Equal Tee

What is an Equal Tee?

An equal tee is a T-shaped butt-welded fitting with all three ends the same size, used to split or combine flow at a 90-degree branch connection. It is the most common branch fitting in industrial piping, allowing a main pipe run to have a branch line of identical diameter. Equal tees provide a straightforward, reliable junction for process, utility, and service piping.

Standards and Specifications

Equal tees are manufactured to ASME B16.9 and ASME B16.28, conforming to MSS SP-75 and ASTM A234. All three ends are the same nominal size. Sizes range from NPS 1/2 to NPS 48 (DN15 to DN1200), with wall schedules from SCH 10 to SCH XXS. Both standard and reduced branch patterns are available, with equal being the default. Ends are beveled for butt welding.

Materials and Grades

Carbon steel A234 WPB is standard for oil, gas, water, and steam service. Stainless steel 304/304L and 316/316L provide corrosion resistance for chemical, food, and marine applications. Alloy steel WP11, WP22, and WP91 grades handle high-temperature refinery and power service. Low-temperature A420 WPL6 serves cryogenic systems. All material is traceable by heat number.

Pressure and Temperature Ratings

Equal tees are rated for pressure classes 150 through 2500. The branch opening is reinforced by the tee geometry, with the branch designed to withstand internal pressure and external loading. Temperature range depends on material: carbon steel to 425 degrees Celsius, alloy steel to 600 degrees Celsius. Each tee is hydrostatically tested.

Applications

Equal tees are used in refineries, petrochemical plants, oil and gas production, chemical processing, power generation, water treatment, HVAC, and fire protection. They create branch connections for instrument lines, sampling points, safety relief valves, utility take-offs, and pump recirculation lines from process headers.

Advantages

The equal bore design provides symmetric flow split with minimal turbulence. Butt-welded construction creates a permanent, leak-free joint with full structural continuity. Standard dimensions ensure interchangeability. Equal tees are available in a complete range of materials and wall thicknesses to match any piping specification.

Installation Guidelines

Bevel all three ends, align the tee with the run and branch, and tack weld. Complete the three butt welds using GTAW root and SMAW fill passes with matching filler metal. Apply preheat and post-weld heat treatment as required. Radiographic inspection verifies weld integrity. Provide support near the branch to handle loads.

Quality Assurance

Each equal tee is marked with size, grade, heat number, wall thickness, and manufacturer's stamp. Inspection includes dimensional checks at all three ends, wall thickness verification, and NDE when specified. Material test certificates to EN 10204 3.1 are provided. Tees are coated with rust-preventive oil and bevel ends are capped for shipping.