Kemper Valve and many other oilfield fluid control product manufacturers, produce high pressure quick connect pipe fittings, commonly referred to as Hammer Unions.

Hammer Unions join piping sections or other specialty fittings, by hammering the lugs of the Nut component, bringing the ball seat of the Male component into pressure tight contact with the concave seat of the Female component. The Female has external Acme threads matched to the internal threads of the of the Hammer Lug Nut.

Certain union components for the same nominal pipe size but with different Figure Numbers, such as the 2" Figure 1502 and Figure 602, when not positively identified, may appear to properly make-up. The extreme sloppiness of the thread fit between a 2" 1502 Hammer Lug Nut and a 2" 602 Female could be ignored, and when hammered

together, this mismatched connection might actually hold pressure for a minimal time. The graphics on this page show the proper make-up of the Acme threaded components as opposed to the hazardous mismatch that can result from the failure to positively identify the union size, Figure Number, and pressure rating.

This illustrated instance is one example of how, by failure to positively identify hammer union components, the mismatch of these components will result in an unsafe connection, might fail after pressurization, causing property damage and servere injury or death of personnel. The Kemper "Cautions and Warnings" page includes references to other hammer union installation and usage conditions that could result in potentially hazardous connections.