Hydraulic pressure is most often used to create, fabricate and produce items, from refining oil to building homes and even maintaining cars, but not all uses of hydraulics are productive; some hydraulic machinery is designed to break items like locks and metal frames. The emergency services are one of the biggest users of destructive hydraulic equipment including the Jaws of Life, which are used to cut and stretch mangled vehicles, and lock breaking devices used to gain access to buildings. Hydraulic lock breakers use hydraulic pressure to force the door from the frame. The equipment is usually operated via a hand pump, which means it can be used in dangerous and potentially explosive situations as there is no danger of a spark being generated. The hydraulic pressure operates two wedges, which are placed in the gap between the frame and the door, and as pressure is generated these are driven apart, forcing the door open. The spreading force can be up to 90 kN, which is enough to crack even the most substantial lock. These hydraulic lock breakers are a vital piece of equipment for police officers as they provide rapid access, even when a door is heavily reinforced, and it allows officers to enter the premises long before anyone inside has a chance to prepare or escape. Hydraulic lock breakers are a rare piece of equipment, in that they do not use external power sources but rely instead on the human power capacity operating the hand pump. Most hydraulic equipment does not use human power as an input, so for something powered in this manner to still be the device of choice, it means that it has to be the most appropriate solution. In a world where automation is king it represents the simplicity and efficiency of using tried and tested power sources for certain jobs, where they have been proven to be the best method. The Jaws of Life, also used by the emergency services (usually the fire service) are hydraulically powered destructive devices. The term “Jaws of Life” was coined by one of the inventors, Mike Brick, after he heard people saying that the equipment had “snatched people from the jaws of death.” It is a catch-all term which encompasses hydraulic shears, spreaders and extension rams, all of which are used to cut, bend and distort metal wreckage to free anyone trapped inside. The power input can be manual, via a hand or foot pump, or connected to the power generator of the fire engine. It is important that these pieces of apparatus can be powered in different ways as each situation in which they are deployed has different risks, including ignition, accessibility of the vehicle and the location of said vehicle. Hydraulic shears use the high pressures generated to cut through metal, including vehicle frames, gates and other immovable objects. Because no spark is produced, as there would be if using a grinder, they can be used in situations where fuel leaks are common without the risk of explosion or fire. Spreaders and extension rams are used to prise open metal bars which may be trapping someone, including in cases where people get their heads stuck in gates, bus stops and other objects, which is more common than you may think. Hydraulic spreaders are typically used to create a gap in a small space, examples being, opening jammed car doors or creating a space between two vehicles that are impacted together. Extension rams are used in larger spaces, such as car foot-wells or in the space initially created by a hydraulic spreader. Having looked at the types of destructive hydraulic devices, we can see that although these pieces of equipment may be used to break and cut objects, the overall effect is a preservation of life and the pursuit of criminal elements, both of which are ultimately productive in nature. You know what they say, “you've got to crack a few eggs to make an omelette”.