What’s in, what’s out, what’s new, and what’s needed
In 1993 OSHA enacted 29 CFR 1910.146 “Permit-Required Confined Spaces.” In 2015, a major new confined space regulation, 1926 Subpart AA, expanded regulatory requirements to cover permit required confined spaces during construction. As part of the new rule, OSHA has clarified and expanded the list of applicable permit required confined space, training requirements, communication requirements, assignment of responsibilities and use of gas detectors and atmospheric monitors. Testing and calibration requirements have been clarified as well.
The manufacturers of equipment used in confined spaces have not been idle. The new rules have driven many changes, especially in the performance and capabilities of confined space gas detectors, including:
- Good communication among contractors and CSE team members is mandatory.
- Decisions need to be based on real time information
- Confined space gas detectors offer real-time wireless communication via Blue Tooth, license free RF wireless or cellular connection.
- Each method has benefits and limitations
New types of sensors:
- Solid polymer electrolyte (SPE) O2 sensors can last 5 years or longer without needing replacement
- Infrared LEL sensors need less power, but have different limitations in the way they measure gas
- Dependable electrochemical sensors that can be used to measure gases like H2S, SO2 and NO2 with increasingly low exposure limits
- PID sensors for toxic VOC and fuel vapor detection
Compact size, easier to use designs:
- Full-size versus miniaturized electrochemical sensors
- Five gas and six gas instruments becoming the norm
- With or without an internal pump
- Better batteries, longer operation
Automatic record keeping solutions:
- Conformity without proof is not enough
- Keeping good records is mandatory!
Docking stations and automatic test stations:
- Performing a daily bump test is mandatory in many jurisdictions, what does OSHA say?
- Automatic docking stations make testing and calibration simple
Jamie: Hello, and a warm welcome to everybody. We would like to wish everyone a good morning, a good afternoon, or a good evening depending on where you are in the world today. My name is Jamie and I’m one of the co-founders of Safeopedia.
Safeopedia’s mission is to support the EHS professionals, operational folks and any safety-minded individuals through free, educational content, tools and resources. We really want to thank those dedicated professionals with the great work they do on a daily basis.
Today, we’re very proud to present Recent Changes in the Rules for Confined Space Entry: What’s in, What’s out, What’s new, and What’s Needed. This Safeopedia webinar has been made possible by GfG Instrumentation, a preferred supplier/member of SafetyNetwork. SafetyNetwork demands excellence, so demand SafetyNetwork.
It is now my pleasure to introduce to you my good friend, and today’s presenter, Bob Henderson. Bob is the president of GfG Instrumentation. He has over 37 years of experience in the design, marketing and manufacture of gas detection instruments. He is a past chairman of both the American Industrial Hygiene Association, Real-Time Systems Society Technical Committee and Occupying Spaces Committee. He is also a past chairman of the Instrument Products Group of the International Safety Equipment Association. He has a B.S. in Biological Science and an MBA from Rensselaer University. I now invite you to sit back, relax and enjoy the presentation. With that, Bob, please take it away.
Bob: Thank you very much, Jamie and hello everyone and thank you for signing on to the webinar. Confined space entry is a huge topic, whether it’s entry that is done pursuant to the general confined space entry requirements in 1910.146, or whether it’s entries done with the—according to the newer construction confined space entry rule, it’s a big topic. And an hour is not long enough to get very deeply into it. So I hope that this is the first step, not the last step, that you all take in understanding these important topics.
For those of you who don’t know much about GfG, we specialize in gas detection equipment, instrumentation for safety, environmental hygiene monitoring. We have factories in the United States, Germany, Switzerland, and South Africa and it’s all we do. We are specialists in gas detection and if you have any questions or thoughts or just want to talk some of these issues over later, please, please send us an email, we are looking forward to responding.
One of the things that I’m very proud to be able to point to is our company website, which is goodforgas.com. One of the things that we have on the website is a variety of technical resources and support materials. I’m very proud of the fact that they are not sales-oriented, they are factual, neutral and designed to really give you some guidance to the best of our ability with regards to using gas detection equipment, making decisions about which kinds of sensors will do the best job in terms of your monitoring requirements, and just being a source of helpful information.
At a number of points in the presentation, I’ve included links to both our own application notes and also to some of the resource materials that are published by OSHA that explore some of the points that we’re discussing in greater detail. And you will need some additional detail as you use today’s information to conform with the requirements in the confined space rules.
So, before we get to the construction confined space rule, I think it’s useful to give you a quick historical summary of where we’ve been and where we are going with the confined space rules. In 1993, OSHA enacted, or promulgated, 29 CFR 1910.146 Permit-Requirement Confined Spaces. During this presentation, I’m going to shorthand that by referring to it as 1910.146, or the general confined space rule. The provisions in 1910.146 apply to general industry work. The original intent was to extend 1910.146 to include construction. So when you looked in the construction rule, the original intent was to see a brief sentence or reference that 1910.146 was applicable, but that did not happen because it was quickly recognized that 1910.146 did not fully address issues that are unique to the construction industry. For instance, higher employer turnover rates, worksites that change frequently in the course of construction activities, and a multi-employer business model that includes prime contractors, subcontractors, employers, specialists—it’s very complicated often in terms of the personnel issues.
The OSHA rules are divided into horizontal rules and vertical standards. The horizontal rules apply across the board to workplace activities that are defined by what you’re doing. And you have vertical rules that are focused on a specific industry, or a more specific kind of defined activity. The confined spaces rule 1910.146 is a horizontal rule. It includes requirements and practices and procedures to protect employees. In general industry, if you’ve got a confined space, it’s going to be covered under the confined space general industry rule.
If an employee is working in an industry where there is a vertical or an industry-specific standard, but then the vertical standard takes precedence. If a vertical standard is not applicable, the general industry standard prevails. If you have a vertical standard, then that’s where you go first for guidance and your requirements. The big problem is when the vertical standard does not have much to say about the activity that you’re undertaking. And 1910.146 does not apply to those vertical standards or industries that are governed by vertical standards such as agriculture, construction, shipyard telecommunications—and that left a gap. Even though the construction activity might be taking place in a confined space, 1910.146 did not apply. But that has been addressed, finally after 22 years is, as of 2015, construction finally has its own standard for confined space and tree activities and that’s 29 CFR 1926 Subpart AA. So shorthand during this presentation, I’m going to refer to the construction rule as the construction rule, or 1926, or Subpart AA. It’s just too big a mouthful to give it the complete title every time that it comes up.
But the construction rule is similar to content and organization to the general industry confined spaces rule. It also is centred on and includes a permit program, designed to protect employees from atmospheric and physical hazards associated with the work that’s being done in confined spaces. Under both standards—under both rules—the definition of a confined space remains the same. A confined space is simply an enclosed space that is large enough for the worker to enter, it’s not designed for continuous worker occupancy, and has limited openings for entry and exit.
Not all enclosed spaces, by the way, are confined spaces per this definition. For instance, here are a few examples. The guy who is crawling into a pipe is entering a confined space. But the guy who is opening the door to enter the container, is not entering a confined space. The guy going into the sewer—confined space? Yes. The guy in the very shallow thigh-high trench? No. Now, just because it’s not a confined space, does not mean that it has no dangers. Customs inspectors and other people that enter containers that are coming from off-shore, and which may have been fumigated during transit, opening the door may unleash—or release—a wash of very toxic fumigant gas. It’s not as if if you have—if you don’t meet the confined space definition—you have no dangers. And the general duty clause says that you must keep workers safe under the circumstances. So don’t completely overlook the hazards just because it’s not a confined space. But in today’s presentation, we are going to focus on the environments that meet the confined space definitions.
Now just because you have a confined space, does not mean you have a permit-required confined space. You need the presence of an additional danger associated with the confined space to trigger its inclusion in the permit-required confined space category. The types of hazards—number one, first and foremost—is the tendency of a confined space to retain, trap or develop dangerous atmospheric conditions. Hazardous atmosphere, known or potential, is the most common serious safety danger that triggers the inclusion of a confined space in the permit-required confined space category.
But that’s not the only kind of hazard that does the job. The hazard can be that the spaces associated with material that has the potential to shift or engulf. Sometimes it’s the physical danger of the space if it’s a space with inwardly sloping walls, dangerously sloping floors that could trap a worker. Or it can be any serious safety hazard. If it’s in that confined space, then that turns it into a permit-required confined space. Under both rules, you have the same choices in terms of how you make the entry into the permit-required confined space. The options include temporary reclassification as a non-permit space. If the hazards in the permit space are exclusively atmospheric in nature and can be handled and the environment rendered safe by means of continuous ventilation, then you can use the alternate entry confined space procedures. If the hazards go beyond atmospheric hazards—or if you have to do more than ventilate to render the environment safe, the confined space safe for occupancy, then you need to follow the provisions in a permit that step-by-step takes you through all of the things that you need to do to keep workers safe.
Under 1910.146, after construction was over, then and now, environments like crawl spaces and elevator pits where there are no particular dangers that are present, those are not deemed to be permit spaces. They are confined spaces—they’re large enough to enter, they’re not designed for continuous worker occupancy, they have limited means for entry and exit, but absent-specific serious safety hazards, they’re not a confined space. A big change under 20, 1926 Subpart AA, and something that is over and over hammered in the new standard—is that during the construction process, at many stages, these benign confined spaces can become very dangerous because of the activity that is going on at that moment. For instance, when a sealant is being applied in a crawl space, you have the potential for the release, or generation, or toxic, or flammable vapours. In the case of freshly-poured concrete, or sealants and paints that are catalyzed by oxygen—while these materials are curing or drying, they can actually absorb oxygen and you can wind up with an oxygen deficiency. Or if the vapours that are being released are heavier than air, they can settle. So during construction, these benign environments can actually be quite dangerous.And under the construction rule, what you need to do depends on what’s going on at that moment.
And another thing that is hammered on in the construction rule, is they give you a lengthy list of confined spaces that are covered by the new rule, just to make it clear that environments like attics and crawl spaces are environments that you need to consider in light of confined space issues and dangers. Some of the environments that are specifically called out—confined spaces that are specifically called out under the construction rule include boilers, manholes—this includes sewers, storm drains, electrical vaults, communication vaults, utility vaults, precast concrete manhole units, like you see in the lower right hand of the picture on this slide. Freshly poured concrete does absorb oxygen. Materials that get into the bottom of the manhole, maybe there’s a little of water, maybe there’s a little bit of organic material that has gotten in there. You can easily have an oxygen deficiency. The concrete itself can absorb oxygen. Sometimes that manholes are inserted into ground that has other things going on and materials leak in, or you have the presence of external contaminants that can get into the atmosphere in the manhole. You got to consider it as a confined space. Concrete pier columns, sewer storm drains, ducts—this is another one. A duct is often not a dangerous confined space after construction is over, but depending on what’s going on at that moment, a duct can definitely be a very dangerous permit space. Mixers, reactors, turbines, silos—these are all environments that you need to consider as potentially dangerous confined spaces. If they’re not, they’re not. If they are, then you have to govern them with a permit-entry procedure.
Something that OSHA has done is to create a number of really useful information of documents and sources of information. I like this one. It’s posted on the OSHA site. It’s in simple to read English. Not too complicated and it’s available for download. I like the title also. You’ll notice it’s Protecting Construction Workers in Confined Spaces: Small Entity Compliance Guide. Note the word “small” in the title of this document. You might be a small contractor or a contractor or firm company that’s involved in construction of small projects. Just because the project is small—just because your company is small— you’re not relieved of the obligation of complying with the confined space entry rule. You don’t get a pass because you’re a small company, you still are held accountable to do the right thing to keep your workers safe.
Another important point that is addressed in the construction rule and in the general confined space rule, is that you don’t have to have a fully enclosed environment—space—to meet the confined space definition, and to have a really dangerous confined space. Many of the worst confined space accidents that have occurred over the years, have occurred in open-topped confined spaces. Open-topped water tanks, digesters, lift stations, bins, degreasers, pits—these are all confined spaces. And I think one of the reasons that you’ve seen some of the worst confined space accidents, in terms of worker injuries and death in these open-topped confined spaces, is that they look visually so darn harmless. Remember—but that the easiest ways to get—some of the easiest ways to get killed in confined space accidents—are by exposure to dangerous atmospheric conditions, which are not well-detected by human senses. You can’t smell an oxygen deficiency. You can’t smell a build-up of carbon dioxide. You can’t smell a build up, or the presence, of carbon monoxide. These dangerous contaminants and conditions are invisible to your human senses. All you see is sometimes an empty harmless looking pit, you go in, and, unfortunately, over the years, many workers have not come out. So OSHA again, has a very nice fact sheet about confined spaces in—or construction—in pits. Over the years in the United States, we’ve accumulated enough accidents and injuries and deaths to have a large number of examples to use in a fact sheet of this kind. It’s something I’m hoping we will continue to avoid in the future and see more and more reductions in the accident rates and the fatal statistics as companies do a better job of following the procedures in the confined space entry rules.
Crawl spaces and attics—again this was certainly controversial. OSHA absolutely has not backed down or backed off on this one. During construction, attics and crawl spaces are potentially dangerous. When OSHA publishes a new rule in the federal register, generally there is a preamble to the rule that explains why it is that the rule contains the provisions that it does. In the preamble, they will generally reference accidents and examples of the kind of dangers that we want to guard against and prevent from causing injuries or death to workers. If you’re interested, you can read the preamble to the construction rule which includes a number of examples. There are several examples of accidents that occurred in crawl spaces and attics. These are real. In one case, two workers died while applying primer. They were burned and killed when there was a flash fire when an incandescent lamp—which was not designed as an intrinsically safe lighting source—provided a source of ignition, ignited the vaghylo.pours and the guys were killed. Another flash fire killed a worker who was spraying foam insulation in an enclosed attic and the lack of ventilation was—because of the lack of ventilation—the combustible gas over time accumulated, reached a flammable level, there was a source of ignition, and the worker was killed.
The general requirements under both rules are very similar. You need, as an employer, to identify the confined space hazards. You need to inform employees by posting signs, “This is a dangerous confined space.” You need to prevent entry by unauthorized persons. At a construction site, it’s just harder to do. You need to be vigilant. You really need to have well-trained people who are going to stop people from making a mistake going into a permit space—going into a confined space where they don’t have any business being. And you’re going to have work hard to use gates, signage, locks, anything you can do to prevent entry by unauthorized persons who are centred on getting something done, and who are overlooking the fact that they are now violating the procedural requirements for entry into a confined space.
Employers need to ensure that the required equipment is available. If it’s your own employees who are involved in the entry, then you need to supply it directly to those employees. If you’re using a contractor, then you need to make sure that the contractor has and is using the required equipment. The types of equipment include testing and monitoring equipment, ventilation equipment, communications, lighting, barriers, other personal protective equipment, and—and we’ll be talking more about this as we go on—any required rescue and emergency equipment. You need to as an employer to establish the procedures and practices to allow safe entry into confined spaces. That is your permit system. You need to either train your own employees, or if you’re using a contractor, verify that any workers who are on-site doing jobs that you are paying for, that you verify that those workers are competent and can prove their competency with documentation that they are appropriate to be involved in confined space activities. You need to ensure that the required equipment is available and used. And wherever possible, eliminate the hazards. For Pete’s sakes, if you can avoid having to make a permit entry, that’s the safest course of all. If you can inch and near the hazards out of the confined space on a permanent basis, that is a great thing to do. Unfortunately, in the case of construction, maybe after the construction is done, that’s more feasible, but during construction that’s often very challenging, which increases the obligations for what you’re doing on a moment to moment basis to keep workers safe under the circumstances.
You need to protect workers from external hazards. You need to enforce your procedures. It’s not enough to have a great program on paper. You’ve got to make sure that people are following your guidelines and procedural requirements. And rescue. Calling 9-1-1 after the accident occurs is not an acceptable means of dealing with the need to rescue people if they get into trouble. If you have any doubts about how far you can depend on dial 9-1-1, there’s another nice OSHA fact sheet on your obligations with the regards to the need to have a plan to deal with rescue. By far and away, what we want to do—the best way to tackle the whole rescue issue—is to use techniques and procedures which allow you to identify conditions at a time when they are just a little bit abnormal and when workers can self-rescue. So you’re using continuously operational monitors, atmospheric monitors. When the lull alarm sounds, the idea is that it is activated at a concentration which allows workers to self-rescue. You always want to aim at self-rescue. You don’t want to have conditions deteriorate to the point that the worker is not able to self-rescue. The second-best approach would be to use retrieval systems where the standby attendant can extricate—remove—the effected worker from the confined space without actually entering the confined space. And it is really important to understand that attendants do not jump into the confined space to conduct a rescue, unless they are authorized to do so—unless the program says that that is part of their expected duties, and unless they can turn the attendant duties over to another persons who is qualified to be the attendant. You don’t want to be statistic. Today, nothing has changed much in this regard over the last 30 years. Still, two out of three of the workers who are killed in confined space accidents are would-be rescuers. Typically—unfortunately—what continues to be the case is the first worker goes down—loses consciousness—another worker jumps in. That worker is affected by the same conditions and sometimes you have unfortunately multiple fatalities as more workers are drawn in to attempt to rescue the guys who have got into trouble beforehand. Hard lesson to learn, but the attendant is supposed to remain outside the space, unless specifically authorized to enter the space to conduct a rescue. If you have to go into the space to conduct a rescue, that’s the least preferred option. It takes much more training, equipment, personnel. You really want to limit the need to enter the space to conduct a rescue, because it’s very difficult to do and you’re really going to have to plan and train, and it’s just tough.
Training throughout the construction rule—there’s a lot of emphasis on training. One of the issues with construction confined spaces is that you’ll have a contractor or a group of people that will be on site to do a specific job at a specific time during the construction process. Training can be a big issue when you have new guys turning up on-site every couple of days. One of the things that you want to do is to establish the criteria which will allow you to decide whether that worker who’s coming on-site is properly trained. You might handle this with putting workers—all workers—through your own confined space course. Or you might make sure that the contractor worker has his own documented training certificate where a third party that you agree is appropriate has done that training. But by hooker by crook, anybody who is doing a confined space entry at your best as an employer, needs to have the necessary competence. They need to be able to understand the hazards, the methods that are used to keep workers safe. They need to know what to do in an emergency or if it becomes necessary to conduct a rescue. The construction rule has a lot of emphasis on communication as well. Often during construction, a confined space is not an event that starts and stops in a couple of hours. A confined space might be open and different things are going on at different times. It might be open for days or even weeks in the case of some of the sites that I’ve visited. The entry employer must ensure that all entry supervisors, authorized entrants and attendants are properly trained, and that they follow the confined space—the employer’s—confined space entry program. Whenever responsibility for a PRCS—that’s a permit-required confined space—whenever responsibility for a PRCS is transferred, the entry supervisor needs to determine that entry conditions and operations remain consistent with the terms of the entry permit and that acceptable entry conditions are maintained. If you can’t do that, then you don’t transfer ownership of the confined space to a new entry supervisor. You’re going to have to seal it up and just end the entry and the next guys can start from step one and re-authorize the space as fit for use with the next crew. Typically, you’re going to turn it over to a new entry supervisor, who is also competent and completely trained, and you do have knowledge that the conditions remain safe.
Also, keep these records. You want to keep these records for 25 years. That’s a really, really long period of time. Fortunately, in the age of computers, keeping and retaining records is not as difficult as it used to be. At least most of the time you’re not winding up with a warehouse full of slowly deteriorating paper. Don’t discard your permits and your other records indicating that you’ve been following your rules. You’re going to want to have those records if you’re explaining or defending yourself sometime in the event that you are inspected, or God forbid, there’s been an accident. One of the issues that is—has certainly driven improvements and changes in atmospheric monitors and other safety equipment—the need for communication is now being—you have wireless communication that is embedded in the gas detection equipment. Sometimes in the SCVA and other types of protective equipment that you’re using.If you need it, it’s available and it’s one more thing to evaluate when it’s time to decide what you need in the way of monitoring equipment. With regards to atmospheric monitoring equipment, one of the things that the standards—both standards—really have at home is that you have to maintain and operate the equipment in the way that the manufacturer says that it needs to be calibrated and operated, and also you need to test it by exposure to gas. Best practice is to perform a “bump check” on the instrument by exposing it to test gas before each day’s use. Why is this so important? It’s because instruments can break, sensors can lose sensitivity. They can be poisoned by exposure to contaminants during the course of normal operation, and the only way to know that the instrument is safe for use is if you expose it to test gas and the sensors respond. The requirements are lengthy. The reasoning is good behind putting the stress on importance on performing bump checks before each day’s use. If you want to know what the regulations say and what the regulatory agencies think, we’ve got a nice application note. I’ve posted the link here. The application note is on our GoodforGas website and I hope you’ll have a look.
If you want to see the official take from the OSHA perspective, OSHA also has a nice document where they lay out the requirements for you. The OSHA definition for a bump check is—or a “bump test”—it’s very simple. You’re using test gas which has a concentration of gas in the cylinder of gas that you’re using that is high enough to cause the activations of the alarms. What you do in the OSHA bump test, is you throw some gas over your sensors. The alarms either are activated or they are not activated when you expose the sensors to gas—when you expose the instrument to gas. If the alarms are activated, you pass. If the alarms are not activated, you fail. You’ll notice that nowhere in the bump check is there a verification of the accuracy of the readings. The bump check is a qualitative test—a yes-no test. It either shows that the instrument responds or does not properly respond in terms of the alarms being activated when you expose the instrument to gas.
The next level of verification includes an assessment of the accuracy of the readings. OSHA refers to this as a “calibration check.” The difference between a bump test and a calibration check is that you’re using calibration gas, not test gas, to—although you can use calibration gas to do a bump check. In many cases, the test gas is not as accurately manufactured. You don’t really care what the concertation is so much, when all you’re doing is activating the alarms. But in a calibration check, you’re actually looking at the readings. You’re going to watch the reading stabilize while the sensors are exposed to gas, and when the readings stabilize, you need to be within the ballpark tolerances that the instrument manufacturer says that you should expect when you’re using that instrument. If the manufacturer says the readings should fall between plus or minus 20% of the concentration that you’re using when you’re testing the instrument, then that’s the criterion that you use to decide whether you pass or fail the calibration check. The OSHA best practice is to perform a bump test, or a calibration check, before each day’s use. Good news here—it doesn’t take very long. To do a bump check—takes ten seconds. It’s really, really quick. To do a calibration check, you need to wait just a little longer for the readings to stabilize within that window that the manufacturer gives you for the expected accuracy, but generally that’s not going to take you more than 30 seconds. Now if you fail a bump test, or a calibration check—or if the manufacturer says at certain specified intervals that you need to perform a full calibration, you perform a full calibration.
A full calibration includes the adjustment of the sensor to make sure that the readings are as accurate as they can be, given the instrument that you’re using. A calibration is always going to include two steps. In the first step, you make sure that when the instrument is in fresh air, that the readings are at fresh air values. Then, you’re going to expose the sensors to calibration gas and you’re going to make sure that at the end of the adjustment, the readings that you see in the instrument—the display match the concentrations of the gas that you have in the cylinder—or cylinders—of calibration gas.
Remember, the gas detection instruments can only keep workers safe when they are maintained and used properly. Things—if you’re a gas detector—you’re living a brutal life. Users tend to treat gas detectors like they treat wrenches and hammers sometimes. Instruments can get dropped. There are certain substances that can really cause harm to some of the sensors. Things change with regards to the instrument’s ability to properly detect gas. You need to test it periodically to ensure that it is continuing to be a product that is capable of keeping your workers safe. It’s a life-safety critical element of your protective equipment. Take it seriously. Don’t just buy an instrument, never test it, and after two years expect it automatically to be capable of detecting gas. You need to periodically verify that the instrument is capable of properly detecting dangerous conditions.
Now one of the ways that you can really simplify the process of testing and also maintaining proper documentation to prove that the instruments are being maintained and tested in accordance with regulatory and manufacturer criteria. If you have a few instruments, invest in a docking station. The docking station makes it completely automatic. All you wind up doing is having to put the instrument into the docking station and pull it out 20 seconds later and you’ll have performed the necessary test—or check—and you will have automatically generated documentation that then is easy to keep on hand for the next couple of decades.
You want to both monitor continuously and ventilate continuously. If you’re using a gas detector before entry into the confined space, it’s mandatory to determine that the permit-space atmosphere is safe for entry. Remember that many accidents result from changes in the atmosphere after the entry is initiated. You don’t want to test and then put the instrument back in the truck when you’ve done your pre-entry testing. You want to continue to use that instrument continuously as long as the entry is underway. Monitoring determines the area safe. Ventilation keeps it that way. In most cases, you do want to keep that ventilation running continuously for the entire period of time that the entry is underway. The only way to pick up changes before they become life-threatening, is to monitor continuously. Remember, we’re aiming at self-rescue. You’ll want people to leave long before the conditions become life-threatening.
In terms of atmospheric hazards, there’s four general categories that we deal with in confined space activities. There’s oxygen deficiency. There’s also oxygen enrichment. For Pete’s sakes, never deliberately introduce pure oxygen into a confined space. Elevated concentrations of oxygen can accelerate chemical reactions and they also become materials to become highly combustible. Materials that are barely capable of burning in normal atmospheric concentrations of oxygen, can become explosively flammable in elevated enriched concentrations of oxygen. When you have an oxygen sensor in your instrument, the instrument is telling you if the conditions—if the concentration indicates an oxygen deficiency. But even though you may not see an oxygen enrichment alarms very often, your instrument also has a high alarm if the concentration of oxygen becomes elevated. By far and away, the easiest way to have a fatal incident due to atmospheric conditions in a confined space, is to have an oxygen deficiency. Oxygen deficiencies can occur as a function of many different causes. You can displace the oxygen by another vapour or gas in the confined space. You can consume the oxygen by some kind of a combustion process. You can consume the oxygen by bacterial or microbial action—just decomposition in the confined space. One of the many things that can happen is an oxygen deficiency. Sometimes it’s simply rusting in the confined space that depletes the oxygen and leaves you with a very dangerous environment.
You also have toxic gases to be concerned with. By far and away, the most common—the big two—would be carbon monoxide and hydrogen sulfide. Carbon monoxide being a by-product of combustion or incomplete combustion. Hydrogen sulfide, usually in confined spaces, it’s caused by bacterial action. You also have the presence potentially of many combustible gases. That same microbial action that can deplete the oxygen and produce hydrogen sulfide—well, other kinds of bacteria are really good at producing methane—combustible gas. Or, you can have the presence of other combustible gases that have leaked or become present in the confined space by some other source, such as propane or solvents. Solvent vapours are not only toxic, but they’re also at high concentrations, they can become combustible. You need to do something to guard your workers against all four categories of risk.
For oxygen deficiency, traditionally we have used what is called a fuel cell oxygen sensor. A fuel cell oxygen sensor has a lead electrode on the inside of the sensor which is slowly used up over the life of the sensor. When you run out of lead, the sensor is dead, and you need to replace the sensor. These kind of sensors continue to be very popular, continue to be very widely used. Among other reasons, one of the most important is that they take very, very little power to operate. If you have an instrument that you want to use for a year or more, or two years, without even having to recharge the instrument, a fuel cell oxygen sensor lets you do that. The downside to the fuel cell type oxygen sensors, is that you do have to replace the sensor every two or three years, and also the sensor is full of liquid electrolyte which can leak and cause harm to the instrument if a failure to the sensor occurs over the life of the sensor in the instrument. They’ve got some downsides, but they continue to be widely used because they take almost no power.
Alternatively, nowadays on the outside the sensors look exactly the same. On the inside, they’re very different. You have a new generation of lead-free sensors. They don’t eat up a lead electrode or the life of the sensor. The only thing that you use up in the oxygen pump type sensors, is a little bit of electricity. The sensors are warranted—and not for two years or three years—they’re warranted for four years or five years. The sensors can actually last even longer than that. They’re terrific sensors for many, many applications and are widely used in an increasing number of instruments. But you don’t want to use them in instruments with alkaline batteries, because if they use up all the power in the alkaline batteries, they can take an hour or more to stabilize again when you replace the batteries, and you also don’t want to put them in a low power device where you have a limited amount of power available over the life of the instrument. These go into instruments that are periodically recharged, so the instruments have a rechargeable battery. In the case of the instruments that you decide to buy, talk it over with the manufacturer. Most manufacturers, such as GfG—we are perfectly happy to tailor the types of sensors that we put into the instrument as a function of the kind of ways that you’re going to use the instrument. But if you don’t ask, you’re not going to necessarily get the optimal combination of sensors that you need for the best performance and cost of ownership of the product.
Toxic gases and vapours—the most common in confined space entry are definitely carbon monoxide and hydrogen sulfide. However, that’s only the beginning of the kinds of gases and vapours that you can run into during confined space activities, especially during construction. Also, the exposure limits for a number of common toxic gases have been dropping. Some of the other important toxic gases include sulfur dioxide, nitrogen dioxide, carbon dioxide, chlorine, ammonia, hydrogen cyanide if you’re working in foundries, and a big one in construction confined space—volatile organic chemicals—VOCs. Where you look for guidelines for toxic exposure limits—wherever you are—what can get you cited would be the permissible exposure limit in that jurisdiction. It could be based on the federal exposure limits. It could be based on the NIOSH-recommended exposure limits. Or it could be based on the TLVs. The TLVs tend to be the most conservative and the lowest of these three.
Setting toxic alarms can be a little bit complicated. Once again, we’ve got a great application note to help you walk through the reasoning process. Carbon monoxide is a good example of how the exposure limit changes as a function of where you are or what you’re doing. If you’re following federal OSHA-permissible exposure limit guidelines, the exposure limit for CO is 50 parts per million. If you’re one of the 28 states with an OSHA-certified occupational safety and health plan, you’re probably following the NIOSH-recommended exposure limits, so the low alarm is going to be set at 35. If you’re in a jurisdiction or you have corporate policies where you are following the TLV, then the limit is 25. Now this means that when a manufacturer sends you an instrument, it has some kind of default alarms that are set when it left the factory. Those alarms may or may not be the ones that you should be using. Given where you are and what you are doing, verify that the alarms that you are using in your instruments, are the ones that you should be using. Hydrogen sulfide—the TLV—just pointing this out—in 2010, the TLV was dropped from 10 parts per million to 1 part per million for the 8-hour TWA. The STEL alarm was dropped from—or the STEL limit—was dropped from 15 to 5. Make sure if you’re following the TLV limits that you have an instrument that is designed and capable of sounding the alarm according to the newest rules. Sulfur dioxide—the TLV dropped way low! In 2009, the new TLV went into effect and the TWA limit went away. The STEL limit was dropped to 0.25 parts per million. That’s really, really low. A lot of people today have to monitor for SO2 because the limits are now so low. The same is true for NO2, where the limit is now only 0.2 parts per million. Once again, if you have these hazards, make sure that you have an instrument that’s capable.
Measuring combustible gases and vapours—we are going to tell you how close you are to the minimum concentration that supports combustion. Different gases have different LEL limits. For instance, with methane, 100% explosive is only 5% volume methane. For propane on the other hand, 100% explosive is only 2.2%. Where you’re going to set the alarm is way, way below that at down near 5% LEL or 10% LEL. The way that we detect combustible gas traditionally is with a sensor that actually oxidizes or burns the gas on a little bead—a hot bead that’s on the inside of the sensor. These kinds of sensors are really good at measuring small molecules, not so good at measuring really large molecules. But they are—we continue to use these are the best way to detect many combustible gases. They require quite a bit of power. One of the sensors that we see coming into vogue at the moment, are infrared sensors that require a little less power. More on those in just a moment. One of the important lessons to learn with the standard combustible sensor—with any combustible sensor—let the readings stabilize completely before you do something irrevocable. For traditional LEL sensors—for most LEL sensors—different gases take a little bit longer or a little bit shorter time to fully stabilize. You can see the shape of the curve is quite different with a traditional sensor for methane, where you're fully stable after 35 seconds to propane, where it actually takes a lot longer time to get that last little bit of change for the 100% stable reading. Traditional LE sensors also can be easily poisoned. The worst of the poisons out there would be silicones. So, keep silicones away from traditional sensors. For the alternatives that are increasingly popular out there, a lot of folks are looking to infrared sensors, where we measure the gas by absorbing light from an infrared source. If you want to measure combustible gases, you look around this area in the spectrum.If you want to measure carbon dioxide, you look around this end of the spectrum. It’s a great way to measure combustible gas, as long as the gas is measurable by the infrared sensor. But watch out. You’ve got a lot of advantages with infrared sensors. They use a lot less power, but they cannot be used to measure some gases like hydrogen and acetylene. And depending on the sensor manufacturer, they may or may not be all that good at measuring some of the other vapours and combustible gases that you have of interest. So, make sure you talk to the manufacturer, you look in the owner’s manual, and you see what you can measure, what you can’t and make sure that it works.
For VOCs, we’re going to use photoionization detectors. Photoionization detectors detect gas by ionizing the gas with a beam of ultraviolet light and they’re not that hard to use. Once again, we have lots of materials on our website that can help you through the process of deciding what sensors to use.Generally, if you have VOCs, you want to have both a PID sensor and a standard LEL sensor in the same instrument, they work together—they’re not alternatives to each other.
That brings me to the absolute end of the seminar. I hope again, this is just the first step on your journey to learn more about confined space issues and atmospheric monitoring issues in and out of confined spaces. Please give us a call. Drop me an email. We love to hear from instrument users. Thanks very much guys. Have a great day.
Jamie: Awesome, thank you Bob. Absolutely a giant topic. How do you fit it all into the hour? Thank you so much. Everyone, we realize we’re at the top of the hour. Absolutely appreciate if you have to jump off. We do have quite a few questions, so if you have to jump off, we will be sending you the recording along with all the questions that are asked and answered. If you can stay, awesome. We’re happy to have you and we appreciate your time and respect that you are out there keeping the world safe. So with that, let’s get into a few questions here.
We’ll ask Andrew’s first. Bob, what are the regulation differences between a permit-required confined space and a non-permit-required confined space.
Bob: Well, if you have a non-permit-required confined space, then you have an environment that has no serious dangers associated with the space. So not only is it a non-permit space—you don’t have the requirement for a permit—you’re just—people who are working in that non-permit confined space—you just need to use the same level of safety equipment and general PPE that you use on-site outside of confined spaces. Now the big issue is determining whether that non-permit space really is a non-permit space in that moment. In many cases, you’re going to have to test it beforehand and verify that it really is a non-permit space. During your inventory of confined spaces that are present on-site, you identify confined spaces. You look at the potential dangers and you make some sorting decisions. But even in non-permit spaces, a lot of times just on general principals, because anywhere on-site might be subject to the potential presence of dangerous conditions, you may still want to have workers wearing a gas detector. But a non-permit space is a space that—where you follow the rules anywhere on-site that is also not a permit-space.
Jamie: Great, thank you Bob. We have—Jason has a question here. Since infrared LEL sensors cannot be poisoned or affected by exposure to chemicals, do I still have to perform a bump check on them before each day of use?
Bob: Yes, you do. Partly this comes from the certification laboratories. Any instrument that you buy is going to have a certification of safeness for use in explosive atmospheres that comes from a nationally-recognized testing laboratory like UL, or CSA, or FM, they don’t differentiate. If the instrument includes a sensor that is used to measure percent explosive combustible gas, then they’re going to insist that the manufacturer’s own manual has a warning on page one or near to the front of the manual that says you need to test before each day’s of use. OSHA also does not differentiate on the basis of the type of sensor technology that you use to measure the gas. Even if the sensor itself cannot be poisoned, don’t forget, one of the things that you do with the bump check, or the calibration check, is you verify that the readings are accurate, and also that the gas can reach the sensor, that the sensor also properly responds to the gas and that the alarms are activated. You might have a sensor that is perfectly good at detecting gas, but if the audible alarm is broken, you’ve still got an instrument that is not going to properly give you the warning that you need later on when you use the instrument in actual operations. So no matter what the technology, you’re still under the obligation to perform that bump check or that calibration check before each day’s use.
Jamie: Great, thank you Bob, yeah, pretty darn important. All right, Sarah has a question. Given that hazards change from job to job, how do I decide what and which sensors to use in my instrument?
You definitely need to do some planning. Try to understand the potential hazards that might exist in the various confined spaces that you deal with and once you have a sense of what hazards might be present, talk with the manufacturer of your instruments. They have ae lot of resources and a lot of good guidance that they can provide. In terms of the bare minimum for confined space, the bare minimum is generally a four-gas instrument. It’s hard to defend using less than the basic four types of sensors in a confined space instrument. That would be LEL, oxygen—LEL-combustible gas—oxygen, carbon monoxide, and H2S. If you’re dealing with solvents and VOCs, then you probably need a fifth sensor, which is a PID. Five-gas that includes PID, is kind of the equivalent of a swiss army knife. That will keep you safe under most circumstances—or I should say—is able to detect what you need to detect under most circumstances. If you have the specific presence of a particular gas, then both the general rule and the construction rule say that you really have to measure that additional gas directly. It might be NO2, or SO2, or chlorine, or one of the many other gases on a very lengthy list. It’s often easiest to use a separate instrument, a separate single sensor instrument of the oddball gas once in a blue moon, rather than include a sixth or seventh sensor in the multi-sensor instrument. But for other folks where, let’s say you’re dealing with the presence of a lot of diesel exhaust—this would be the case in a lot of underground mines. Instead of a four-gas instrument, they’ll use a five-gas instrument where the fifth sensor is NO2, because of the diesel exhaust issue. The main thing is to do everything you can to understand the hazards before you go shopping. And if you have any questions, talk to the manufacturers, talk to your distributor. Your distributor has access to multiple lines of gas detection and can really walk you through the process. And your distributor has a lot of experience in dealing with these issues. So, don’t forget, they’re part of your team also.
Jamie: Okay, it says my workers are doing construction AND general industry work in confined spaces, which standard should we follow?
Bob: Where it’s general industry clearly, if the confined space already exists, it’s not in the process of being made or constructed, then the general rule applies. If it’s a confined space that’s in the process of being constructed, then the vertical construction rule applies. If you’re not quite sure, follow the provisions in both rules. And as it turns out, the requirements are just not that different. So don’t be afraid if you need to follow the provisions in both rules. You might have to strengthen your program a little bit, especially on the communication and training side to easily be able to conform to both. But the key is whether you’re entering an existing confined space after the construction process has ended, or whether the confined space is still under construction. Probably the grey in all of that, comes from confined spaces which exist but which are undergoing extensive repair, I can think of some cities that are now ripping out an entire existing sewer system and replacing it with an updated new system and I’m not the lawyer that wants to argue whether that’s new construction or it’s an entry into an existing confined space. Make sure you conform in cases like that to both the general and the vertical construction rule.
Jamie: Great, thanks Bob. We do have a bunch more questions coming in. We’re ten minutes after the hour. What we’ll do is if it’s okay with everybody that’s submitted a question, we’ll have Bob follow up with you directly, if that’s all right. We really want to be respectful of everybody’s time. So with that, we’ll grant the last question to Thomas here. And Thomas asks, does the construction rule apply to residential construction?
Bob: That one’s easy. Yes. You don’t get a pass just because you’re a small company working on a small project, or whether the confined space is in a private residence or at the site of an oil refinery. You’re still beholden to keep workers safe if it’s a confined space then you need to—and it’s something that you are entering in the course of construction, then the construction rule applies.
Jamie: Thanks Bob. All right, well with that, Bob, any final words before we close the webinar?
Bob: Just I look forward to answering the questions. Depending on the volume, if I got a complete river of emails to respond to, it may take me a couple of days, but I will do my best. Thank you very much again for signing on for the webinar.
Jamie: Great. And thank you Bob for putting this all together. I know, personally, you’re super busy, so really appreciate you taking the time to do this. Thanks to GfG Instrumentation, without you we couldn’t be doing this webinar. Most of all, you the audience. Without the audience, really none of this even makes sense, so we’re super grateful that you took your time. We know that you have your choice of where to sit, and we’re extremely grateful you spent it with us. With that, everybody take care and stay safe.