Combine toxic atmospheres with conditions of low visibility, entanglement hazards, moving parts, the risk of engulfment and restricted methods of entry and you are presented with the possible conditions within a confined space and one of the most challenging forms of technical rescue.
Confined space rescue involves completing the rescue of entrapped or injured personnel often within very small and narrow spaces that may expose crews to a variety of hazards. It is one of the most dangerous forms of technical rescue, as it combines a hazardous atmosphere with other less encountered hazards such as engulfment and entanglement. For fire crews to complete safe rescues of personnel within confined spaces they must understand the hazards that may be found within confined spaces, understand what skills and knowledge ‘local workers’ may provide, and complete specific confined space rescue training across a variety of typical scenarios that are common within their response area.
To reduce the likelihood of fatalities and injuries to firefighters, they must be equipped them with an understanding of their local ‘typical’ confined spaces, a thorough understanding of confined space hazards and an understanding of the typical control measures that may be used to make the rescue safer.
Confined Space Hazards
Hazard identification is part of daily emergency response activities by fire crews worldwide. Confined space hazards however present specific hazards and risks and can present real dangers to fire crews. Hazards often involve the design and operation of the confined space as well as the atmosphere and the conditions found within. Hazards in confined spaces include but are not limited to:
- Oxygen deficiency and excess
- Hydrogen sulphide and carbon monoxide
- Explosive atmospheres
- Entanglement and injury from moving parts such as augers, agitators and belts
- Engulfment by a solid, liquid or gas
Confined space hazards different greatly due to the type of industry and the type of confined spaces encountered. These hazards must be fully understood by fire crews as they may be encountered in any number of confined space incidents.
The cat down the drain scenario
At 1500 hours you responded to a cat trapped within a storm water drain on a quiet residential street. Once on scene you are told by the cat’s owner that the cat has disappeared down into the storm water drain on the street corner. Two firefighters open the storm drain cover and look down to see an eight-metre deep storm water drain. You see a cat at the bottom of the drain lying very still. You call out to the cat but no answer. One of your firefighters grabs the ladder from the truck and gets ready to pitch the ladder into the drain.
What do you do and what hazards do you consider? What caused the cat to die? What hazards could be within the drain? What hazards may affect your crew? Should you get the cat out for the owner? Should you let your firefighter descend the ladder and rescue the cat? Is this a confined space?
The situation described above is not uncommon. Many fire crews would simply descend the ladder to rescue the cat, but what are the risks and what are the consequences?
This is an example of how confined spaces that are outside of a typical industrial confined space rescue scenario can be presented to fire crews. Obviously, all crew members start to consider the hazards of confined spaces while en-route to a rescue. However, in common emergency callouts such as this, if fire crews are not well educated in what a confined space is and the potential hazards within, they may be at risk of an injury or fatality.
Let us consider the above example. What hazards may be present and what control measures should be considered? Typical hazards for the scenario above include but are not limited to:
Oxygen deficiency occurs below 19.5% oxygen concentration. As the level of oxygen drops within the storm water drain, it will affect the human body. While the initial effects include headache and a lack of coordination, as the level of oxygen decreases personnel will become unconscious and eventually die.
Hydrogen Sulphide (H2S)
Hydrogen Sulphide is caused by the decomposition of organic waste. In this situation, the dead cat could actually be decomposing and giving off Hydrogen Sulphide. H2S deadens the sense of smell and can cause severe illness. H2S may displace oxygen and cause effects to the human body.
Has there been rain or flooding in the last few days? Is there water flowing within the drain? Are there small or large outlets within the drain (considering that large outlets may cause engulfment or drowning to occur more quickly)?
Falls from height
The fall risk in this scenario is eight metres, which is sufficient to cause multiple serious injury or death. The example above should cause those of us that are well trained to size-up the situation and consider what appropriate control measures should be used. Realistically we should consider several active control measures for each of the hazards outlined above. Consider the following control measures to be the absolute minimum that should be implemented prior to recovering the cat:
A gas test should be performed across all levels of the space but paying particular attention to the lowest area within the space. Hydrogen sulphide is heavier than air with an air density of 1.19. It will accumulate at the lowest point within the space. Perform a gas test to check for unsafe atmospheres. Pay particular attention to the Oxygen, H2S and possibly methane levels.
Currently you have an open manhole and a risk of a fall from height. Consider barrier taping the area and implement a control zone to reduce the likelihood of having a bystander or a firefighter fall into the drain.
If you consider recovering the body of the cat, you really should consider using a tripod and winch or a davit and winch to provide active fall protection and emergency rescue. The method of fall protection should be based on the equipment that is available at the time and the familiarity of your crew with the equipment.
Personal Protective Equipment
You should consider getting your personnel to wear rubber gloves to avoid bacterial infection when handling the cat.
You should consider contacting your local water board or water authority to obtain any flooding reports or reports based on water movement within the drainage system.
While many firefighters may consider the control measures above an unnecessary hindrance, the dangers posed by confined spaces are real and they must be considered and controlled. The safety of firefighters is our number one priority, so do not let a dead cat affect the safety of your personnel.
Fire crews may receive an emergency call for a confined space rescue and find themselves at a site with a multitude of hazards to consider with no real technical knowledge of the confined space itself or the surroundings (after all we are firefighters not engineers). Wherever possible, seek out local knowledge and help as soon as practicable on arrival to assist in your size-up. Track down local workers who have knowledge about the confined space and ask them about the hazards and risks before any rescue is considered.
Question the local personnel about at least the following:
- What are the hazards within this confined space?
- How long has the person been in there for?
- Has a gas test been completed and what were the results?
- Is the confined space isolated?
- What do you think has caused this incident?
- Are there multiple entry points?
- What should we consider prior to entry?
The answers to these questions will often provide you with valuable information about the confined space and may cause you to either complete a rescue or wait until the conditions within the confined space have been made safer.
Industrial confined spaces can be very complex and I have encountered spaces that have in excess of 100 individual isolations. Consider the advice of local technical experts very carefully and always look at the worst case scenario before implementing a rescue. For fire crews to understand typical hazards from confined spaces within their response area, they should liaise with local workplaces and industry and complete regular ‘walk-arounds’. These walk-arounds of local industry are useful to help fire crews understand the types of hazards that may be encountered.
Localised and specific confined space rescue training
Fire crews are experienced in utilising SCBA and atmospheric monitoring equipment at fires and HazMat incidents. However, fire crews will be less experienced in rescuing personnel from within industrial confined spaces such as boilers, pressure vessels and vats. Fire crews often practise confined space rescue in storm water and sewerage drain, which is very useful to build foundation skills. However, when was the last time that your personnel completed rescue drills within tanks, boilers, kilns, grinding mills or pressure vessels?
The reality is that many urban fire brigades do not complete such drills. They believe that it is ‘too hard’ and industry does not want them in their workplaces. My experience is that nothing could be farther from the truth. Often, personnel in industry feel ‘lost’ when it comes to confined space emergencies and most are only too happy to have their local fire brigade come and complete a rescue drill or scenario.
We need to train in environments that are as realistic as possible. Whenever possible involve your local industry and train your firefighters in the types of rescue that are most realistic within your response area.
After instructing in confined space entry and rescue for over five years, I often hear prospective clients who want advice and assistance from their local fire brigade and will only be too happy to include you in their drills and simulations. By involving your local industries in emergency preparation, you will feel more comfortable with this challenging and often dangerous type of technical rescue.
Confined space rescue is one of the most challenging forms of technical rescue as it combines the hazards of structural firefighting with the challenges and intricacies of vertical rescue within small and often hard to reach confined spaces. For fire crews to attend confined space rescues and complete a rescue safety, they must be educated in the hazards of confined space rescue and they also must consider their local response area and the types of confined space incidents that may occur.
Article first appeared in Asia Pacific Fire