RESUMEN
A new design method is proposed to calculate outdoor air ventilation rates to control respiratory infection risk in indoor spaces. We propose to use this method in future ventilation standards to complement existing ventilation criteria based on the perceived air quality and pollutant removal. The proposed method makes it possible to calculate the required ventilation rate at a given probability of infection and quanta emission rate. Present work used quanta emission rates for SARS-CoV-2 and consequently the method can be applied for other respiratory viruses with available quanta data. The method was applied to case studies representing typical rooms in public buildings. To reduce the probability of infection, the total airflow rate per infectious person revealed to be the most important parameter to reduce the infection risk. Category I ventilation rate prescribed in the EN 16798-1 standard satisfied many but not all type of spaces examined. The required ventilation rates started from about 80 L/s per room. Large variations between the results for the selected case studies made it impossible to provide a simple rule for estimating the required ventilation rates. Consequently, we conclude that to design rooms with a low infection risk the newly developed ventilation design method must be used.
RESUMEN
This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Ventilación/normas , Adolescente , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Aldehídos/análisis , California , Comercio , Monitoreo del Ambiente/métodos , Femenino , Encuestas Epidemiológicas , Humanos , Masculino , Percepción , Compuestos Orgánicos Volátiles/análisis , Adulto JovenRESUMEN
Nuestra experiencia en evaluación de sistemas de ventilación existentes en edificios destinados a trabajos de oficina nos ha permitido detectar con una frecuencia relativamente alta problemas relacionados con el diseño y gestión de estos sistemas, que dificultan la obtención de ambientes sanos y confortables. En cuanto al diseño, éste requiere considerar las bases, parámetros y estándares que permitan obtener de ellos las condiciones que las personas necesitan y, una vez logrado lo anterior, la gestión correspondiente para controlar su aplicación y existencia permanente, que implica la evaluación periódica de los parámetros a través de mediciones y dispositivos de observación, así como de regulación y mantención de sus elementos constituyentes. Los resultados de las mediciones de estos parámetros deben ser verificados con estándares nacionales o internacionales reconocidos, utilizados en el diseño.
Our experience in evaluation of ventilation systems installed in buildings intended for offices has allowed us to detect rather frequent problems related to the design and management of these systems, which hamper the achievement of healthy and comfortable environments. With regard to design, it is necessary to consider the bases, parameters and standards that allow the achievement of the conditions that people require, and once this has been achieved, the corresponding management for controlling its application and continuous existence that implies the periodic evaluation of parameters through measurements and observation devices, as well as the regulation and maintenance of its constituent elements. The results of the measurements of these parameters must be verified with recognized national or international standards used in the design.