ASTM F1387 Standard Specification for Performance of Piping and Tubing Mechanically Attached Fittings

Get Certified ASTM F1387 Testing for Reliable Piping and Tubing Joints

ASTM F1387 testing helps verify whether mechanically attached piping and tubing fittings meet established performance requirements. Test data helps manufacturers and buyers determine whether a fitting design can withstand pressure, resist pressure surges and bending, and remain securely attached under load. The testing process helps identify potential weaknesses in fitting designs and supports product quality assessment. It also provides data to compare fitting performance across different operating conditions. Following ASTM F1387 testing procedures supports quality control, improves confidence in joint reliability, and helps manufacturers select suitable fittings for demanding industrial piping and tubing applications.

The scope of ASTM F1387 includes

• Product type: MAFs that attach to pipe or tube by mechanical deformation and create a seal and a restrained joint
• Design types: Radially swaged, flared, flareless (bite-type), grip-type, shape memory alloy, and axially swaged fittings
• Materials: Carbon steel, stainless steel, nickel-copper, copper-nickel, brass, and nickel titanium
• Pressure classes: Ten classes based on pressure rating
• Qualification tests: Pneumatic proof, hydrostatic proof, impulse, flexure fatigue, tensile, hydrostatic burst, repeated assembly, rotary flexure, and mercurous nitrate
• Supplementary tests: Added tests that apply only when the purchaser specifies them, including a fire performance test
• Units: SI values are standard; values in parentheses are for information only
• Limits: The tests apply only to MAFs and are not intended for non-MAF products

What are the uses of ASTM F1387 Testing?

ASTM F1387 testing gives manufacturers, buyers, and laboratories a common basis for assessing fitting performance. Engineers use the results to compare fittings and confirm that they suit a piping application. This standard:

•  Qualifies a fitting design for its pressure class.
• Defines the pass or fail result that laboratories report for each test.
• Lets purchasers add supplementary tests, such as thermal cycling, vibration, or fire performance, to an order.
•  Applies the supplementary requirements in whole to U.S. Navy contracts, unless the contract states otherwise.
•  Gives engineers design types, materials, and pressure classes to compare fittings.

What materials can be tested under ASTM F1387?

The standard ASTM F1387 covers mechanically attached fittings for use in piping and tubing systems. This applies to fittings such as radially swaged, flared, flareless, grip type, shape memory alloy, and axially swaged ones, which are made from carbon steel, stainless steel, nickel-copper, copper-nickel, brass, or nickel titanium; the tests carried out in the laboratory involve the fitting when it has been assembled onto a pipe or tube since it is precisely through this assembly that the joint achieves a seal and holds the tube in place. Fittings that are not MAFs are outside the range of the testing.

Why is ASTM F1387 Important?

Because the fitting is mechanically connected, not welded, brazed, or threaded, the design must demonstrate that the joint is secure. If a fitting leaks or becomes loose or separates when pressure, pressure pulses, bending, or pulling is applied, this may result in a loss of fluid and in system failure. ASTM F1387 includes tests for all of these conditions and establishes a single qualification standard which both manufacturers and buyers can use. ASTM Committee F25 on Ships and Marine Technology maintains this specification because of its application in shipboard and other demanding piping systems.

ASTM F1387 Testing Process and Data Collection

Technicians begin testing by looking over each specimen and fitting it onto the pipe or tube. They then perform pneumatic and hydrostatic proof tests, followed by impulse, flexure fatigue, rotary flexure, tensile, and hydrostatic burst tests. For separable fittings, they also perform a repeated assembly test. They note the test pressures, the number of cycles completed, and any leakage, cracking, loosening, or separation. If the purchaser has specified any additional tests, they carry out those tests as well and make the same observations. The laboratory then issues a pass-or-fail result for each test.

 Common Challenges and Troubleshooting

Incorrect assembly can cause leaks or weak joints; under-tightening, over-tightening, and misalignment can prevent the fitting from achieving the seal and restraint intended by the design. A tube that does not conform to the fitting design, for example, one of the wrong size, wall thickness, or material, can also prevent a reliable joint from forming. If the fitting and tube materials do not match, the seal will deteriorate over time. When assembling each fitting, technicians follow the manufacturer’s instructions and ensure the fitting grade matches the tube material. If a fitting leaks during testing, the laboratory reviews the assembly procedure, tube preparation, and material compatibility before retesting.

•  A proof test pass means the fitting does not leak at the proof pressure.
• An impulse or flexure fatigue pass means the fitting stays sealed through the pressure pulses or bending cycles.
• A tensile pass means the pipe or tube stays in the fitting under the pulling load.
• A hydrostatic burst pass means the fitting reaches the required burst pressure without leaking or failing early.
• Leakage, separation, or cracking fails the test, and the design does not qualify.
• The report lists the design type, pressure class, test pressures, completed cycle counts, and any leakage, cracking, loosening, or separation.
• Engineers compare the results with the acceptance criteria for the design type and pressure class to decide whether the fitting qualifies.
• Passing the tests does not establish suitability for every service condition. 

Link to ASTM F1387 Standard