Wind-Driven Roof Turbines: A Novel Way to Improve Ventilation for TB Infection Control in Health Facilities

Abstract

ObjectiveTuberculosis transmission in healthcare facilities contributes significantly to the TB epidemic, particularly in high HIV settings. Although improving ventilation may reduce transmission, there is a lack of evidence to support low-cost practical interventions. We assessed the efficacy of wind-driven roof turbines to achieve recommended ventilation rates, compared to current recommended practices for natural ventilation (opening windows), in primary care clinic rooms in Khayelitsha, South Africa.MethodsRoom ventilation was assessed (CO2 gas tracer technique) in 4 rooms where roof turbines and air-intake grates were installed, across three scenarios: turbine, grate and window closed, only window open, and only turbine and grate open, with concurrent wind speed measurement. 332 measurements were conducted over 24 months.FindingsFor all 4 rooms combined, median air changes per hour (ACH) increased with wind speed quartiles across all scenarios. Higher median ACH were recorded with open roof turbines and grates, compared to open windows across all wind speed quartiles. Ventilation with open turbine and grate exceeded WHO-recommended levels (60 Litres/second/patient) for 95% or more of measurements in 3 of the 4 rooms; 47% in the remaining room, where wind speeds were lower and a smaller diameter turbine was installed.ConclusionHigh room ventilation rates, meeting recommended thresholds, may be achieved using wind-driven roof turbines and grates, even at low wind speeds. Roof turbines and air-intake grates are not easily closed by staff, allowing continued ventilation through colder periods. This simple, low-cost technology represents an important addition to our tools for TB infection control.

The epidemiology, pathogenesis, transmission, diagnosis, and management of multidrug-resistant, extensively drug-resistant, and incurable tuberculosis

“…493 Other methods exist for infection control, including increasing ventilation in the home and providing patients with surgical masks, which might be effective and less invasive of patient rights. 494,495 Furthermore, from a programmatic point of view, focusing solely on prevention of infection risk late in the course of the disease overlooks the fact that most transmission probably occurs before diagnosis in the community. [496][497][498][499] Enforced confinement is a poor strategy to prevent transmission at a community level, might drive the epidemic underground, and is not justified as a routine measure.…”

Infection control in households of drug-resistant tuberculosis patients co-infected with HIV in Mumbai, India

“…A number of studies have investigated aspects of TB IC in health facilities, but few have been carried out in patients' homes. [5][6][7][8][9] Early case detection followed by prompt initiation of a robust treatment regimen and good adherence support remain the most effective IC measures to prevent TB transmission to household contacts and the community. The World Health Organization (WHO) recommends that patients with MDR-TB be treated using mainly ambulatory care rather than models of care based principally on hospitalisation.…”

“…2 TB infection control (IC) measures aimed at reducing the risk of TB transmission are well recognised. 3,4 Although a number of initiatives have been adopted for IC in health care settings, [5][6][7][8] limited work has been done to reduce the risk in patients' households. 9 Similar to the situation seen in health care workers in direct contact with TB patients attending health care facilities, 10 the incidence of active TB disease among household contacts of TB patients also exceeds that reported in the general population.…”

Rooftop Turbine Ventilator: A Review and Update

“…The outcome results of its performance were discussed in terms of (i) ventilation rate (in l/s, m³/s, ACH and CMH) (ii) air velocity (m/s) (iii) air temperature (reduction) (°C). Dale and Ackerman (1993), Mihailov, Dinchev, Vlaseva, Petrov, and Tenev (2003), Lai (2003) and Cox et al (2011) studied the effectiveness of conventional type of rooftop turbine ventilators applied in different types of building and under different climatic conditions. On the other hand, Porfirio (2004) and Kuo and Lai (2005) investigated the effect of combining the turbine ventilator with electrical extractor fan ventilation system.…”