PPE-volution – How the Golden Gate Bridge Inspired PPE

America’s Industrial Revolution and ingenuity brought about many important advances in worker safety and PPE (Personal Protection Equipment).

At the start of the American Industrial Revolution, worker safety and health were nowhere near the priority they are today. As manufacturing grew, so too did worker injuries and deaths. The idea of safe work grew slowly from a small glimmer to a bright flame inside the collective consciousness of the American workforce.

Although the creation of OSHA regulations was many decades away, the evolution of PPE progressed on its own with the creation of new types of protective devices and advancements in pre-existing devices. Much of this early PPE had a major influence on worker safety’s advancement and will continue to do so.

Hard-Headed PPE Golden Gate Bridge
San Francisco’s Golden Gate Bridge, built in 1933, is an excellent early example of PPE’s influence on safety. Constructing a cable-suspension bridge that was 4,200 feet long was a task that had not been attempted before, one that presented many hazards. The project’s chief engineer, Joseph Strauss, was committed to making its construction as safe as possible.

The bridge’s construction played a particularly significant role in the successful development of one form PPE: It was the first major project that required all of its workers to wear hard hats. Although the hard hat was in its infancy at the time, head protection wasn’t new; gold miners had learned long before the importance of taking steps to protect against falling debris. Michael Lloyd, head protection manager at Bullard – a company in business since 1898, said many early miners wore bowler hats, which were hard felt hats with rounded crowns. Often dubbed “Iron Hats,” these were stuffed with cotton to create a cushioning barrier against blows.

Inspired by the design of his “doughboy” Army helmet, Edward Bullard returned home from World War I and began designing what was to become known as the “hard-boiled hat.” The hat was made of layered canvas that was steamed to impregnate it with resin, sewn together, and varnished into its molded shape. Bullard was awarded the patent in 1919. Later that year, the Navy approached Bullard with a request for some sort of head protection for its shipyard workers. The hat’s first internal suspension was added to increase its effectiveness, and the product’s use quickly spread to lumber workers, utility workers, and construction workers. By the time of the Hoover Dam’s construction in 1931, many workers were voluntarily wearing the headgear. Soon after, the Golden Gate Bridge construction provided a true test of the hard hat’s protective capability because falling rivets were one of the major dangers during the project.

Other innovations came in the form of different materials. In 1938, Bullard released the first aluminum hard hat. It was more durable and comfortable, but it conducted electricity and did not hold up well to the elements. In the ’40s, phenolic hats became available as a predecessor to fiberglass hats. Thermoplastics became the preferred material a decade later for many head protection products; it’s still used by many manufacturers today.
PPE-Hard-hats
From Left to right: Vintage Bullard Miners hats, Vintage Bullard Hard Boiled Hard Hat 1930’s (Used on the Golden Gate Bridge Project, Hard Boiled aluminum Safety hard hat w/Liner and a current day hard hat

In 1953, Bullard introduced the process of injection-molded hats. “Before, [thermoplastic] was kind of laid out on a mold. In the injection-mold process you actually have a closed mold that you pump into. It makes a more consistent helmet and a higher-quality product, which in the long run is also going to be the same thickness all the way through. It’s going to be a safer helmet,” Lloyd said.

Despite the hard hat’s effectiveness and relatively low cost, its use wasn’t officially required at most job sites until the passage of the Occupational Safety and Health Act in 1970. OSHA’s head protection standard, 1910.135, obligated employees to protect workers and instructed manufacturers and employers to turn to the American National Standards Institute’s Z89.1 standard for the appropriate usage guidelines.

Many new materials have since been created, such as the use of General Electric’s high-heat-resistant polyphthalate-carbonate resin in firefighters’ helmets. New hard hats have been designed that provide side protection, which are designated type 2 hats in ANSI Z89.1. “A hard hat was originally designed to protect if something falls from that sky and hits you in the head,” Lloyd said. “But what happens if you run into something? What happens if you bend over and something hits your helmet?”

Because hard hats are a mature market, except for the development of other materials, most innovations will be comfort features and technologies enabling them to withstand different temperature extremes, Lloyd predicted. Easier-to-use designs are appearing that allow users to adjust a hard hat’s suspension with one hand. In the last couple of years, manufacturers have come up with different types of vented helmets designed to help workers keep cool. Hats are accessorized with attachable face shields, visors, and ear muffs, and some have perspiration-absorbing liners. Some come with AM/FM radios, walkie-talkies, and camcorders.

Netting a Safe Return
Although primitive by today’s standards, the solution for the problem of falls also was addressed during construction of the Golden Gate Bridge. Three years into the construction, delays had convinced Strauss to invest more than $130,000 (these were Depression-era dollars, remember) on a vast net similar to those used in a circus. Suspended under the bridge, it extended 10 feet wider and 15 feet farther than the bridge itself. This gave workers the confidence to move quickly across the slippery steel construction. There were reports of workers being threatened with immediate dismissal if found purposely diving into the net.

Strauss’ net was heralded as a huge success until the morning of Feb. 16, 1937, when the west side of a stripping platform bearing a crew of 11 men broke free from its moorings. After tilting precariously for a moment, the other side broke free and the platform collapsed into the net, which contained two other crew members who were scraping away debris. One platform worker, Tom Casey, managed to jump and grab a bridge beam before the platform fell; he hung there until rescued. The net held the platform and the others for a few seconds before it ripped and fell into the water. Two of the 12 men who fell survived.

Read the original article here.

At Hercules SLR we provide a wide range of PPE solutions, from Lanyards and harnesses, to hard hats and rescue equipment.  We also repair, service and certify PPE equipment. We stock leading industry brands and can provide you with expert advise on your PPE options depending on your project. Call us on 1-877-461-4876 for more information.

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

A Brief History of Elevator Wire Ropes

The humble hoisting rope occupies a unique place in the history of vertical transportation. A simple hemp rope lies at the center of one of the best-known elevator stories — Elisha Graves Otis’ demonstration of his Improved Safety Device at the 1854 Crystal Palace in New York City.

Currently, a sophisticated carbon nanotube “rope” is the primary innovation driving the conceptual (and possibly literal) development of the proposed “space elevator”. However, the wire rope retains pride-of-place in elevator history as the longest-serving suspension means. It is the subject of numerous 19th-century articles that questioned its safety, and has been featured in countless contemporary books, movies and TV programs that predicate disaster on its failure. Today, we look at the introduction of wire elevator ropes in the 19th century and its development into the 20th century.

The invention of wire rope more-or-less paralleled the invention of the passenger elevator, and, by the 1870s, wire rope had become the rope of choice for elevator use. Since they were new, both the elevator and wire rope faced similar challenges regarding safety concerns. The older hemp hoisting rope had a long history of use, and its strengths and weaknesses were well known. However, a rope made of wire was an entirely different matter. This difference was effectively summarized in the June 22, 1878, issue of American Architect and Building News, which included a brief article on elevator ropes. The article expressed the primary concern in its opening sentence:

“The sudden introduction in our large cities of elevators, most of which are hung by wire ropes, has led people to wonder what will happen when they have had a year’s wear, and why there should not, after a while, be a breaking of ropes, and consequent accidents all over the country.”

The key concern centered on the endurance of wire rope and its reaction to constant and repeated bending as it passed around winding drums and over sheaves. One of the aforementioned article’s key assumptions was that “everybody knows, at least, that reiterated bending weakens wire, whether it be by granulation or by the constant extension of its fibers.” The challenge was, in spite of “knowing” that this action occurred, there was no easy way to judge when a rope was no longer safe for use.

The ICS author also addressed rope replacement, noting that “particular attention must be given to the fastenings.” The chief recommendation was to “carefully reproduce the joint as it was originally made” by the elevator manufacturer. A typical shackle used by Otis Elevator is described below in figure 1.

Figure 1: “Otis Elevator Co. Shackle,” ICS Reference Library (1902).

It consists of a split rod, the two legs A, A of which are bulged out and provided with noses at the ends. A collar B straddles the legs and eventually abuts against the noses. The rope is brought through the collar, bent over a thimble C, and passed back again through the collar, after which the free end is fastened by wrapping with wire. The wrapped end of the sections that address elevator ropes serves as a reminder that different elevator systems required different types of rope:

Chapter 1: Standard Methods and Facilities for Testing Wire Ropes
Chapter 2: Materials Composing Wire Rope and Their Properties
Chapter 3: Standard Types of Wire Rope Construction
Chapter 4: Variety of Uses of Wire Rope
Chapter 5: Mechanical Theory of Wire Rope
Chapter 6: Practical Hints and Suggestions
Chapter 7: Instructions on Ordering Wire Rope
Chapter 8: Typical Applications of Wire Rope in Practice

“When ordering rope for elevators, state whether hoisting, counterweight, or hand or valve or safety rope is wanted, also whether right or left lay is desired. The ropes used for these purposes are different and are not interchangeable.”

The diversity of elevator ropes was reflected in the design of American Steel & Wire’s standard hoisting rope, which was produced in six grades or strengths: Iron, Mild Steel, Crucible Cast Steel, Extra Strong Crucible Cast Steel, Plow Steel and Monitor Plow Steel. The company’s standard iron rope was primarily designed for use on drum machines and was “used for elevator hoisting where the strength is sufficient” (Figure 2). It was also described as “almost universally employed for counterweight ropes, except on traction elevators.” Their Mild Steel Elevator Hoisting Rope was designed “especially for traction elevators in tall buildings where, on account of [the] usual quick starting and stopping, a stronger and lighter rope is required.” Shipper or control ropes (also called tiller or hand ropes) differed from standard ropes in that they were composed of six strands of 42 wires each, which were wrapped around seven hemp cores (Figure 3).

wire rope figure 3 and 4

Figure 5: “Side Plunger Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

wire rope fig 5
Figure 5

In addition to providing detailed information on a wide variety of wire ropes, the catalog included schematic drawings that illustrated their proper application. These included 17 elevator-related drawings that depicted direct-, side- and horizontal-plunger hydraulic elevators; geared and traction electric elevators; and electric and belt-driven worm-geared elevators. The drawings’ emphasis on the application of wire ropes makes them a unique resource. Two versions of direct-plunger elevators were depicted — one with a shipper rope and one with an in-car controller — and the presence of two elevation drawings for each system permits a thorough understanding of these elevators (Figure 4). The same level of detail was provided for side-plunger hydraulic elevators (manufactured by Otis) and horizontal-plunger hydraulic systems (Figures 5 and 6).

Figure 6: “Horizontal Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913)

Figure 5
Figure 6

The electric elevator drawings are of particular interest, because, in 1913, they represented the newest systems on the market. The electric drum machine featured an interesting array of sheaves for the car and counterweight ropes, while the worm-gear machine employed a winding drum located near the midpoint of the shaft (Figures 7 and 8). The traction elevator drawing effectively illustrated its inherent simplicity and the potential of this new design (Figure 9).

The variety of elevator types illustrated in American Steel & Wire’s catalog represented the diversity of elevator systems prevalent in the early 20th century, as well as the importance of wire rope to their operation. Part Two of this article will follow this story through the 1930s, which encompasses the continued development of the traction elevator and the writing of the first elevator safety codes.

Figure 7: “Electric Drum Machine,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 7

Figure 8: “Worm Gear Electric Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

figure 8

Figure 9: “Traction Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 9

Original article can be found here at Elevator World Inc. 

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.