Developments in a multi-tracer gas system and measurements using portable SF6 equipment.

In this paper we describe the development of a multi-tracer gas system for measuring interzonal air movement in buildings. The system consists of simple and stand-alone gas injectors and sampling units. The injectors are capable of releasing up to four perfluorocarbon tracer gases in different parts of a building. Following tracer gas injection and mixing, small samples of air are collected using automatic sampling units. Each unit consists of a 16-position valve and a group of removable stainless steel tubes packed with solid absorbent.

Some induced-pressure measurements in a high-rise office building.

Induced-pressure measurements were made in the tower of an eleven-story office building usiInduced-pressure measurements were made in the tower of an eleven-story office building using a fan. The fan was used to depressurize the entire tower as well as a single floor. Sulphur hexafluoride (SF6) tracer gas was used totrace air movements from floor to floor during single-floor depressurization. Average flow coefficients for the tower and for the single floor were estimated from single point measurements. The effect of opening and closing office doors also was determined.

Air infiltration measurements in large military aircraft hangars.

Air leakage measurements by the tracer dilution technique were performed in five military aircraft hangars. The hangars were located in regions of the country having diverse weather characteristics. In several of the hangars, distinct measurements were performed to assess the degree of homogeneity of the air-tracer gas mixture in these large volume structures. Air leakage rates in the range of 0.6 to slightly above 2.0 air changes per hour (ACH)were measured. Surprisingly, these values do not differ significantly from those which might be measured in single-family residences.

Air leakage and fan pressurization measurements in selected naval housing.

Data from detailed tracer concentration decay and induced pressurization measurements were obtained in tests of duplex and row apartments at Norfolk, Virginia and Pensacola, Florida to accurately determine air leakage characteristics of selec

A tracer gas system to evaluate the efficiency of ventilation systems or simulate the consequences of an accident.

The tracer technique can be used in ventilation and contaminant spreading investigations. We have chosen sulphur hexafluoride. We have constructed aspecific instrumentation to perform indoor tests. All components are portable and battery operable. We use generators with remotely controlled flow, real-time chromatographs as analysers, continuous SF6 monitors and field-use calibrators. We have performed numerous tests, in the nuclear industry (Laboratories, reprocessing facilities and PWR), in conventional industries and in hospitals.

Tracer gases as a ventilation tool: methods and instrumentation.

Tracer gas techniques, used for routine ventilation checks or trouble shooting are outlined with emphasis on their applicability in a variety of situations. 

Measured ventilation and infiltration rates in eight US government office buildings.

Ventilation and infiltration rates were measured in eight office buildings using an automated tracer-gas measurement system. The buildings range in size from a two-story building with a floor area of about 2000 m2 to a 15-story office building.

The use of a constant concentration tracer gas system to measure ventilation in buildings.

A constant concentration tracer gas system was designed and constructed to continuously measure the air infiltration rate in as many as ten zones of a building. The portable, microcomputer controlled system injects a metered amount of tracer


A comprehensive computer program for the prediction of air flow and smoke migration in the building was applied to the 11 story administration building of the National Bureau of Standards. Natural air leakage rates under various climatic conditions for several ventilation system operations were obtained. The computed results were compared with measured air leakage rate by using the sulphur hexafluoride tracer gas technique. Smoke migration was simulated for the selected pressurization conditions.