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




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Objective

Tuberculosis 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.

Methods

Room 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.

Findings

For 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.

Conclusion

High 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.



Author: Helen Cox , Rod Escombe, Cheryl McDermid, Yolanda Mtshemla, Tim Spelman, Virginia Azevedo, Leslie London

Source: http://plos.srce.hr/



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