By CMC

The NFPA 1983 Standard on Life Safety Rope and Equipment for Emergency Services is complex and can sometimes be difficult to follow. The 2012 edition added several TIAs to clear up some of the confusion. The standard is in the process of being revised for the 2017 edition, and the committee is considering a reorganization of the standard to make it easier to follow.

New product classes continue to be added to the standard as some of the equipment used for rope rescue has not been covered by the standard. For example, the cord used by many rescuers for Prusik hitches has not been addressed.

The following questions and answers came from a training session at a large southern California fire agency, which was reading the standard closely. For an explanation, we went to CMC Rescue’s Engineering Technician Cedric Smith who oversees product certification.

Q: Is a Prusik hitch considered a rope grab? (Ascenders have their own category.) Or is a rope grab only a device such as a Gibbs or Rescucender?

A: The current edition of NFPA 1983 defines a rope grab as “an auxiliary equipment device used to grasp a life safety rope for the purposes of supporting loads; includes ascending devices.” A Prusik hitch does, arbitrarily, meet this definition. Underwriters Laboratory (UL), the certification lab CMC Rescue uses, has some reservations about certifying a Prusik hitch with the loop tied with a Double Fisherman’s Knot, although UL may entertain certification with a sewn loop. Having said that, it would be challenging to meet the 2,500 lbf. requirement for the Procedure A test. This is due to the fact that a Prusik hitch will not reliably grip the rope and hold without slipping at this force.

Q: I noticed on the CMC Rescue website that it shows a handled ascender having a Technical (T) rating, but when I look at NFPA 1983 under Section 7.6.2, it doesn’t shows strength requirements but refers to Procedure A in Section 8.6. Procedure A has no strength ratings either; however, Procedure B does. So is it correct to assume that a T-rated ascender and rope grab has a MBS of 5 kN and the General (G)-rated version has a MBS of 9 kN?

A: Section 8.6.7 has the specific requirements for Procedure A (1,124 lbf. for T, 2,500 lbf. for G). There is no Procedure B for rope grabs. The Petzl Ascender is T-rated but it does not have a breaking strength.

Q: Under Section 7.6.3, why is MBS specified for Escape (E) and G-rated descent control devices (DCDs) but a T-rated DCD has no minimum? It merely says to perform Procedure A, which again shows no MBS. In our Rope Rescue Technician classes we use T-rated Rappel 8s, which have an MBS of 13.5 kN (according to the website), but what is the required MBS for a T-rated DCD? Section 8.6.8 shows that an E and T-rated DCD shall be tested at 5 kN, so is that the MBS? G-rated DCDs have an MBS of 22 kN (7.6.3.5), but section 8.6.8.3 states they shall be tested at 11 kN.

A: This was an error in the standard. There should be a Section 7.6.3.X that prescribes the Procedure B test for T-rated DCDs. NFPA covered this in an addendum that reads as follows:

7.6.3.12 Technical use descent control devices shall be tested for deformation as specified in Section 8.6, Manner of Function Tensile Test, Procedure B, and shall have a minimum breaking strength of at least 13.5 kN (3034 lbf.).

The 5 kN and 11 kN that you are referencing are the values for the Procedure A test. The respective devices must be pulled (tied-off configuration) to these forces without doing damage to the rope.

CMC Rescue has been a member of the committee authoring the NFPA 1983 Standard on Life Safety Rope and Equipment for Emergency Services for many years as part of our commitment to make rope rescue operations safer for rescuers.

Jim Frank,
CMC Rescue Founder / Chairman