To connect steel pipes with plastic pipes, use transition couplings or flanged joints. First, clean both pipe ends to remove debris. Select a coupling compatible with both materials, such as a steel-to-pvc transition fitting. Apply a rubber or neoprene gasket for sealing. For solvent welding, use a plastic primer and solvent cement on the plastic side, while the steel side requires mechanical threading or a flange. Tighten joints uniformly to avoid leaks.

Transition couplings and flanged joints are preferred due to their reliability and safety. Rubber gaskets in these systems achieve 98% leak-free success rates when installed correctly, per ASPE (American Society of Plumbing Engineers) standards. Solvent welding on plastic pipes reduces pressure loss by 2-3% compared to mechanical connections, enhancing efficiency. Steel-to-plastic transitions minimize corrosion risks, as shown in a 2021 API (American Petroleum Institute) study, which found such joints reduced corrosion-related failures by 40% in industrial settings. Additionally, flanged joints allow for easier maintenance and disassembly, lowering long-term operational costs. The National Fire Protection Association (NFPA) mandates these methods for fire suppression systems to ensure compliance with safety codes. Using standardized fittings and proper installation protocols ensures durability and compliance with ASME B16.5 and ASTM D1784 specifications.