Ventilation (architecture)

Abstract: About the author John E. Janssen, Member ASHRAE, has served as chairman of SPC 62-1981R since 1983 when an early review of Standard 62-1981 was started. He also served as vice chairman of SPC 62-73R, the committee that produced Standard 621981. Janssen retired from Honeywell after 35 years during which he conducted research on controls for ventilation, temperature control, flowmeters and thermal radiation properties.

Abstract: This paper reviews current literature on the associations of ventilation rates and carbon dioxide concentrations in non-residential and non-industrial buildings (primarily offices) with health and other human outcomes. Twenty studies, with close to 30,000 subjects, investigated the association of ventilation rates with human responses, and 21 studies, with over 30,000 subjects, investigated the association of carbon dioxide concentration with these responses. Almost all studies found that ventilation rates below 10 Ls -1 per person in all building types were associated with statistically significant worsening in one or more health or perceived air quality outcomes. Some studies determined that increases in ventilation rates above 10 Ls -1 per person, up to approximately 20 Ls -1 per person, were associated with further significant decreases in the prevalence of SBS symptoms or with further significant improvements in perceived air quality. The carbon dioxide studies support these findings. About half of the carbon dioxide studies suggest that the risk of sick building syndrome symptoms continued to decrease significantly with decreasing carbon dioxide concentrations below 800 ppm. The ventilation studies reported relative risks of 1.5 - 2 for respiratory illnesses and 1.1 - 6 for sick building syndrome symptoms for low compared to high ventilation rates.

Abstract: A 1-d point-prevalence study was performed with the aim of describing the characteristics of conventional mechanical ventilation in intensive care units ICUs from North America, South America, Spain, and Portugal. The study involved 412 medical-surgical ICUs and 1,638 patients receiving mechanical ventilation at the moment of the study. The main outcome measures were characterization of the indications for initiation of mechanical ventilation, the artificial airways used to deliver mechanical ventilation, the ventilator modes and settings, and the methods of weaning. The median age of the study patients was 61 yr, and the median duration of mechanical ventilation at the time of the study was 7 d. Common indications for the initiation of mechanical ventilation included acute respiratory failure (66%), acute exacerbation of chronic obstructive pulmonary disease (13%), coma (10%), and neuromuscular disorders (10%). Mechanical ventilation was delivered via an endotracheal tube in 75% of patients, a tracheostomy in 24%, and a facial mask in 1%. Ventilator modes consisted of assist/control ventilation in 47% of patients and 46% were ventilated with synchronized intermittent mandatory ventilation, pressure support, or the combination of both. The median tidal volume setting was 9 ml/kg in patients receiving assist/control and the median setting of pressure support was 18 cm H(2)O. Positive end-expiratory pressure was not employed in 31% of patients. Method of weaning varied considerably from country to country, and even within a country several methods were in use. We conclude that the primary indications for mechanical ventilation and the ventilator settings were remarkably similar across countries, but the selection of modes of mechanical ventilation and methods of weaning varied considerably from country to country.

Abstract: Partial table of contents: Flow Through Envelope Openings. Basic Mechanisms of Mass Transport Within Buildings. Momentum and Buoyancy Induced Primary Air Flows. Flows in Rooms. Flow Through Large Internal Openings. Tracer Gas Techniques for Ventilation Rate Measurements. Tracer Gas Techniques for Measuring Age Distribution and Ventilation Efficiency. Index.

Abstract: A barometric method for measurement of ventilation of newborn infants is described. Experiments with cats are reported to show the degree of accuracy obtainable at present. The variation from standard methods was found to average±1 per cent. Minute volume, frequency, and tidal volume of premature infants measured by the barometric method are within the range of such measurements made by plethysmographic methods. The barometric principle deserves further study since it offers the possibility of securing ventilation data with a minimum disturbance to the infant.