When talking about ambient gas measurements, the first thing that comes to mind is occupational health and safety maintenance. It is one of the most important issues in terms of work and health. Occupational safety is among the series of measures to be taken in order not to allow employees to suffer work accidents and to create a safe working environment. In parallel with the industrialization and technological developments in our country and in the world, some problems arise regarding the safety of employees at workplaces. For these problems, necessary measures should be taken before they arise and workplaces should be made safe.
In the workplace, during the execution of the work, some gases may be released to the environment due to the process. If there is no effective ventilation system in order to prevent the spreading of gases, it is necessary to measure and monitor the gases in the workplace ambient air in order to prevent work accidents and occupational diseases in such workplaces.
This problem is present in establishments, foundries and all other workplaces where paint and welding work is usually carried out.
For this purpose, gas measurements are carried out by our experts in the workplace. The results are evaluated and the measures to be taken are reported to the workplaces.
The aim of occupational safety studies is to protect the employees from the negative effects of the working environment, to create a healthy working environment for the employees, to ensure the best possible harmony between the work done and the employees, to completely eliminate the possible dangers in the workplace or to minimize the possible effects, to prevent the material and moral damages that will arise and to increase the working efficiency as a result of all these. Taking necessary measurements in order to ensure occupational health and safety is an important measure. In this context, with the gas measurements made in the environment, it is aimed to prevent the hazards and occupational diseases that will arise from exposure to chemicals in the working environment. In order to take the necessary precautions against the risks arising from chemical substances, the ambient gas measurements are an important issue in terms of occupational health and safety.
Our company performs ambient gas measurements within the scope of gas measurements. In these studies, the relevant legal regulations, standards and test methods published by domestic and foreign organizations are complied with. These standards are based on a few standards:
- TS EN 689 Workplace air - Guidelines for the comparison of exposure to inhaled chemicals with limit values and evaluation of the measurement strategy
- TS EN 45544-1 Workplace air - Electrical devices for the direct detection and concentration of toxic gases and vapors - Part 1: General rules and test methods
- TS EN 45544-2 ... Part 2: Performance requirements for devices used for exposure measurements
- TS EN 45544-3 ... Part 3: Performance requirements for general gas detection devices
In Occupational Hygiene Measurements, Gas Measurement is an important issue in terms of occupational health and safety in order to prevent occupational diseases that may occur by exposure to chemical substances and to take necessary precautions against risks arising from chemical substances.
Material safety forms (MSDS) of the chemicals used in the workplace gas measurement departments should be examined and the possible possible gases should be determined correctly.
In Gas Measurement, the limit values for some chemicals are given in the Occupational Health and Safety Regulation.
Lead: ISGT. Article 61 / 7 Lead amount shall be determined periodically by taking samples from workplace air and this amount shall not exceed 0, 15 milligram / cubic meter.
Mercury: ISGT. Substance 62 / 3 Periodically, samples shall be taken from workplace air to determine the level of mercury and ensure that this level does not rise above 0, 075 milligram / cubic meter.
Arsenic: ISGT. Article 63 / 3 Periodic emission of sample fumes from ambient air at arsenic-treated locations to ambient air shall be prevented. A suitable aspiration system shall be installed on the edges of the coating tanks close to the liquid level, and the amount of cadmium in the ambient air shall not exceed 0, 1 milligram / cubic meter.
Beryllium: ISGT. Article 69 / 1 In workplaces where beryllium and its compounds are used, with appropriate ventilation, an appropriate aspiration system shall be installed and the amount of beryllium (2) shall not exceed milligram / cubic meter in this workplace air.
Benzene: ISGT. Article 71 / 5 In workplaces with benzene, the concentration of benzene in the air shall not exceed 20 per million by volume. In workplaces that have to work with a higher concentration of benzene, workers will be provided with appropriate air masks, where liquid benzene is used, and protective equipment such as special shoes, gloves and special work clothes.
Carbon Sulfur: ISGT. Article 74 / 2 In places where carbon sulphide is used, together with general ventilation, an appropriate aspiration system shall be installed, the works shall be in a closed system and the amount of carbon sulphide in the workplace air shall in no way exceed 20 PPM or 60 milligram / cubic meter.
Sulfur hydrogen: ISGT. Substance 72 / 2 The amount of sulfurous hydrogen in the workplace air shall not exceed 20 per million.
Dangers Encountered in Limited-Closed Area Works such as Wells, Sewers, Tunnels, Silos, Mines
Confined Space
Work area is designed to be large enough, not designed as a continuous working area, with limited clearance for entry and exit (warehouse, silo, sewer, tunnel, etc.) areas are 1-5.
Hazards in Limited Field Studies
Hazards / risks encountered in these areas can be grouped under two main headings:
Atmospheric hazards relate to respiratory air content in the work area.
2) Physical hazards relate to tools and situations encountered in the work environment.
Atmospheric Hazards
Inadequate or lack of ventilation system in limited field works reduces the atmospheric composition of the environment below the vital limit. Degradation of natural substances, biological activities, oxidation, percolation of vapors and structural leaks lead to the formation and accumulation of toxic and / or flammable gases in the environment. As a result of these processes, the amount of oxygen required in the working atmosphere is exhausted considerably. Workers working in the environment are contaminated with harmful gases, or in most of the oxygen, unconscious drowsiness and death without understanding what is happening. The most important rule in limited field studies may not immediately feel that our body senses are depleted. Since many toxic gases are colorless and odorless, they cannot be detected by the senses. One of the deaths encountered in this case is not to act with confidence. Once the reliability of the working environment has been determined using the appropriate measuring and monitoring devices, the closed area to be studied must be entered1-5.
1.1. Oxygen deficiency / excess
Without adequate oxygen in the breathing air, vital activities cannot be sustained. In limited working areas, the depletion of oxygen in the atmosphere occurs as a result of the development of aerobic bacteria, oxidation of metals, combustion and displacement with other gases. Conversely, the amount of oxygen present in the breathing air may be higher than it should be. An excess of oxygen in the respiratory air creates an explosive atmosphere or accelerates chemical reactions. The amount of oxygen in the respiratory air must be a maximum of 20.9-23.5%, and a minimum of 19.5% 1-5.
1.2. Toxic gases
In limited work areas, a variety of toxic gases with varying sources and physical characteristics can be found. We can divide these into two groups according to their effects on humans: asphyxans (simple asphyxans, chemical asphyxans) and irritants6,7.
The concentration, pH, particle size, solubility in water, contact time of the person with the toxic substance, and whether the medium is open or closed are important in determining the first pathological response to occur. Age, smoking habit, respiratory system or other organ disease, the use of devices such as protective masks, whether the person is the main characteristics of the individual determining the course of the disease. Small particles inhaled by air are mainly deposited in the airways by impaction and sedimentation. This increases in particular with particle size and velocity, and decreases with increasing airway diameter. Brown particles are important for 1 µm and smaller particles. Large particles with a diameter of 15-20 µm tend to accumulate in the nose, smaller ones in the trachea and bronchi and those between 0.5-7 µm tend to accumulate at the alveolar level. Almost half of very small particles, approximately 0.1 µm in size, are stored in the alveoli. Liquid suspensions can be absorbed as gas when they evaporate. Gas molecules can diffuse directly from the airways 8.
Inhaled toxic substances; they may initiate an inflammatory response by direct irritation, whereas simple asphyxan substances, although inert, may form asphyxia by substituting oxygen in the atmosphere, produce asphyxia chemically, enter the bloodstream and create a systemic toxic effect. The harmful effects of asphyxia-forming gases depend on concentration, contact time and ventilation. If the oxygen content in the respiratory air is sufficient, it has little or no physiological effects. They are not irritating to the respiratory tract, nor are they systemically toxic. Clinical symptoms occur when the oxygen concentration in the air is below 15% and death occurs at rates below 6-10%. Gases such as methane, ethane, acetylene, hydrogen, nitrogen, argon, neon, carbon dioxide form asphyxia by reducing the oxygen content in the air. Such asphyxia stories may be the result of long periods of confined space, such as quarries, wells, silos, ship hatches. However, the presence of a more complex lung injury cannot be ruled out, as non-inert materials may also be present in such spaces (such as nitrogen dioxide in silos, sulfur hydrogen in sewers and mines).
1.2.1. Gases forming asphyxia
A) Gases forming asphyxia of environmental type
Carbon dioxide
Carbon dioxide is a colorless, odorless gas that is heavier than air formed by the complete combustion of carbonaceous substances. Because it is heavier than air, it is collected in mines, ships, old wells, sewers and garbage dumps. % 10 Toxic effect is observed by inhalation of CO2. % 25-30 Inhalation of CO2 leads to respiratory retardation, drop in blood pressure, anesthesia and death. The cause of death is pulmonary edema and hemorrhage.
Carbonmonoxide Poisoning (Acute)
After 20% of hemoglobin converts to CO-Hb, the symptoms gradually increase:
- headache
- dizziness
- nausea, vomiting,
- tachycardia and elevated blood pressure,
- sometimes pectanginous complaints,
- tinnitus,
- thoughtfulness,
- general exhaustion,
- Apathy,
- sometimes muscle muscles,
- cherry red color on the skin,
- loss of consciousness (% 50 CO-Hb formation),
- Death (% 60-70 CO-Hb formation)
hydrocarbons
Among the hydrocarbons, high concentrations of short-chain aliphatic hydrocarbons such as methane, ethane in the environment can lead to death by asphyxia. Aliphatic, alicyclic and aromatic hydrocarbons have similar effects to anesthetics, and when inhaled at toxic levels, they cause narcotic symptoms such as headache, dizziness and nausea. As other volatile anesthetics, myocardial sensitivity to catecholamines can increase and cardiac rhythm disturbances may occur. Aliphatic hydrocarbons have chemical toxic effects (polyneuropathy, cancer, etc.) as well as irritant effects on respiratory mucosa.
Acetylene, hydrogen, nitrogen, argon, neon
If acetylene cylinders used in welding and as illumination gas remain open indoors or if calcium carbide (carbide) mixes with water, the rate of acetylene gas may rise to dangerous levels and cause asphyxia. Gases such as hydrogen, nitrogen, argon and neon can reach dangerous levels in closed and airless environments due to the fact that the tubes remain open during use. In the event of an asphyxia with gases in this group called asphyxiators which acts by reducing the oxygen in the air, the first measure to be taken is to take the patient to the fresh air and apply oxygen and mechanical ventilation if necessary. In the long term, it may remain sequelae in organs more susceptible to hypoxia, such as the heart and central nervous system. Ischemia, infarction, arrhythmia, convulsion, coma and brain edema may be observed depending on the severity of the level of exposure; followed by multiple organ failure may occur10,11.
B) Gases forming chemical asphyxia
Gases that chemically form asphyxia are also known as tissue asphyxans and inhibit the uptake of oxygen by the tissue. Carbon monoxide prevents oxygen from binding to hemoglobin by forming carboxyhemoglobin or by stimulating nitrogen dioxide methemoglobin formation. Sulfuric hydrogen (H2S), cyanide and partially carbon monoxide block cell respiration. Some chemical asphixanes (nitrogen dioxide, sulfur hydrogen, etc.) also have irritant effects on the respiratory tract10-12.
Carbon Monoxide (CO)
Carbon monoxide is released as a result of incomplete combustion of carbon-containing fuels. It is a colorless, odorless gas that is lighter than air. Burns with a blue flame to form carbon dioxide. Fires together with other toxic gases; As a result of burning organic fuels such as wood, coal, gas oil, natural gas in places with poor ventilation, carbon monoxide poisoning is frequently seen in mines, garages or similar places and may result in death. The amount of carbon monoxide in the respiratory air is determined by sampling with special detector tubes. For the purpose of toxicological research, carbon monoxide determination in blood, UV-visible spectrophotometer, gas chromatography and color tests are performed. The binding affinity of carbon monoxide to hemoglobin is 200 times higher than oxygen. It also affects the cytochrome oxidase system and reduces blood oxygen carrying capacity. In addition to disrupting oxygen transport, carbon monoxide shifts the oxygen dissociation curve to the left, causing less oxygen to reach the tissues. The organs most affected are those with the most metabolic activity. Although symptoms such as dizziness and headache are stimulating, people cannot escape from carbon monoxide intoxication because of sudden loss of consciousness without pre-symptoms. Since the oxygen level in the blood is not low, the chemoreceptors that are sensitive to oxygen pressure do not stimulate, and since CO2 in the blood does not increase, there is no stimulatory symptom in CO poisoning. Even at very low levels (0.5%), inhalation of carbon monoxide for 2 hours can result in death. When the carboxyhemoglobin level reaches 20% in the blood, symptoms begin; Loss of consciousness at 60%; 80% 8,9,13-16.
In carbon monoxide poisoning, the pink color of the tissues and tissues is very characteristic. In case of death, the cherry red color of COHb is present in almost all body skin and mucosa. Leather gets a bright red color. In general, in cases of death with carbon monoxide, COHb level in postmortem blood increases above 50%. The cause of death was reported as geyser and tube gas poisoning and to a lesser extent exhaust gas poisoning. In CO intoxication, the measurement of COHb levels in the blood is done to demonstrate exposure, severity, and efficacy of treatment.
Sulfur hydrogen (H2S)
Sulfur hydrogen is a colorless gas with strong and characteristic rotten egg odor and accumulates in pits (silos, sewers, manure pit, etc.) because it is heavier than air. It can be found in the oil industry, rubber and paint factories, sewerage network, volcanic gases, some mines and natural hot water sources. The scent is not a reliable stimulant because of high concentrations of insensitivity in the olfactory nerves. Pathological findings in cases of death give information about poisoning with H2S. Irritation symptoms and delayed deaths due to the formation of postmortem sulfhemoglobin in the abdominal organs is an important clue to the formation of green color. On the other hand, the determination of H2S in the air where poisoning occurs occurs is also helpful. The determination of sulfur before alteration in tissues may be useful in the identification of intoxication in terms of analytical toxicology. H2S can be determined qualitatively and quantitatively with lead acetate or with sulfides it gives with silver cyanide8,9,10,14-17.
Hydrogen cyanide (HCN)
Hydrogen cyanide poisoning can occur in gold mines by burning polyurethane, cellulose, nylon, wool, silk and asphalt in closed work areas. Hydrogen cyanide (HCN) is a type of cyanide that is normally present in the gas phase. A bitter smelling gas that resembles bitter almonds. Although its odor is characteristic, it can only be detected in 60% of the cases. The lethal dose is 50 mg for HCN and 200-300mg for potassium and sodium cyanide. Inhalation 0.2-0.3 mg / L HCN inhalation immediately lethal; 0.13 mg / L (130 ppm) HCN inhalation is lethal after one hour. In case of death, forensic toxicology laboratories should look for cyanide in blood, stomach and intestinal contents. Normal human blood can contain cyanide up to 100 micrograms in 15 ml. In inhalation poisoning, this amount may be at the level of 100 microgram in 100 ml. In postmortem analysis, cyanide can be recognized from death to 2.5-6 months. Once extracted from the biological material, it can be identified by suitable color reactions or gas chromatography apparatus 8,9,11,14-16.
1.2.2. Irritant gases
Since these substances react with water on the mucosal surface in varying proportions to form toxic products, their effect is related to their solubility in water and physical particle diameters. Ammonia, sulfur dioxide, which are highly soluble in water, are absorbed mainly on the conjunctival surface of the eye and mucous membranes of the upper respiratory tract, whereas less soluble substances (phosgene, ozone, nitrogen dioxide, etc.) can reach the level of terminal bronchiole and alveoli. Therefore, low-solubility substances have almost no irritation to the upper airways and have no significant symptoms. Since there is no stimulant effect, people may be exposed to these toxic substances for a long time without realizing it. Apart from their solubility in water, the size of the inhaled particles is also important in pathogenesis. Since particles of diameter 5 µm and below can reach the level of terminal bronchioli and alveoli, their effect is mainly in this region. The damage is caused by harmful gases that reach the lung both by the particles themselves and by adhering to the particles9,14-16.
Ammonia
Ammonia is a colorless, water-soluble gas with a density less than air and a pungent odor. It is used in ammonia, fertilizer, explosive materials, petroleum, paint, plastic and pharmaceutical industries. It can be recognized by its smell when at least 53 ppm in the air. Inhalation damage occurs where concentration is intense. 0.5-1-10000-9-11,14-19 can be lethal in a few minutes as a result of respiratory irritation when XNUMX-XNUMX (XNUMX ppm) is used in the room air.
Chlorine
Chlorine is a green-yellow gas, heavier than air and has a characteristic odor. It is used in alkaline and bleach making industry, disinfectant, paper and textile industry. Exposure to chlorine gas often occurs either by mixing household cleaning agents in the home environment or during pool or spa maintenance. Exposure between 35-50 ppm causes 60-90 to die within minutes. Death at a concentration of 1000 ppm develops even with a few breaths. Since the odor threshold is above the threshold of respiratory irritation, the absence of odor does not indicate exposure.
Nitrogen oxides
Nitrogen oxides are seen in welding, electrolysis, metal cleaning processes, as harmful gases during fire, in exhaust gases of motor vehicles and in silos.
Nitrogen dioxide is a brown gas that is heavier than air, irritant and partly insoluble. Inhaled nitrogen dioxide produced by fermentation in grain storage silos is known as ın Disease of Silo Fillers ”. Nitrogen dioxide resulting from enzymatic degradation and oxidation of the nitrate content of the plant, as well as CO2 gases released by the decomposition of carbohydrate content, are deposited in the silo directly above the grain surface and in particular in the debris areas. The gas formation process starts within a few hours after filling the silo, 2 peaks daily and decreases every two weeks. If the silo is entered in the first week, the risk of poisoning is high. Poisoning cases have been reported until 6 weeks after filling the silo. Inhalation of 250-500 ppm nitrogen dioxide in air can be fatal in a very short time. Metabolism and excretion of nitrogen oxides has not been studied much. However, it has been shown that nitrites are collected in tissues.
Phosgene
Phosgene is heavier than air, colorless and liquefied at 80ºC. It is similar to the smell of freshly cut straw in low concentrations, so its irritant properties are low and the person may be exposed to gas for a long time. At higher concentrations, a pungent odor is felt. Acceptable value in air is 0.1 ppm. Due to its low solubility in water, it is especially effective in distal airways, while symptoms are insidious. Inhaled phosgene is excreted from the lungs and kidneys by hydrolysis to CO2 and HCl in the organism. Phosgene does not occur naturally. It was first synthesized by passing chlorine and carbon monoxide through charcoal in 1812. Today, it is formed during the production of pesticides, plastics, paints and pharmaceuticals as intermediates in the synthesis of isocyanates. Firefighters, welders and paint removers may encounter chlorinated hydrocarbon-containing substances (eg, solvents, paint release agents, dry cleaning agents and methylene chloride) during heating8,11.
Sulfur dioxide (SO2)
It is a colorless, heavier than air, sharp, irritant gas and is one of the basic elements of air pollution. In industry, especially in paper production, refrigeration tanks, oil refining, mining, battery production and fruit preservation. Upon contact with the mucosal surface, sulfur dioxide rapidly converts to sulfur and sulfuric acid. The smell of SO0.5 in 2 ppm concentration can be felt in the air. 400 ppm SO2 inhalation is dangerous, 1000 ppm with 10 per minute death occurs8,11,14.
