API RP 7HU1:2009 pdf download

API RP 7HU1:2009 pdf download.Safe Use of 2-inch Hammer Unions for Oilfield Applications.
3 Mismatch Description
3.1 General
The most common designations in the petroleum industry for hammer union components with the potential for mismatch, and wch are covered by this RP are:
— 2.inch Figure 402,
— 2-inch Figure 602,
— 2.inch Figure 1002, and
— 2.inch FIgure 1502.
These hammer union components have a history of failing under pressure due to incorrect matching of components (pressure ratings andlor incompatible geometry). The list of hammer union components that can be incorrectly matched is not meant to be all-indusive. Users should establish controls to ensure hammer union combinations are safe, especially when more than one manufacturers components are used.
3.2 Example of the Hazard
The mismatching of either the female 2-inch Figure 402, female 2-inch Figure 602 or the female 2-inch Figure 1002 hammer union component (sub) with a male 2-inch Figure 1502 hammer union component (wing nut) is a woddwide issue in the Industry and can cause senous Incidents, including fatalities. Complete and proper make-up of hammer union components is required to attain the rated working pressure of the equment
The root cause of the mismatch is that the 2-inch Figure 402, 2-inch Figure 602 arid 2-inch Figure 1002 unions were designed with the same thread pitch as the 2-inch Figure 1502 and the female subs have a major (external) thread diameter that is just large enough to engage the minor (internal) diameter of the 2-inch Figure 1502 wing nut intemal acme thread. Consequently, although these mismatched hammer union components (2-inch Figure 1502 wing nut with a 2-inch Figure 402. Figure 602 or Figure 1002 female sub) may fully make-up and hold some level of pressure. an explosive failure of the mismatched unions wl occur well below the raled working pressure of any of the components. putting people and property at risk.
See IADC Alerts 98-01, 99-33. 00-15. 03-16, and 06-01 for additional information.
3.3 Mismatching 2-Inch FIgure 402, Figure 602 and. Figure 1002 with 2-inch Figure 1502
A 2-inch Figure 1502 wing nut can be threaded onto a 2-inch Figure 402. 2-inch Figure 602 or 2-inch Figure 1002 female sub as shown In Figure 1. Although the acme thread diameters are different, the pitch (number of threads per inch) is the same. The resulting mating overlap of the threads between these mismatched hammer union components.