A New Shield for Pressure Test Safety
For many years, manufacturers of high pressure equipment have used concrete or steel bunkers to protect personnel during the initial proof testing of the equipment they built. This was a logical and reasonable thing to do considering the manufacturing process. However, when the equipment left manufacturing to be assembled or repaired, in many cases having an onsite bunker was not reasonable. This lead to using makeshift wooden barriers, clearing the area of non-essential personnel, and hiding behind the service truck (or in most cases just trusting the work done was good and nothing would fail). If you don’t get too close, it probably won’t hit you anyway. After all, I have been doing this for years and nothing significant has happened.
As we in industry become less tolerant of risk taking and place a higher value on employee safety, efforts to shield high pressure equipment has become more important. Many companies with the financial ability are adding and improving test bunkers. This has still not done much for field work. In addition to this, the fracking industry has brought more high pressure operations to the oilfield. In response to these changing events, a new technology is emerging. This technology involves Auxetic woven materials, which get denser as they are stressed. This is called a negative Poisson’s ratio. These materials have shown to have the same projectile stopping capability of 1/4 inch steel or 4 inches of reinforced concrete, and yet only weigh about 3/4 pound per square foot. This makes them easy to move around and configure to whatever situation is needed.
To achieve this capability, in addition to the resistance of cutting or tearing, they are extremely energy absorbing. They give way to the projectile and can actually catch it like a baseball glove. This has opened the opportunity for safety professionals and supervisors to bring an increased level of protection to operations where no reasonable solution was previously available. This technology is gaining acceptance, particularly due to equipment being assembled that is larger than most bunkers, and there is a greater desire to retrofit installations with a barrier between people and high pressure equipment. Since this woven material is light weight and flexible, it is much easier to work into and around existing equipment. This technology is not yet gaining traction in the everyday work environment in the field, expectedly, since extra costs and additional steps require a change in the mindset of the workers, which will need to be addressed by management.
Since this is an emerging technology, it is not inexpensive, but more importantly is an entirely different approach to controlling projectiles. The engineering assessment of different applications is very specialized and only understood by companies significantly invested in research and testing of available materials. Even weaving of the materials is not mastered by many fabric manufacturers. Care should be taken to verify the supplier’s capability in this technology, as it is a completely different science than stopping bullets. The threat of a bullet is penetration of the material. The threat with pressure testing and high pressures with large equipment is being able to dissipate the very high energies in the projectiles without the system failing. It is a more complex science.