Acetylene’s disadvantages: highly flammable (2.5%-82% range), unstable above 15 psi, higher costs ($200/month vs. $100 for propane), and toxicity requiring $1,500 detectors.
Highly Flammable
The possibility to ignite in the air at concentrations from 2.5% to 82% in the air make acetylene one of the most dangerous industrial gases. As a highly flammable compound, it falls beyond the range for many other gases. A nitrogen atmosphere having 2% acetylene becomes more flammable than 15% gas. Such peculiarities make this chemical compound a considerable risk for any working environment in which it has to be present.
In other words, a minor leak in any welding shop would mean that within a minute, the premises could be ready to blow up. One of the revolution capacities of acetylene is its reactivity to numerous substances, transforming their degeneration into more fire-prone conditions. No wonder the Industrial Revolution saw many “acetylene explosions” at various plants. In general, the use of acetylene implies an enormous risk of explosion that can be hard to avoid given the peculiarities of modern production. It is always difficult to control the state of gas in large premises. Lack of proper ventilation can at times result in the explosion of the whole workshop.
On one occasion, a relatively small leak in one of the largest and best-protected workshops led to a highly productive explosion that ruined most of the premises and inflicted heavy injuries on numerous workers. To diminish that risk, special equipment can be installed for the purpose of measuring gas concentration. Such devices generally emit a signal when acetylene is as little as 1% in the air, which is safely beyond its lower explosive limit. The price of gas alarms is not that high, yet it is still in the thousands of dollars. Considering such costs, the proclivity to look for a safer alternative like propane would be an evident option.
Instability
One of the major difficulties associated with the use of acetylene is that the latter is incredibly unstable and may lead to decomposition and an explosive effect when stored or transported at the pressure that is higher than 15 psi. Although acetylene is a common industry gas, which is used in a variety of industries, the nature of acetylene is such that it requires storage and transportation methods that are unique for acetylene and are designed specifically with acetylene’s purpose and purpose in mind. This means that when utilizing acetylene in one’s holding or entering a contract to deliver a large quantity of acetylene to another location, one must utilize cylinders that are specifically designed to implement a method of stabilizing the acetylene that they contain. This is usually done through the use of porous materials.
The use of these porous materials may significantly increase the cost of the cylinder, as porous materials will need to be shipped to the production side where they will be mixed with acetone or another solvent and then shipped to one’s location. These specialized cylinders will have a cost of $100 to $300 for an acetylene cylinder as opposed to $50 to $150 for the standard propane cylinder. Moreover, proximity to an unstable gas that is likely to explode if the vehicle carrying the acetylene is in a collision with another vehicle or another object will lead to penalties for improperly stored or transported goods. Apart from possible legal liability for any damage caused by the explosion, the cost of fines will increase if the fine for poor transport of acetylene exceeds $10,000.
As this is a major increase to a company’s budget, transporting cylinders with unstable gas will be incredibly costly. Finally, one of the major problems with acetylene is that it has a relatively short storage life, in contrast to nitrogen, which may be stored for decades without any reducing its quality. Instead, most companies anticipate having to replace their acetylene cylinders every few years. The cost of transporting vehicle tanks with unstable gas content also raises the overall costs.
Cost
The first reason is that acetylene is much more costly compared to other fuel gases. Its price per cubic meter is usually 1.5-2 times higher compared to those of propane or natural gas. This is the case because it undergoes a relatively complex process of production and requires somewhat large costs for the special storage and transportation equipment. In simpler terms, this would mean extra money that some businesses just do not have. For example, for a small welding shop, the expense for this type of fuel is around $200 a month. If selecting propane for work, the businessman would only pay around $100. Hence, on a yearly basis, the difference would amount to about $1,200, which is quite significant in terms of net income for a small or medium enterprise.
The second reason is the maintenance cost of the equipment and accessories that are required for acetylene. It is well-known that its cylinders have to be checked and maintained regularly, which means that they will have to spend extra money. The overall counting for yearly expenses for both leak checks and regulator replacements is $500-$1,000. As for the condition with propane, this number is approximately half lower – around $300-$600 a year.
The third reason for welding shops is that acetylene is unduly hazardous gas, and therefore the businessmen will have to provide much more safety and maintenance training for their employees compared to propane. Of course, these measures cost some money as well. A shorter 1-2 day long training would cost the shop around $500-$1,000 per worker, which is twenty-five to fifty percent less of about $1,000-$2,000 offered for acetylene exposure. In the case of propane, businesses would only need to invest some $500 a year in employee training.
Another reason why various businesses avoid using acetylene as a fuel gas is that the insuring expenses of this gas are relatively high because the companies who use it often become targets of explosions and fires. As a result, the premiums of these businesses are likely to be 20-30% higher than those of the businesses that operate safer gas types. In the case of a small company, this will amount to about $2,000-$5,000 a year.
Toxicity
Acetylene is normally not very toxic but it presents great danger due to its ability to displace oxygen. If acetylene accumulates to high concentration in a closed or poorly-aired space, it can cause asphyxiation to people. Therefore, there is the need to monitor and control the dangerous working gases all the time. In the case of industrial usage of acetylene, it must be continuously monitored. The example of implementation can be a factory where acetylene is used for welding. In that case, the administration of the factory will have to acquire high-quality gas detectors to have the air quality of the working place constantly checked. The prices for a single monitor can be in the range of 500-1500 USD reflecting the quality and specification of the device. In addition, they require calibration and maintenance that can cost about 200-500 USD per device annually.
In case acetylene is used, a big investment must be made in the ventilation systems to avoid acetylene build-up due to its density and explosive mixture in the air. The price of a good ventilation installation in the working place can range from 10,000 to 50,000 USD depending on the size of the place and complexity of the system. The maintenance of such a system and the energy spent will require an additional 1,000-3,000 USD expenses annually.
Moreover, the decomposition of acetylene in the air leads to the formation of carbon monoxide and soot. The latter can be used for cancerogenic chemicals deposition. Therefore, the untrained people can emit carbon monoxide and soot in significant quantities. In addition, their gas welding resulting in less complete burning of acetylene creates big quantities of carbon monoxide. Long-term positive concentration of these chemicals is unhealthy. The workers must be regularly checked and must wear respirators when working in improperly aired places. The cost of a good respirator is about 50-300 USD per respirator and about 20-50 USD for the filter. Moreover, the workers must be regularly checked that costs about 100-300 USD per person annually.
Finally, trade unions groups of employees or else can demand trainings for employees to avoid health damage. The trainings can be expensive and can have about 1,000-2,000 USD cost per person annually. They are also required by law and their absence can have disciplinary fines up any court fines for any further employees’ health damage. An emergency scheme must be worked out and stored resulting in an expense of 500-1000 USD annual expense.