Overview
There has been a growth in use of natural gas over the past decades. It has become an integral part of many people’s lifestyles. It is used for domestic purposes for cooking, heating and also for industrial use in glass, plastics and fabric manufacturing, as a source of power etc.
The main constituent of natural gas is methane, which is very flammable and can easily cause death by suffocation. This means there is always danger of accidents happening as it is pumped from fields and transported via pipelines to the consumer. The general safety issues in onshore gas development are related to seismic exploration and production drilling which may cause environmental hazards such as noise, air emissions, spills, liquid and solid wastes etc.
Additional development, production and transportation activities which may cause explosion and fire due to pipe corrosion, well blowouts and bad air quality due to the release of toxic gases; support and ancillary operations such as the speed of response to an emergency and how well prepared the gas producer is to handle any emergency.
The above highlighted matters have led to severe distresses concerning wellbeing of the concerned parties. How do Gas Companies ensure that their employees and the public in general are protected from the stated hazards from the time the discovery of the gas is made, to transportation through pipelines and finally to the delivery points?
Facilities safety
To ensure safety of personnel and the public, the well owners should get relevant information that is known that assures the safe operation of the field. Work being done should always be under supervision of an authorised person who can start, change or stop the operations as deemed fit so as to ensure the personnel are well protected (Hotlina Basin 2007,p.6).
American petroleum Institute (API) formulated operating standards that are to be followed and applied in the gas industry in order to promote public and personnel safety. The essential safety practise is the proper training of employees in relation to their duties in order to prevent them from injuring themselves. All staff members are expected to follow strictly set standards to prevent or minimize injuries while doing production of gases (American Petroleum Institute 2001, p.5).
Workers safety
Workers assess their work zones in order to determine the kinds of hazards that are present. If the hazard cannot be reduced to acceptable levels, personal protective equipment (PPE) is used. These include; safety boots, gloves, dustcoats, overalls, respiratory protection equipment, noise PPE etc. Gas leaks should be promptly cleaned up to prevent fire hazards.
Office safety
Work areas should be free of any tripping hazards and there should be a clear access to emergency equipment, control devices and emergency shutdowns so that in case of fire along the pipelines, valves can easily be shutdown using the control device available.
Machinery and tool safety
The personnel should only be allowed to operate equipment and machines they are familiar with and all machinery should be well maintained to prevent hazards.
Electrical safety
The electrical installations used should be safe and proper grounding should be done to prevent the build-up of static electricity and lightening hazards.
Construction safety
The construction process involves drilling and setting up of the necessary equipment in order to harness the gas. Solid and liquid wastes are usually produced as a result. Therefore, proper management of the waste should be done to avoid causing an environmental hazard.
Transportation hazards
Gas produced from wells has to travel long distances to its consuming points for usage by the large gas users and also the retail or residential users. This requires an effective, efficient and elaborate transport system. The gas transportation structure are made of a set of connections of pipelines that are intended to be capably, dependably and rapidly convey it to regions where there is great demand for the product. Three major gas pipeline systems exist namely:
Gathering system
The diameter of the pipe used in this system is small (0.5 to 6 inches). These pipes are low pressured and are majorly employed in conveying raw gas to manufacturing plant from gas well.
Interstate/ intrastate system
This is the transmission network of the system. The pipe diameter ranges from 6 to 48 inches. The nation-to-nation transportation structure is employed in conveying gas across the nations or states whilst the intrastate transportation system is utilized in conveying gas within a nation. The interstate system transports the gas from the processing plant to the high demand areas. The gas is transported at high pressure thus reducing its volume and propelling it forward along the pipeline (Natural Gas Supply Association 2010, p.8).
Distribution system
The pipe diameter in this system is small like that of the gathering system. This pipe is used for supplying end users of the gas.
The main pipeline, termed as the ‘line pipe’ is made of strong carbon steel while the distribution pipes are made of advanced plastic to ensure versatility, flexibility and the simplicity and easiness in pipe replacement. Line pipes are usually coated to prevent corrosion and rusting. Regardless of this, decay on the partitions of the pipes “can occur when they are exposed to contaminants such as O2, CO2, H2S, chlorides and water” (International Finance Corporation & World Bank 2007, P.8). The combination and concentration of the given contaminants as well as the pipeline’s operating conditions such as the temperature and the velocity of the gas determine the extent and nature of the damage i.e. a certain composition of the gas under a particular operating condition may cause corrosion but not others.
Microorganisms living on the wall of the pipe may also cause corrosion. This occurs when the availability of nutrients, corrosion products, deposits and water form favourable conditions and sites for microbes’ colonization, which in turn produce organic acids, or gases creating an aggressive environment for carbon steel. According to International Finance Corporation & World Bank (2007), sulphur element or its chemical compounds “too can be metabolized by the microbes to produce corrosive products to steel or which can accelerate the corrosion of steel due to its attack”( p.9).
discovery of interior decay in a gas pipeline network is carried out by employing a smart pig, which checks the pipe “thickness, roundness, any corrosion signs, leaks or any other defect such as areas of metal loss” (National transportation Safety Board 2003, p.6).
The safety precautions, which can be undertaken to avert the problem of corrosion, include; aerial patrols of the pipeline, using detecting equipment to detect gas leaks, using pipeline markers to indicate the presence of underground pipeline, routine sampling of the gas to ensure its quality and preventive maintenance of valves and the pipeline network.
Risk assessment
“At 5.26 a.m. on Saturday, August 19, 2000, a 30-inch diameter natural gas transmission pipeline operated by El Paso Natural Gas Company ruptured adjacent to the Pecos River near Carlsbad, New Mexico”( National transportation Safety Board 2003, p.7). The released gas ignited and burnt for 55minutes. Twelve lives were lost and three automobiles damaged when concrete-decked steel that they were camping under collapsed due gas. Two neighbouring gas network piping suspension bridges were expansively smashed. According to El Paso Natural Gas Company, property and other damages or losses totalled $998,296.
Malmasi, Fam & Mohebbi (2010, p. 1) stated that ‘in order to reach sustainable development aims and decreasing harmful EHS risks, it is necessary to conduct EHS risk management studies. In order to distinguish and assess nature of risks (probability, intensity, frequency, and consequences etc.), one must choose an appropriate method’.
According to National transportation Safety Board (2003,p.8), the chief security problems in the exploration were in the plan and assembly of the pipeline network, the sufficiency of El Paso Natural Gas Company’s interior decay management program, the competence of Federal security set of laws for ordinary gas pipelines, and the capability of Federal mistake of the pipeline machinist.
The highest risk related to the pipe outburst due to the reduction of the thickness of the wall, the medium risk related to the inadequacy of the company’s control program while the lowest risk related to the inadequacy of federal safety regulations (BPA Air Quality Solutions 2007, p.4).
From the incidence, the company’s personnel took drastic measures to curb the spread of fire by switching of valves.
The following table illustrates the major hazards that occur in the field, their health impact, the risk rate and the solutions to prevent their occurrence.
Conclusion
Some of the measures to curb and control risks include decreasing frequency of occurrence, preventing and decreasing damages, rectification of damages from risk occurrence and protecting and repairing expenses. The safety of the citizens comes first and so adequate measures should be put in place to reduce hazards. Therefore, all gas production companies must ensure that all safety precaution measures are taken every time.
List of References
American Petroleum Institute, 2001, Recommended practice for occupational for onshore oil and gas production operation, Wiley, Washington, D.C.
BPA Air Quality Solutions, 2007, “Research industrial accidents- methane and natural gas: Industrial accidents involving natural and methane gas, “Air Quality Solutions Journal, vol.2, no1, pp.1-10.
Hotlina Basin, 2007, “Specific issues related to geophysical hazards and gas transportation,” Final Best Interests Finding, vol. 23, no.7, pp.1-7.
International Finance Corporation & World Bank,2007, Environmental, health, and safety guidelines: onshore oil and gas development, Prentice Hall, New York.
Malmasi, S, Fam, I & Mohebbi, N 2010, ‘Health, Safety and Environment Risk Assessment in Gas Pipelines,’ Journal of Scientific& Industrial Research, vol.69, no.2, pp 662-666.
National Transportation Safety Board, 2003, Natural Gas Pipeline Rupture and Fire near Carlsbad, New Mexico, August 19, 2000. Pipeline Accident Report, Wiley, Washington, D.C.
Natural Gas Supply Association, 2010, The transportation of natural gas, Prentice Hall, New York.