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Protect Your Workers from Gas

Published: 07th Nov 2012

It is a well known fact that oil and gas resources are a huge part of the world economy. What may not be as well known are the dangers that come along with working in this industry.

It is the largest industrial source of emissions for hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) that both may contribute to health problems.

Such hazards lurk in the world's oil and gas reserves, which are concentrated in a small number of geographic regions around the globe. The region that dominates the world's oil production is the Middle East. Of the world's 20 largest oil deposits, 13 are in the Middle East, with five deposits alone in Saudi Arabia, including the Ghawar field, the largest deposit in the world.

These five countries - Saudi Arabia, Iran, the United Arab Emirates, Iraq and Kuwait - each produce more than two million barrels per day, contributing by far the largest proportion of regional production. Given the extent of its known reserves, the dominating status of the Middle East seems likely to intensify as this region alone represents more than 50% of known oil reserves and 40% of gas reserves.

These are big numbers, and even bigger are the numbers dealing with the hundreds of thousands of people employed by this industry - all of which are at risk of several potential hazards that are present in the workplace every day.

Since oil and gas industry processes involve the use and manufacture of highly dangerous substances, the occasional escape of toxic and combustible gases inevitably occurs, creating a need for gas detection systems for flammable, toxic, and Oxygen gases to lower the potential hazards to the industrial plant, its employees, and people living nearby.

The large amount of highly flammable Hydrocarbon gases involved is a serious explosive risk, and additional toxic gases, such as Hydrogen Sulphide, are often present.

With the several upstream activities that the oil and gas industry performs, from the on and offshore exploration and production to the transportation, storage, and refining of oil and gas, here are some typical areas in the industry that require proper training and air monitoring:

• Exploration drillings rig

• Production platform

• Onshore oil and gas terminal

• Refineries

From respiratory issues to explosive risk, worldwide incidents involving asphyxiation, explosions, and loss of life are a constant reminder of how dangerous gas leaks can be, and an understanding of such hazards and how to control, contain, and minimise risk through gas detection is crucial for the safety and health of all oil and gas workers.

Types of risks

Given its dangerous nature, as well as the amount of people employed in this sector, there is a high potential for some kind of gas-related accident to occur at an oil and gas drilling or production site. The presence of toxic gases in or around oil production activities may result from leaks in piping that vent toxic byproducts of a manufacturing process, a biological or chemical process from material stored within a confined space, or from toxic gases expelled during a maintenance operation.

Here is a list of several activities that have the potential to release harmful gases into the atmosphere, thereby putting workers at risk:

• Drilling accidents

• Improper construction and maintenance

• Pipeline transportation accidents

• Storage problems, including contamination

• Confined spaces

Numerous kinds of toxic gases are known to cause death in workers in the oil and gas industry, which can include carbon monoxide, hydrogen cyanide, hydrogen sulphide, arsine, chlorine, oxides of nitrogen and ammonia.

This is because the raw materials are a mixture of hydrocarbons and chemicals, some of which may be altered by a process. For example, crude oil is separated into many materials using processes referred to as fractionation, or fractional distillation, which are further converted using processes such as ‘cracking’ or ‘catalytic reforming’.

Gas hazards are therefore likely to be represented by many substances. There are three main types of gas hazard:

1. Flammable - Risk of fire and/or explosion; examples are Hydrocarbon gases Methane, Butane, Propane gases

2. Toxic - Risk of Poisoning; examples are Carbon Monoxide, Hydrogen, Hydrogen Sulphide, Carbon Dioxide, Chlorine 3. Asphyxiant - Risk of suffocation, such as Oxygen deficiency. Oxygen can be consumed or displaced by another gas

Flammable gas risk

Working in environments with the potential for a hazardous gas leak leads to a possible ignition, which leads to an explosive risk. An ignition source, typically a spark, flames, or hot surface mixed with Oxygen and the toxic gas could cause a chemical reaction.

The power of the explosion depends on the gas and its concentration in the atmosphere, and for ignition to take place, the concentration of gas in the air must be at such a level to react?chemically with the Oxygen. Not all concentrations of flammable gas or vapour in air will burn or explode.

Flammable gas detection equipment is generally designed to provide a warning of flammable risks before the gas reaches its lower explosive limit (LEL), with the first alarm level typically being set at 20% LEL, and the second stage alarm at 40-60% LEL.

Lower explosive limit levels for gases and vapours in the workplace can be defined in various international standards, with the original long established standards being measured using a static concentration of gas.

More recent European and international standards list LEL levels measured using a stirred gas mixture, as some substances are more volatile when in motion and represent an explosive risk at lower concentrations than indicated on previous ‘static’ tests.

The LEL is the lowest concentration of gas in the air that will burn. The long established LEL is 5% by volume in the air for most flammable gases, although the ‘new’ LEL recognised in Europe and other territories is 4.4% LEL, and calibration practises have been changed accordingly. This low volume of LEL means that there is a high risk of explosion even when relatively small concentrations of gas or vapour escape into the atmosphere.

Toxic gas risk

Toxic gas causes death by other mechanisms, such as competing with Oxygen on the cellular level or directly damaging the respiratory system. Under many circumstances, the gases and vapours released from oil, gas and petrochemical processing activities can have harmful effects on the workers exposed to them.

Whether it be inhalation, being absorbed through the skin, or swallowed, people exposed to harmful substances may develop illnesses such as cancer many years after the first exposure. Many toxic substances are dangerous to health in low ‘ppm’ (parts per million) or even ppb (part per billion) concentrations.

Asphyxiant (Oxygen deficiency) hazard

Since air is made up of several different gases including Oxygen, asphyxiant gas is a nontoxic or minimally toxic gas which reduces or displaces the normal Oxygen concentration in breathing air, and is normally not hazardous.

A hazard exists only where elevated concentrations of asphyxiant gases displace the normal Oxygen concentration. For air to be considered normal ambient air, it must contain an Oxygen concentration by volume of 20.9%, and when the Oxygen level dips below the 19.5% by volume mark, the air is considered Oxygen deficient. Oxygen concentrations by volume that fall below 16% are considered unsafe for humans. Breathing Oxygen depleted air can lead to death by suffocation. Because asphyxiant gases are relatively inert and odourless, their presence in high concentration may not be noticed until the effects of elevated blood carbon dioxide are recognised by the body.

Why air monitoring?

Air monitoring is essential for these large oil and gas production facilities, not only to keep their productivity levels high, but also to make the work environment a safer place and to save the lives of their workers.

Air monitoring systems take samples to capture the contaminant from a known volume of air, measuring the amount of contaminant captured, and expressing it as a concentration.

Because of air monitoring and gas detection systems, there has been irrefutable evidence of serious threats?to human health from air pollutants emitted during oil and natural gas production, including sulphur dioxide, nitrogen oxide, and volatile organic compounds (VOCs), including air toxins such as benzene and formaldehyde, as well as increasing levels of ozone and particulate matter.

These pollutants can worsen asthma, cause heart attacks, and harm the circulatory, respiratory, nervous, and other essential and vital life systems, and are also linked to cancer, developmental disorders, and even premature death. Without the use of specialised gas meters and detection systems, some toxic gases, like the examples listed previously, may not be detectable until damage has already been done. For example, high concentrations of hydrogen sulphide can cause paralysis of the olfactory system, rendering the victim unable to smell the gas, which can lead to disorientation, respiratory failure, loss of consciousness and even death.

Training is essential

Even though operators, technicians and safety personnel in the oil, gas, and petrochemical industries have a good understanding of flammable and toxic gas hazards, providing continuous training and refreshment of knowledge to both new and current employees is essential to avoid potential incidents. Both operational responses, in the event of an alarm, and emergency responses that try to limit the spread or the effect of gas that has already escaped, must be covered in the training to workers in hazardous industries like oil and gas.

Along with the several training programmes that are available for the design, installation and operation of gas detectors, employees must also get general training on how to work in their specific hazardous environment, as well as an understanding of what to do in an emergency, such as how to avoid asphyxiation if there is a leak, injuries from explosion of fire, or skin damage due to toxicity.

Proper and consistent training will help keep companies’ workplaces safer and more productive, especially for new personnel who are often assigned work activities in potentially hazardous areas with only very limited training about gas hazards and the use of gas detection equipment.

Factors to consider in monitoring air

1. Climate - When looking at air monitoring stations for use in the Middle East, you have to consider the climate, as it is generally hotter and more humid when compared to other areas of the world. A common disruption to the air quality monitoring are dust and sandstorms in the central and desert regions, which has led to the need for developing power efficient, highly insulated, storm proof air quality stations. Changes in temperature and humidity also affect instrument performance, especially carbon monoxide and ammonia analysers. For this reason, instruments working in this climate need to be installed in well designed and properly insulated shelters, with air conditioning customised to that particular location’s climatic conditions.

2. Standards - One of the best and most consistent ways to measure air pollution is to do so with either the US Environmental Protection Agency (US EPA) or European Norms (EN) approved analysers that would be installed in an air conditioned monitoring shelter (operated in accordance with US EPA/EN guidelines). Most countries’ air quality standards are based on international standards, such as the World Health Organization (WHO), the European Union, or the US EPA, which specify a maximum one hour concentration for a particular criteria gas, such as CO, O3, NO2 and SO2. In order to provide a high level of confidence in the measurement of these gases, monitoring procedures based on either EN or US EPA should be adopted. These procedures detail how an air quality monitoring system should be operated, maintained and calibrated. An analyser with demonstrated approval from any of these organisations can then be used with confidence providing good operation, maintenance and calibration procedures are employed.

3. Calibrating your Instruments - To receive more accurate and traceable results, calibrating your instruments for air monitoring is a very important step and is best performed when using one or more cylinders of calibration gas, a dilution calibrator, and a zero air generator. This setup allows for automatic daily zero and span calibration checks to be performed, as well as full off-site multipoint calibrations if needed, that can eliminate some of the inconsistencies and problems associated with calibration using internal permeation tubes.

Location and Operating Details - Other factors that should be taken into account are the site selection, proper selection of monitoring shelters to suit the local climate, suitable design of sample manifolds, and the use of traceable calibration gas for these analysers. Operation, calibration, maintenance, data collection and reporting procedures are also of critical importance in order to obtain data which can be relied upon by environmental authorities and the local community.

The monitoring of air quality is very important to the health of people within any community; even more so to industry workers who are potentially exposed to harmful gases every day. Monitoring the air in the Middle Eastern oil and gas refineries and plants is essential to understand the risk of what workers may face and already are facing on the job.

Because of the several upstream activities that the oil and gas industry performs, it is inevitable that the occasional escape of toxic and combustible gases from the on and offshore exploration and production, transportation, storage, and refining of oil and gas will occur, creating a need for gas detection systems and training to lower the potential hazards to the industrial plant, its employees, and people living nearby.

Published: 07th Nov 2012 in Health and Safety Middle East

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