Warning: Miller Back Biter Lanyards

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SPERIAN Fall Protection, Inc.

Summary Statement

This manufacturers notice warns of the importance of lanyard inspection. A case is reported of an employee using a Miller Back Biter double lanyard who noticed the locking keeper of one of the snap hooks fell off.
June 25, 2009


It Is Important That This Notice Be Transmitted To All People In Your Group

DATE: 25 June 2009

SUBJECTS: Miller Back Biter lanyards

Information: Miller Back Biter lanyards

Event Summary: Employee working for contractor group onsite. Employee was utilizing a Miller Back Biter double lanyard attached to his harness and inspected this fall protection prior to use. While maintaining 100 percent tie-off (continually transferring one of his two lanyards to anchor points), employee noticed something fall out of the corner of his eye. Employee looked down and saw the locking keeper of one of the snap hooks had fallen to the ground. At the time of the failure, employee had the lanyard looped around an anchor point and tied back into itself (appropriate usage). Employee immediately descended to grade level and found the locking keeper and the rivet that held the keeper in place.

Photo of miller Back Biter lanyard being used by employee at time of failure.
Miller Back Biter lanyard being used by employee at time of failure. Date of manufacturer of this particular lanyard is 05/09/08. In service date of this lanyard was 02/17/09.

Photo of the detached locking keeper and the rivet that held the keeper in place.
The detached locking keeper and the rivet that held the keeper in place. Upon inspection, neither appear to show signs of damage or abuse. The head of the rivet appears to be cleanly sheared off.

Photo of side by side comparison of the two snap hooks on the lanyard that failed.
Side by side comparison of the two snap hooks on the lanyard that failed. Neither snap hook appears to show any signs of damage or abuse. A better look at the clean shear of the rivet holding the locking keeper to the snap hook.

Action Needed: There was an identical incident in October of 2008 at another facility (same manufacturer, same model and same failure). If you are currently using Miller Back Biter lanyards (either single or double legged), an immediate inspection by a competent person is needed. If there is any question to the integrity of a lanyard, remove it from service and contact your supervisor or a contractor safety professional on a path forward. Additionally, your company should evaluate whether to continue to utilize this lanyard.

Regardless, this incident points to the importance of a thorough harness and lanyard inspection prior to use regardless of the brand of harness or lanyard used. If you have any questions on how to complete a proper inspection on your harness or lanyard, don't hesitate to contact a safety professional.

Backbiter rivet issue

Photo of back back biter lanyard

Background: We were notified of a backbiter rivet shearing, causing the keeper on the snap hook to detach from the unit. Note: The snap hook and gate were still intact. With the keeper becoming unattached, this resulted in the loss of dual-action functionality of the snap hook. The lanyard and snap hook were drop tested at our facility and passed all applicable ANSI testing. Rivet was analyzed and was to specification metallurgical^.

Corrective action: A letter was published to our customers explaining the situation. We were not able to duplicate the failure in our test lab. From the analysis we performed, we concluded that the rivet pin, if repeatedly struck, drug across rough surfaces, and abused, could possibly cause the rivet pin to shear. (We had no test data to prove, but we did have two instances in the field). We instructed our customers to carefully inspect the rivet heads for signs of wear prior to use.

Preventative action: Immediately, we switched to a different design which shielded the rivet pin from damage, Note the countersunk rivet head. This countersunk design protects the pin from accidental blows and wear over time.

Photo of old style Photo of new style
Old style New style

Date: November 10, 2008

To: Valued Sperian Protection Customers

Subject: Miller BackBiter Shock-Absorbing Lanyard Model No. 8798B

The Miller* BackBiter™ shock-absorbing lanyard was the first fall protection lanyard that has been designed specifically for tieback applications. Introduced in 1999, the BackBiter lanyard was designed with heavy-duty 12,000 pound lanyard webbing and a patented 5K (5,000 pound) rated snap hook. The 12,000 pound lanyard webbing and the 5K snap hook were designed into the product to address issues related to excessive lanyard wear and the potential hazards associated with the standard snap hooks and their ability to fail when subjected to impact forces when used in a tieback application. Thus, the Miller BackBiter shock absorbing lanyard was designed to double as a shock-absorbing lanyard and an anchorage connector for tieback applications.

Recently, there have been several emails sent to contractors:

  1. Stating that there is a "problem" with the Miller BackBiter and/or

  2. Showing photos of the snap hook with the pin for the lock-lever removed.

The original sender issued a safety alert regarding the functionality of the BackBiter snap hook. We would like to address this issue with the following information:

  • A Sperian Protection sales representative was informed of the issue on October 4th and alerted our Quality Assurance department immediately.

  • Sperian Fall Protection requested additional information and for the product to be sent back to the factory in Franklin, Pennsylvania for an Engineering inspection and evaluation. The purpose of an Engineering inspection is to identify the root cause of any product problem.

  • As a point of clarity, this lanyard was NOT involved in a fall.

  • Upon receipt of the lanyard, it was determined that one of the rivets that holds the lock-lever to the snap hook body had sheared off, causing the lock-lever to become loose and eventually detach from the unit. Note, the lock-lever is a redundant safety feature on the snap hook that locks the snap hook gate closed to prevent unintentional disengagement.

  • On October 20, 2008, Sperian Fall Protection contacted it's supplier for the BackBiter snap hook to advise them of the situation. The snap hook components were sent out to two independent metallurgical laboratories for metallurgical evaluation and to performing a failure mode analysis. The results of the evaluation showed that all metal properties and strength were within specifications.

  • While awaiting the metallurgist results, we also conducted several abusive and destructive tests on the snap hook to see if the issue could be duplicated. The snap hook was loaded with forces up to 5,000 pounds in every direction and we were unable to duplicate the damage to the snap hook. We also conducted a series of dynamic drop test using the Backbiter lanyard with the snap hook lock-lever removed to see what would happen in the event of a fall if the lock-lever was missing from the snap hook. The results were positive. The fall was arrested and the BackBiter 5,000 pound snap hook remained secure to the anchorage. We are confident that if this were to be a real scenario the users' fall would have been arrested.

  • So far we have identified two snap hooks with this issue. This is an extremely low number when compared to the high level of sales of this product. We continue to investigate this issue and expect that we will not see this repeat in the future.

  • Additionally, we've completely inspected our inventory of BackBiter snap hooks and found none with loose or defective rivets.

Sperian Fall Protection treats these issues seriously. Our Quality Assurance process takes measures to prevent a product from shipping to the field with a defective condition. We continue to look at all possibilities and strongly believe that these two incidents are isolated and unique situations. We are confident that the Miller BackBiter shock-absorbing lanyard, when used properly, is one of the safest products on the market today. As with any safety equipment, a daily inspection by the user and a periodic inspection by a company-appointed competent person should be done according to the manufacturer's instructions to ensure that the product is in good usable condition.

Should there be any questions regarding the proper use, inspection, care and maintenance of your Miller fall protection equipment, please feel free to contact our Technical Service Department at 1-800-873-5242.

Photo and diagram of gate, rivet, and lock-lever