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 In April of 2005, the Ergonomic Fuel Line Residual Fuel Hose Gravity Drainer was evaluated by certified professional ergonomist, Ian Chong. His evaluation of our product highlights these strengths of our design:

  • Hose lifting tool removes risk and strain for potential injury in fuel delivery truck drivers.
  • Efficient use of time when employing the Fuel Hose Drainer
  • Low cost of the Fuel Hose Drainer is an added benefit to savings in health care costs.

Cover Letter

Mr. Bruce Johnson - 20 April 05

Western Washington Safety Consultants

PO Box 24743

Federal Way, WA 98093

Re: Fuel Hose Draining Tool Analysis

Dear Mr. Johnson:

As requested, attached is our analysis and critique of your hose handling tool design.

We approached the analysis, looking at several items.

  • current means or task performance of draining fuel hoses
  • biomechanical and injury issues associated and apparent with the current methodology
  • hose handling tool design and description
  • benefits of using such a tool

Overall it appears your design will perform as intended and will eliminate a significant portion of the at-risk conditions observed with handling hoses by hand. In pure biomechanical terms, the tool will offload a high level of at-risk conditions observed with current hose handling methodology.

With the offloading of the at-risk conditions, it is apparent that the task can be performed with less risk and effort than previously performed. Additionally the tool will allow those with symptomology to perform the task without increasing their symptomology and will go a long way in preventing future injuries, thus allowing and/or allowing damaged anatomy a chance to recover and also allow drivers to perform the tasks as they age

Thank you for this opportunity to provide our ergonomics expertise for Western Washington Safety consultants.

Sincerely,

Ian Chong

Certified Professional Ergonomist

Analysis of Ergonomic and Injury Prevention Features of Fuel Hose Draining Tool

Executive Summary

Hose draining has historically been performed by manual methods (described following) and can be associated with various at-risk conditions contributing to various hand, arm, shoulder, back and knee injuries.

The following "white paper" has been written to analyze the newly developed tool to reduce at-risk lifting and handling condition when fuel distribution drivers manipulate and lift large hoses from ground level to drain residual fuel and clear hoses for storage. The tool has been developed by Western Washington Safety Consultants / Bruce Johnson. Fuel transfer hoses used to transfer fuel from tanker trucks to underground tanks at distribution centers are approximately 4" in diameter and approximately 20' long.

The specific task addressed by the tool is the current method of manually raising / lifting the hoses by drivers to drain the residue fuel into underground station tanks. Once the fuel transfer is completed before the hoses are placed into storage tubes on the truck or tank trailer. The tool is also useful in other applications in which manual lifting of large hoses is required for draining.

Current Methodology

  • Drivers remove hoses from storage tubes / holders (on truck or tank trailers)
  • Hoses are connected to filler nozzle (in ground)
  • Hoses are connected to appropriate tanker discharge nozzle
  • Once fuel transfer is complete, driver must lift hose from ground level beginning at tanker discharge nozzle and walk along the hose using a "hand-over-hand" posture with forward lean to move residual fuel from hose into underground tank.
  • Hoses are disconnected from underground tank and discharge nozzles
  • Hoses are lifted and placed in storage tubes / holders

At-risk conditions

Manipulating hoses involves four main anatomical aggregates

  • Hands / wrists
  • Upper arm
  • Low back
  • Knees

The specific at-risk task (addressed by the new roller tool) occurs after the fuel transfer from the truck to the underground tank is complete. The task is in draining the hoses from the residual fuel remaining in the hoses, manipulating / raising the hoses in such a manner that the residual fuel drains from the hoses into the underground tanks, leaving the hoses empty for storage on the truck / tanker.

The overall approach is to keep a section of the hose raised to a high level above the ground, moving (hand-over-hand) from the truck / tanker to the underground tank "forcing" the fuel to drain from the hose by gravity, eliminating spillage while the hoses are disconnected.

Biomechanical Analysis

To effectively drain the hose, the driver bends over and lifts the hose to waist level at the truck / tanker discharge valve, allowing gravity to pull the residual fuel through the hose, draining into the underground tank.

The driver uses a "hand-over/under-hand" motion as he walks along the hose, keeping the hose in a raised position. The driver continually uses this motion through the entire hose until the residual fuel is drained into the underground tank and the empty hose can be placed and stored in the storage tubes on the tanker / truck. Thus for nearly the length of the hoses, the driver is holding a significant weight of 15 or more pounds, while loading the wrists in a palm up position.

To pick up and continually manipulate / drain the hose; the driver uses his hands in a static flexed position, holding the hose at about waist level. The flexed position of the wrist is held throughout the task as the driver performs the "hand-over-hand" motion while walking the length of the hose.

A Shimpo force meter was used to measure the force needed to lift the hose to a draining level. The force varies as the amount of fuel being drained effects the weight. The meter measured a lifting force of 15 - 18 lbs, increasing as the hose is lifted to shoulder height.

This is the force that must be overcome by only the lift. As the hands are in static flexion with all fingers "curled" or flexed a severe continual repetitive action is apparent at the hand wrist aggregate.

The four-inch diameter hose forces the fingers and hands into such a posture enabling the driver to obtain a controlled purchase on the hose as he "walks" the fuel from the hose.

As the driver uses the "hand-over-hand" methodology, the hose must be held (also in a static load) at approximately waist level since the hose is placed at the side of the body for clearance.

Deliberate raising the hose to a high level (shoulder or above) is often performed to apply more gravity to the fluid to be drained. This activity is performed with the at-risk hand conditions described. The all inclusive task performance also affects back and arm structures. While it may decrease the drain time slightly, it is nevertheless placing the drivers into a biomechanical compromising position.

Overall conclusion with current methodology

Overall, the static loading of the hands in continued flexion as well as the fingers also held in static flexion are obvious contributors to a carpal tunnel syndrome or tendinitis / tenosynovitis condition at the wrist. Additionally it not only the static positioning / loading of the hand wrist aggregate, it is the muscular force that is required to manipulate the hoses that has an effect on the hand wrist structures.

With the static loading of the wrists and the additional manipulative force used for the hose manipulation, it is apparent that the wrist structures are in a continual at-risk biomechanical condition.

The continued hand /wrist flexion positioning the hand in a supinated (palm up) position, simply to hold or maintain purchase on the hose forces the medial nerve and associated tendons in and about the carpal tunnel into a compressed situation. This compression can either develop classic carpal tunnel syndrome (compression of the median nerve in the carpal tunnel) or a tendinitis / tenosynovitis condition as the tendon structures become inflamed through overuse.

An additional issue is the posture of the low back, since it is apparent the driver may not always drain the hoses in a complete upright position. Thus, a moment on the low back is imparted, and continues throughout the task. The moment is not only generated by the body weight (center of gravity) acting on the back, but also by means of the weight lifted by the hands/arms at an extended position.

The knees are also anatomical structures placed in at-risk condition. As the constant kneeling or squatting to a low level, merely to pick up the hoses for draining, places repetitive and forceful stressors on the knee, over time a repetitive stress injury may occur.

Overall Conclusion

Should the injury (ies) not be addressed by either a different methodology the occupational injuries can become permanent and debilitating forcing drivers with these conditions to leave the fuel delivery profession. Especially at-risk are the aging workforce, drivers who are currently experiencing symptomology and drivers who have been performing hose draining tasks for length periods.

It is very apparent that this tool will greatly reduce the at-risk conditions experienced by any driver performing manual hose draining tasks. The result will be a recuperation of injuries already in existence of drivers performing these tasks. Additionally use of this tool will help prevent future injuries for those who are either approaching threshold to injury or who are otherwise at-risk, such as an older population of drivers.

The Residual Fuel Drainer tool description

The residual fuel drainer is a tool with two main components, a padded handle and a roller (see drawing / photo). The padded handle connecting to the roller by a vertical strut is designed to allow drivers to drain fuel product hoses eliminating at-risk bending, stooping and lifting postures, as is common with the current methods of draining fuel delivery hoses.

The Residual Fuel Drainer tool function

The tool allows the driver to lift a section of hose by "hooking" the hose onto the roller, and being held by the padded handle does not require continual bending or forceful hand postures as in handling the hose manually (without a tool).

The roller allows the driver to walk along the hose in an upright position, pulling the hose to a higher position with the tool. As the hose is lifted and the driver moves along the hose, the tool effectively rolls under the hose lifting a section up approximately 18". The lift by the tool replicates the manual hose handling of the driver to drain the residual fuel. As in manual handling, the residual fuel if forced by gravity to drain into the underground tanks (without any hand activity).

By means of the design, the tool is easily inserted under the hose for draining activity and is also easily removed once the draining process is complete.

The overall and successful function of tool is to completely eliminate the at-risk and static loaded hand postures required for manual hose draining / handling. The continual forward lean also associated with manual hose handling is also offloaded.

Benefits of the Residual Fuel Drainer tool

  • Completely eliminates the static loading and at-risk hand postures which are contributory to the associated occupational injuries such as carpal tunnel syndrome, wrist and forearm tendinitis / tenosynovitis
  • Continual forward lean affecting back musculoskeletal structures while walking the length of the hose is completely eliminated
  • Remaining muscular activity for hose draining tasks are performed by the upper arm and large shoulder musculature which are larger and better suited for continual heavy lifting
  • Low level bending or squatting is eliminated, as the hose can be manipulated using an entirely standing position
  • Hose draining tasks are performed faster with an equal amount of efficiency
  • Time to employ the tool for draining tasks is very minimal
  • The impact for improved performance / productivity and injury prevention more than significantly offsets its low cost