Low Velocity vs High Velocity Powder Actuated Tool
When you are doing heavy construction, one of the most useful things you can have handy is a powder actuated tool. Powder actuated tools are basically nail guns on steroids. They are used when you are trying to secure objects to surfaces such as concrete or steel. This is normally referred to as direct fastening. Powder actuated tools are also commonly referred to as Ramset guns or Hilti guns. When you are deciding on the right direct fastener for the job it is important to know the two different types, low velocity and high velocity.
How Do Powder Actuated Tools Work?
Powder actuated tools are much more powerful than your common nail gun. The reason is because the direct fastening is possible because of a controlled explosion that is set off within the tool. This explosion is a result of combustible chemicals that give off a chemical propellant charge. It is technically the same basic design used in most firearms. The tools were developed during World War II for use in repairing massive Naval ships. The fasteners that are most frequently used include large reinforced nails and can even include thread or washers on the tip to grip softer surfaces.
There are few differences between low and high velocity powder actuated tools. The main factor distinguishing one from the other is the total velocity at which they operate. High velocity tools produce much more velocity than the low velocity versions and must be handled with certain restrictions because of this.
For the high velocity variety, there is no piston in the chamber so the chemically induced propellant is directly charged against the fastener. This type of Ramset gun can charge the fastener well over 492 feet per second. That is the line dividing high and low velocity powder actuated tools. High velocity tools are not currently manufactured or sold in the United States but some still exist (and are still in use). The operation of a high velocity actuated tool is almost identical to that of a handgun.
Low velocity powder actuated tools produce a velocity less than 492 feet per second. The difference in the mechanics of the tool is that low velocity tools use a piston in the chamber. This piston absorbs the charge from the chemical propellant and fires into the fastener lowering the total overall velocity in which it fires.
Safety and Regulations
Most powder actuated tools (both low and high velocity) usually include a muzzle safety interlock. If the muzzle of the tool is not pressed firmly against a surface then it will block the firing pin and not allow it to go off. This prevents the tool from firing by mistake or if it is dropped. Most jobs that require the use of a Ramset gun require proper training and certification before someone is allowed to use the tool on a job. Other countries have additional regulations and laws in effect to make sure the guns are safely operated at all times.