Currency
November 07, 2019
Data1 suggests that more than half of all deaths at work in confined spaces result from the atmosphere that is in them, such as lack of oxygen or presence of toxic/ flammable gases. Furthermore, 60% of such deaths are among those attempting to rescue others and who were, presumably, unaware of the extreme danger they were in.
In this article, NEBOSH Head of Product Development, David Towlson, highlights the need for careful planning whenever people work in confined spaces.
One tragic incident that occurred in 2019 in Saudi Arabia highlights just how quickly confined space can lead to multiple fatalities2.
Bulk carrier, Bahri Bulk was berthed at Dammam, Saudi Arabia having originally sailed from San Lorenzo, Brazil with a cargo of wheat bran pellets.
An Able Seaman entered the closed hold and collapsed. The Ship Master and Chief Officer rushed to assist the unfortunate seafarer, but also collapsed in turn. Despite hospital treatment, all three men died.
Before looking more closely at how to avoid deaths in confined spaces, it is important to understand what a confined space is and just how severe the consequences of failing to manage the relevant risks can be.
“the ship master and chief officer rushed to assist the unfortunate seafarer, but also collapsed in turn”
OSHAD (Abu Dhabi Occupational Safety and Health Center) describes a confined space within its technical guidance as having a combination of two features. Firstly, it is a place which is substantially (though not always entirely) enclosed and, secondly, there will be a reasonably foreseeable risk of serious injury from hazardous materials or conditions within the space or nearby.
While some confined spaces are fairly easy to identify, such as closed tanks, vessels and sewers, ‘OSHAD-SF – Technical Guideline – Safe Work in Confined Spaces’ makes it clear that they may not necessarily be enclosed on all sides. Some confined spaces, for example, vats, silos and ships’ holds, may have open tops.
In addition, it’s important to recognise that the conditions inside an enclosed space can change. That means there are some places which may not normally be considered to fall within the definition of a confined space except very occasionally, perhaps due to the type of work to be undertaken such as a room during spray painting.
If we look to the UK, it’s Confined Spaces Regulations (1997) specify the risks of working in confined spaced as:
Serious injury due to fire or explosion
Loss of consciousness arising from increased body temperature
Loss of consciousness or asphyxiation arising from gas, fume, vapour, or lack of oxygen
Drowning from an increase in the level of a liquid
Asphyxiation arising from a free-flowing solid or being unable to reach a respirable environment due to being trapped by such a free-flowing solid
To understand how the risks can be managed, I spoke to HSE Advisor for Cairn Oil & Gas, a HSE Expert, Amitabh Bhattacharya, who holds a NEBOSH International General Certificate in Occupational Health and Safety and an MBA in Disaster Management. He has nearly a decade of experience in HSSEF working in oil and gas, refinery construction and waste management industries in Saudi Arabia and India.
Amitabh told me: “Before entering a confined space, a gas test must be carried out to make sure that the environment inside has between 19.5% and 23.5% oxygen and no harmful gases. If harmful gases are present, ventilation has to be carried out mechanically using things like blowers and fans, for example. I would always look to ventilate at the rate of at least four volumes per hour, but larger spaces may require more than this.”
He went on to say that gas detection is generally carried out by Authorised Gas Testers (AGTs) who are qualified and competent to perform gas testing in confined spaces. Detection is normally carried out using multi gas detectors, which also have a probe to reach inside confined spaces for gas testing without exposing the operator to danger. Multi gas detectors usually have four or more sensors, depending upon the location and industry being worked in and the probability of certain harmful gases. To ensure accuracy any such sensors are calibrated every six months.
Oxygen (O2)
Lower Explosive Limit (LEL) for hazardous atmosphere An LEL detector checks for flammable/ explosive gas or solvents, and will signal an alarm well before any dangerous flammable/exposure fuel/air mixtures are formed.
Carbon monoxide (CO) Carbon monoxide is a gas that can cause people to lose consciousness quickly and is often called the “silent killer” because it is colourless, odourless, tasteless and non-irritating. It can be produced in dangerous amounts when using petrol-powered equipment and gas appliances.
Hydrogen sulphide (H2S) Hydrogen sulphide is a fast-acting poison. It is commonly found during the drilling and production of crude oil and natural gas, as well as in wastewater treatment and utility facilities and sewers. The gas is produced as a result of the microbial breakdown of organic materials in the absence of oxygen.
Chlorine (Cl2) Chlorine is used in many industries, such as paper manufacture, cleaning products and plastic manufacturing. Exposure to low levels of chlorine can result in nose, throat and eye irritation, while higher levels can cause respiratory issues and lung damage, sometimes severe depending on the level of exposure.
Methane (CH4) Methane is an extremely flammable gas.
Amitabh said: “Gas detection needs to be carried out at three levels of the confined space: at the bottom, at the middle part and at the surface. This is because various gases have different properties that may either settle low on the ground or can be at the surface level. Importantly, continuous gas monitoring is advised depending upon the criticality of the task or for highly hazardous atmospheres.
“gas detection equipment; can it be repaired? can it be calibrated? is it robust enough for the environment? how accurate is it?”
“A standby person is always required to check and have constant communication with the personnel involved in a confined space task and this standby person is also responsible for activating emergency response and rescue if required. Tripods with a hoist, lifeline, and full body harness are often used for pulling people out in an emergency. Only after everything is checked and permit approval is given can work be initiated within confined spaces.”
Jacques Krog is the Safety, Health, Environmental and Quality (SHEQ) Manager at Refraline, a company that has its headquarters in South Africa, but which operates in many other parts of the world. Jacques holds the NEBOSH International Diploma in Occupational Health and Safety and has over 20 years’ experience working in health and safety.
Refraline specialises in the design, installation, repair and maintenance of refractory and corrosion solutions for a wide range of industries including ferrous and non-ferrous metals, chemical, petrochemical, power generation and mining. “Refractory engineering involves boilers and furnaces and things like that, so generally we do a lot of confined space work, including breaking these things down from the inside,” explained Jaques.
He continued: “Noise hazards and heat stress are some of the less obvious hazards our teams face; however, perhaps the biggest threat to our workers is the accumulation of gases such as carbon monoxide or nitrogen. Because every confined space situation presents different risks, we tend to rely on a subject matter expert, someone who will understand the kind of gases likely to be present and where they might accumulate within the space. There will then be a period of rigorous testing to decide what steps are needed.
“Planning these operations is critical. How you do it, where you do it and what time you do it – all of these things play a part. Who is going to work in the vessel is also a key question, because people need to be declared physically and psychologically fit to work in confined spaces. And, of course, it is really important that every single person that enters the confined space is fully trained, including in what to do in an emergency and how to use their equipment properly. Even things like the passing of tools is not the same as in an open space. The risks are different.”
When it comes to Personal Protective Equipment (PPE), Jacques told me this can be very specific for confined space use. He said: “It’s not necessarily the same as standard PPE, there can be specialist respiratory equipment, gas testing equipment and even timers. The petrochemical industry, for example, has certain catalysts inside and you cannot work for longer than 15 minutes, no matter what you wear. You need to time that the person works exactly 15 minutes and they have to come out and the next group goes in for 15 minutes.
“When it comes to gas detection equipment what I have learned is that cheaper is not better. You need to think about simple things like maintenance; can it be repaired? Can it be calibrated? Is it robust enough for the environment? How accurate is it? I was once in a confined space myself when an alarm went off on the monitor. I started to panic a little, but when I looked it was a battery alarm! This equipment is a lifeline and you have to understand it and test it regularly. It’s also worth noting that with some confined spaces you simply cannot go in at all. Here we’ve used telescopic semi-robotic machines to break down the structure from the inside to fully eliminate any risk.”
In this article, NEBOSH Head of Product Development, David Towlson, highlights the need for careful planning whenever people work in confined spaces.
One tragic incident that occurred in 2019 in Saudi Arabia highlights just how quickly confined space can lead to multiple fatalities2.
Bulk carrier, Bahri Bulk was berthed at Dammam, Saudi Arabia having originally sailed from San Lorenzo, Brazil with a cargo of wheat bran pellets.
An Able Seaman entered the closed hold and collapsed. The Ship Master and Chief Officer rushed to assist the unfortunate seafarer, but also collapsed in turn. Despite hospital treatment, all three men died.
A tale of two features
Before looking more closely at how to avoid deaths in confined spaces, it is important to understand what a confined space is and just how severe the consequences of failing to manage the relevant risks can be.
“the ship master and chief officer rushed to assist the unfortunate seafarer, but also collapsed in turn”
OSHAD (Abu Dhabi Occupational Safety and Health Center) describes a confined space within its technical guidance as having a combination of two features. Firstly, it is a place which is substantially (though not always entirely) enclosed and, secondly, there will be a reasonably foreseeable risk of serious injury from hazardous materials or conditions within the space or nearby.
While some confined spaces are fairly easy to identify, such as closed tanks, vessels and sewers, ‘OSHAD-SF – Technical Guideline – Safe Work in Confined Spaces’ makes it clear that they may not necessarily be enclosed on all sides. Some confined spaces, for example, vats, silos and ships’ holds, may have open tops.
In addition, it’s important to recognise that the conditions inside an enclosed space can change. That means there are some places which may not normally be considered to fall within the definition of a confined space except very occasionally, perhaps due to the type of work to be undertaken such as a room during spray painting.
If we look to the UK, it’s Confined Spaces Regulations (1997) specify the risks of working in confined spaced as:
Gas testing
To understand how the risks can be managed, I spoke to HSE Advisor for Cairn Oil & Gas, a HSE Expert, Amitabh Bhattacharya, who holds a NEBOSH International General Certificate in Occupational Health and Safety and an MBA in Disaster Management. He has nearly a decade of experience in HSSEF working in oil and gas, refinery construction and waste management industries in Saudi Arabia and India.
Amitabh told me: “Before entering a confined space, a gas test must be carried out to make sure that the environment inside has between 19.5% and 23.5% oxygen and no harmful gases. If harmful gases are present, ventilation has to be carried out mechanically using things like blowers and fans, for example. I would always look to ventilate at the rate of at least four volumes per hour, but larger spaces may require more than this.”
He went on to say that gas detection is generally carried out by Authorised Gas Testers (AGTs) who are qualified and competent to perform gas testing in confined spaces. Detection is normally carried out using multi gas detectors, which also have a probe to reach inside confined spaces for gas testing without exposing the operator to danger. Multi gas detectors usually have four or more sensors, depending upon the location and industry being worked in and the probability of certain harmful gases. To ensure accuracy any such sensors are calibrated every six months.
Sensors generally include:
Checking levels
Amitabh said: “Gas detection needs to be carried out at three levels of the confined space: at the bottom, at the middle part and at the surface. This is because various gases have different properties that may either settle low on the ground or can be at the surface level. Importantly, continuous gas monitoring is advised depending upon the criticality of the task or for highly hazardous atmospheres.
“gas detection equipment; can it be repaired? can it be calibrated? is it robust enough for the environment? how accurate is it?”
“A standby person is always required to check and have constant communication with the personnel involved in a confined space task and this standby person is also responsible for activating emergency response and rescue if required. Tripods with a hoist, lifeline, and full body harness are often used for pulling people out in an emergency. Only after everything is checked and permit approval is given can work be initiated within confined spaces.”
Risk assessment and planning
Jacques Krog is the Safety, Health, Environmental and Quality (SHEQ) Manager at Refraline, a company that has its headquarters in South Africa, but which operates in many other parts of the world. Jacques holds the NEBOSH International Diploma in Occupational Health and Safety and has over 20 years’ experience working in health and safety.
Refraline specialises in the design, installation, repair and maintenance of refractory and corrosion solutions for a wide range of industries including ferrous and non-ferrous metals, chemical, petrochemical, power generation and mining. “Refractory engineering involves boilers and furnaces and things like that, so generally we do a lot of confined space work, including breaking these things down from the inside,” explained Jaques.
He continued: “Noise hazards and heat stress are some of the less obvious hazards our teams face; however, perhaps the biggest threat to our workers is the accumulation of gases such as carbon monoxide or nitrogen. Because every confined space situation presents different risks, we tend to rely on a subject matter expert, someone who will understand the kind of gases likely to be present and where they might accumulate within the space. There will then be a period of rigorous testing to decide what steps are needed.
“Planning these operations is critical. How you do it, where you do it and what time you do it – all of these things play a part. Who is going to work in the vessel is also a key question, because people need to be declared physically and psychologically fit to work in confined spaces. And, of course, it is really important that every single person that enters the confined space is fully trained, including in what to do in an emergency and how to use their equipment properly. Even things like the passing of tools is not the same as in an open space. The risks are different.”
PPE and supervision
When it comes to Personal Protective Equipment (PPE), Jacques told me this can be very specific for confined space use. He said: “It’s not necessarily the same as standard PPE, there can be specialist respiratory equipment, gas testing equipment and even timers. The petrochemical industry, for example, has certain catalysts inside and you cannot work for longer than 15 minutes, no matter what you wear. You need to time that the person works exactly 15 minutes and they have to come out and the next group goes in for 15 minutes.
“When it comes to gas detection equipment what I have learned is that cheaper is not better. You need to think about simple things like maintenance; can it be repaired? Can it be calibrated? Is it robust enough for the environment? How accurate is it? I was once in a confined space myself when an alarm went off on the monitor. I started to panic a little, but when I looked it was a battery alarm! This equipment is a lifeline and you have to understand it and test it regularly. It’s also worth noting that with some confined spaces you simply cannot go in at all. Here we’ve used telescopic semi-robotic machines to break down the structure from the inside to fully eliminate any risk.”
SOURCE:
https://www.hsmemagazine.com/article/working-in-confined-spaces/
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