JLN Associates - Your Safety Team. | CONFINED SPACE AWARENESS
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By Thomas Negrelli, JLN Safety Specialist

Many workplaces throughout the United States contain spaces which are considered “confined” due to: their configuration, how you enter and exit them, and the work that is involved inside them.  Not all confined spaces are the same.  The industry that you are involved with can showcase several types of confined spaces. One thing that we really know is, just because all confined spaces are not the same, we still must follow the rules of the Occupational Safety and Health Administration (OSHA), regarding confined spaces.  The general industry standard for OSHA regarding Confined Spaces is 29 CFR 1910.146.  Confined spaces contain several types of hazards and accidents can, and do, happen.


The failure to take proper precautions for confined space entry operations has resulted in injuries and fatalities.  There are several hazards that may be present with confined space entry.  Some hazards are not identified until the space is fully opened.  Having the ability to fully understand the hazards associated with the space you are about to enter comes from your pre-plan of the confined space and your pre-job walkdown/briefing.  During that time, you should review the space, review what is inside the space, what is/was stored there, are there any mechanical devices, electrical devices etc.
One of the most common hazards associated with confined spaces are Atmospheric Hazards.  The atmosphere inside a confined space can be extremely hazardous due to the lack of natural air movement.  There are three types of atmospheric hazards; oxygen-deficient atmospheres, flammable atmospheres and toxic atmospheres.  Oxygen-deficient atmospheres are calculated at less than 19.5% available oxygen.  When you have a confined space with an oxygen-deficient atmosphere of less than 19.5%, entry shall not be made without supplied air equipment or self-contained breathing apparatus (SCBA).
Flammable atmospheres are comprised of two things: (1) the oxygen in the air; and (2) a flammable gas, vapor, or dust in the proper mixture. If an ignition source is introduced into a space containing a flammable atmosphere, an explosion will occur.
Toxic atmospheres are substances such as; liquids, gases, vapors, mists and dusts.  These should all be considered hazardous inside a confined space.  When products are stored inside a confined space, toxic substances can come from them.  Sometimes the product can even be absorbed into the walls of the confined space and give off toxic gases when removed.  Not only do you need to be aware of the toxic atmosphere inside the space you are entering, but any adjacent spaces that connect somehow, may be contaminated as well.
One of the most important tools in determining whether you have an oxygen-deficient space or a flammable atmosphere is to have an air-monitoring metering the inside of the space.
In addition to atmospheric hazards there are general and physical hazards associated with confined spaces as well.  When you are evaluating a confined space, you should consider some of these potential hazards:

  • Temperature Extremes
  • Engulfment Hazards
  • Noise
  • Slick/Wet Surfaces
  • Falling Objects
  • Released Energy or Materials


Air quality and monitoring are two very important aspects of confined spaces.The Occupational Safety and Health Administration conducted a review and the data showed that asphyxiation is the leading cause of death in confined spaces.The asphyxiation that occurred inside those spaces has resulted from oxygen deficiency and some form or toxic atmosphere.Having the proper monitoring device could have saved the lives of many workers.

When choosing monitoring devices for all confined space entries, there are four things that should be looked at:

  1. Portability:  Instrument should be small and lightweight, have battery power or no power requirements.
  2. Ability to provide useful results:  Readings and results should be easy to read and understand.
  3. Sensitive and Selective:  Having the ability to detect and measure only the target product and the device should have the ability to refer to the lowest detectable amount of substance.
  4. Intrinsically Safe:  Depending on what you are doing inside the confined space or what is in there for atmosphere, having intrinsically safe equipment will reduce the possibility of having an ignition source.

When monitoring confined spaces, it is important to understand that some vapors or gases are heavier than air and will settle to the bottom of the space that you are entering.Also, some gases are lighter than air and may rise, and will be found at the top of a space.This fact is important to remember if you are entering a confined space from the bottom ground level and making your way vertical up a structure or space.The power plant industry sees a lot of this when contractors enter a space called a Heat Recover Steam Generator (HRSG), and the access point being somewhat ground level and the work being performed sometimes 40 to 50 feet high inside.

Before any atmospheric tests of a confined space, there must be two equipment calibration checks prior to any confined space readings.First, the monitor must be calibrated per the manufacturers’ specifications.The second would be to field check the monitor prior to testing.This is also known as “Fresh Air Calibration”.After equipment monitoring is completed, this will allow you to proceed with atmospheric testing to determine if a space needs to be ventilated to remove the bad air quality or if no ventilation is needed.


 Do you know what the OSHA Standards are regarding Confined Space Rescue? Have you done a proper evaluation of the rescue services that you have on standby? Do you just use a local fire department to handle all rescues and assume they will come once you dial 911? Understanding all these questions and knowing the answers will help you reduce fatalities or injuries during confined space entry operations.

OSHA statistics have shown that there are almost 240,000 establishments, with 4.8 million permit-required confined spaces.Not all these spaces are entered at the same time or have the same type of hazards. These spaces get entered to perform maintenance work or any other necessary task. OSHA has shown, on average, that 92 fatalities happen per year and roughly 60% of those deaths are due to other workers trying to perform a rescue of a co-worker or individual inside a space that went down.

Paragraph K of the Standard sets forth the requirements for all rescue and emergency services. All employers who have permit-required confined spaces (PRSC) are required to provide rescue services.There are a few ways this can be accomplished and supplied. One way is to have your own in-house team with all the necessary equipment that can handle all the diverse types of rescue or entries that you may face on-site at your facility.The second is to have an agreement with an off-site service team, whether it’s a local fire department’s rescue services or a third-party rescue service.

If the local fire departments are going to provide confined space rescue services, the standard requires the fire departments to train their personnel in multiple areas of confined spaces. Some of the trainings that would be required are, rescue equipment, PPE, simulated rescues, SCBA, First Aid & CPR, LOTO, air monitoring, and many more. The employer must also bring the fire department on-site and do a drill so that the employer can evaluate them to make sure they are proficient and can handle the rescue that may be needed. This also goes for any third-party rescue service as well.One of the most important parts of the confined space standard 1910.146(k)(1)(i) is “evaluate a prospective rescuer’s ability to respond to a rescue summons in a timely manner, considering the hazard(s) identified”. OSHA does not define what “timely manner” constitutes as. Let’s take a minute to talk about the effects that occur if we encounter an oxygen-deficient atmosphere and a worker goes down inside the space. Research has shown that between 30-180 seconds of oxygen deprivation, you may lose consciousness. At the 1-minute mark, brain cells begin dying. At 3 minutes, neurons suffer more extensive damage, and lasting brain damage becomes more likely. At the point of 5 minutes, death becomes imminent and at 10 minutes, even if the brain remains alive, a coma and lasting brain damage are almost inevitable.Lastly, after 15 minutes, survival becomes nearly impossible. (www.spinalcord.com).

So what do you think a timely manner is, in regards to rescue?

Can your local fire department rescue service get there in enough time, or do you need to have a service team on-site ready to go?

These are all great questions to ask and think about. Going home at the end of your workday is the most important part of the day. Taking these precautions in regards to air monitoring, knowing the hazards, and having a suitable rescue plan and team in place will help reduce the risk of injury and fatalities.