The article presents the formation of physical models of fittings of ventilation systems in the conditions of change of linear sizes and forms of adjacent sections of air ducts of ventilation systems. The aim is to minimize waste materials in the manufacture and sale of pipe billets of different diameters of the ventilation system, reduce metal consumption, increase production productivity and efficiency of procurement for installation of ventilation in industrial premises, identify ways to improve the installation of ventilation in industrial premises for various purposes and justification calculation methods. The use of the obtained physical models to determine the required parameters in the manufacture of sweeps of ventilation system fittings can significantly increase the efficiency criteria for procurement and installation work.

Deshko, V., & Buyak, N. (2016). A model of human thermal comfort for analysing the energy performance of buildings. Eastern-European Journal of Enterprise Technologies, Vol. 4, Issue 8-82, 42-48.
Kapalo, P., Domnita, F., Bacotiu, C., & Spodyniuk, N. (2018). The impact of carbon dioxide concentration on the human health - case study, Journal of Applied Engineering Sciences, Vol. 8, no. 1, 61-66. ISSN 2284-7197,
Kapalo, P., Meciarova, L., Vilcekova, S., Burdova, E., Domnita, F., Bacotiu, & C. Peterfi, K. (2019). Investigation of CO2 production depending on physical activity of students. International Journal of Environmental Health Research. Vol. 29, Issue 1, 31-44. ISSN:09603123.
Kapalo, P., Sedláková, A., Košicanová, D., Voznyak, O., Lojkovics, J., & Siroczki,P. (2014). Effect of ventilation on indoor environmental quality in buildings. The 9th International Conference "Environmental Engineering", 22-23 May 2014, Vilnius, Lithuania SELECTED PAPERS, eISSN 2029-7092 / eISBN 978-609-457-640-9 Section: Energy for Buildings. doi:10.3846 / enviro.2014.265.
Kapalo, P., Voznyak, O., Yurkevych, Yu., Myroniuk, Kh., & Sukholova, I. (2018). Ensuring comfort microclimate in the classrooms under condition of the required air exchange, Eastern European Journal of Enterprise Technologies, Vol 5/10 (95), 6-14.
Kapalo, P., Vilcekova, S., & Voznyak, O. (2014). Using experimental measurements the concentrations of carbon dioxide for determining the intensity of ventilation in the rooms, Chemical Engineering Transactions, Vol. 39, 1789-1794.ISBN 978-88-95608-30-3; ISSN 2283-9216. doi: 10.3303/CET1439299
Kapalo, P., Vilceková, S., Domnita, F., Bacotiu, C., & Voznyak, O. (2017). Determining the Ventilation Rate inside an Apartment House on the Basis of Measured Carbon Dioxide Concentrations - Case Study, The 10th International Conference on Environmental Engineering, Vilnius, Lithuania, Selected Papers, 30-35.
Voznyak, O., Korbut, V., Davydenko, B., &Sukholova, I. (2019). Air distribution efficiency in a room by a two-flow device. Proceedings of CEE, Advances in Resourse-saving Technologies and Materials in Civil and Environmental Engineering, Springer, Vol 47, 526-533.
Voznyak, O., Myroniuk, K., & Dovbush, O. (2005). Relationship between a Person Heat Exchange and Indoor Climate. Selected scientific Papers 10thRzeszow-Lviv-Kosice Conference 2005 Supplementary Issue. Technical University of Kosice.148-152.
Gumen, O.M., Dovhaliuk, V.B., & Міleikovskyi, V.O. (2016). Determination of the intensity of turbulence of streams with large-scale vortices on the basis of geometric and kinematic analysis of macrostructure. Proc. of Lviv Polytechnic National University: The theory and building practice, No.844, 76-83 (in Ukrainian).
Dovhaliuk, V.B., & Міleikovskyi, V.O. (2007). Efficiency of organization of air exchange in heat-stressed premises in compressed conditions, Journal: Building of Ukraine, No.3, 36 (in Ukrainian).
Dovhaliuk, V.B., & Міleikovskyi, V.O. (2008). Estimated model of non-isothermal stream, which is laid out on a convex cylindrical surface.Ventilation, Illumination and Heat and Gas Supply: Scientific and Technical Collection, Issue 12, Kyiv, KNUBA, 11-32 (in Ukrainian).
Dovhaliuk, V.B., & Міleikovskyi, V.O. (2013). Analytical studies of the macrostructure of jet currents for calculating energy-efficient systems of air distribution. Energy efficiency in construction and architecture, Issue 4, 11-32 (in Ukrainian).
Zhelykh,V.M, Voznyak, O.T, Dovbush, O.M, Yurkevich, Yu.S., & Savchenko, O.O. (2019).Technologies of procurement and installation of heating and ventilation systems. Lviv: Lviv Polytechnic Publishing House (in Ukrainian).
Zmrhal V., Schwarzer J. (2009). Numerical simulation of local loss coefficients of ventilation duct fittings // Eleventh International IBPSA Conference July 27-30. Glasgow, Scotland, 2009. Vol. i. P. 1761-1766.
Liu, W., Long, Z., Chen, Q.  (2012). A Procedure for Predicting Pressure Loss Coefficients of Duct Fittings Using CFD (RP-1493). HVAC&R Research. 18(6), 1168-1181.
Santos, APP., Andrade, CR., Zaparoli, El. (2014). CFD Prediction of the Round Elbow Fitting Loss Coefficient. International Scholarly Scientific Research & Innovation. 8(4): 743-747.
Seongjong Park, Yonghwan Park, Bongjae Kim and Jaewoong Choi (2019). A Study on the Dynamic Loss Coefficients of Non-standard Fittings in Ship Exhaust Gas Pipes. Journal of Ocean Engineering and Technology 33(5), 479-485 October, 2019.
Mak, Cheuk Ming. (2007). Development of generalized prediction methods for flow-generated noise produced by indoor ventilation systems. Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science). 35. 104-107.
Jing, Gang & Cai, Wenjian & Cui, Can. (2019). An Energy-saving Model-based Air Balancing Method for the Ventilation System.
G. Jing, W. Cai, D. Zhai, S. Liu, and C. Cui. (2018). A model-based air balancing method of a ventilation system. Energy and Buildings, vol. 174, pp. 506-512, 2018.
G. Jing, W. Cai, H. Chen, D. Zhai, C. Cui, and X. Yin (2018). An air balancing method using support vector machine for a ventilation system. Building and Environment, pp. 487-495, 2018.