Filter ventilation is a key cigarette design parameter for cigarette manufacturers to achieve low tar deliveries. Historically smoke testing has been conducted at a single set of smoking conditions, but the new aggressive testing conditions mandated by certain governments require higher puff volumes. Designing cigarettes for these aggressive smoking conditions will require an understanding of the influence of higher air flow rates on cigarette ventilation levels.

This paper describes the design and construction of a new instrument for measuring filter properties. The instrument was built by Custom Electronic Systems, Inc. and is a Model CES 508 Cigarette Pressure Drop & Ventilation Tester. It uses two NIST traceable laminar flow elements to measure the total and ventilation air flows. The design provides good precision and accuracy for flow rates up to 100 ml/s. Digital micro processors are used to provide flow control and automatic compensation for environmental conditions and for moderate changes in house vacuum. Filter tip pressure drops can be measured up to 1000 mm of water. A specially designed test head allows the measurement of ventilation level over the range of flow rates without a bias due to high air flows.

To demonstrate the instrument?s unique capabilities, the ventilation levels of various cigarette designs were measured at a range of flow rates. The results show that cigarette ventilation levels change with the higher puff volumes seen with aggressive smoking conditions.