STSI is certified, in accordance with the HRN EN ISO 3834-2 standard, for manufacturing and installation of pipelines and pressure vessels of category II, III and IV.
Manufacturing plants in Zagreb and Graberje Ivanićko consist of manufacturing workshops with a surface area of 3500 m2, with four industrial cranes with a capacity of 2-20 t.
Scope of works is as follows:
• Manufacture of lightweight and heavyweight steel structures
• Manufacture and installation of pipelines
• Rehabilitation of existing pipelines
• Manufacture of underground and above-ground drilling equipment

Applicable materials in accordance with the ASME and EN standards:
• carbon steel
• carbon steel for low and increased temperatures
• low-alloy steel for increased temperature
• high-alloy steel
• copper-titanium alloys

Specialist staff at the sites are the following:
• three EWE engineers
• eight engineers in manufacture preparation
• 20 welders
• 9 pipefitters
• 20 machinists

Some of the machines used by STSI in manufacturing the equipment are the following:
• automatic ESSAB SAW welding machine
• sheet metal bending machine for thickness up to 50 mm
• CNC machining centre
• CNC press brake for angular bending of sheet metal
• CNC plasma/gas cutting machine
• hydraulic scissors
• TIG, MMA, MIG/MAG welding machines
• classic and CNC lathes
• machine park with thirty devices for machining