Why does AZTEC promote the use of 2 cables?

Every safety engineer who takes into account the human safety component always considers a backup or failsafe configuration that acts in conjunction or separately from the primary system.

Whether a person is a design engineer or a zip line operator the question that should be asked is; 'What if a system failed?'

We at AZTEC advocate that adding a second cable needs to be seriously considered by the zip line industry in order to better serve the riding public.

Some are suggesting that a second cable is unnecessary and liken it to wearing two life vests.

Its a misleading analogy and a disservice to the riding public to rebuff a two-cable system based on this kind of reasoning. That type of logic is similar to suggesting that cars don't need airbags because seatbelts are sufficient.

Participant or rider safety is always paramount which is the reason why experts who design vehicles, amusement park rides or airplanes carefully research and incorporate reasonable backup systems. A two-cable system is entirely reasonable.

It has also been suggested that two cables will become entangled.

We have witnessed multiple thousands of participants ride double cable zip lines and there has never been a single case of cable entanglement.

More and more operators in the United States and Canada are
installing second cables in their infrastructure for the
same reasons we outline in this website.

But doesn't the cable breaking strength rating nullify the need for a second cable?

The issue isn't just the cable. Some zip line contractors falsely highlight the breaking strength of the cable as the overriding safety issue thus inferring that safety is optimized due to a cable's breaking stength of 14,000 - 25,000 lbs. We don't argue that point and the chances of a cable breaking is extremely remote. However, there are reports of it happening.

Operators need to understand the cable itself is not a stand-alone entity because the supplemental connecting hardware that includes cable clamps, thimbles, etc. influence the integrity of the cable.

FOR EXAMPLE: Cable clamps can only handle 80% of the cable strength.* Furthermore, the added weakness that cable kinks and reverse bends create become the basis for a recalculated rating system for the entire zip line infrastructure regardless of the cable itself. In addition, most engineers advising zip line operators are not aware that an inverted cable clamp decreases the integrity of the clamp. These issues and correctly calculating the cable's Safe Working Load (SWL) rating and the manner in which is cable is used should also be considered.

We at AZTEC propose this question: 'What is the worse case scenario that could happen, and what can we do to provide a higher degree of safety?' As the saying goes, a chain is only as strong as it's weakest link.

Our position is that a backup system added to a primary configuration, regardless of the cable rating, significantly multiplies the safety factor.

Ultimately, our riders continually reaffirm their greater sense of security knowing they are connected into two cables.

*Source:
www.globalsecurity.org/military/library/policy/navy/nrtc/14251_ch5.pdf
www.tpub.com/ceb/2.htm
www.tpub.com/content/construction/14043/css/14043_110.htm

Note: The minimum standard safety factor ratio for calculating the Safe Working Load is 4 (the recommended ratio is 8). Therefore, a 14,400 lb breaking strength rated cable has a safe working load of 3600 lbs. If the use of a cable clamps reduces the integrity by 20% the actual SWL is 2,880 lbs.

Does a second cable make the project too expensive?

Adding a second cable does not require complicated engineering and is not cost prohibitive considering the majority of construction costs go into the launch platform infrastructure, the supporting towers and the purchase of safety equipment. Adding a secondary cable is a comparatively minor cost. For example, the price of 17,500 lb rated cable in the Philippines is less than $3/meter.

Does AZTEC market itself to the North American zip line industry.

AZTEC was established to serve the Philippines and adjacent Asian countries only. It does not intend to promote itself in any way to the North American industry- although we believe the information in this site is relevant to the North American industry. We receive many inquiries from people in the US and Canada for assistance and consultation, but we refer them back to the industry leaders respective of North America.

Why AZTEC in Asia?

AZTEC's sister organization has been operating zip lines for more than 10 years and we recognized a significant lack of published standards respective of the zip line industry here in Asia. More specifically, we were concerned that well defined guidelines regarding the promotion of back-up systems was not being adequately addressed. Upon observation of several zip lines we determined that minimum US-based standards were not even being followed. Some zip lines are accidents waiting to happen.

We believe Asian countries have qualified engineers fully competent and capable of designing safe infrastructure. Furthermore, the operators in many of the poorer Asian countires simply cannot afford the fees to 'import' a US-based certifier to review their systems. For this reason, AZTEC took it upon itself to fund the cost of a comprehensive US-based review and invited certified experts to assess our infrastructures. We were advised that our systems far surpass the published industry standards. In addition, there is a team of highly skilled structural and civil engineers who design and build our infrastructures and serve as advisors for the promotion of AZTEC's objective to help promote rider safety.

Is AZTEC a commercial organization?

No. AZTEC is an organization that was created to serve as an advocate for rider and participant safety. Technically it serves as a trade organization that researches, compiles, publishes and set standards for safety.

Does AZTEC set standards for equipment?

No. AZTEC promotes the use of appropriately rated cables and UIAA/ASTM certified equipment sourced from internationally recognized manufacturers such as Petzl who are global leaders in this industry.

AZTEC does, however, set standards for zip line certification that is conditioned upon the compliance by the operator to use cables and equipment that meets or surpasses internationally published standards for this industry. Simply put; too many zip lines here in Asian are using locally fabricated materials which we are proctively addressing.