top of page

Assembly and Testing Services

Radiography - Dye Penetrant - Pressure Testing - Load Testing

Testing is a large part of what we do here at FAB Source.  We manufacture many "one of a kind" pressure vessels, and they do not leave our doors until we confirm that they are air tight and operationally fit per the customer specifications.

Our assembly technicians are trained in both Dye Penetrant and Radiographic Inspection to ensure that all vessel welds are flawless even before the completed vessel is pressure tested.  We are also capable of performing both pneumatic and hydraulic pressure tests based on project and customer requirements.

Every lifting device is proof-tested to 125% of its rated load capacity in accordance with OSHA 1926.251(a)(4).  We ensure that every FABSource-designed rigging apparatus is safe to put into production.


Dye penetrant testing is a non-destructive process used to detect weld defects.  The process involves first thoroughly cleaning the weld zone of a part.  A red dye is then applied to the area.  The red dye has a very low viscosity and can get into very tiny voids and cracks.  A special cleaner is then used to remove all visible signs of the red dye.  Although the red dye may appear to have been cleaned away, small traces of the dye will be left inside any tiny pores or cracks in the weld.  A white developer is then sprayed over the surface and allowed to react with the red dye.  If there are any defects, the red dye will be absorbed into the white developer and show up as tiny red dots that are easily detectable against the white developer.  Each step in this process is carefully timed to allow for proper reactions to take place.

Non-destructive Testing


All ASME code stamped Section VIII pressure vessels must undergo a pressure test.  The pressure test is meant as a verification of the vessel design and workmanship.  The test must always be performed after all other fabrication steps are complete.


Hydraulic Pressure Test

Hydrostatic testing is the default type of testing per the ASME code.  Hydrostatic testing is inherently safer than pneumatic testing because the compressed gas has a much higher energy content compared to that of water.

A hydraulic pressure test is performed by filling the vessel  with water and pressurizing the chamber to the test pressure required by the code.  Once the hydrostatic test is complete, the vessel is drained and disassembled so that it can be thoroughly cleaned.  The vessel is then reassembled and packaged for shipment.


Pneumatic Pressure Test

Despite the safety advantages of a hydrostatic test, there are still instances in which a pneumatic test is required.  Pneumatic tests are used when the vessel cannot be properly drained or when the test fluid is not compatible with components of the chamber.


Each vessel must be examined under the requirements of UW-50, which requires that all openings, welds, and attachments be examined before testing.  Nitrogen gas is then used to pressurize the chamber to the required test pressure.

Pressure Testing


In its simplest form, load testing involves applying a load to a structure or piece of equipment.  A proof test demonstrates the fitness of a load-bearing structure. Such tests may be required as part of a thorough examination in line with OSHA 1926 that place duties on people and companies who own, operate or have control over lifting equipment.

A proof test is usually expressed as a percentage of the working load limit (WLL) that equipment is designed to withstand. The exact requirements of proof testing and the extent of each test can vary depending on standards, equipment or industries involved, as well as individual requirements from customers or as part of our own quality controls.

OSHA Section 1926.251(a)(4) requires that all special custom design grabs, hooks, clamps, or other lifting accessories, for such units as modular panels, prefabricated structures and similar materials shall be proof-tested prior to use to 125 percent of their rated WLL.

We test each custom lifting device to at least this benchmark before the appliance leaves our facility.

Load Testing
bottom of page