This paper presents a study focused on increasing production capacity in a company that produces fire protection equipment. The main goal of the research was to develop and apply solutions that would allow a significant increase in the number of products manufactured each month, due to the growing demand from customers. The analysis was based on a selected product type and used known lean manufacturing tools, such as bottleneck analysis and waste identification. The study focused on problems such as unnecessary activities, unbalanced workloads and poor communication of schedule changes. Based on these observations the improvements were proposed. These included reorganizing workstations, using supermarket and kanban systems to manage inventory and production flow and digitalizing the way the production schedule is shared with workers. The results show that the introduced changes improved the production process and helped to meet the main aim of the study, which was increasing production capacity. This confirms that lean manufacturing methods can be useful in improving production efficiency, especially in manufacturing companies that make products to order. The study also shows that technical improvements should go together with proper planning and analysis to be effective.