Installing plumbing fittings requires careful consideration of the best options for that specific job. The right fittings depend on the material of the pipes, as well as the plumbing application and requirements of local plumbing codes. Choosing the correct fitting can reduce the risk of leaks and improve the lifespan of the system. With this guide, contractors will understand the factors they need to evaluate when selecting fittings. 

Material Compatibility 

Material compatibility is perhaps the most important factor. Plumbing pipes are made from a variety of materials, and the fitting material generally should match that of the pipes. Some materials are versatile, allowing contractors to use different metals or PVC, but they often require dielectric unions or brass barriers when connecting dissimilar metals. 

Common plumbing fitting materials include: 

• Copper: The gold standard for durability 

• PVC/PEX: Easy to install and lower cost than other materials 

• Stainless steel: Ideal for many commercial and industrial plumbing needs 

• Brass: Works well for most applications 

The right material can make the difference between long-term success and quick failures. 

Temperature and Pressure Ratings 

While many plumbing jobs just involve water pipes for typical home or commercial use, some industrial applications require an assessment of the temperature ranges and pressure that the pipes must withstand. Running very hot water or high-pressure liquids through the pipes and fittings calls for the correct materials. For example, stainless steel is a common go-to for high-temperature and high-pressure applications. Copper is better for thermal conductivity, and brass can also handle high pressures. PVC or PEX are often unsuitable for these applications. 

Transport Fluid Compatibility 

Before choosing pipes or fittings, contractors should evaluate the transport fluid. Plumbing for industrial, medical, or laboratory uses might need to stand up to chemical waste or prevent contamination of deionized water. The fittings must handle the fluid without compromising the seal and causing a leak. Materials such as stainless steel or Kynar® offer excellent corrosion resistance and chemical resistance. 

Sealing Methods 

The sealing method can determine how well fittings prevent leakage, as well as the difficulty in installing or repairing those fittings. Welded fittings provide a tight seal, but they can be harder to install in tight spaces. Contractors dealing with welded fittings will also need to perform more work to remove or replace the fittings if it becomes necessary. Threaded or flanged fittings are easier to install, remove, and repair, but they often require periodic tightening to prevent leaks. 

Cost 

A simple plumbing system may have hundreds of fittings, which can significantly contribute to the cost of the project. PVC or PEX fittings are rising in popularity in large part due to their lower cost, but they do not work for every project. When estimating the total cost for the project, contractors should: 

• Evaluate the number and types of fittings they will need, like Schedule 40 PVC caps 

• Compare prices and cost of installation 

• Provide detailed information to the property owner 

This level of detail can help guide the most appropriate material choice for the project. 

Local Plumbing Codes 

It’s unsurprising that municipal governments take an interest in the types of materials and installation methods that contractors choose to use for plumbing. Municipalities typically create a set of building codes based on the zoning of the property, the project, and the application. Contractors need to be familiar with the codes they must follow and research the requirements in advance. For example, if a contractor is installing pipes and fittings for oil or natural gas, they may need to follow standards such as the International Fuel Gas Code (IFGC) or NFPA 54, depending on jurisdiction.  

Plumbing is a critical system in homes and commercial spaces. Improperly selected fittings can lead to leaks, corrosion, and other hazards that put people at risk and are expensive to fix. The correct fittings can prevent leaks and ensure better performance over the lifespan of the plumbing system. By evaluating these factors, contractors can prevent problems and provide better service to their clients. 

AUTHOR BIO: Khris Kaylor is IT Manager at Maxx Supply, a leading distributor of PVC supplies. Kaylor began his IT career in 1995 and holds an MCSE certification. With a decade of experience in POS systems — including installation, programming, training and support — he later transitioned to hardware and software support. Kaylor has also collaborated on managing multiple brand websites within the food and beverage industry.