Stainless steel water pipes are widely used in various building water supply systems due to their corrosion resistance, high strength, and long service life. However, improper handling of external forces during installation can lead to pipe deformation, affecting water flow and even causing leaks. To avoid such problems, a systematic approach is needed, encompassing material selection, cutting procedures, connection methods, fixing and support, construction protection, thermal expansion and contraction compensation, and post-installation inspection.
Before installation, the appropriate material and specifications must be selected based on the operating environment. Different grades of stainless steel (such as 304 and 316) have significantly different corrosion resistance, requiring matching based on water quality, temperature, and media characteristics. Simultaneously, the pipe wall thickness must meet design pressure requirements to prevent deformation under external forces due to insufficient strength. For example, high-rise building water supply systems require thicker pipes to withstand water hammer impacts. Furthermore, pipes should be protected from impacts during transportation and storage, and stacking should not be excessive to prevent bending due to prolonged pressure.
Cutting is the first step in installation; improper operation can easily lead to pipe deformation. Specialized tools, such as stainless steel cutting discs or laser cutters, should be used during cutting. Avoid using thermal cutting tools like angle grinders to prevent localized annealing and softening of the pipe due to high temperatures. Keep the pipe fixed during cutting to prevent skewed cuts caused by rotation or shaking. After cutting, remove burrs with specialized tools and chamfer the ends to prevent burrs from scratching the sealing ring or affecting water flow. For example, un-chamfered pipes may leak during connection due to damaged sealing rings, and burrs can alter water flow direction, increasing local resistance.
The choice of connection method directly affects the pipe's resistance to deformation. For welded connections, welding parameters must be strictly controlled to avoid excessive current or prolonged welding time, which could lead to pipe burn-through or coarsening of the grains in the heat-affected zone, reducing strength. For crimp connections, ensure the fitting and pipe are fully in place, apply sufficient pressure with specialized tools to ensure uniform deformation of the sealing ring, and prevent loosening or force shifting due to weak connections. For threaded connections, apply sealant and control the tightening torque to avoid over-tightening, which could deform or crack the pipe threads. For example, if the crimp connection is not properly tightened, the pipe may loosen due to long-term vibration, leading to leaks or deformation.
Fixed supports are a key measure to prevent pipe deformation. The spacing of supports needs to be rationally designed based on the pipe diameter, material, and system pressure to ensure pipeline stability. For example, the support spacing for pipes below DN50 should be controlled within 1.5 meters, while for pipes above DN50, it can be appropriately widened to 2 meters. The support material must match the pipe material to avoid electrochemical corrosion. Stainless steel or galvanized fasteners should be used for fixing to prevent rust from causing the pipe to loosen. Furthermore, the support installation location should avoid stress concentration areas such as pipe bends and tees to prevent pipe deformation due to excessive local stress. For example, if no support is installed at an bend, the pipe may bend or the joint may loosen due to water flow impact.
Protective measures during construction are equally important. During installation breaks or after completion, pipe openings should be sealed promptly to prevent cement, dust, and other impurities from entering the pipe, avoiding difficulties in later cleaning or scratching the pipe wall. During electric welding operations, fireproof cloth must be used to isolate the pipes to prevent sparks from damaging the pipe surface. When pipes pass through walls or are buried underground, sleeves must be installed to prevent pipe deformation due to wall settlement or external pressure. For example, buried pipes without sleeves may flatten due to ground loads, affecting water flow or even causing rupture.
Thermal expansion and contraction is another important factor causing pipe deformation. Although stainless steel water pipes have a low coefficient of thermal expansion, compensation measures still need to be considered for extreme temperature changes or long-distance straight laying. This can be achieved by appropriately setting bends or installing expansion joints to absorb length changes and avoid stress concentration in the pipes due to thermal expansion and contraction. For example, when the straight length of a hot water pipe exceeds 15 meters, a corrugated compensator must be installed, along with fixed supports, to prevent tensile or compressive deformation of the pipes due to temperature changes.
After installation, a comprehensive inspection and testing are required. Visual inspection confirms that the pipe surface is free of scratches, dents, or other damage, and that the supports are securely fixed without loosening. During the water pressure test, the pressure should be slowly increased to the design pressure, and the pressure drop should be observed to ensure it meets the standard. Simultaneously, all connections should be checked for leaks. For example, if the pressure drop exceeds 0.05 MPa or leaks are found at connections, pipe deformation or loose connections should be investigated. Furthermore, the pipeline system must be flushed and disinfected to ensure the water quality meets hygiene standards.
