Everything You Ever Wanted to Know About Safety Harnesses, But Were Afraid to Ask - Part II

In the last installment of this series we debunked some of the myths about racing safety and covered information about restraints, styles of belts, materials of webbing, proper belt placement and fitment on the body, and the benefits of 7-point harness systems.

Your racing harness is only a part, albeit a key part, in your cockpit safety system. If your harnesses fail and allow your body to be thrown around inside your car in a crash, then it doesn't matter if your seat, rollbar, helmet, head and neck restraint, etc., are up to spec—you have other problems.

In the same manner, you can have the best safety harness in the world, but if it's mounted improperly, then you could dramatically increase the possibility of your harness failing under the forces of a high G-force incident.

The "high G-force" concept is important to keep in mind. Imagine trying to break a string or some tape. It wouldn't break at first, but after giving it a sharp snap or jerk, it will break. In the same way, it is the transient, peak G-force that your harness and its hardware need to be able to withstand.

SFI specifications have evolved over decades from data gathered from thousands of tests and analysis of thousands of accidents and real world results. They are not to be taken lightly, as a tremendous amount of engineering and research is behind each specification.

There are now four different SFI restraint specifications:

  • The 16.1 specification covers the restraints that a majority of amateur and sportsman racers use.
  • The 16.2 specification covers Junior motorsports restraints which typically use smaller webbing
  • The 16.5 specification was mostly seen in Stockcar racing (NASCAR) however with the transition to the 2 inch restraints, NHRA has adopted this specification because of the active adjuster webbing slippage test requirement and the increased webbing breaking strength requirement.
  • The 16.6 specification is for "advanced motorsport assemblies" and is a new spec that was just voted on and passed by the committee earlier this year.  NASCAR will be fully 16.6 compliant starting in 2016.  Indycar will probably move to this spec for 2016 as well.  This spec will typically not be seen by the average racer and will be specific to professional motorsports such as Indycar and NASCAR.

There are two primary considerations when mounting your safety harness: angles and hardware. The buckles, locking mechanism and mounting hardware provided by every major, well known harness manufacturer is designed and built to SFI specification minimum, if not better. Your main hardware concern comes down to the bolts used to mount your harness and the physical mounting locations. The mounting points need to be both strong enough to overcome stresses in an accident, and be located in such a way to ensure that each harness is at the correct angle.

The angles for mounting a harness are simple and easy to understand. The angle of the harnesses is critical to maximize its strength in an accident and its ability to allow your body to survive the forces it will be subjected to, yet minimize the possibility of injury. Harness technology is more than just materials and fatigue strength, it also includes how best to transfer the forces applied to the body in a crash into the harnesses and then into the structure of the car. There is an optimal placement where lap, shoulder, crotch and anti-submarine harnesses can best absorb the energy of sudden deceleration imparted to them from the driver's body in a crash while also providing the absolute minimum risk of injury to vital internal organs.