In confined space work, ensuring air quality is a top priority. With directives from OSHA and consensus recommendations from ANSI & NFPA, understanding the ins and outs of atmospheric monitoring is key. This article will briefly review what OSHA requires as well as what ANSI, NFPA and Roco recommend for practices that ensure worker safety remains the top priority in working in these challenging environments. While the OSHA General Industry standard allows for periodic monitoring and sets no exact timespan between testing – however, as a safer way, Roco recommends continuous air monitoring any time workers are in the space.

OSHA 1910.146 refers to testing the internal atmosphere before an employee enters the space and testing as necessary to maintain acceptable entry conditions. Testing should be based on the hazard assessment for a given space as well as how rapidly those hazards could cause a change in the atmosphere, which may require additional action for safe entry.

OSHA’s Confined Spaces in Construction (1926-Subpart AA) also references monitoring frequency. It states continuous monitoring is required unless periodic monitoring is sufficient to ensure entry conditions are maintained, or continuous monitoring is not commercially available.

Note: Also take into consideration any previous work activities that may have introduced atmospheric hazards into the space as well as any known history of hazardous atmospheric conditions.

"Roco strongly encourages continuous monitoring while workers are inside a permit-required confined space."

Looking at best practice consensus standards, ANSI Z117 advocates for continuous monitoring in situations when a worker is present in a space where atmospheric conditions have the potential to change.

The national consensus standard, NFPA 350 Guide for Safe Confined Space Entry and Work 2022, also generally refers to “continuous air monitoring” when possible. Here’s a quote from NFPA 350, Section 7.13.1 (www.nfpa.org), Continuous Atmospheric Monitoring, “Atmospheric conditions can change quickly or gradually over time; without continuous atmospheric monitoring, air contaminants may increase, or the oxygen percentage may decrease or increase, creating dangerous confined space atmospheric conditions.” NFPA adds, “Entrants, Attendants, and other personnel may be unaware of changing conditions if the air quality was only initially monitored and determined to be acceptable. The atmosphere within and outside the confined space should be monitored continuously to ensure continued safe working conditions.”

PRE-ENTRY TESTING

Although OSHA does not define a specific timeline to conduct pre-entry monitoring, Roco uses as a guideline that a “baseline test” is to be conducted approximately 30 minutes prior to the entry and then again immediately prior to entry. If ventilation is being used as a control measure for atmospheric hazards, initial atmospheric monitoring should be conducted without ventilation to establish a baseline atmosphere.

A comparison of these readings could indicate that atmospheric changes have occurred inside the space. If a space has been vacated for a period of time, it is recommended that similar baseline testing be repeated. This is critical as it may reveal the presence of previously unrecognized or unanticipated atmospheric hazards.

Again, confined space work is inherently hazardous – and atmospheric hazards are a leading cause of fatalities. Do everything you can to keep your people safe. Don’t let your guard down even for a minute!

Additional Resources: 

Frequently Asked Questions: OSHA PRCS Standard Clarification 

How much periodic testing is required?

The frequency of testing depends on the nature of the permit space and the results of the initial testing performed under paragraph (c)(5)(ii)(c). The requirement in paragraph (c)(5)(ii)(F) for periodic testing as necessary to ensure the space is maintained within the limits of the acceptable entry conditions is critical. OSHA believes that all permit space atmospheres are dynamic due to variables such as temperature, pressure, physical characteristics of the material posing the atmospheric hazard, variable efficiency of ventilation equipment and air delivery system, etc. The employer will have to determine and document on an individual permit space basis what the frequency of testing will be and under what conditions the verification testing will be done.
 
What does testing or monitoring "as necessary" mean as required by 1910.146(d)(5)(ii) to decide if the acceptable entry conditions are being maintained?

The standard does not have specific frequency rates because of the performance-oriented nature of the standard and the unique hazards of each permit space. However, there will always be, to some degree, testing or monitoring during entry operations which is reflective of the atmospheric hazard.

Some of the factors that affect frequency are:

* Results of test allowing entry.
* The regularity of entry (daily, weekly, or monthly).
* The uniformity of the permit space (the extent to which the configuration, use, and contents vary).
* The documented history of previous monitoring activities.
* Knowledge of the hazards which affect the permit space as well as the historical experience gained from monitoring results of previous entries.

Knowledge and recorded data gained from successive entries (such as ventilation required to maintain acceptable entry conditions) may be used to document changes in the frequency of monitoring.

Learn More

By Skip Williams

Contributors: Deputy Chief Kenneth Jenkins, Captain Tom Horn and Captain Anthony Morley, Charleston Fire Department, Rescue 115, and Russ Fennema, Jay Dee Contractors

Note: The following article recounts a very successful rescue that took advantage of available resources at the scene. Roco Rescue wants to share stories like this one to remind our readers that lessons learned can be gleaned from successful rescues just as they can from rescues that didn’t go so well. The important point is to take the time to perform a debriefing as soon as possible after the rescue effort. This is the time to capture the thoughts and comments from the team members while it is still fresh in their memories. Any important lessons learned need to be captured through documentation and then SHARED. The learnings can become part of your SOP/SOI or they can become integrated into your formal training. 

The other point that this article makes is to know and understand your equipment. We regularly train with our ropes and hardware, and we all tend to learn the operating limits and capabilities of said equipment. However, we need to be just as familiar with our peripheral equipment such as atmospheric monitors, radios, and etcetera. Consider spending some of your team training time learning more about that equipment and how to properly use it and what its idiosyncrasies may be. All the equipment we use should be considered life support equipment, and the word “life” should grab your attention and motivate you to know all you can about it. 

In March 2019, Rescue 115 of the Charleston Fire Department was dispatched at 09:02 hours to “man down” at an address on Shepard Street some 5 1/2 blocks NW of station 15 on Coming Street. En route, Captain Tom Horn realized the address was familiar as the entrance to the Coming Street retrieval shaft of the Charleston tunnel project (Figure 1). Now they were 2 blocks from the scene and he immediately called for Ladder 4 also from station 15, and nearby Engine 6 and Battalion 3 from nearby station 6. R115 arrived at 09:06 hours.

The Coming Street retrieval shaft is a vertical shaft 168 feet down and 20 feet in diameter to a 15-foot diameter tunnel being bored for flood control (Figure 2). Just as R115 arrived at the scene, the 12-man cage had been weight tested and prepared for lowering by crane. As R115’s four-man crew was about to be lowered into the shaft, Captain Horn eyed Captain of Ladder 4 and transferred command to him.

Just as R115’s crew got to the bottom, the patient arrived at their location from three quarters of a mile in the tunnel on a horizontal flat car driven by a battery-powered locomotive (Figure 3).

Captain Horn called for the lowering of the backboard and Stokes basket. The topside crew decided to use the crane again rather than lower with ropes. The county EMS was not included as joint training is not done. Back down at the tunnel, the patient was secured, placed in the  12-man cage, along with R115 members and 2 construction workers. The patient at the top of the shaft was treated by county EMS and was off to the hospital at 09:40 just 38 minutes from the initial call.

There are always lessons learned at any rescue. From prior experience, a member was assigned to the crane operator to ensure that the crane was moved under Fire Department control. The Fire Department used the construction company’s gas detectors because they knew that the detectors were calibrated daily. In retrospect, the Fire Department would use its own gas detectors. Also, the backboard and Stokes basket should have gone down on the first lowering to the tunnel.

The usage of gas monitors had been delayed because of differences in calibration between the fire department monitor and a plant monitor. There is no one gas that is best for calibration of fire department gas detectors because many different exposures are encountered. For a particular industrial site, the explosive gases are most likely known. 

Figure 4 shows that the Lower Explosive Limit (LEL) varies according to which hydrocarbon is present. Figure 5 shows correction factors if the monitor is calibrated with one gas and exposed to another. The Fire Department meter was calibrated with methane so that 0.5% by volume of methane reads 10% of LEL. A meter calibrated with pentane has a correction factor of 2 for methane. So, if a meter calibrated with pentane reads 10% LEL in pentane, the meter would read 5% LEL in methane. lf anything, the gas in the tunnel would be methane, but in actuality, the meters read zero no matter what calibration gas was used. 

The reason pentane is sometimes used for calibration is that it overestimates the actual LEL. The caveat is that if the meter is poisoned for methane, a methane bump test is indicated. A sensor can be poisoned by chemicals like silicone.  Note well, silicone is a component of Armor All which should not be exposed to a LEL meter on a fire truck. The lesson learned here is to understand the effect of different gases on a sensor and a Fire Department may encounter many different gases.

Author Bio:

Skip Williams was a volunteer firefighter for 20 years. His last position was captain of the high-angle rescue team and emergency medical technician. He has a Bachelor of Electrical Engineering from Georgia Tech and M.S. and Ph.D. from Rutgers University and has held teaching positions at Rutgers University and the Medical College of Georgia. He designed and patented an artificial heart assist device. He is a Registered Professional Engineer in New Jersey and is a practicing engineer with Condition Analyzing Corporation engaged in condition monitoring of ships. 

Note: Captain Tom Horn is a graduate of two Roco Rescue courses.

Our congratulations to the Burlington (Iowa) Fire Department on a successful grain bin rescue that happened in their community back in May of this year (2018). The incident was reported on Firehouse.com.

The Burlington Fire Department responded to an incident with a man trapped up to his neck inside a corn grain bin in a rural area. Upon arriving at the scene, the initial ambulance unit spoke with the victim’s son who told them that his father was buried up to his armpits inside the bin. The son had thrown a rope down to his father to prevent slipping further down into the corn. Fortunately, the victim remained calm and was able to communicate with the responders.

The bin, designed to hold up to 30,000 bushels of corn, was two thirds full on that morning.

Having been involved in training for 30 years, I have had the opportunity to observe how various organizations in many different fields approach confined space entry and rescue. And, when it comes to training for Entrants, Attendants and Entry Supervisors, the amount of time and content varies greatly.

Before I go any further, I have also seen tremendous programs that foster cooperation between the three functions and use more of a confined space “entry team” approach. This helps to ensure that the entry is performed safely and efficiently.

It also allows all parties to see the overall big picture of a safe entry operation.

However, I am often surprised to find that Entrant and Attendant personnel have little information about the entry and the precautions that have been taken. They are relying solely on the Entry Supervisor (or their foreman) to ensure that all safety procedures are in place. If you have a well-tuned permit system and a knowledgeable Entry Supervisor, this may be acceptable, but is it wise? As the quality of the permit program decreases, or the knowledge and experience of the Entry Supervisor is diminished, so is the level of safety.

In my opinion, depending exclusively on the Entry Supervisor is faulty on a couple of levels. First of all, the amount of blind trust that is required of that one person. From the viewpoint of an Entrant, do they really have your best interest in mind? And, we all know what happens when we “ass-u-me” anything! Plus, it puts the Entry Supervisor out there on their own with no feedback or support for ensuring that all the bases are covered correctly. There are no checks and balances, and no team approach to ensuring safety.

  

These are very real scenarios. Scary, but true. It often shows a lack of knowledge and cooperation between the three functions involved in an entry. And, that’s not even considering compliance!

We ask, would it not be better to train your confined space entry team to the Entry Supervisor level? Wouldn’t you, as an Entrant, want to know the appropriate testing, procedures and equipment required for the entry and specified on the permit? Would it not make sense to walk down LOTO with the Attendant and Entrant? This would better train these individuals to understand non-atmospheric hazards and controls; potential changes in atmosphere; or, how to employ better air monitoring techniques. All crucial information.

More in-depth training allows the entry team to take personal responsibility for their individual safety as well as that of their fellow team members. It also provides multiple views of the hazards and controls including how it will affect each team member’s role. Having an extra set of eyes is always a good thing – especially when dealing with the hazards of permit spaces. Let’s face it, we’re human and can miss something. Having a better-trained workforce, who is acting as a team, greatly reduces this possibility.

Many times, we find that the role of Attendant is looked upon as simply a mandated position with few responsibilities. They normally receive the least amount of training and information about the entry. However, the Attendant often serves as the “safety eyes and ears” for the Entry Supervisor, who may have multiple entries occurring at the same time. In reality, the Attendant becomes the “safety monitor” once the Entry Supervisor okays the entry and leaves for other duties. So, there’s no doubt, the better the Attendant understands the hazards, controls, testing and rescue procedures – the safer that entry is going to be!

As previously mentioned, training requirements for Entrant, Attendant and Supervisor are all over the board with little guidance as to how much training or how in-depth that training should be. Common sense tells us that it makes better sense to train entry personnel for their jobs while raising expectations of their knowledge base.

OSHA begins to address some base qualifications in the new Confined Spaces in Construction standard (1926 Subpart AA) by requiring that all confined spaces be identified and evaluated by a “competent person.” It also requires the Entry Supervisor to be a “qualified person.” Does the regulation go far enough? We don’t think so, nor do some of the facilities who require formal, in-depth training courses for their Entrant, Attendant and Entry Supervisor personnel.

There are countless injuries and deaths across the nation when workers are not taught to recognize the inherent dangers of permit spaces. They are not trained when "not to enter" for their own safety. Many of these tragedies could be averted if workers were taught to recognize the dangers and know when NOT to enter a confined space.

While this incident happened several years ago, it emphasizes the senseless loss of life due to a lack of proper atmospheric monitoring and confined space training. Generally, the focus for training is for those who will be entering spaces to do the work. However, we also must consider those who work around confined spaces – those who may be accidentally exposed to the dangers. Making these individuals aware of the possible hazards as well as to stay clear unless they are properly trained.

The manhole was 18 feet deep with an opening 24-inches in diameter (see photo above). Worker Victim I started climbing down the metal rungs on the manhole wall wearing a Tyvek suit and work boots in an attempt to clear a sewer blockage. The DPW foreman, another firefighter and FF Victim II walked over to observe. They saw Victim I lying on the manhole floor motionless. They speculated that he had slipped and fallen off the rungs and injured himself. The Fire Chief immediately called for an ambulance.

Contributors to the Firefighter's Death:
• Firefighters were not trained in confined space rescue procedures.
• FD confined space rescue protocol was not followed.
• Standard operating procedures (SOPs) were not established for confined space rescue.

The DPW had developed a permit-required confined space program but stopped implementing it in 2004 when the last trained employee retired. They also had purchased a four-gas (oxygen, hydrogen sulfide, carbon monoxide and combustible gases) monitor and a retrieval tripod to be used during the training. It was reported that a permit-required confined space program was never developed because DPW policy “prohibited workers” from entering a manhole. However, the no-entry policy was not enforced. Numerous incidents of workers entering manholes were confirmed by employee interviews.

This incident could have been much worse. Training is the key, whether it’s just an awareness of the dangers in confined spaces or proper entry and rescue procedures. In this case, the victims had no C/S training even though they may have to respond to an incident, and the worker had not had on-going training through out his career. Periodic training to keep our people safe and aware of proper protocols is key to maintaining a safe work force.

Unfortunately, training is usually one of the first things to be cut when the budget gets tight; however, after an incident, it usually becomes the primary focus. Often the lack of training is determined to be a key element in the tragedy.

Investing in periodic training for the safety of your workforce includes spending the time and money to keep your trainers and training programs up to speed and in compliance. The old saying, “closing the barn doors after the horses escaped,” is no way to protect your people – a little investment in prevention goes along way in preventing these tragedies.

One last comment on my biggest pet peeve – proper, continuous air monitoring. This one step can reduce the potential of a confined space incident by about 50%! Don’t take unnecessary chances that can be deadly.