Metal Roofing Fall Protection
Regardless of how many workers are trained in safe work practices and increased improvements in fall protection equipment, the Bureau of Labor and Statistics reports annually that fatal falls account for around 33 percent of construction fatalities in the United States. This figure has fluctuated much in the past decade. Tragically, fall fatalities are over 70 percent for the roofing trades. Steep- and low-slope metal roofs still hold a significant share of the residential and commercial roofing markets and, as such, bring a cadre of greater hazards to the metal roofer and sheet metal installer.
Correctly installed metals require only a minimum pitch to drain, yet most applications are deemed effective above 4:12 pitch. Although panel seaming and fasteners have improved, the basic materials and methods associated with metal roofing have not changed that much. Usually composite pitched roofs are meant to be walked on during installation, whereas metal usually requires an installation plan that minimizes the time spent on such a slippery and unreliable surface.
The Accident Reports Speak for ThemselvesI was raised on the construction adage: “More guys fall off of shallow pitches than steep ones,” and it has certainly proven true in my 35 years of construction history. Over the years I have either witnessed or investigated 20 residential or commercial roof fall accidents. Fifteen of these falls (75 percent) occurred from low-pitch roofs (0-4:12). Out of these 15 low-pitch falls, eight were precipitated by poor housekeeping (tripping or stumbling over materials, tools and hoses as well as other workers); four were caused by poor material handling (loosing footing while carrying materials); one was insufficient hole guarding methods and inattentiveness on the part of the roofer (fall through a skylight); and one was failure to evacuate the roof in unsafe conditions (ice, snow and wind). All of these flat or low-pitched roofs were constructed of stone and ballast, membrane, asphalt rolled roofing or shingles.
Of the five high-pitch (greater than 4:12) roof fall accidents (25 percent), three were off metal roofs and two off of composite shingles. The high-pitch shingle falls were 10:12 or greater and the vertical metal panel falls were both 12:12. Of the three high-pitch falls from metal, two were caused by poor material-handling methods. One was due to sheer stupidity — the roofer was just “free climbing” to set two last screws in a ridge cap on the last day’s punchlist. The two roofers who fell during handling of the formed metal sheets on different work sites had attempted to secure themselves on the 45-degree slope by means of synthetic ropes: one to a body belt (prohibited PFAS since 1998) and one to a slip knot around his waist (never legal). In each case, they had a helper situated on a portable ladder at the eave.
Analysis and AbatementI often approach my weekly toolbox safety talks by reviewing actual roofing accidents and near misses. The best means I’ve found to introduce the OSHA safety standards is to first address the actual site conditions and work practices leading up to the accident. After looking at the root causes of an accident or near-miss, I often ask the roofers to itemize safe work practices, design hazard mitigation systems, and select equipment to prevent them from happening again in the exact same way. After all, analysis and abatement is the whole reason we fill out those accident reports in such detail in the first place. While attempting to remove those specific hazards that created the events and/or conditions that effected one particular fall, we will often discover previously unseen factors that could create other potential accidents. Some crewmembers have called this “web effect.” Here are just 10 of the many solutions which roofing crews have arrived at to prevent falls off of metal roofs such as those I’ve described.
Safe Access and EgressIn every job, the standard operating procedures and material, labor and equipment costs should be considered early. One or more safe means of access and egress to and from the roof are required not only for personnel, but equipment, tools and materials. In emergency conditions, separate access and egress routes should be planned, in case one or more are blocked for any reason. The amount of time, energy and cost incurred in establishing a safe and convenient access/egress to and from the roof is directly proportional to the percentage of profit on any roofing job. Safety always starts in the bid room, so plan ahead for establishing routes of access and material deployment.
Permanent Ridge AnchorsNo one should attempt to install a metal roof of any style without first designing and erecting a personal fall arrest system for every roofer on the deck. Permanent vs. temporary fall anchorage is always a subject for debate. Categorically, metal roof fall prevention has lagged behind much of the rest of the market when it comes to innovative anchoring devices that are both practical to install, structurally sound and appealing in design.
Ridge anchors may be designed for either temporary or permanent installations, but most are basically designed for shingle roof applications. They are constructed of 12-gauge galvanized sheet steel, welded 1/4-inch carbon steel plate or nylon webbing with a stitched D-ring. Some manufacturers are in R&D to develop anchor devices constructed of lightweight, non-corrosive carbon fiber materials. Anchors may be integrally installed beneath shingle or cap coursing or applied with lag bolts and sealed with a butyl gasket over the top of the ridge caps. The fasteners must always be securely fastened through the roof deck into the structural framing (rafters or purlins).
For a variety of reasons, roofers often are pushed when installing PFAS and the fasteners quite often miss the structure and are held only by the roof boards or plywood decking. This condition is often not discovered until the anchor is removed. A fall event in this case could have tragic results.
I have seen several metal roofs where the contractor installed 1/4-inch vinyl- coated aircraft cable loops to both sides of the ridge with swagged fittings anchored to the rafters below. He then placed the ridge cap over the cables, exposing only the anchor loops. From the ground they were practically invisible if you didn’t know they were there. I have only used temporary ridge anchors on metal, which require alternate anchorages by the time the ridge cap was installed. There is no reason why a sturdy, low-profile, venting, waterproof design couldn’t be fabricated and sent out the galvanizer or built from stainless steel. Once lagged into the ridge beam, or U-bolted around the trusses or rafters, they could remain in place to support a horizontal 3/8-inch aircraft-cable static line from which the roofers could carabiner their vertical lifelines. Retractable lifelines could also be rigged from either the anchors or the static line to increase maneuverability and practicality.
Remember that the leading cause of injury and death to roofers who are 100 percent tied off with PFAS is anchorage failure. Designing and building a good anchorage system is time and money well spent.
Rope GuardsLocated between the full body harness with lanyard and a suitable anchor point, lies the lifeline. These ropes are rated at 5,000-pound minimum tensile strength per roofer, with no more than one worker attached to a lifeline at any one time. They can be either 5/8-inch diameter twisted nylon or 10-millimeter kernmantle. They should be of a suitable length so attachment and disconnects can be made comfortably from a ladder, stair, scaffold or structural access/egress point. A competent person should be committed to inspecting lifelines at least preshift and as often during the shift as he deems necessary.
Wherever ropes contact an abrasive edge or a short-radius bend, care should be taken to provide suitable rope guards to prevent damage and potential failure. Whenever such a condition is observed, the ropes should be protected from defects with the use of rope guards. These come in many styles, sizes and price ranges from a simple, inexpensive nylon sleeve with velcro closures that surrounds the rope to a hinged set of roller bearings over which the rope rolls effortlessly.
All rope guards are manufactured with the means to tie a safety back-up line to secure the device in place. Making either rapid or repeated deployments — such as lowering or positioning a worker — would mandate the use of the roller guard because the nylon sleeve could produce harmful heat build-up due to friction. Whether you buy or custom-build a corner rope guard on your own, the features you should consider are strength, versatility, flexibility and security.
Non-slip BootsIf there were, apart from personal fall arrest systems, only one hazard abatement method available to roofers on metal decks of any pitch, I would recommend they all wear non-slip boots. There are many slip-resistant boots on the market today, but claims of “non-slip” are made by only a few. (e.g., Shoes-for-Crews, Tingley and Cougar Paws). The technology of sticky tires has finally trickled down to the shoe market. Shoes are now designed with new synthetic substances and manufactured with either small micro-pores or surface textures, which envelope the contours of the roof deck and increase the
coefficient of friction by many times. Actually, the more weight uniformly applied to the soles of these boots, the stronger the bond between the sole materials and the roof deck.
Some manufacturers provide a convenient Velcro cinch strap across the instep to help support the ankle when the roofer stands transversely across a steep pitch. There are some boots that take low-cost replacement souls, attached with industrial strength Velcro to a shaped indention on the bottom of the boot, thus greatly extending the service life of the boot. It is critical that any roofer wearing these slip-proof boots perform a thorough inspection of the deck to ensure that there is no loose materials that could be stepped on, such as tracked-in dirt, construction debris (sawdust, metal shavings, mineral granules), leaves, lichen, algae or even tree pollen.
Most metal roof panels are often manufactured and shipped with a micro-thin coating of oil that will also nullify the effects of the non-slip boots. A non-abrasive, soapy hand or pressure wash and rinse may easily eliminate your oily surface entirely. Be sure that any panel upon which weight is to be placed is thoroughly secured before the live load is applied.
Of course the most important feature to remember of this or any other personal protective equipment is that it does not remove the potential fall hazard. Slip-proof boots should work in conjunction with PFAS on all roofs.
Stop BlocksI have also seen my share of near misses when it comes to roof falls. In most near-miss cases, the roofer’s slide, roll or tumble down the slope was arrested primarily because of what he didn’t do, rather than what he did. He didn’t panic. No screaming, no flailing of the arms or kicking legs. It was simply a case of command and control that stopped disaster from happening at the eave.
Many metal roof designs here in the Northeast incorporate snow-and-ice guards that break up the dangerous snow slides before they clear the eaves and potentially strike a pedestrian below. Several manufacturers provide a set of double stainless steel bars mounted horizontally to stainless steel triangular gussets and adjustable mounting plates to be screwed to either roofing ribs or standing seams. The units are approximately 3 to 4 inches above the roof panel and come in an assortment of lengths, styles and colors to match the roofing. Sometimes they are overlapped and installed in two staggered lines, but most often the plans call for 36-inch snow guards installed in a line 12 to 18 inches above the eave, with no more than 24 inches between them. These snow guards, if properly fastened to the structure of the rafters or purlins below, may also act as a stop board for a fallen roofer.
We have also installed our own temporary stop boards using 2x6s screwed together lengthwise, with diagonal gussets reinforcing the ell-shaped stop board. We then install them on top of the ribs of the metal panel, driving redheads or Timberlok® screws into the framing below. The bottom of the 2x6 stop block received a bead of clear silicone prior to attachment. At the end of the job, these were removed and a 3 1/2-inch butyl gasket screw was replaced in the hole with its threads coated with construction adhesive. Even with PFAS or a catch-platform in use, that last resort should always be a redundant row of stop blocks.
Catch PlatformsThe impact of the fall and the ensuing injuries incurred in the slide can be damaging enough, but it is the free-fall that must be prevented. When every protective measure fails, it’s always comforting knowing there’s a platform below on which to land. Installing a catch platform as close to the eaves as feasible can certainly minimize the effects of falling to a limited distance (2 to 3 feet). Most contractors prefer to pair a catch platform with a scaffold, enabling them to access the roof, load materials and install facia, soffits and frieze boards. By this time, the catch platform is 3 to 4 feet below the drip edge. This is a significant distance when you’re tumbling or sliding at an increasing rate.
The fall victim, in this case, misses the catch platform all together. He may strike the guardrail above midrail height or miss it completely. Although more costly in labor, it is a safer work practice to lower the scaffold or wall brackets as required for trim work only after the metal deck has been completely installed.
The construction, use and maintenance of catch platforms are regulated by OSHA’s Subpart L (1926.450) Scaffold Standard. The roofing contractor is responsible to designate an experienced, trained competent person on-site to be responsible for inspecting the catch platform preshift and after any incident that may affect its structural integrity. Whether built with gusseted wall brackets clamped to the upper wall framing or full-length supported, welded, end-frame scaffolding, both systems should be constructed with scaffold planks/platforms and compliant guardrails (42-inch top rail, 21-inch mid rail, 4-inch nominal toe board).
Both of these platforms should be run the entire length of the eaves plus 2 feet, to better enable the falling worker to land safely anywhere on them, preferably feet-first to absorb the short drop impact to the deck. The guardrail systems on catch platforms should obviously exceed the minimum strength requirements (200 pounds lateral and down) because the fall victim is often accelerating (and gaining mass) when he finally reaches the guardrails and posts and his impact force may easily exceed 200 pounds. Adequate bracing, tying or guying may be required to resist the forces that may be applied in a fall impact.
Whenever the catch platform has been involved in a fall, it should be thoroughly tagged out and inspected by the competent person for defects and damages before being repaired, replaced or put back into service.
Panel PlatformsIf there is one function that roofers seem to do exclusively, it’s material handling. Sometimes, it appears as if every shingle or panel was handled at least a dozen times before it finally rests securely in place. When it comes to a bulky, unweildy roof material such as a 20-foot-long, 3-feet-wide galvalume ribbed panel, the more thought that goes into material handling, the more profit appears in the bottom line. Any mechanical advantage that is feasible on the site should be considered.
I once witnessed a 40-foot articulating all-wheel-drive Lull with a self-leveling carriage outfitted with a custom-built angle-iron framework. This carried 20-plus pieces of 20-foot sheet metal up to a convenient location above the rafters and purlins. The lightweight frame was adjustable to various roof pitches. The unit was gently set down level across eight to 10 rafters against strong-back blocking below the leading edge. Safety chains were then strung between the trusses and attached to the opposite rafter cord and locked off with carabiners. From this position, the roofers were able to select and handle the sheets at their own pace and the forklift was free to tend other jobs on the site. Panel platforms are completely removed from the roof at the end of shift and prior to any potentially hazardous weather events.
A qualified person, or professional engineer, is required to calculate the maximum-intended load vs. the maximum-rated load of the roof structure. It is recommended that the qualified person calculate a minimum 2X safety factor. The increased efficiency of pre-loading several panel platforms (also called “roofing bunks”) and placing them ahead of the roofing crew, gave this employer a profitable advantage as he continued to roof half a dozen large gable-end college dormitories. It is important for the competent person to take the time and expense to install a practical personal fall arrest system that is feasible and does not create a greater hazard for the crew working with a panel platform.
Counter-rigged LifelinesAnother system I have used is the counter-rigged PFAS lifeline. We were applying a ribbed sheet metal roof to a post-and-beam barn. First we ran 1/2-inch diameter aircraft cable horizontally outside at the sill beam. It was fastened at each end to the corner posts and carried with pick-up cables next to each vertical post. Then we attached two 5/8-inch nylon lifelines with carabiners to the anchor cable on the sill on one side, ran it up over the ridge and back down to the anchor cable on the opposite sill with another carabiner. We left enough slack in the nylon so we could lift it about 12 inches above the ridge. We attached our double-legged lanyards to rope-grabs on the lifelines. This design gave us ample maneuverability as we sheathed the purlins on both sides simultaneously working from one gable end toward the other. The ability to slide the lifeline horizontally along the anchor cables (with assistance from our ground person) increased our lateral range.
With double-legged lanyards we could also switch lifelines with each other and still remain 100 percent tied off. Most importantly, we were securely protected from opposite-side falls as we approached ridge height. As we got close to either gable end, we left the lifelines about 5 feet back from the edge. If we happened to fall off the rake edge, the counter-rigged lifeline would stretch both anchor cables between pick-up lines and the lifeline could not move more than 12 inches at the ridge, thus providing a simple, strong anchoring system.
Pre-shift and regular intra-shift inspection of the anchor cables, lifelines harnesses and lanyards is of extreme importance. The most important procedure in this system is to protect the lifelines at wear points at the ridge and drip edges. For this, we took old tire inner tubes and duct taped them around the rope for about 3 feet in length and finished taping them to the rope at the ends of the “sleeve.” Even if they were brought up over the metal edge, they remained protected.
Fall Protection Training ProgramThere simply is no substitute for worker training. OSHA’s Subpart M (Fall
Protection) clearly states in 1926.503 the employer’s competent person trainer requirements. Certified employee fall protection training should always be site-specific. Job safety analyses prove that different jobs have totally unique conditions. The standard requires that your written training program address the “nature of fall hazards in the work area.” OSHA also requires that the exact “roles of employees in fall protection plans” be clearly specified in the program. Assigned worker responsibilities may include fall protection installation and removal, regular site safety auditing, emergency action plan participation and competent person training.
Training should always include a “hands-on” portion in order to be effective, practical and even enjoyable. Roofers also seem to be allergic to sitting in a room under fluorescent lights for more than four hours. By their nature, construction workers are problem-solvers and well-equipped to deal with site conditions with the materials and equipment available. Some of the major improvements in fall safety I’ve discovered came while trainees were practicing field evaluations on the roof after the classroom.
Refresher training is mandated whenever: 1) workplace conditions change rendering previous training obsolete; 2) there are changes in types of fall protection equipment; or 3) observed inadequacy in an affected employee’s knowledge or use of fall protection equipment. Training is a value-added function of your company. Whatever costs are initially incurred, fall protection training will pay big dividends by reducing losses and increasing productivity.