Some specialised tools use power sources other than electricity or compressed air.

This particularly applies to nail guns used on-site, which are sometimes powered by an in-built gas canister or a small explosive powder cartridge.

Let's look at each of these specialised items in turn.

Gas-powered guns

Nail guns powered by gas have a combustion chamber that works like a tiny car engine.

When the chamber behind the piston fills with gas and is ignited by a spark plug, the small explosion pushes the piston forward and drives a nail into the material.

Gas-powered guns have replaced pneumatic guns for many carpenters and other on-site workers, because they don't require an external air compressor.

This does away with the problem of having air hoses draped across the work area and causing a trip hazard.

Powder-actuated guns

Powder-actuated (PA) tools are designed to fire fasteners into concrete, steel and other hard materials.

They use the same principle as a firearm, with a small explosive charge placed behind the projectile.

In the case of a PA gun used by a floor layer, the projectile would be a hardened steel nail, or 'drive pin'.

Its most likely use would be to fix timber battens or carpet grippers to a concrete floor.

In the past, they were all manufactured as high velocity tools, where the explosive charge acts directly on the fastener.

However, more modern versions use a piston to drive the fastener, allowing a more efficient low velocity charge to propel the piston.

The high velocity tools are potentially more hazardous than the low velocity ones, and require greater care when you're using them.

But bear in mind that all powder-actuated guns are potentially dangerous, which is why there are special safety precautions that apply to their use, especially on a jobsite with other workers around.