Grantville Gazette, Volume VIII Page 24
There are modern safety glasses in Grantville; for example, in Nat Davis' machine shop. (Cresswell and Washburn, When the Chips are Down, ROF1). These will be used when the down-time equivalents just aren't safe enough, and they will also come in handy as "gold standards" for testing purposes.
There is one other approach to eye protection that I need to mention: the reflective coating. The disadvantage of absorbing light is that the energy is converted to heat, which can crack the glass. So why not silver the surface of the glass, using a coating that is just the right thickness to reduce the light to tolerable levels, while permitting the workpiece to be seen? Well, it sounds good in theory. In practice, it may be difficult to control the thickness of the film, and then to protect it from abrasion and chemical reaction. Another problem is a phenomenon called the "ultraviolet transparency of metals"; in essence, metals which reflect visible light may be quite transparent to ultraviolet light.
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Nose/Lung Protection. Many industrial processes result in the emission of gases or dusts which it is dangerous to breathe in. The final line of defense against these threats is the personal respirator. One type purifies the air; the other supplies breathable air. It may be self-contained (like SCUBA for divers), or hooked up to a fixed reservoir.
Respirators will have a tight-fitting "face-piece" which at least covers the mouth and nose (quarter-mask), and may reach under the chin (half-mask) and even up to the hairline (full-facepiece). The facepiece needs to be impervious to vapors, and, if it covers the eyes, also have a "window" to see through. Modern facepieces are usually made of rubber, plastic or silicone. However, in the 1632 universe, we may need to make do with leather, or some kind of coated cloth.
Respirators intended to fend off dust will have some kind of particulate filter. Absolute protection is provided if the pores are smaller than the particles. But there's a trade off here; the smaller the pores, the less the airflow, and the more trouble it is to breathe. Most respirator filters trap particles by forcing them onto convoluted paths, on which they collide with fibers, or just settle on to them. Filters can be electrically charged to help them capture particles with the opposite charge. The most common particulate filter is a disk of "random laid, non-woven fiber material." In essence, a felt (which people have made since 6,500 BC).
Protecting against dangerous gases is trickier. The respirator needs to provide a purifying agent, which can be an adsorbent or a neutralizing agent. The most common adsorbent in current use is activated charcoal. Encyclopedia Americana says that it is "produced by heating animal bones or certain types of vegetable charcoal to temperatures of 800 to 900 oC (1470-1650 oF) in steam or carbon dioxide. This treatment results in the formation of a highly developed internal pore structure with a very large surface area...." It is usually granulated. Other adsorbents include fuller's earth (a clay), activated alumina and silica gel.
The adsorbents can be chemically treated to increase their affinity for particular gases, for example, iodine treatment to remove mercury vapor. This is not likely to be discussed much in the encyclopedias and textbooks, but it may be mentioned in the manual for a particular respirator which contains such an adsorbent.
Neutralizing agents are specific to a particular chemical threat. For example, if the worker is going to be exposed to acid gases, the respirator can be charged with sodium or potassium hydroxide, perhaps combined with lime to increase absorption.
The respirator can also provide a catalyst. Hopcalite is "a mixture of porous granules of manganese and copper oxides which speeds up the reaction between toxic carbon monoxide and oxygen to form carbon dioxide."
The protective agent can be stored in a small cartridge, mounted directly on the facepiece, or in a larger cannister, connected to the facepiece by a tube. Cannisters can be chin-, front- or back-mounted. The higher the concentration of the gas, the more likely it is that you will need a cannister-based design.
I am not going to review air-purifying respirators, other than to say that it is in Canon that there are people with SCUBA apparatus (1633, Chaps. 29, 34).
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Skin Protection. Skin may need to be protected against points and edges, flying debris, chemicals (liquid and gaseous), heat or cold.
The hands are usually the most vulnerable part of the body, since they are operating machinery or manipulating the workpieces. Gloves, mitts and the like have been used since time immemorial. To guard against slashes and punctures, chainmail comes in handy, and of course chainmail manufacture is a well-established trade in the 1630s. If you need to prevent burns or frostbite, then you need an insulated glove. Basic oven mitts and pads are readily available in Grantville. and can be copied. The most problematic threats are the chemical ones, for which the modern worker would prefer a latex glove.
Other parts of the body can also be vulnerable, and hence there will be a demand for aprons, hoods, and so forth.
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Foot protection. Safety boots have a steel "toe", as that's where you're most likely to drop a workpiece. Soles will at least be skid-resistant, and may contain steel to protect against puncture. For particular industries, it may be important that the boots are impervious to chemicals, or electrically insulating.
The safety boots are likely to be made, initially, of leather, although I expect that rubber would be preferred. Curiously, the 1911 EB says that wooden clogs were preferred by agricultural and forest laborers, dyers, bleachers, tanners, and workers in sugar factories, chemical works, provision packing warehouses, etc.
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Heat protection. Heat protection can take a number of forms, such as aluminized or asbestos clothing. Asbestos, of course, presents its own hazards, and aluminum is hard to come by. We will probably be making do with wool, possibly wetted down.
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Fall protection. "Schwarza Falls" also mentioned the use of "safety ropes" to arrest a fall. Some up-timers should be familiar with modern safety harnesses for building construction and maintenance.
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Miscellaneous. Just in case you need to be rescued, it's prudent to be wearing conspicuous clothing. In "Schwarza Falls", guard officer Franz Saalfelder reported that each of the three up-timers he met on May 19, 1631 (Julian) was wearing "a yellow helmet and an orange vest; the orange color was unnaturally bright."
Summary Table
The following table summarizes typical hazards and the corresponding safeguards.
Hazard
Safeguards
dust and noxious gases
dust control in machinery design, isolation of dusty or gas-producing processes, air filtration or neutralization, ventilation, respiratory protection
heat and cold
shielding of radiant sources, insulation, protective clothing, air conditioning, air douche, enforced rest in refuge
Light
baffles, filter windows, goggles, eye rest
Vibration
static and dynamic balancing of equipment; operation outside of resonance regions; frictional and viscous damping; elastic connections; shock absorbing soles
Noise
reducing noise generation; soundproofing; ear protection
electricity
guards to allow inspection without contact; emergency disconnects; first aid training; low voltage systems; distancing of naked conductors; insulation; grounding; protective equipment (dielectric gloves and boots; insulating tongs, mats); lightning protection
pressure vessels
inspection; pressure and temperature gauges; safety valve;
Fire
fire drills; fire fighters; access road to buildings; water supply; fire-resistant structures (overall and fire stops); fire exits and refuges; fire extinguisher; sprinkler systems
machinery
guards; interlocks; safety catches; screens; ergonomic controls; grounding; chip/dust collection and disposal; limits on required force; hoists; hand signals
Special Hazards
; There are a number of industries which are prominent in the 1632 universe and which present special hazards which deserve discussion.
Mining Safety
The subject of mine safety was briefly addressed in Laura Runkle's Mente et Malleo (GG2): "By 1632, there had already been several notable mining disasters. Usually the resulting [safety] rules did not involve the safety of individual miners, but rather the safety of the whole mine—drainage, ventilation, and the placement of tunnels and shafts."
There is no doubt that this is an issue on which the Grantville miners will have a lot to say. They also have firsthand experience with uptime mine safety equipment. Grantville even has a resident mine safety engineer, Ron Koch. (DeMarce, Rudolstadt Colloquy, GG1).
Despite that expertise, by January 1635, the Grantville coal mining fraternity had already experienced its first post-RoF mine disaster. See Mark Huston, "Twenty-eight Men" (Grantville Gazette volume 10).
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In seventeenth century mining, the principal threats to life would have been rock falls, and methane and coal dust explosions.
Inadequate lighting, ventilation, and temperature, noise and dust control would also have resulted in accidents and chronic health problems.
Room-and-pillar mining, in which pillars of rock are left standing to support the roof, is very old, and there would also be artificial roof supports. However, in the seventeenth century these supports would still have been made of wood, and there was no scientific method of determining the spacing or diameter of the supports. Modern miners use machines to place bolts into the roofs.
The most primitive method of detecting carbon dioxide was to take a canary underground. If the canary suffocated, it meant that ventilation was inadequate.
Ventilation initially was simply provided by (if you were lucky) digging ventilation holes. Later, furnaces were used to heat air and generate a draft. Still later fans were introduced, both above and below ground, but bear in mind that improved ventilation was not completely a blessing because the increased air movement could stir up coal dust.
Safety lamps were introduced in 1815. They were used, not just to provide light, but to detect the presence of methane (which would cause the lamp to burn brighter). However, they could cause an explosion, rather than forestall one, if the miners disassembled the lamp, removing the protective wire mesh surrounding the flame.
Primitive black powder explosives were replaced by more stable ones such as dynamite (remember, Nobel thought he was benefiting mankind).
Mines have also introduced fireproof ropes, "escape capsules," and "self-rescuers." The latter can convert carbon monoxide to carbon dioxide, or supply oxygen.
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In Grantville, coal mining will continue to make heavy reliance on powered equipment, but operations elsewhere will be manual for some time to come, and hence will have a somewhat different spectrum of accident causes. Nonetheless, it is worth reviewing late twentieth century accident statistics.
According to the Mine Safety and Health Administration statistics for 1986-95, in coal mining, fatal injuries occurred when using or operating tools or machinery (27.6%), constructing, repairing or cleaning (23.7%), during vehicle/transportation operations (19%), while handling materials (11%); or during other activities (18.8%) (Table 4-4). The death was most often the result of fall of ground (31.7%), followed by powered haulage (23.1%), machinery (16.6%), electrical (8.2%); ignition/explosion of gas or dust (6.1%).
The leading cause of fatal injuries in modern coal mining is "fall of ground" (31.7% in 1986-95). In 1996-98, roof, rib and face falls resulted in nearly half of the underground fatalities. "Ground control" includes testing roof rock quality and providing adequate roof support, escape paths, signage so miners don't wander into areas of unsupported roof, and fall warning devices. Small falls also cause nonfatal injuries, which can be mitigated by personal "bolter screens."
Pillar recovery (taking out support pillars of rock as you retreat out of the mine, allowing the roof to collapse behind you) is particularly dangerous.
The second most important cause of coal mine fatalities is "powered haulage" (23.1%), the horizontal transport of workers, coal, supplies and waste by a variety of vehicles. Accidents can occur during entry, exit, operation or maintenance. Miners can be run over or pinned by the equipment.
Machinery poses the third biggest threat to life (16.6%). The risks, and preventatives, are those typical of factory machinery.
In fourth place, we have electrical (8.2%). Almost half of the electrocution deaths occur during maintenance and repair. Overhead power lines have been involved in many electrical accidents involving mobile mining equipment. Precautions could include some kind of power line proximity warning system, and simple methods of disconnecting all electrical circuits within an electrical enclosure.
While ignition or explosion of gas or dust is the cause of death most likely to result in coverage on the national news, it ranked only in fifth place (6.1%) according to the cold statistics. In part, its media prominence is because these incidents can result in multiple fatalities. It was the 1951 explosion at Orient No. 2, in West Frankfort, Illinois, that prompted the enactment of the Federal Coal Mine Safety Act.
The dangers are controlled by gas and dust monitoring, ventilating the mine to remove gas and dust, adding rock dust to inert the coal dust, eliminating ignition sources, isolating worked-out areas with seals, and placing barriers where they can intercept a blast.
The remaining causes of fatal injuries include explosives/breaking agents (2.9%), falling/rolling/sliding material (2.9%), and slip or fall of person (2%) (with 6.3% unclassified) (IIAHE, Table 4-5 and Figure 4A-4). The unclassified causes would have included exploding pressure vessels, fires not otherwise accounted for, hand tools, hoisting equipment, failure of an impoundment, and inundation.
The leading causes of nonfatal injuries were handling materials, slips/falls, and hand tools.
Coal miners are exposed to respirable dust, machinery noise, and other stresses. Not surprisingly, they suffer a variety of chronic illnesses, including coal workers' pneumoconiosis (66%), hearing loss (20%), repetitive trauma (7%), and heart attack (2%) (IIAHE Fig. 5-1).
Chemical Plants
By December 1633 post-RoF, Magdeburg had a coal gas plant. There, coal was cooked in a furnace, producing coke, coal gas and a residue. Unlike coal, coke can be burnt with little smoke, making it useful for railroads. It also is used as a fuel and reducing agent in the blast furnaces of steel plants. The coal gas was burnt in Magdeburg as a fuel and illuminant. The residue (loosely speaking, "coal tar") can be separated into pitch, light benzoils, and other hydrocarbon fractions.
In Chapter 2 of Eric Flint's 1634: The Baltic War, a grate was imprudently removed from the coal chute, the gas main leading out of the coal gas plant got blocked by tar and coal dust, gas backed up into the furnace, and the coal in the furnace caught fire (as opposed to being merely charred to form coke).
The fire brigade sprayed water onto the smokestacks, trying to bring down the temperature and put out the fire. In retrospect, this was not a good idea. The water dissolved the firebrick in the reverberatory furnace, and reacted with the coal to form hydrogen and carbon monoxide. Air mixed with the coal gas, too. The result was a double explosion. Actually, a triple one; once the fire reached a shed used to store fertilizer — ammonium nitrate.
Even without an explosion, working with coke ovens can be dangerous. Because the coal is heated to at least 2000 degrees F, coke oven workers must be concerned about heat stress. The coking operation should be a closed system, but a leak can occur, exposing the operators to various noxious dusts and gases — some of which also are flammable.
The coal gas plant explosion in Magdeburg was probably the most dramatic chemical plant accident in canon, but it is not the only one. Hydrofluoric acid — possibly the nastiest of the commonplace industrial chemicals — got on the skin of one of Dr. Phil's laborants, resulting in the emergency amputati
on of an arm. See Kerryn Offord, "Dr. Phil's Family" (Grantville Gazette, Volume 10).
The number of different chemicals which might be manufactured in the USE is enormous. Hence, this discussion will be a general one.
Chemical raw materials are usually supplied as powders or liquids. The powders have to be transported to the plant in containers which minimize leakage. The containers may need to be sealed to keep out air, or even filled with nitrogen or carbon dioxide.
The contents of the individual containers must be transferred to a storage silo, and from there, to the reactor. These transfers should be performed, as much as possible, in closed systems, because each open transfer is an opportunity for release of dust. In addition, there can be a static charge buildup, which creates a risk of fire or explosion.
The preferred transfer mechanism is probably pneumatic. If that is beyond the technological capacity, then we will want to at least provide local ventilation.
Liquids will also be delivered to the plant. The most common ones are solvents (acetone, toluene, methylene chloride, isopropyl alchohol) and mineral acids (hydrochloric acid, sulfuric acid, nitric acid). The liquids will be directed into storage tanks and subsequently to the reactor.
Again, a closed system is desirable, to minimize vapor release. Ideally, the transfers are by permanent, hard-piped lines. If the operation is not of at a scale which favors dedicated lines, and pipes must be moved around depending on the chemical being produced, then there will be an opportunity for chemical release whenever lines are disconnected or reconnected.
Obviously, it is important to maintain the lines to ensure that leaks don't develop. Also, piping connections can be shielded with jackets for further protection.
Storage tanks are preferably above ground, to make it easier to inspect them, and should have some kind of leak detector. Liquid chemicals can be transferred into the reactor by some kind of pump. A steam ejector can be used to create a vacuum in the reactor to suck in the chemical.