An appropriate type of dilution tunnel is chosen, based on the international standards, user's needs and the manufacturer's requirements. During the design process, a number of restrictions specified in the standards for emission and Venturis were taken into account. The data required to address basic concepts were obtained from numerous emission tests performed at the IMR Institute. A short algorithm of calculation of the critical flow Venturi (CFV) is also presented. Specific attention is paid to the problems of the measurement of particulate emissions using the dilution method, which does not allow us to use the unique thermodynamic and flow parameters. A method of evaluation of particulate emissions for two extreme cases which were expected during the tests was adopted. Using the results of calculations, a full flow dilution tunnel with CFV was manufactured and tested at the IMR Institute.