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5 July 2024
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Featured FRI Magazine article: Confined space rescue by Colin Deiner (FRI Vol 2 no 5)
If the confined space presents a respiratory risk, the entry team should bring a supply of breathable air for the victim and place it on the victim as soon as possible
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Communication between the entry team and the rescue team on the outside will be crucial to ensure that the raising operation goes smoothly
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Should a vertical lift be required, a rescue team outside the space should be established who will identify and set up the necessary anchor points as well as the mechanical raising system to safely move the patient upwards and out
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Any manufacturing or processing equipment must be shut down prior to entry
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For confined space rescue, it is essential that a purpose manufactured (confined space) harness be selected
The bulkiness of an SCBA also limits the movement of the wearer in a confined space
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All gas monitors must be activated in fresh air
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https://www.frimedia.org/uploads/1/2/2/7/122743954/fri_vol2no5_lr.pdf
This week’s featured Fire and Rescue International magazine article is: Confined space rescue written by Colin Deiner (FRI Vol 2 no 5). We will be sharing more technical/research/tactical articles from Fire and Rescue International magazine on a weekly basis with our readers to assist in technology transfer. This will hopefully create an increased awareness, providing you with hands-on advice and guidance. All our magazines are available free of charge in PDF format on our website and online at ISSUU. We also provide all technical articles as a free download in our article archive on our website.
Confined space rescue
By Colin Deiner, chief director, Disaster management and Fire Brigade Services, Western Cape Government
Scenario 1
A 22-year-old worker enters a toluene storage tank that is three and a half metres in diameter and seven metres high. Although a self-contained breathing apparatus was present, the worker was not wearing it when he entered the tank to carry out a cleaning task. The worker is overcome and collapses onto the floor of the tank and he subsequently dies before the fire department arrives. Upon arrival, the fire department attempt to rescue the worker, fire fighters begin cutting an opening into the side of the tank. The tank explodes, killing a 32-year-old fire fighter and injuring 15 others.
Scenario 2
A 27-year-old sewer worker enters an underground pumping station via a fixed ladder inside a one metre diameter shaft. Because the work crew is unaware of procedures to isolate the work area and ensure that the pump has been bypassed, the transfer line is still under pressure. Therefore, when the workers remove the bolts from an inspection plate that covers a check valve, the force of the waste water blows the inspection plate off, allowing sewage to flood the chamber and trapping one of the workers. A co-worker, a supervisor and a member of the local emergency services attempt a rescue and die. The first two deaths appear to be due to drowning and the latter two appear to be due to asphyxiation as a result of inhalation of ‘sewer gas’.
Scenario 3
The fire department responds to a request from a local resident to remove the remains of a dead animal from a seven-metre water well. The fire fighters decide to first pump the water out of the well. One fire fighter climbs down into the well on an aluminium ladder and builds a wooden platform at the two-metre level. A second fire fighter climbs down into the well to help position a gasoline engine-powered pump as it is lowered down to the platform. The two fire fighters start the engine but are unable to prime the pump. Within a few minutes the first fire fighter becomes dizzy and exits the well. The second fire fighter remains in the well and becomes unconscious. In a rescue attempt, the first fire fighter climbs back down into the well, turns the engine off and then collapses unconscious over the engine. By this time, the engine has run for approximately eight to nine minutes. Within minutes several other fire fighters responding to radio emergency calls arrive at the scene. Over the next three hours, eight fire fighters enter the well in rescue attempts. Only two of the rescuing fire fighters are wearing breathing apparatus. The first fire fighter is rescued and revived. The second fire fighter and two other fire fighters attempting the rescue are tragically killed in the line of duty.
The above scenarios would most definitely require the response of a confined space rescue team and many people’s response to these incidents would be to doubt whether any emergency service would allow their staff to conduct themselves in such a manner. The scary part is that all of the above incidents did happen.
Emergency responders are not exempt from the law (although some of us sometimes like to think so) and must follow the provisions of the Occupational Health and Safety (OHS) Act when entering confined spaces even if it is in an emergency situation.
How do we plan our response to confined space rescues?
This can best be addressed if we take the time to find the answers to the following questions:
1. What laws and regulations exist concerning confined space rescue?
2. What type of equipment is needed for confined space rescue?
3. What components are needed for an effective confined space rescue standard operating procedure (SOP)?
4. What is the state of readiness of our emergency service to perform confined space rescue?
The problem of confined space rescue was identified a long time ago. In fact, up until 2001 the highest number of rescuer casualties worldwide was due to confined space incidents. According to the 1986 National Institute for Occupational Safety and Health (USA) report, up to 60 percent of confined space fatalities where rescuers. There are literally thousands of people working in confined spaces on a daily basis. The potential for an accident and subsequent emergency response is huge.
Confined spaces can masquerade in many different shapes and sizes and can be found in a multitude of configurations. Many are located below ground, however some are found above ground, inside buildings, on the roads, railways and even on water.
The law
Working in confined spaces in South Africa is governed by regulations in the Occupational Health and Safety Act, 1993 (Act No 85 of 1993), which requires an employer or a user of machinery to take steps to ensure that a confined space is entered by an employee or other person only after the air therein has been tested and evaluated by a person who is competent to pronounce on the safety thereof and who has certified in writing that the confined space is safe and will remain safe while any person is in the confined space, taking into account the nature and duration of the work to be performed therein.
Should this not be possible, steps must be taken to ensure that any confined space in which a hazardous gas, vapour, dust or fumes may exist, or that might have an oxygen content of less than 20 percent by volume, is purged and ventilated to provide a safe atmosphere therein and measures necessary to maintain a safe atmosphere therein have been taken; and has been isolated from all pipes, ducts and other communicating openings.
Should this also not be possible and you absolutely have to enter the space, you should then do so wearing the appropriate respiratory protection, use a safety harness (with someone on the other end!!) and have someone trained in cardiopulmonary resuscitation (CPR) available to assist if things don’t go so well.
The regulation also requires that where the hazardous gas, vapour, dust or fumes are of an explosive or flammable nature, an employer shall further take steps to ensure that such a confined space is entered only if:
• the concentration of the gas, vapour, dust or fumes does not exceed 25 percent of the lower explosive limit of the gas, vapour, dust or fumes concerned where the work to be performed is of such a nature that it does not create a source of ignition or
• such concentration does not exceed 10 percent of the lower explosive limit of the gas, vapour, dust or fumes where other work is performed.
What is a confined space?
For a space to be classified as a ‘confined space’, it should comply with the following criteria:
• Be large enough and so configured that a person can bodily enter and perform assigned work
• have limited or restricted means for entry or exit and
• not be designed for continuous occupancy.
If one looks at the OHS Act requirement for people entering confined spaces, the following can be added:
• contains or has known potential to contain a hazardous atmosphere
• contains material with the potential for engulfing an entrant
• has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls, or a floor that slopes downward and tapers to a smaller cross-section or
• contains any other recognised serious safety or health hazard.
Confined space hazards
The greatest danger in confined spaces is hazardous atmospheres. Hazardous atmospheres can be divided into three categories: asphyxiating, flammable, and toxic.
Asphyxiating atmospheres are atmospheres that contain less than 19,5 percent oxygen. Below this concentration a person’s respiratory function may be compromised and such an atmosphere is therefore considered to be oxygen-deficient.
Between 15 to 19 percent oxygen people could demonstrate a decreased ability to work strenuously. Their coordination could be impaired and persons with coronary, pulmonary or circulatory problems could demonstrate serious symptoms of impairment.
A more deficient atmosphere will continue to negatively impact on people and in extremely low concentrations (five to 10 percent) convulsions, cessation of respiration and finally death will be the ultimate result.
Flammable atmospheres are those that will present a serious fire or explosion hazard if a flammable gas or vapour is present at a concentration greater than 10 percent of its lower flammable limit (LFL) or if a combustible dust is present at a concentration that obscures vision at a distance of two metres, or less.
Flammable atmosphere can also arise from oxygen-enriched atmospheres. Oxygen-enriched atmospheres are generally those containing more than 23,5 percent oxygen.
Toxic atmospheres refer to any atmosphere containing gases, vapours, or fumes known to have poisonous physiological effects. The most commonly encountered toxic gasses are carbon monoxide (CO) and hydrogen sulphide (H2S). These atmospheres may be caused by a manufacturing process, a product stored, or a work activity being performed in a confined space.
Exposure to an atmosphere containing more than 100 parts per million (ppm) will result in severe headaches and eventually, as the concentration increases, unconsciousness and eventual death.
Hydrogen sulphide exposure is much more severe with an atmosphere as low as 1 000ppm being potentially fatal.
Other than the three hazard classes mentioned above, one should also not lose sight of all the potential physical hazards that also exist in confined spaces. Physical hazards in confined spaces are those associated with (1) limited opportunities for entry and exit; (2) limited size of entry and exit points; (3) limited size of the confined space itself; (4) sharp objects; (5) irregular, dirty and slippery walking surfaces and (6) stored flowing solids ie sand, grain, gravel, etc.
Electrical and other energy-related hazards must, as a legal requirement, be isolated before the space is entered to do any work. Emergency services must also have their own procedures in place to isolate and lock-out energy hazards before they attempt any rescue operations.
Entry control
Most responsible employers will generally have a robust confined space entry control system whereby an entry permit will be generated before work is conducted. This permit will include all the details relevant to purpose of entry, the authorised employees within the space, the hazards within the space to be entered and the measures used to isolate and eliminate the hazards before entry was allowed.
But as we have all come to learn: Emergency services don’t primarily exist for responsible employers!!
While the equipment requirement for employers doing confined space work is generally well defined, there is no official equipment requirement for emergency services. What you will need and how much of it will largely depend on your appreciation of the risk and (sadly) your budget.
A strict procedure must be in place for emergency responders to adhere to before entering a confined space for rescue purposes. The procedure must provide guidance for hazard identification, testing and evaluation, entry procedures, ventilation, breathing apparatus, protective equipment and rescue and victim removal systems.
The first priority upon arrival should be to obtain the entry permit (assuming one has been generated) and/or interview the supervisor. The information you obtain from these sources will allow the incident commander to appreciate the type of hazards they will be dealing with, the shape and configuration of the confined space and the number and possible condition of the victims.
This information will allow the incident commander to develop the plan of action that will in turn guide the activities of all responding personnel (more about this later).
Equipment
Most responsible employers will procure their own confined space equipment and will keep it serviced and available for use by their own internal response teams. The equipment may, however, be exclusively configured for the specific risk on their premises and may not have the versatility required by emergency services.
The equipment inventory for confined space rescue response must include atmospheric monitoring devices, ventilation systems, breathing apparatus, personal protective equipment, extrication devices, lighting equipment, energy hazard controls and elevation rescue equipment.
An impressive array of highly researched equipment is available for this rescue discipline. Instead of dealing with each bit of kit individually, I will just share some thoughts on certain categories.
Atmospheric monitors
Atmospheric monitors should be able to provide the rescuer with an audible warning of the following conditions:
• Methane: produced by the fermentation of organic material (shafts containing leaves and water or sewers) or released through leaks in gas pipes
• Hydrogen sulphide: produced by decomposing organic material
• Carbon monoxide: produced by incomplete combustion, eg smouldering fires in cable ducts, or released through leaks in exhaust gas pipes or as exhaust fumes from heating systems or motor vehicles
• Lack of oxygen due to the consumption of oxygen during the decomposition of organic material, during smouldering fires or when oxygen is displaced by gas leaks (eg methane from gas pipes). Atmospheres below 19,5 percent
• Oxygen rich atmospheres (caused in areas where personnel work with oxygen) means that substances of low flammability in normal atmospheres, burn more easily, more quickly and at higher temperatures. Explosive fires can be caused. Atmospheres with oxygen concentrations in excess of 23,5 percent by volume.
When working in confined spaces, it is important to remember that concentrations of hazardous atmospheres can also change while the work is in progress. Due to the relative density and behaviour of these products, concentrations may be more intense at different points in the space. Given that this is the case, personal measurements should be done at regular intervals and at various pre-identified locations.
Ventilation equipment
A portable, intrinsically safe confined space blower with sufficient ducting able to effectively improve the atmosphere inside a confined space, is an integral part of a rescue team’s inventory. Blowers provide fresh air on a continuous basis, maintain the atmosphere at acceptable oxygen levels and provide a means of egress of the contaminated air.
Blowers could be used either to draft the air out of the space or, more preferably, to force air into the area, causing a positive atmosphere inside and expelling the contaminants out of the space.
If sufficient ducting is available, the blower can be set-up in an area with enough fresh air to sustain the atmosphere inside the confined space.
Breathing equipment
Breathing support equipment comprises the standard self-contained breathing apparatus (SCBA) and airline breathing apparatus.
Self-contained breathing apparatus are open circuit apparatus with a cylinder of compressed air supplying air to the user via a full face mask. Various sizes are available giving working times up to 45 minutes. These times are shorter when the user is operating in a highly stressful environment. In air temperatures of 36 degrees Celsius, for example, safe wearing time may be no more than 20 minutes. Under these circumstances, the tasks must be accomplished quickly and effectively and if it is appreciated that accessing a patient, treating and packaging the patient and exiting the confined space should take up more time than this the practicality of an SCBA is questionable. The bulkiness of an SCBA also limits the movement of the wearer in a confined space and can preclude the use of a confined space harness. Certain modern SCBAs have however been designed to wear over a harness.
Airline breathing apparatus are used where working times beyond 45 minutes are required. Airline breathing apparatus broadly comprises fresh air, constant flow and demand flow systems, sometimes used in conjunction with a small backup cylinder. Demand flow airline systems can probably at best provide 100 metres range, with simple fresh air lines limited to less than 10 metres.
Any airline system will require a careful process of line management that could limit the movement through a space with many angles or turns.
Another option would be to use a closed circuit SCBA offering two hours or more duration. This option will provide the same challenges as the open circuit SCBA and also requires specialist training. These systems are generally used by mines rescue teams.
Communication equipment
An adequate communication system will be needed and should enable communication between those inside the confined space, those inside the confined space and those outside and to call for help the case of an emergency.
Portable powered communications equipment for confined space operation falls essentially into two categories; ‘wireless’ and ‘wired’. These two categories essentially comprise radio systems and hardwired intercom systems. For confined space and tunnel working, the following four technologies are generally available:
• Mobile radio using free space propagation, possibly with repeaters;
• Mobile radio using leaky feeder guided propagation;
• Hard-wired point to point intercom systems; and
• Low frequency wire-guided inductive communication systems.
The mobile radio technology is reliant on open space or line-of-sight environments and, although reliable, they have an unpredictable range depending on the configuration of the confined space.
Active portable repeaters can increase the coverage but the deployment may not always be practical. This technology is most useful for surface attendant to rescue service communications.
Leaky feeder guided propagation is not suitable for rapid deployment. It is however better suited to fixed tunnel communications and is used extensively in the Gautrain rapid rail system for emergency communications. For this technology repeaters are required every 300 to 500 metres.
Hard-wired point-to-point intercom systems allow for point-to-point communications only and provide integrated communications equipment suitable for fixed cable lengths only. The technology does provide for secure, good quality, interference free and intrinsically safe communication. One of the more innovative manufacturers has developed a hard-line system which runs inside an NFPA grade rescue rope. This decreases the number of attachments and snag hazards and is ideal for confined space rescue.
Wire-guided low frequency inductive communications are new to the confined space environment but have a proven record in the underground mining environment. This technology inductively couples the signal into communications wire allowing communications between any points along the entire length of the wire (20 metres to 10 kilometres).
The systems rapid deployment capability, lightweight cable and reels, push-to-talk, simplex, open channel operation and intrinsically safe features makes it Ideal for rescue and rapid deployment tunnel communications.
A predominant communications-related concern is the difficulty in communicating whilst using breathing apparatus. In a high-stress rescue situation, the importance of effective communications for decision-making and relaying of safety related messages is critical. In low visibility, high-noise environments even face to face communication through breathing apparatus is problematic.
Modern breathing apparatus and communications system design has seen the introduction of integral speech ports and diagrams, face piece integrated microphones, throat microphones and bone microphones. Specialist microphones are increasingly being adapted to interface with intercom and portable radio systems.
Retrieval systems
For confined space rescue, it is essential that a purpose manufactured (confined space) harness be selected. This type of harness is designed to ensure a vertical centre of gravity with multiple attachment points, shoulder lift points and fall arrest points. A practical new addition to confined space harnesses are handgrips that have been added to the back for assisting the rescuer out of tight spaces. The harness should also have attachment for hooking on communication devices and gas detection monitors.
The rescue procedure
Assessment phase
The first in response team must conduct an immediate assessment of the hazards present and implement measures to secure and control them.
As mentioned earlier, the first arriving unit should try to get as much information as possible, which includes obtaining a copy of the entry permit and interviewing an attendant or witness to the accident to determine exactly what happened. If no witness is present, the rescue team should look for clues on the scene that may indicate what has happened.
A determination of the number of victims involved, how long they have been inside the space, the mechanism of injury and the survivability profile of the victim(s) is imperative.
Depending on the survivability profile of the victim(s), the incident command must make an early decision as to whether the operation will be conducted as a rescue or recovery.
Should it be conducted as a rescue and it is in any way possible communications with the victim must be established as soon as possible.
Part of the initial assessment should be to gather as much information about the actual confined space as possible. Determine what type of products are stored or used in the space; what known hazards are present ie electrical, mechanical, stored energy etc and how stable is the space structurally.
Also, try to obtain a diagram of space, including points of ingress and egress.
Safety
A safety zone (hot zone) must be established. The size of this zone will be determined by the atmospheric conditions, wind direction, size and shape of the space.
It might also be necessary to initiate ventilation as soon as possible. Also, consider the removal of all vehicles and machinery emitting exhaust fumes that could enter the confined space where the victims might be located.
Incident command should establish a safety sector that will be responsible for determining the hazards and contaminants within the confined space. The safety officer and his/her staff must monitor the space to determine oxygen level, flammability and toxicity. Based on these findings, the safety officer should advise incident command of the proper level of personal protective equipment.
All gas monitors must be activated in fresh air and the following parameters must be followed:
• Audio-alarm activated;
• Calibrated to 10% of the LEL of the calibrant gas; and
• Audio-alarm set at:
o oxygen-deficiency: 19,5% and oxygen-enrichment: 23,5%
o flammability: 10%
o toxicity: carbon monoxide 35ppm and hydrogen sulphide 10ppm
Any manufacturing or processing equipment must be shut down prior to entry. All equipment involved in the confined space operation must be locked out and maintained in a zero-energy state until operation is terminated. Secure and lockout utilities, including electrical, gas and water and secure or blank off any product that is flowing into the space.
Ventilation sector
Incident command should assign ventilation sector who should consult with the safety sector to determine the proper type of ventilation for the space ie positive or negative pressure ventilation.
Consideration should also be given to where the discharged air from within the confined space is being discharged to.
Entry team
Only trained confined space rescuers should be utilised as the entry team. A back-up team should also be on standby.
The correct level of personal protective equipment should be worn by all entry and backup teams. This shall include rescue type helmet, gloves, proper footwear, eye protection, appropriate skin protection, fall arrestor and a rescue rated harness as a minimum.
If the confined space has a flammable atmosphere, entry personnel should have intrinsically safe or explosion-proof communication and lighting equipment.
Prior to entry into the confined space, the entry team should check all diagrams and other pertinent information regarding the layout of the space and all personnel should be made aware of the action plan and all emergency evacuation signals and routes.
Patient rescue and extrication
Upon reaching the victim, entry personnel should do an immediate primary survey. If possible, emergency medical care should begin immediately. In the event of a fall injury, C-spine management should be prioritised. If the confined space presents a respiratory risk, the entry team should bring a supply of breathable air for the victim and place it on the victim as soon as possible.
After the immediate life threatening injuries have been addressed, the victim(s) should be prepared for removal from the space. This may include using a spinal immobilisation device and stretcher capable of supporting a vertical lift out of the space. The entry team should have determined the appropriate method of extrication. Should a vertical lift be required, a rescue team outside the space should be established who will identify and set up the necessary anchor points as well as the mechanical raising system to safely move the patient upwards and out.
Communication between the entry team and the rescue team on the outside will be crucial to ensure that the raising operation goes smoothly. If the space is too narrow, it might not be possible to attach a medical rescuer to the stretcher to monitor and support the patient on the way out. If possible, spend some extra time to ensure that the patient is adequately packaged and that no snag hazards will prevent the smooth upward movement of the litter.
Treatment sector
Immediately after reaching the point of egress, the entry team should transfer the victim to the treatment sector. A decontamination site might have to be set up to remove any product that may have contaminated the victim before removal to a hospital.
Also remember to decontaminate all staff and equipment if necessary.
Termination
Once all victims have been removed and all personnel have exited the confined space, incident command should ensure that the entire area has been made safe before handing over to the owner of the site and leaving the scene. This may include taking a final reading of the ambient atmosphere.
Finally
In this article I have really tried to stress the fact that a seemingly routine call to remove a victim from a confined space could turn into a tragedy if not approached in a safe and professional manner. History has proved this.
Granted, we can’t have confined space rescue equipment on all our response units. It is therefore that we need to try to identify the sites in our response areas that may pose the biggest risks for confined space entrapment and ensure that when we get the call our response is swift and functional.
Confined space rescue training is not difficult. For a start there is no shortage of training props. Many companies will be happy to allow you onto their premises to exercise your skills. By building these relationships, you will not only be able to hone your own skills but also build the relationships with the industries in your community that will one day help you save a life.
This week’s featured Fire and Rescue International magazine article is: Confined space rescue written by Colin Deiner (FRI Vol 2 no 5). We will be sharing more technical/research/tactical articles from Fire and Rescue International magazine on a weekly basis with our readers to assist in technology transfer. This will hopefully create an increased awareness, providing you with hands-on advice and guidance. All our magazines are available free of charge in PDF format on our website and online at ISSUU. We also provide all technical articles as a free download in our article archive on our website.
Confined space rescue
By Colin Deiner, chief director, Disaster management and Fire Brigade Services, Western Cape Government
Scenario 1
A 22-year-old worker enters a toluene storage tank that is three and a half metres in diameter and seven metres high. Although a self-contained breathing apparatus was present, the worker was not wearing it when he entered the tank to carry out a cleaning task. The worker is overcome and collapses onto the floor of the tank and he subsequently dies before the fire department arrives. Upon arrival, the fire department attempt to rescue the worker, fire fighters begin cutting an opening into the side of the tank. The tank explodes, killing a 32-year-old fire fighter and injuring 15 others.
Scenario 2
A 27-year-old sewer worker enters an underground pumping station via a fixed ladder inside a one metre diameter shaft. Because the work crew is unaware of procedures to isolate the work area and ensure that the pump has been bypassed, the transfer line is still under pressure. Therefore, when the workers remove the bolts from an inspection plate that covers a check valve, the force of the waste water blows the inspection plate off, allowing sewage to flood the chamber and trapping one of the workers. A co-worker, a supervisor and a member of the local emergency services attempt a rescue and die. The first two deaths appear to be due to drowning and the latter two appear to be due to asphyxiation as a result of inhalation of ‘sewer gas’.
Scenario 3
The fire department responds to a request from a local resident to remove the remains of a dead animal from a seven-metre water well. The fire fighters decide to first pump the water out of the well. One fire fighter climbs down into the well on an aluminium ladder and builds a wooden platform at the two-metre level. A second fire fighter climbs down into the well to help position a gasoline engine-powered pump as it is lowered down to the platform. The two fire fighters start the engine but are unable to prime the pump. Within a few minutes the first fire fighter becomes dizzy and exits the well. The second fire fighter remains in the well and becomes unconscious. In a rescue attempt, the first fire fighter climbs back down into the well, turns the engine off and then collapses unconscious over the engine. By this time, the engine has run for approximately eight to nine minutes. Within minutes several other fire fighters responding to radio emergency calls arrive at the scene. Over the next three hours, eight fire fighters enter the well in rescue attempts. Only two of the rescuing fire fighters are wearing breathing apparatus. The first fire fighter is rescued and revived. The second fire fighter and two other fire fighters attempting the rescue are tragically killed in the line of duty.
The above scenarios would most definitely require the response of a confined space rescue team and many people’s response to these incidents would be to doubt whether any emergency service would allow their staff to conduct themselves in such a manner. The scary part is that all of the above incidents did happen.
Emergency responders are not exempt from the law (although some of us sometimes like to think so) and must follow the provisions of the Occupational Health and Safety (OHS) Act when entering confined spaces even if it is in an emergency situation.
How do we plan our response to confined space rescues?
This can best be addressed if we take the time to find the answers to the following questions:
1. What laws and regulations exist concerning confined space rescue?
2. What type of equipment is needed for confined space rescue?
3. What components are needed for an effective confined space rescue standard operating procedure (SOP)?
4. What is the state of readiness of our emergency service to perform confined space rescue?
The problem of confined space rescue was identified a long time ago. In fact, up until 2001 the highest number of rescuer casualties worldwide was due to confined space incidents. According to the 1986 National Institute for Occupational Safety and Health (USA) report, up to 60 percent of confined space fatalities where rescuers. There are literally thousands of people working in confined spaces on a daily basis. The potential for an accident and subsequent emergency response is huge.
Confined spaces can masquerade in many different shapes and sizes and can be found in a multitude of configurations. Many are located below ground, however some are found above ground, inside buildings, on the roads, railways and even on water.
The law
Working in confined spaces in South Africa is governed by regulations in the Occupational Health and Safety Act, 1993 (Act No 85 of 1993), which requires an employer or a user of machinery to take steps to ensure that a confined space is entered by an employee or other person only after the air therein has been tested and evaluated by a person who is competent to pronounce on the safety thereof and who has certified in writing that the confined space is safe and will remain safe while any person is in the confined space, taking into account the nature and duration of the work to be performed therein.
Should this not be possible, steps must be taken to ensure that any confined space in which a hazardous gas, vapour, dust or fumes may exist, or that might have an oxygen content of less than 20 percent by volume, is purged and ventilated to provide a safe atmosphere therein and measures necessary to maintain a safe atmosphere therein have been taken; and has been isolated from all pipes, ducts and other communicating openings.
Should this also not be possible and you absolutely have to enter the space, you should then do so wearing the appropriate respiratory protection, use a safety harness (with someone on the other end!!) and have someone trained in cardiopulmonary resuscitation (CPR) available to assist if things don’t go so well.
The regulation also requires that where the hazardous gas, vapour, dust or fumes are of an explosive or flammable nature, an employer shall further take steps to ensure that such a confined space is entered only if:
• the concentration of the gas, vapour, dust or fumes does not exceed 25 percent of the lower explosive limit of the gas, vapour, dust or fumes concerned where the work to be performed is of such a nature that it does not create a source of ignition or
• such concentration does not exceed 10 percent of the lower explosive limit of the gas, vapour, dust or fumes where other work is performed.
What is a confined space?
For a space to be classified as a ‘confined space’, it should comply with the following criteria:
• Be large enough and so configured that a person can bodily enter and perform assigned work
• have limited or restricted means for entry or exit and
• not be designed for continuous occupancy.
If one looks at the OHS Act requirement for people entering confined spaces, the following can be added:
• contains or has known potential to contain a hazardous atmosphere
• contains material with the potential for engulfing an entrant
• has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls, or a floor that slopes downward and tapers to a smaller cross-section or
• contains any other recognised serious safety or health hazard.
Confined space hazards
The greatest danger in confined spaces is hazardous atmospheres. Hazardous atmospheres can be divided into three categories: asphyxiating, flammable, and toxic.
Asphyxiating atmospheres are atmospheres that contain less than 19,5 percent oxygen. Below this concentration a person’s respiratory function may be compromised and such an atmosphere is therefore considered to be oxygen-deficient.
Between 15 to 19 percent oxygen people could demonstrate a decreased ability to work strenuously. Their coordination could be impaired and persons with coronary, pulmonary or circulatory problems could demonstrate serious symptoms of impairment.
A more deficient atmosphere will continue to negatively impact on people and in extremely low concentrations (five to 10 percent) convulsions, cessation of respiration and finally death will be the ultimate result.
Flammable atmospheres are those that will present a serious fire or explosion hazard if a flammable gas or vapour is present at a concentration greater than 10 percent of its lower flammable limit (LFL) or if a combustible dust is present at a concentration that obscures vision at a distance of two metres, or less.
Flammable atmosphere can also arise from oxygen-enriched atmospheres. Oxygen-enriched atmospheres are generally those containing more than 23,5 percent oxygen.
Toxic atmospheres refer to any atmosphere containing gases, vapours, or fumes known to have poisonous physiological effects. The most commonly encountered toxic gasses are carbon monoxide (CO) and hydrogen sulphide (H2S). These atmospheres may be caused by a manufacturing process, a product stored, or a work activity being performed in a confined space.
Exposure to an atmosphere containing more than 100 parts per million (ppm) will result in severe headaches and eventually, as the concentration increases, unconsciousness and eventual death.
Hydrogen sulphide exposure is much more severe with an atmosphere as low as 1 000ppm being potentially fatal.
Other than the three hazard classes mentioned above, one should also not lose sight of all the potential physical hazards that also exist in confined spaces. Physical hazards in confined spaces are those associated with (1) limited opportunities for entry and exit; (2) limited size of entry and exit points; (3) limited size of the confined space itself; (4) sharp objects; (5) irregular, dirty and slippery walking surfaces and (6) stored flowing solids ie sand, grain, gravel, etc.
Electrical and other energy-related hazards must, as a legal requirement, be isolated before the space is entered to do any work. Emergency services must also have their own procedures in place to isolate and lock-out energy hazards before they attempt any rescue operations.
Entry control
Most responsible employers will generally have a robust confined space entry control system whereby an entry permit will be generated before work is conducted. This permit will include all the details relevant to purpose of entry, the authorised employees within the space, the hazards within the space to be entered and the measures used to isolate and eliminate the hazards before entry was allowed.
But as we have all come to learn: Emergency services don’t primarily exist for responsible employers!!
While the equipment requirement for employers doing confined space work is generally well defined, there is no official equipment requirement for emergency services. What you will need and how much of it will largely depend on your appreciation of the risk and (sadly) your budget.
A strict procedure must be in place for emergency responders to adhere to before entering a confined space for rescue purposes. The procedure must provide guidance for hazard identification, testing and evaluation, entry procedures, ventilation, breathing apparatus, protective equipment and rescue and victim removal systems.
The first priority upon arrival should be to obtain the entry permit (assuming one has been generated) and/or interview the supervisor. The information you obtain from these sources will allow the incident commander to appreciate the type of hazards they will be dealing with, the shape and configuration of the confined space and the number and possible condition of the victims.
This information will allow the incident commander to develop the plan of action that will in turn guide the activities of all responding personnel (more about this later).
Equipment
Most responsible employers will procure their own confined space equipment and will keep it serviced and available for use by their own internal response teams. The equipment may, however, be exclusively configured for the specific risk on their premises and may not have the versatility required by emergency services.
The equipment inventory for confined space rescue response must include atmospheric monitoring devices, ventilation systems, breathing apparatus, personal protective equipment, extrication devices, lighting equipment, energy hazard controls and elevation rescue equipment.
An impressive array of highly researched equipment is available for this rescue discipline. Instead of dealing with each bit of kit individually, I will just share some thoughts on certain categories.
Atmospheric monitors
Atmospheric monitors should be able to provide the rescuer with an audible warning of the following conditions:
• Methane: produced by the fermentation of organic material (shafts containing leaves and water or sewers) or released through leaks in gas pipes
• Hydrogen sulphide: produced by decomposing organic material
• Carbon monoxide: produced by incomplete combustion, eg smouldering fires in cable ducts, or released through leaks in exhaust gas pipes or as exhaust fumes from heating systems or motor vehicles
• Lack of oxygen due to the consumption of oxygen during the decomposition of organic material, during smouldering fires or when oxygen is displaced by gas leaks (eg methane from gas pipes). Atmospheres below 19,5 percent
• Oxygen rich atmospheres (caused in areas where personnel work with oxygen) means that substances of low flammability in normal atmospheres, burn more easily, more quickly and at higher temperatures. Explosive fires can be caused. Atmospheres with oxygen concentrations in excess of 23,5 percent by volume.
When working in confined spaces, it is important to remember that concentrations of hazardous atmospheres can also change while the work is in progress. Due to the relative density and behaviour of these products, concentrations may be more intense at different points in the space. Given that this is the case, personal measurements should be done at regular intervals and at various pre-identified locations.
Ventilation equipment
A portable, intrinsically safe confined space blower with sufficient ducting able to effectively improve the atmosphere inside a confined space, is an integral part of a rescue team’s inventory. Blowers provide fresh air on a continuous basis, maintain the atmosphere at acceptable oxygen levels and provide a means of egress of the contaminated air.
Blowers could be used either to draft the air out of the space or, more preferably, to force air into the area, causing a positive atmosphere inside and expelling the contaminants out of the space.
If sufficient ducting is available, the blower can be set-up in an area with enough fresh air to sustain the atmosphere inside the confined space.
Breathing equipment
Breathing support equipment comprises the standard self-contained breathing apparatus (SCBA) and airline breathing apparatus.
Self-contained breathing apparatus are open circuit apparatus with a cylinder of compressed air supplying air to the user via a full face mask. Various sizes are available giving working times up to 45 minutes. These times are shorter when the user is operating in a highly stressful environment. In air temperatures of 36 degrees Celsius, for example, safe wearing time may be no more than 20 minutes. Under these circumstances, the tasks must be accomplished quickly and effectively and if it is appreciated that accessing a patient, treating and packaging the patient and exiting the confined space should take up more time than this the practicality of an SCBA is questionable. The bulkiness of an SCBA also limits the movement of the wearer in a confined space and can preclude the use of a confined space harness. Certain modern SCBAs have however been designed to wear over a harness.
Airline breathing apparatus are used where working times beyond 45 minutes are required. Airline breathing apparatus broadly comprises fresh air, constant flow and demand flow systems, sometimes used in conjunction with a small backup cylinder. Demand flow airline systems can probably at best provide 100 metres range, with simple fresh air lines limited to less than 10 metres.
Any airline system will require a careful process of line management that could limit the movement through a space with many angles or turns.
Another option would be to use a closed circuit SCBA offering two hours or more duration. This option will provide the same challenges as the open circuit SCBA and also requires specialist training. These systems are generally used by mines rescue teams.
Communication equipment
An adequate communication system will be needed and should enable communication between those inside the confined space, those inside the confined space and those outside and to call for help the case of an emergency.
Portable powered communications equipment for confined space operation falls essentially into two categories; ‘wireless’ and ‘wired’. These two categories essentially comprise radio systems and hardwired intercom systems. For confined space and tunnel working, the following four technologies are generally available:
• Mobile radio using free space propagation, possibly with repeaters;
• Mobile radio using leaky feeder guided propagation;
• Hard-wired point to point intercom systems; and
• Low frequency wire-guided inductive communication systems.
The mobile radio technology is reliant on open space or line-of-sight environments and, although reliable, they have an unpredictable range depending on the configuration of the confined space.
Active portable repeaters can increase the coverage but the deployment may not always be practical. This technology is most useful for surface attendant to rescue service communications.
Leaky feeder guided propagation is not suitable for rapid deployment. It is however better suited to fixed tunnel communications and is used extensively in the Gautrain rapid rail system for emergency communications. For this technology repeaters are required every 300 to 500 metres.
Hard-wired point-to-point intercom systems allow for point-to-point communications only and provide integrated communications equipment suitable for fixed cable lengths only. The technology does provide for secure, good quality, interference free and intrinsically safe communication. One of the more innovative manufacturers has developed a hard-line system which runs inside an NFPA grade rescue rope. This decreases the number of attachments and snag hazards and is ideal for confined space rescue.
Wire-guided low frequency inductive communications are new to the confined space environment but have a proven record in the underground mining environment. This technology inductively couples the signal into communications wire allowing communications between any points along the entire length of the wire (20 metres to 10 kilometres).
The systems rapid deployment capability, lightweight cable and reels, push-to-talk, simplex, open channel operation and intrinsically safe features makes it Ideal for rescue and rapid deployment tunnel communications.
A predominant communications-related concern is the difficulty in communicating whilst using breathing apparatus. In a high-stress rescue situation, the importance of effective communications for decision-making and relaying of safety related messages is critical. In low visibility, high-noise environments even face to face communication through breathing apparatus is problematic.
Modern breathing apparatus and communications system design has seen the introduction of integral speech ports and diagrams, face piece integrated microphones, throat microphones and bone microphones. Specialist microphones are increasingly being adapted to interface with intercom and portable radio systems.
Retrieval systems
For confined space rescue, it is essential that a purpose manufactured (confined space) harness be selected. This type of harness is designed to ensure a vertical centre of gravity with multiple attachment points, shoulder lift points and fall arrest points. A practical new addition to confined space harnesses are handgrips that have been added to the back for assisting the rescuer out of tight spaces. The harness should also have attachment for hooking on communication devices and gas detection monitors.
The rescue procedure
Assessment phase
The first in response team must conduct an immediate assessment of the hazards present and implement measures to secure and control them.
As mentioned earlier, the first arriving unit should try to get as much information as possible, which includes obtaining a copy of the entry permit and interviewing an attendant or witness to the accident to determine exactly what happened. If no witness is present, the rescue team should look for clues on the scene that may indicate what has happened.
A determination of the number of victims involved, how long they have been inside the space, the mechanism of injury and the survivability profile of the victim(s) is imperative.
Depending on the survivability profile of the victim(s), the incident command must make an early decision as to whether the operation will be conducted as a rescue or recovery.
Should it be conducted as a rescue and it is in any way possible communications with the victim must be established as soon as possible.
Part of the initial assessment should be to gather as much information about the actual confined space as possible. Determine what type of products are stored or used in the space; what known hazards are present ie electrical, mechanical, stored energy etc and how stable is the space structurally.
Also, try to obtain a diagram of space, including points of ingress and egress.
Safety
A safety zone (hot zone) must be established. The size of this zone will be determined by the atmospheric conditions, wind direction, size and shape of the space.
It might also be necessary to initiate ventilation as soon as possible. Also, consider the removal of all vehicles and machinery emitting exhaust fumes that could enter the confined space where the victims might be located.
Incident command should establish a safety sector that will be responsible for determining the hazards and contaminants within the confined space. The safety officer and his/her staff must monitor the space to determine oxygen level, flammability and toxicity. Based on these findings, the safety officer should advise incident command of the proper level of personal protective equipment.
All gas monitors must be activated in fresh air and the following parameters must be followed:
• Audio-alarm activated;
• Calibrated to 10% of the LEL of the calibrant gas; and
• Audio-alarm set at:
o oxygen-deficiency: 19,5% and oxygen-enrichment: 23,5%
o flammability: 10%
o toxicity: carbon monoxide 35ppm and hydrogen sulphide 10ppm
Any manufacturing or processing equipment must be shut down prior to entry. All equipment involved in the confined space operation must be locked out and maintained in a zero-energy state until operation is terminated. Secure and lockout utilities, including electrical, gas and water and secure or blank off any product that is flowing into the space.
Ventilation sector
Incident command should assign ventilation sector who should consult with the safety sector to determine the proper type of ventilation for the space ie positive or negative pressure ventilation.
Consideration should also be given to where the discharged air from within the confined space is being discharged to.
Entry team
Only trained confined space rescuers should be utilised as the entry team. A back-up team should also be on standby.
The correct level of personal protective equipment should be worn by all entry and backup teams. This shall include rescue type helmet, gloves, proper footwear, eye protection, appropriate skin protection, fall arrestor and a rescue rated harness as a minimum.
If the confined space has a flammable atmosphere, entry personnel should have intrinsically safe or explosion-proof communication and lighting equipment.
Prior to entry into the confined space, the entry team should check all diagrams and other pertinent information regarding the layout of the space and all personnel should be made aware of the action plan and all emergency evacuation signals and routes.
Patient rescue and extrication
Upon reaching the victim, entry personnel should do an immediate primary survey. If possible, emergency medical care should begin immediately. In the event of a fall injury, C-spine management should be prioritised. If the confined space presents a respiratory risk, the entry team should bring a supply of breathable air for the victim and place it on the victim as soon as possible.
After the immediate life threatening injuries have been addressed, the victim(s) should be prepared for removal from the space. This may include using a spinal immobilisation device and stretcher capable of supporting a vertical lift out of the space. The entry team should have determined the appropriate method of extrication. Should a vertical lift be required, a rescue team outside the space should be established who will identify and set up the necessary anchor points as well as the mechanical raising system to safely move the patient upwards and out.
Communication between the entry team and the rescue team on the outside will be crucial to ensure that the raising operation goes smoothly. If the space is too narrow, it might not be possible to attach a medical rescuer to the stretcher to monitor and support the patient on the way out. If possible, spend some extra time to ensure that the patient is adequately packaged and that no snag hazards will prevent the smooth upward movement of the litter.
Treatment sector
Immediately after reaching the point of egress, the entry team should transfer the victim to the treatment sector. A decontamination site might have to be set up to remove any product that may have contaminated the victim before removal to a hospital.
Also remember to decontaminate all staff and equipment if necessary.
Termination
Once all victims have been removed and all personnel have exited the confined space, incident command should ensure that the entire area has been made safe before handing over to the owner of the site and leaving the scene. This may include taking a final reading of the ambient atmosphere.
Finally
In this article I have really tried to stress the fact that a seemingly routine call to remove a victim from a confined space could turn into a tragedy if not approached in a safe and professional manner. History has proved this.
Granted, we can’t have confined space rescue equipment on all our response units. It is therefore that we need to try to identify the sites in our response areas that may pose the biggest risks for confined space entrapment and ensure that when we get the call our response is swift and functional.
Confined space rescue training is not difficult. For a start there is no shortage of training props. Many companies will be happy to allow you onto their premises to exercise your skills. By building these relationships, you will not only be able to hone your own skills but also build the relationships with the industries in your community that will one day help you save a life.