Q. What is a Safety Breakaway Coupling?
A. A safety breakaway coupling comprises two half couplings that are held together with shear break bolts to form a leak tight coupling The breakaway coupling is installed between the terminal pipework and the flexible loading hose. The Safety Breakaway Coupling is designed to be the weak-link in the system so that in the event of the road, rail tanker or ship moves off while still connected the coupling separates and instantly shuts down the flow. The Safety Breakaway Coupling is used in an emergency only and is not normally connected/disconnected on a frequent basis.
Q. What is a Drybreak Coupling?
A Drybreak Coupling usually comprises a female (hose end) fitting and a male (tanker fitting) that are connected/disconnected on a regular basis to form a liquid and pressure tight coupling. Drybreak Couplings generally have a valve arrangement that shuts down the liquid flow prior to the disconnection of the male and female couplings. More sophisticated Drybreak Couplings such as the Alpha Fluiseal are fully interlocked to close down the product flow prior to coupling disconnection.
Q. What is an ERC Breakaway Coupling?
A. An ERC (Emergency Release Collar) coupling is specifically designed for use on loading arms. The ERC Coupling performs very similarly to the safety breakaway coupling with collar arrangement replacing the break bolts as the means of holding the two coupling halves together. The ERC coupling is usually activated by means of an simple activating cable that comes into tension prior to the loading arm exceeding its’ working envelope. This helps to prevent higher stresses on the loading arm swivel joints, couplings and pipework.
Q. Does APC recommend using Break bolt type couplings on loading arms?
A. APC DOES NOT recommend using the break bolt type coupling on loading arms. The main reason for this is that APC have conducted extensive testing since 1989 and conclusively proved that there is an increased risk of product leakage between the two coupling halves if the coupling is subjected to unforeseen stresses during the filling operation. APC have also been notified on numerous occasions that break bolt type couplings (not APC manufacture) have developed leaks or have prematurely separated when being used on loading arms. APC suggests that only Emergency Release Collar Couplings should be used for driveaway protection on loading arms.