A majority of onsite injuries in the energy services industry result from the use of hammers to make and break wing union connections. These injuries almost universally occur during rig-up and rig-down of high-pressure manifold equipment. The injuries can be immediate or long-term issues that usually arise from the strain experienced when swinging a hammer. This paper discusses the development and testing of a safer alternative to the current method of tightening connections called the pneumatic union driver (PUD),1 which uses compressed air as the power source to tighten connections.
The current hammer union has been a staple of the industry since it was patented in 1942.2 This connection has historically been made by repeatedly striking the lug face with a sledge hammer. Most personnel use a sledge hammer in the range of 4 to 10 lb, and each connection is typically struck from 4 to 8 times. Because locations may have 20 to 80+ connections, a typical job can present personnel with as many as 600 opportunities for injury. Hammering jobs are also typically assigned to the least experienced personnel and often performed in adverse environmental conditions (i.e. dark, cold, wet, hot, etc.).
The PUD is a modified pneumatic chipping hammer designed to apply controlled impact energy to the current hammer union. The PUD is placed on a hammer union using an adapter that fits over one lug and aligns the tool bit with the next lug. When the trigger is depressed, the chipping hammer repeatedly strikes the lug. This impact energy reduces friction in the connection. While the lug is being impacted, a moderate amount of force (20-30 lb) is applied to the handle of the tool to tighten the connection. This paper details the testing and performance requirements for the PUD. Comparison testing with conventional hammers indicated that the time required to tighten connections for both methods was approximately the same.
The service company reports more than six hammer-related injuries per month that result in lost-work time for well stimulation operations in the United States. These injuries primarily occur during rig-up and rig-down of high-pressure iron. This estimate does not include long-term issues that may arise from the strain experienced when swinging a hammer.
The current hammer union has been a staple of the energy services industry since its patent in 1942. This connection has historically been made by repeatedly striking the lug face with a sledge hammer (Fig. 1). Most personnel use a sledge hammer in the range of 4 to 10 lb. Each connection is typically struck from 4 to 8 times, and a location may have 20 to 80+ connections. Therefore, a typical job may offer personnel as many as 600 opportunities to injure themselves. This job is also typically assigned to the least experienced personnel and performed in adverse environmental conditions (i.e. dark, cold, wet, hot, etc.) In this paper, an alternative to the current connection method will be discussed.