Water fed poles (WFPs) have revolutionized the window cleaning industry over the past decade, allowing window cleaners a safer method for reaching mid-story building windows while remaining on the ground.
Although WFP usage has undoubtedly reduced the number of ladder-related falls and injuries, there’s an unspoken health-related concern that has not been addressed by the industry – until now.
This month, Douglas J. Mills, M.D., and Perry Tait are releasing a new study conducted to examine repetitive motion-type injuries that can result from the use of WFPs, and to suggest solutions to the problem. Douglas J. Mills, M.D., is a licensed medical practitioner in the state of Texas, and is a former Medical Director of the Occupational Health Clinic in Fort Hood, as well as the Medical Director for the Preventative Medicine Department. Perry Tait is the founder of the Future of Cleaning and the Reach-iT brand of water fed poles.
Tait began using water fed poles at around the age of 40, and suffered from injuries after just a few years of being on the poles part time. “I’ve met a number of guys who started later in life, like me, who have obtained injuries as well,” he explained. “It has always concerned me.” And Tait is not alone.
In December, the research team reached out to industry members online to ask if anyone had experienced pain from WFP usage. Over 70 professional window cleaners responded who identified wrist pain, numbness of fingers, elbow pain, shoulder pain, upper and lower back pain, neck pain and tension headaches, all of which aligned with the symptoms related to the WFP risks identified by Dr. Mills. These risks could be increased based on three criteria: pole efficiency, the work cycle frequency, and awkwardness of movement.
WFPs come in a wide variety of qualities and price ranges – primarily based on weight and design material. There is no accepted guide to determine which works best for specific usages. Buyers, therefore, often go for the cheapest option. Cheaper models are usually made from cheaper materials, such as aluminum and fiber glass tubes. These, however, are heavier and “floppier” than more expensive options, such as fiberglass/carbonfiber mixtures or 100 percent carbonfiber tubes. (“Floppy” is a term that has been adopted by industry mem
bers on the forums, and refers to the amount of flexibility displayed by the pole when a force is applied.) The floppier the pole, the more difficult it is to handle, and the higher the likelihood of repetitive motion injuries.
To determine the efficiency of a pole, the team used the classic equation for work: Work (W) = Force (F) through Distance (s). In this situation, force means the amount of effort required to move a pole to complete a stroke. Distance refers to the amount of distance required to move a pole to complete a stroke.
The stroke of a floppy pole is about 2.5 times as far as the distance of a rigid pole. When Dr. Mills first saw the use of a rigid water fed pole, he generally commented on the biomechanical difficulties that he observed. But, when he observed the operator using a flexible pole, he became alarmed by the exponential increase in risk of injury due to the mechanical inefficiency of the floppy pole.
A floppy pole requires more work (i.e., force through a distance). The floppier the pole, the further the operator has to swing the pole to obtain the same agitation/rinse function at a distance. Additionally, the inertia of a heavier pole, when combined with greater floppiness, requires more work.
From an ergonomic standpoint, a waterfed pole with a higher stiffness-to-weight ratio allows the operator to complete his work with the least amount of effort, which means working more efficiently and reducing the risk of repetitive motion injury.
The Work Cycle Frequency:
According to the study, a typical professional WFP operator will use the agitate (up and down) stroke motion or the rinse (side-to-side) stroke at an average of one stroke per second. A stroke cycle would equate to two strokes – i.e., up then down, or side then side, and takes about two seconds.
Based on this definition, the typical WFP operator performs 30 cycles per minute, 1800 cycles per hour, and 9000 cycles in a five-hour working shift. Done five days a week, this equates to 45,000 cycles per 20 hour work week, which is an astounding 1,800,000 cycles per year.
Of course, many WFP users do not use their poles nearly that much. So, for the point of the study, the team distinguished three categories of users: Professional Users = more than 10 hours per week
Part-Time = 2-10 hours per week
Occasional = less than 2 hours per week
Awkwardness of Movement:
Dr. Mills observed the typical posture and action of a worker using both a floppy and a stiff water fed pole and found that the biomechanics required to manipulate the WFP are “awkward at best.”
A biomechanical analysis of the operating motion reveals several areas of concern. The inferior hand’s forward thrusting movement repetitively places the wrist in both excessive radial and ulnar deviation. This may result in repetitive motion injuries such as De Quervains Tendinitis, Carpal Tunnel Syndrome, etc.
The inferior hand is frequently called upon to apply a rotatory movement to the long axis of the pole, thereby necessitating a strong gripping action. This may result in epicondylitis of the elbow, tendinitis of the wrist, etc.
The arm is frequently cycled through hyperextension with a flexed elbow. This may cause excessive traction on the ulnar nerve, predisposing toward neuropathy.
Additionally, an overhead linear bimanual hand tool (i.e. a water fed pole) forces the operators’ limbs and torso into awkward positions during the operating movement, with the risk of injury increased by reaching for windows to the far left or the far right of the operator.
What Should be Done?
Through their study, the team determined that yes, water fed poles can put window cleaners at risk of long-term injuries. This risk is greater when using a heavier or floppier pole (i.e, pole efficiency) – especially for long work hours (i.e., work cycle frequency) – and using the natural/accepted methods for handling the pole (i.e., awkwardness of motion).
But what does that really mean for the industry?
“I believe it’s the window cleaning industry’s responsibility to find a means to modify the risk factors in order to reduce the possibility of injury,” Tait contends.
The only way to reduce “frequency of cycle” is to limit the number of hours an operator can work, and that’s not economically feasible for most businesses. Therefore, the research team’s proposed solutions are based on the other two criteria – pole efficiency and awkwardness of movement.
Testing for Floppiness
First, the team recommends that poles be tested – and rated – for floppiness. Not all end users will be able to afford the more ergonomically correct options, and so it does not make sense to mandate all poles be made of lighter, more rigid materials. However, the team believes that operators should at least be made aware whether the pole they are choosing is appropriate for the amount of work they intend to conduct.
Because, as shown earlier, the more rigid the pole, the more efficiently it cleans, the team recommends testing a pole’s rigidity. Their proposed method for doing this is by measuring a pole’s resistance to deflection by an applied weight. The greater the deflection, the less rigid – and less efficient – the pole.
The team created and recommends a simple test that can be conducted both by pole manufacturers as well as end users to determine efficiency. The test is done as follows:
• Extend the pole to 25 feet and suspend it between two supports of even height (such as chair backs).
• Place the ends of the pole on mounts with an overlap of six inches. The ends must not be fixed to the mounts.
• Measure the height of the mounted ends.
• Set a tape measure at a minus one foot, which will be the target deflection (flex).
• Attach weight to the center of the pole, and keep adding weight until you achieve the target deflection (one foot) at the underside of the center of the pole.
The amount of weight used in pounds is the floppiness index.
Another method uses the same methods for steps 1 through 4, but instead of weights, hang a bucket capable of holding 5 liters of water. Slowly pour water into the bucket until the center of the underside of the pole is at the one-foot target deflection. Determine the volume of the water in the bucket when the pole center flexes to the one foot target deflection.
• Use the following equation to determine the weight of water used: 1 litre of water = 1 kg.
Multiply the number of litres by 2.2 to convert from kgs to lbs. This value in pounds is the Floppiness Index.
The team defined a “floppy” pole as one that deflects by one foot with less than two pounds of weight. A “stiff” pole can be defined as a pole that requires more than 10 pounds weight to deflect one foot.
The Floppines Index number is equivalent to the number of hours the pole should be used per week. For example,
• A Floppiness Index of 2 or less suits a workload of 2 or less hours per week.
• A Floppiness Index of 10 or more suits a workload of 10 or more hours per week.
The Floppiness Index does not address the actual weight of the water fed pole. However, the Index does increase immediately with the initial
flex of the pole under its own weight. The Floppiness Index also does not address aluminum water fed poles. Further study and test results are required to determine where the characteristics of aluminum poles fit into the team’s index.
The Floppiness Index is a measure of
performance, not composition of the WFP, and therefore its usefulness will not be affected by changes in pole technology. The Floppiness Index also will enable manufacturers to present their products as the correct tool for any given workload, and empower users to buy the right tool for the job.
More Ergonomic Movements
The natural way to hold a water fed pole is in a manner that is awkward for the user, which increases the chance of injury. The first step in approaching this problem is to teach WFP users less injurious methods for operating, such as switching hands, avoiding the use of control muscles for power movements, and staying centered.
Dr. Mills, who is an ergonomic tool designer as well as an occupational health physician, worked alongside Tait and his son, Harrison, and Joab “Bob” Froam, a design engineer, to develop and begin to patent two new handle system for water fed poles. They are calling these the “Power and Control” ergonomic handles.
The new handles are designed to reduce the demands of smaller control muscles during power movements using a water fed pole. Rather than launch these into mass production, the team is having several window cleaners test them in the field and provide feedback. Additionally, rather than sell the handles at this point, Tait has decided to give them to his current Reach-iT customers, free of charge, and they can in turn give a donation back to him based on their perceived value of the product.
“I have felt a huge indebtedness to the window cleaners that chose to buy a Reach-iT pole during our first four years of business. Without the support, faith, and, at times, patience from these people, our dreams, our potential and our current reality would not have become true,” Tait added.
In addition to the Power and Control handles, Tait is working on adding a work stroke counter that can be added to help the team collect more data to present to OSHA.
To OSHA and Beyond
The ultimate goal of this research team is to present the information presented in their study to OSHA and similar agencies in other countries, such as Australia and the U.K. “We want to change the industry and make it safer,” Tait concluded. “We are likely going to have a lot of philosophical opposition, but change rarely comes without resistance. I think we’ve created something that is responsible and for the greater good of professional window cleaners.”
To read the study, click here., or listen to an audio version, visit http://www.power-and-control.com/i-14window-cleaning-safety-submission-2015.html