It was just another workday for Tom. The gear was loaded on the truck, everyone piled in and then the drive to the morning’s worksite. The crew had worked together for a couple of years, so everyone knew what their role was, and without much discussion the process of dismantling the two large cottonwoods began. Tom had the tough assignment for the day, dragging and chipping brush.
The cool morning weather quickly transitioned to hot and humid as the day heated up. The heat and humidity caused the sweat to drip from Tom’s forehead. He took his helmet off, just to feel the breeze and wipe the sweat from his face. As Tom was standing just to rest for a minute, he got a call from another ground worker to help fuel saws. He walked under the tree in the direction of the truck, forgetting to don his helmet.
Job briefings and procedures
Job briefings were not routine for this company, and many other procedures were neglected, such as a command and response before cutting a branch. The procedure was for the climber to look to be sure ground workers were clear, shout “headache” and make the cut. The climber cut a short stub, about 10 pounds, and it bounced through the canopy as it fell. As it accelerated on its downward fall, its trajectory intersected Tom’s path as he was walking.
The stub struck Tom on the left side of his head. The contact was with the side of the stub, not the end, so the force was less concentrated. Tom woke up in the hospital with a traumatic brain injury (TBI). These are disruptions in the brain’s normal function because of an outside force. TBIs can be minor and short lived or have lifelong implications. Tom was hospitalized for a week and had episodes of depression and sleep disorder for years afterwards.
Struck by a falling branch is one of the most common incidents to tree workers. TBIs are one of the outcomes of these struck-by incidents. A factor in the severity of the injuries is whether the struck worker was properly wearing a helmet.
Head protection is one of the required pieces of personal protective equipment (PPE) for tree workers in the ANSI Z133 -2017 Safety Requirements for Arboricultural Operations. They can protect against impact from falling or swinging objects and electrical hazards. The helmet, like most PPE, is your last protection from injury. Everything else has already gone wrong – walking through a drop zone, the lack of a command-and-response communication system, the falling stub – so the helmet had better work. But helmets provide a measure of protection that is not absolute. Understanding this limitation is important – they are not a substitute for safe work practices.
Head protection started with shipbuilders. There was always the risk of debris or tools falling, so workers wore tar-coated cloth caps. Head protection caught on for other industries and progressed to leather, steel, aluminum and plastic. The traditional hard hat has given way to the safety helmet. These helmets, which were first used in recreational sports such as climbing, have evolved to fit the needs and requirements of our industry.
Modern helmets fulfill the primary function of the hard hat – protection from impact and penetrating force – but have far exceeded this basic requirement. The modern helmets are better balanced, for example, and less prone to falling off when worn without the chin strap secured. Many are ventilated, with adjustable vents along the sides. Recessed hearing protection and face shields keep ropes and twigs from catching on the sides of the helmets. Add in Bluetooth communication, and you have a helmet that does far more than just protect the head.
Most of our helmets are made of non-conductive ABS (acrylonitrile butadiene styrene). They come with suspension that has between four and eight load-bearing points. The suspension is usually connected to the helmet with pinlocks and has a ratchet to tighten or loosen the fit. Most helmets come with a chin strap, and some have straps that can be positioned to break away if caught by something while working on the ground, or to hold under impact, such as ricocheting through the tree during a fall.
Our helmets must conform to ANSI/ISEA Z89.1 – 2014 (R2019) American National Standard for Industrial Head Protection. Helmets conforming to this standard are designated by Type and Class. Type I helmets are designed to provide a measure of protection against a blunt or penetrating force from above. Type II helmets provide protection from lateral forces – impacts on the side of the helmet – as well as from the top.
Since Type II helmets must provide protection from lateral impact, they all have a chin strap that must be used. The chin strap must remain attached during an impact and not stretch more than 1 inch. Type II helmets are not required for tree workers, but since we can be struck by a falling or swinging object, protection from top and lateral impacts might be a good idea.
The helmet, whether Type I or II, is designed in one of two classes. Class C (Conductive) is for general tree work, not in the vicinity of energized electrical conductors. Class E (Electrical), once called Class B, is worn by incidental and qualified line-clearance arborists working near conductors. These helmets have dielectric properties and meet the minimum standard of withstanding 20,000 volts for three minutes after impact with leakage not exceeding 9 milliamperes. This means the helmet survives contact, not necessarily that the head does, so never violate the minimum approach distance with these helmets! Class E helmets are not vented. Also, a reminder, do not attach decals to Class E helmets. They can affect the dielectric properties.
Some helmets are identified with a symbol of two arrows curving in opposite directions. This signifies reverse donning, that the helmet can be worn in either direction, forward or backward. Reverse donning is found on some Type I helmets, but is rare for Type II.
Many hard hats come with a full brim. Most safety helmets do not have a brim, or at best have a small front brim. There is no requirement regarding a brim, but a front brim can keep the rain out of your eyes. Most important, a front brim is a barrier to keep a long, swinging object from hitting your face – possibly a branch or chain bar.
Color options once were limited for helmets. Most were white. White helmets have a few drawbacks. First, it can be difficult to determine if it has been stored properly. Is it faded or not? It is much easier for the user to inspect the outer shell for ultraviolet degradation on a colored helmet. Second, damage can be more easily identified during a visual inspection due to discoloration that commonly occurs with brighter helmets. Last, if you have a required item of PPE in an industry where struck-by injuries are prevalent, why not make the PPE highly visible?
Helmets contain more than a shell. Some come with a polypropylene or polystyrene liner that acts as a shock absorber. Helmets also have suspension that supports the shell. The suspension is often forgotten – except when it pinches the forehead. But it is part of the shock-absorber system for many helmets, dispersing the impact force over a larger area and time period.
ANSI Z133-2017, Section 3.1.2, states, “Employers shall instruct their employees in the proper use, inspection and maintenance of personal protective equipment (PPE).” The old days of tossing someone a helmet their first day with the simple instruction of “wear it” are over. When issuing PPE to a worker, an employer is required to train the employee on when to wear it, how to don, how to doff and care and maintenance of the equipment. Understanding the do’s and don’ts of your PPE is a “shall,” which means a must in ANSI terminology.
Anything designed to protect you is worth a little care. Helmets should be periodically cleaned with a mild, non-filming soap and warm water, then rinsed and dried. If the helmet has a liner, this can be removed and cleaned. The same with the suspension. How often you clean it depends on your tolerance to grime, but regardless of frequency, be sure to follow any cleaning recommendation from the manufacturer. Solvents and degreasers can weaken shells.
When to retire your helmet
When to retire a helmet? You only have one head, so you might want to be sure the helmet will work if you need it to. There is no set time to retire a helmet, as it is impossible to know how the helmet is being used. Is it set on the top shelf in a dark cabinet within an air-conditioned office and only worn on occasion? Or is it out in the field every day, with the weather fluctuating with the seasons between cloudy, dry and 20 F to sunny, humid, 95 F days?
Useful service life
The useful service-life guideline for many helmets is five years. The maximum lifespan from manufacturing is 10 years, even if stored on a shelf. But most helmets are used every workday. Working means that the helmet is going to be subjected to the environment – heat, cold, sun, rain – and forces that include minor impacts, such as dropping the helmet you are carrying.
Helmets, as with other PPE, shall be inspected daily. The wearer should check the shell for cracks, even thin, hairline cracks or tiny networks of cracks, and note that stickers can hide cracks. Also check the shell for bubbling and warping. All these are indicators that a new helmet is needed. Most important, if the helmet was subjected to an impact or penetration, it must be replaced.
Most helmets will be replaced within 10 years. They get grungy by then. But there are always some helmets that get placed and forgotten in a cabinet – if you find one of these, how old is it? If you need to know how old a helmet is, check the serial number. Manufacturers are required to label the date of manufacturing. The manufacturer’s website usually explains how to read the label numbers and letters to determine when a specific helmet was made.
Suspension retirement date
What is often forgotten is that the suspension retirement date may differ from that of the helmet. The suspension, as the name implies, suspends the helmet from the head. This acts as a shock absorber for many helmets, cushioning the impact and working in concert with the shell, which is designed to deform on impact. If the pinlocks or slot become brittle, the suspension may fail when subjected to impact. Inspect the suspension for cracked or missing pin slots. Also inspect for fraying on the band or a broken ratchet. Any of these defects are a good reason to replace the suspension. Even in the absence of these defects, it is a good idea to replace the suspension every year.
A new helmet can cost anywhere from $90 to $400. That is not a lot of money for the last thing that might save your life when everything else goes wrong.
John Ball, Ph.D., BCMA, CTSP, A-NREMT (Advanced – National Registry of Emergency Medical Technicians), is a professor of forestry and TCIA member/student advisor at South Dakota State University, as well as a frequent presenter on industry safety and other topics at industry events throughout the U.S.
Mike Tilford, CTSP, ISA Certified Arborist, Municipal Specialist, Certified Tree Worker – Climber Specialist, is director of general tree care for SavATree, an accredited, 36-year TCIA member company headquartered in Bedford Hills, New York. He also is the ISA International Tree Climbing Championship (ITCC) head technician.