freon

Presents the results to date of the use of the multiple tracer gas technique to determine interzonal airflow and ventilation rates in large, multicelled buildings like offices. This work is part of a wider project designed toextend knowledge of natural ventilation in all types of buildings other than dwellings.

Describes a series of tests carried out in two interconnected environmental chambers, to determine the accuracy of airflows calculated from tracer gas measurements using a new rapid sampling system. The system is capable of measuring 3 tracer gases simultaneously.

Ventilation efficiency was measured with freon gas in 3 large industrial buildings under normal working conditions. Size of building varied from 3000 to 10000 m2 and room height from 5-19 m. The ventilation systems were of 3 types: 1. Overhead fresh air supply network with conventional air inlets, 2. Fresh air supply direct to occupied zones by a low impulse system, and 3. Overhead fresh air supply distributed by the Dirivent system. Describes techniques of tracer gas measurements. Illustrates some results in graphs.

A major pathway for loss of conditioned air in East Tennessee homes with externally located heating, ventilation, and air-conditioning (HVAC) systems is leakage in the ductwork. The average infiltration rate, as measured by Freon-12 trace

A tracer method was developed for the evaluation of workplace ventilation. Nitrous oxide or freon was used as the tracer. The concentration of the tracer gas was measured with an infra-red analyser. The versatility of the tracer technique for industrial hygiene applications was improved by the use of a microcomputer for data calculation, display and storage. Three applications are presented: 1. determination of the capture efficiency of a local exhaust hood, 2. the evaluation of the air leakage of a room, and 3. measurement of the local ventilation rates in a large industrial plant.

Describes a technique for measuring air flows between internal zones of houses. Gives the theory of measuring one and two directional flows and describes the equipment used for practical measurements. Uses Freon 12, Freon 114 and BCF as tracer gases, and measures their concentrations using a gas chromatograph. Includes specimen results of one and two directional flows between a house and its roof. Discusses the possible applications of the method in houses.

Reports measurements of air change rates carried out in the living rooms of 39 flats built during the last 20 years using Freon 12 as a tracer gas. Ventilation rates ranged from 0.3 to 2.9 changes per, hour, the average being 1.3 changes per hour. Air temperature, humidity and wind speed were recorded and the ventilation rates corrected for wind speed and temperature. Notes large ranges in ventilation rates for similar flats.

Discusses the use of a tracer to measure the dispersal of air pollutants. Suggest use of Freon-12 or sulphur hexafluoride as tracer. Describes release of tracer, collection of samples in bottles, concentration of sample and analysis in gas chromatograph. Gives results of field trial and concludes that test method is very promising for studying local air movements.