant issues already raised, smoke inhalation can cause headaches, coughs, chest pain, abdominal pain, nausea, heart issues and fainting.
Other toxic gases may be released if the fire comes into contact with certain types of object. Hydrogen cyanide may be released from burning plastics and phosgene from household products containing vinyl.
In part 191 of LWF’s series on fire engineering we will continue looking at the tenability criteria for smoke ventilation system design, by discussing temperature and its effects on a person. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.
Lawrence Webster Forrest has been working with their clients since 1986 to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact the LWF office on 0800 410 1130.
While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.