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Protect Your Hammer Union Threads


Hammer unions are ideal for use in the oil and gas industry but also find applications in other markets. With a threaded male and female connection (or butt-welded for higher operating pressure), they connect flow lines or temporary pipes quickly and easily. Safety during drilling and rigging operations is essential, making the correct utilization of hammer unions a critical production task. As such, it is also important to protect hammer union threads to ensure safe and secure connections.

History and Development of Hammer Unions

Hammer unions are rotary-based connections developed in the 1950s. Since then, manufacturers have continued producing the components based on the initial manufacturing standards. These standards include many different types of figures that determine the safe use and joining combinations. In fact, hammer unions that oil and gas operations use may soon require the American Petroleum Institute (API) standard compliance for safety.

Figure 1502 Hammer Union

The figure number indicates the size and rated pressure of the union. The 1502 figure can withstand operating pressures of up to 15000psi on a two-inch pipe. Male hammer union threads connect to the wing nut (female) subparts. Then, operators hammer securely with a sledgehammer to create the seal. It remains a popular connection type in the drilling industry but does not fall under any specific API standard for size or interoperability.

API is currently conducting research and investigating the standardization of hammer unions due to a number of safety concerns raised. Incidents, where the connections have failed, are widely reported, and addressing these issues is now an industry priority.

API Recommended Procedure

Due to historical designs of the components, some different figures are miss-matched in error during installation. To reduce the risk to staff and environments, API issued a Recommended Procedure (RP) that address the incorrect make-up of hammer unions.

Miss-Matched Unions

Companies use different types of hammer unions during operations. While correct matching is critical, they reported numerous incidents where 402, 602, and 1002 wing nut subs had wrong connections to figure 1502 male subs. Unfortunately, this happens as thread profiles are similar, and operators believe a safe connection is in place. However, they are not aware that there’s an actual reduction in safe operating pressure.

API Procedural Safety Procedure

Some of the key recommendations in the API RP include:

      • Use only Figure 1502 hammer unions for all operations and replace all other components
      • Mark all components clearly with stamping to ensure no faulty connections
      • Implement PTW (Permit to Work) and Job Safety Analysis (JSA) for each hammer union connection performed
      • Color-code different types of hammer unions

Ensuring Safe Operations during Production

While the above API RP will reduce the chances of incorrect connections, the protection of the hammer union threads remains an important factor for safe operations. Damaged threads can cause failures during high-pressure operations, causing damage to either staff or the environment.

To protect the integrity of your hammer union threads, contact NOV’s Tuboscope MSI Pipe Protection Technologies today. They provide high-quality figure 1502 thread protection equipment that ensures improved safety and reduces production downtime. You may call us toll-free at 1-877-276-9208 for immediate assistance.

Protect pipes with MSI, the world’s best pipe protection company.

Contact us today to learn how we can help you.

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