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Keeping Pace with Fall Protection

Tuesday, August 08, 2017

We all know that initial safety training is a crucial element of our programs that aim to keep our employees protected from harm at work. For any and all hazards (or potential hazards} to which we expose our workers, we must ensure they understand the nature of the hazards and how to protect themselves.

Initial safety training and proper safety equipment, combined with good old-fashioned experience, goes a long way in ensuring a safe work environment. But, at times, we must provide re-training for our employees – and there are many reasons for this.
For example, if our employees demonstrate a lack of knowledge or acceptable performance in regards to any particular hazard, we must provide re-training. If the process or equipment changes, we must provide re-training. If new safety equipment (includes systems as well) is brought into the program, we must re-train our employees on its proper use. And, finally, if there are changes to safety legislation or best-known practices, we need to re-train.

It seems that every week a new piece of fall protection equipment is brought to market – and for the most part, these emerging technologies make work-at-height safer than ever before. Additionally, these newer fall protection items tend to be lighter, more comfortable, easier to operate, and can even perform multiple safety functions. This is all great news, but not every item/system is right for the varied situations encountered at our workplaces. But when we do introduce a new piece of fall protection equipment to our workforce, it nearly universally calls for some degree of re-training. The manufacturer’s instructions for use may be a great starting point to satisfy this training, but it is always a good idea to provide some degree of formal training on the equipment, and then document that training.

The extent of this re-training is dependent on the complexity of the new equipment and the authorized person’s general knowledge base. Sometimes the user manual does not cover all the points that the re-training should convey. For example, harness-mounted self-retracting lifelines are becoming more and more prevalent in the work-at-height environment. In addition to the standard training for pre-use and periodic inspections, proper mounting, operating capabilities and limitations, at least one other point of training seems to be required. The worker cannot walk too quickly away from their anchorage lest they engage the arresting mechanism which abruptly stops the worker in their tracks. This may at times create a new hazard by jerking the worker off balance or causing them to drop objects they may have been carrying. I have even heard some tales of individuals suffering minor injuries due to the sudden stop. So, even though you may not find this point of training in the user’s manual, it comes with experience and should be included in the re-training for this type of new equipment.

Another reason to provide re-training for fall protection has to do with an observed deficiency in an authorized person’s knowledge or performance regarding fall protection. Now this can become a little tricky to find the root cause of the deficiency. Is it truly a lack of knowledge on the authorized person’s part, or is it a disregard for required procedures? Sometimes it's a mix of both. No matter the primary cause of the deficiency, if that authorized person is to remain on that job, it is incumbent on the employer to provide proper re-training. And I will say it again, document that re-training!

We have recently had a significant legislative change to the general industry standard for fall protection. On Nov. 18, 2016, OSHA 1910 Subpart D “Walking-Working Surfaces” was published and became effective on Jan 18, 2017. The major changes to this final rule have to do with physical changes to existing and future structures regarding the phase-in of ladder safety systems,

• Eliminating the outdated general industry requirements for scaffolds and adopting the construction industry’s scaffold standards,• Guidance on the use of rope descent systems and qualified climbers, as well as some other changes. But the most significant changes that will drive training and re-training requirements is the added flexibility of using personal fall protection systems for authorized persons. These personal fall protection systems include fall restraint, work positioning, and personal fall arrest systems (PFAS). OSHA has eliminated the mandate to use guardrail systems as the primary fall protection method and now allows the general industry employer to determine the fall protection method that they feel is best suited for the nature of the work at height. And this now includes personal fall protection which was not addressed prior.

For general industry employers, who prior to the new Subpart D did not allow their employees to use personal fall protection systems other than in accordance with 1910.66, the option to do so now will be deemed compliant. And, of course, this will require initial training and re-training for the use of personal fall protection equipment and systems. Additionally, employers that introduce the authorized use of work positioning and personal fall arrest systems to their workplace will also have to provide training on rescue of these workers if they are relying on an in-house rescue capability.

In the years I have been involved with safety and rescue training, one subtlety that I observe is this:

Oftentimes an employer or their employees do not realize they have a training deficiency until after they've gone through the training.
This is certainly true when it comes to rescue training. At the conclusion of nearly every rescue class I teach, at least one of the students says they never realized what all was involved in rescue and what the limitations of certain rescue systems were. And this is consistent with my interviews and reviews of rescue programs when I am asked to perform needs assessments at various facilities. Unless you have a background in technical rescue, it is very difficult to visualize the systems, skills, and equipment required to safely access and rescue a fallen/suspended victim.

Both OSHA and ANSI require employers to provide "prompt rescue" of employees they authorize to work at height while using personal fall arrest systems. OSHA has published a Safety and Health Information Bulletin recognizing suspension trauma as a workplace hazard affecting workers that use personal fall arrest systems. Many employers address rescue of fallen/suspended workers in their fall protection programs, but stop at merely developing written policies that may fall well short of the requirements needed at the time of an incident. This falls back to my earlier point that an employer that has a limited background and understanding of the complexities of performing rope rescue, especially if it requires technical skills beyond the simplest rescue, may not understand what the true requirements are for their facility. Sort of like that general saying last year that “We don’t know what we don’t know.” So, training for rescue is a subcategory of fall protection training that does not have as much easily accessed guidance and resources to rely on as a guide.

Quality training will include several of the points that I have detailed so far. The training will be pretty specific to the job with very little time spent on irrelevant material. The training will be of the type that best transfers the information in either a vocational or academic manner. The training will close the gaps that have been identified and arm the employer and the students with a better understanding of what is truly required to perform the job, which is especially true for rescue. But finally, the training should be delivered in such a manner that it captures the students’ interest. The best outcome of training, the classes where the student finishes with the highest level of retention, understanding and performance, are the classes that compel the students to engage in the learning.

I think it is a safe assumption to say that we have all sat through classes wondering when and hoping for the class to end. Looking at our watch is one thing, but when we are tapping it to see if it is even still working is a really bad sign. I am not suggesting that educators have to provide entertainment, but there is a demonstrated positive difference in classes delivered by an engaging trainer as compared to a very dull, monotonous trainer.

In addition to seeking an engaging trainer, it is important for the trainee to take some ownership in the learning process as well. This is where the adult learner has an advantage over younger learners. We as adults generally understand that the training will result in a better understanding of the job requirements and in many cases is a factor in career progression.

I encourage you to seek out the training that your employees need. Or, as an employee yourself, seek out quality, applicable training. Review the course syllabi and determine if it will close those knowledge and skills gaps that you have identified. Always back up those fancy sales brochures by reaching out to others to get their opinion on their experiences with the training in the past. Also, remember to consider re-training as needed and always document. These things are important for the overall quality and credibility of your safety training programs.

Article by Pat Furr, Safety Officer & VPP Coordinator for Roco Rescue, Inc. 

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Rescue Toolbox: Petzl Rescucender

Wednesday, July 05, 2017

The Rescucender is one more quality piece of rescue hardware for your toolbox. Roco is proud to have been one of the first rescue training companies approached by Petzl to be shown the new device and asked to evaluate it. We were excited to see and use it from Day 1, and we then added it to our training kits as soon as they became available.

There’s no doubt, as computer assisted design (CAD) and precision computer numerically controlled (CNC) machines are used more and more in designing and manufacturing new rescue hardware, we are seeing some absolute gems coming to market. And I say gems, referring to function as well as appearance. There are still times when stamping and casting hardware is appropriate, but if there is a good reason to machine a piece from solid aluminum stock, it generally results in a lighter, smoother, more precise piece of kit.

And that is the case with the new Petzl Rescucender. It is primarily machined out of solid forged aluminum with some bits that are manufactured in a more traditional manner. But the end result is one of those gems. I have been waiting for an NFPA-rated, one-piece mechanical cam for quite some time; and now it is here. My first experience with a one-piece cam was with another Petzl product known as the Shunt. The ease of loading it onto, and stripping it off, the rope made it so much faster and greatly reduced the chance of dropping it. This is especially important when 300 feet or more on a tower!

The limitations of the Petzl shunt made it inappropriate for most technical rescue operations except for certain specialized situations such as during rope access or tower rescue when we are generally dealing with lighter rescue loads. The maximum rope diameter that the Shunt can handle is 11 mm. The new Rescucender is NFPA 1983 T Rated and accepts rope diameters from 9-13 mm.

But as important as the ease of mounting/dismounting is, what I really like about the shunt, and now the new Rescucender is the fact that the shell and the shoe are no longer connected together with a light cable or a thin piece of fabric. I have a few pet peeves, and one of them is seeing rescuers strutting about with a two-piece cam hanging from their gear loop unassembled. The shoe is clipped but the shell is just flapping in the breeze hanging from that thin tether waiting to get jammed into a piece of the structure and break free from the shoe. And, if you don’t believe that happens, you haven’t been doing this long enough, or it may be that your team is really good about assembling their two-piece cams when storing or hanging them from their gear loops. So that whole problem of the shoe ending up in Kansas City while the shell is somewhere in Oshkosh is now eliminated with the introduction of the Rescucender.

The attachment hole in the cam arm is extra-large which allows for rotation of your connector. This doesn’t sound like that big of a deal, but once you start using equipment that allows rotation of the connector from end to end, you will appreciate it. 

As with any piece of rescue equipment, it is important to be properly trained in its use. The action for opening and closing the Rescucender becomes very intuitive in a short amount of time. The engagement and movement of the shoe along its guides oozes precision and the solid feel in your hand lends a high degree of confidence. The device is equipped with a spring that has a light action and is primarily intended to prevent fouling. Our experience is the cam runs rather freely down the rope in vertical applications when attached to a pulley. This provides the convenience of creating longer “throws” with a Z-rig or piggy-back hauling system. The balance between the spring action and the need for the cam to remain open in progress capture applications is spot on. It also has just enough passive camming action to remain in place without back-sliding during rope ascents. It runs free when you need it to, and then grabs the rope when needed.

We all know that the pin needs to be completely seated in most two-piece mechanical cams, the new Rescucender does not have a removable pin but instead has dual safety catches, one on each side of the body. Once the device is installed on the rope, it is important to check that there is no “red” of the visual indicators showing. You will feel and hear a distinct click when the safety catches engage. Additionally, the problem of installing the shoe the wrong way in the shell is now eliminated as the Rescucender does not allow 180 degree rotation of the shoe in relation to the shell.

I continue to be excited about the evolution of rescue equipment. It doesn’t seem that long ago that we moved from goldline ropes to kernmantle, but years would go by without seeing any major breakthroughs in modern equipment. Well, those days are over. It seems that the digital era, as well as the push from various agencies and users, combined with the “out-of-the-box” thinking of equipment designers is driving the rapid emergence of better and better rescue mousetraps.

It’s a good time to be in rescue, it always has been, but the versatility, precision, and safety of modern equipment sure makes our tasks easier today than ever before.

Article by Pat Furr, Safety Officer & VPP Coordinator for Roco Rescue, Inc.
Pictures courtesy of Petzl

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Cal/OSHA Cites Two Companies After CS Death

Tuesday, May 30, 2017

On Oct. 21, 2016, a D&D Construction employee entered a drainage shaft to clean out mud and debris. No personal fall protection was utilized as the worker descended via bucket 10 ft. into the shaft, which was 4.5 ft. in diameter and lined with concrete.

At some point, the worker lost consciousness due to the oxygen deficient atmosphere in the confined space and fell 40 ft., then drowned in a foot of water.

“Cal/OSHA launched a confined space educational program to bring attention to the dangers and preventable deaths that occur in confined spaces,” said Cal/OSHA Chief Juliann Sum in a statement. “The program helps employers identify hazards and create effective safety plans that include air monitoring, rescue procedures and training before work begins.”

General contractor Tyler Development was constructing a single-family residence in the Bel Air area and hired subcontracted D&D Construction to install and service reinforced concrete posts known as caissons on the property, according to the agency’s report.

The state-run occupational safety unit cited Tyler Development and D&D Construction Specialties Inc. a combined $352,570 for ten serious and willful health and safety violations following an investigation. Cal/OSHA said neither company was in compliance with required confined space procedures.

D&D Construction previously was cited in 2012 for similar safety violations at a different job site.

In total, D&D has to pay a proposed $337,700 for 13 violations, including two willful serious accident-related, one willful serious, one serious accident-related, six serious, and three general in nature.

According to Cal/OSHA, the company failed to:
• ensure safe entry into the confined space
• have an effective method to rescue the worker in the confined space in an emergency
• test the environment to determine if additional protective equipment, such as a respirator or oxygen tank, were required to work safely in the shaft.

Tyler Development was cited $14,870 for five violations, three of them serious, for a failure to:
• evaluate the worksite for possible permit-required confined spaces
• ensure that the subcontractor meets all requirements to comply with a permit space program
• protect workers from the hazard of impalement by guarding all exposed reinforced steel ends that extend up to six feet above the work surface with protective covers

A full copy of the report is available here.

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The Clock's Ticking on Timely Response

Tuesday, April 25, 2017

By Dennis O'Connell, Roco Director of Training & Chief Instructor

As Director of Training, I get many questions about rescue techniques and regulations from our students and readers. In the past month alone, I have received three inquiries about "timely response for rescue teams" regarding permit required confined spaces (PRCS). So, let's break it down and try to clear the air on this subject. For clarification, we will refer to the General Industry Standard 1910.146; the Construction Standard 1926-1211; and the Respiratory Standard 1910.134.

In 1910.146, OSHA provides guidance on timely response in Subpart K (Rescue and Emergency Services) and again in Non-Mandatory Appendix F (Rescue Team or Rescue Services Evaluation Criteria). Subpart (k)(1)(i) states: "Evaluate a prospective rescuer's ability to respond to a rescue summons in a timely manner, considering the hazard(s) identified."

This one sentence actually says volumes about response times. The first question to be answered is, "Can the rescue service respond in a timely manner?" It then gives a hint as to what a timely manner should be based on. The second part of the sentence refers to "considering the hazard(s) identified." What this so eloquently says is the response time must be determined based on the possible hazard(s). This means the "known and potential hazard(s)" must be identified for each space to be entered. The hazards discovered -- based on severity, type, how rapidly the hazard could become IDLH or injure the worker, how quickly the need to treat the injury, or how quickly hazards might interfere with the ability to escape the space unaided -- would then be used to determine an acceptable response time. This is why OSHA only alludes to response times and does not set hard and fast times to follow -- it depends on the hazards of that particular space.

Another aspect we need to consider is that "response time" begins when the call for help goes out, not once the team is on scene. It ends when the team is set-up and ready to perform the rescue. So, how long will it take your team to be notified, respond and set-up is a big portion of that acceptable response time calculation. For example, a dedicated onsite fire/rescue team would be able to respond faster than workers who have other responsibilities and need to meet at the firehouse before responding. Or, more quickly than an outside service, such as a municipal department, that would have to respond to the facility, get through the gate, and be led to the scene.

In the note to paragraph (k)(1)(i), it adds: What will be considered timely will vary according to the specific hazards involved in each entry. For example, OSHA 1910.134, Respiratory Protection, requires that employers provide a standby person or persons capable of immediate action to rescue employee(s) wearing respiratory protection while in work areas defined as IDLH atmospheres.

Here we see OSHA better defining an acceptable response time for IDLH atmospheres -- i.e., immediate action! However, it's important to note this doesn't just refer to low O2...depending on the type of contaminant in the atmosphere, other respiratory equipment such as half- or full-face APRs could be used. It may include a dusty environment where the entrant wears a mask and visibility is less than 5 feet. Technically, that would be considered an IDLH environment. Many people get hung up on the use of SAR/SCBA as the trigger for a standby team, and that is just not the case.

For an IDLH atmosphere where respiratory protection is needed, an adequate number of persons (rescuers) is required to perform a rescue from the type of space involved - ready, trained, equipped and standing by at the space -- ready to take immediate action should an emergency occur. So, when dealing with possible IDLH atmospheres, we are looking at "hands-on" the patient in 3-4 minutes as possibly being an appropriate response time. Basically, this is about how long an entrant can survive without air. The only way to safely make rescue entry in that time frame is to have rescuers standing by, suited up and ready to go!

So, if dealing with an IDLH atmosphere, we revert back to 1910.134. Many people think that that is the only time we need a team standing by ready to take immediate action. I pose the question, "If the hazard is a liquid (engulfment hazard), what would be a reasonable response time?" If the victim is Tarzan or Johnny Weissmuller (okay, Michael Phelps, for you younger people), we may have a longer stay-afloat time. But if a non-swimmer, or in an aerated solution or other engulfment hazard, immediate action may be their only chance of survival! And, what about radiation (time, distance, shielding)? I am sure you can think of a few more possibilities.

And, while OSHA referred to an IDLH atmosphere in this example, it's important to consider other IDLH hazards as well. Here's where we note that the definition of IDLH in the Respiratory Standard (1910.134) differs slightly in Permit-Required Confined Spaces (1910.146). The Respiratory standard specifically refers to an IDLH "atmosphere" while the PRCS standard states the following: Immediately dangerous to life or health (IDLH) means any condition that poses an immediate or delayed threat to life or that would cause irreversible adverse health effects or that would interfere with an individual's ability to escape unaided from a permit space. This includes more than simply atmospheric hazards! 

OSHA NOTE: Some materials -- hydrogen fluoride gas and cadmium vapor, for example -- may produce immediate transient effects that, even if severe, may pass without medical attention, but are followed by sudden, possibly fatal collapse 12-72 hours after exposure. The victim feels "normal" until collapse. Such materials in hazardous quantities are considered to be "immediately" dangerous to life or health.

In Non-Mandatory Appendix F (I hate that non-mandatory language), OSHA gives guidance on evaluating response times under Section A - Initial Evaluation. What are the needs of the employer with regard to response time (time for the rescue service to receive notification, arrive at the scene, and set up and be ready for entry)? For example, if entry is to be made into an IDLH atmosphere, or into a space that can quickly develop into an IDLH atmosphere (if ventilation fails or for other reasons), the rescue team or service would need to be standing by at the permit space. On the other hand, if the danger to entrants is restricted to mechanical hazards that would cause injuries (e.g., broken bones, abrasions) a response time of 10 or 15 minutes might be adequate.

Not a bad paragraph for a non-mandatory section of the standard! Here they explain what they are looking for in regards to response times. They even take the OSHA 1910.134 IDLH atmosphere requirement for a team standing by at the space a little further by adding "or into a space that can quickly develop into an IDLH atmosphere." It also states if the hazard is mechanical in nature, 10-15 minutes might be adequate. That’s right, "might" not will be, but might be. Again, it depends on the hazard.

Paragraphs 2-7 in Appendix F goes on to describe other conditions that should be considered when determining response times such as traffic, team location, onsite vs. offsite teams, communications, etc. If you have not done so, I highly recommend that you review the not-so-Non-Mandatory Appendix F. It is also important to note that while it's not mandatory to follow the exact methods described in Appendix F, meeting the requirements are! OSHA also uses the word "should" in Appendix F, not following the OSHA recommendations could certainly lead to some hard questions post incident.

OSHA 1926 Subpart AA Confined Spaces in Construction closely mirrors 1910.146. In this relatively new standard, they simplified the definition of timely response and omitted Non-Mandatory Appendix F, which helps to eliminate the confusion of the "non-mandatory" language, and included the requirements right in the standard, which is good. However, 1910.146 really gives you a better idea of what timely would be for different situations through the notes in Section (k) and Appendix F.

Section 1926.1211 of the Construction Standard for Rescue and Emergency Services (a)(1) states: Evaluate a prospective rescuer’s ability to respond to a rescue summons in a timely manner, considering the hazard(s) identified. This is immediately followed by: Note to paragraph 1926.1211(a)(1). What will be considered timely will vary according to the specific hazards involved in each entry. For example, OSHA1926.103, Respiratory Protection (for construction) requires that employers provide a standby person or persons capable of immediate action to rescue employee(s) wearing respiratory protection while in work areas defined as IDLH atmospheres.

In closing, these regulations are driving you in the same direction for identifying what a timely response would be...THERE IS NO SET TIME FRAME! Each space must be evaluated based on potential hazards and how quickly rescue would need to take place. I hope this will make you take a closer look at "how and what" you consider a timely response. An employer's PRCS program must identify and evaluate the rescue resources to be used. It is then up to the entry supervisor to make sure the identified rescue service is available to respond in a timely manner, which can literally mean life or death for the entrants.

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Pre-entry Atmospheric Clearance Measurements

Friday, March 17, 2017

The following article was written by Russell Warn and published in ISHN magazine (ishn.com), December 2016. Roco comments have been added to the article and are noted in red.

Working in confined spaces presents a unique and dangerous challenge in combatting the unseen – oxygen deficiency, poisonous or explosive gases, and other hazardous substances are among the most frequent causes of accidents associated with work in confined spaces and containers.

From 2005-2009, the Bureau of Labor Statistics reported nearly two deaths per week, or roughly 96 per year, could be attributed to confined space, with about 61 percent occurring during construction repair or cleaning activities.

With conditions subject to change in a moment’s notice, taking steps to protect against life-threatening dangers should always be a top priority in confined spaces. Performing a thorough clearance measurement is a demanding — yet crucial — task that dictates the safety environment, and should not be taken lightly. To help guide you along your road to enhanced safety, outlined below are several best practices based on frequently asked questions.

When should I perform a clearance measurement?

Conduct clearance measurements immediately before operations begin. Environmental factors such as temperature and air flow can change the atmosphere, causing readings to fluctuate. One shift’s measurement taken at 7 a.m. is not representative of the conditions when work operations commence for another shift at 4 p.m. New clearance measurements must be taken immediately to account for the nine hours of changing temperatures and ventilation patterns, depicting the accurate readings of present conditions.

Roco Comment: In addition to pre-entry clearance measurements, entry into permit spaces during construction activities requires "continuous atmospheric monitoring" unless the entry employer can demonstrate that equipment for continuous monitoring is not commercially available or periodic monitoring is sufficient. Ref. 1926.1203 (e)(2)(vi), 1926.1204 (e)1)(ii), and 1926.1204 (e)(2). Additionally, Roco believes that for "ALL" permit entry operations, it is advisable to provide continuous atmospheric monitoring no matter what the industry activity entails.

What’s the importance of zero-point adjustment?

When performing clearance measurements, it’s crucial to determine the reference point of the gas detector by calibrating the zero-point. The zero-point ensures that the indicated values correspond to the actual existing gas concentrations. In order to determine that the actual zero-point has been found, calibrate equipment in an environment where the hazardous substance is not present, such as fresh air environments. With every scientific test, no matter the field, a control group, which serves as a starting point of reference, permits for the comparison of results to show any contrasting changes. The zero-point calibration acts as such, allowing workers to identify the presence, or lack thereof, of different gas concentrations.

Where do I measure/take the sample?

When it comes to measuring samples, there are four things to keep in mind: the physical properties of gases, and the type and shape, temperature and ventilation patterns of the confined space.

Know the differences between light and heavy gases. Clearance measurement experts must have a strong working knowledge of hazardous substances’ properties, as they play a role in where measurements should be taken. For example, if a sample is pulled from the top of the confined space and hydrogen sulfide (H2S) is detected, the sample may not be entirely reliable. H2S has a molar mass of 34 g/mol, which is significantly heavier than that of air (29 g/mol). As a result, H2S sinks to the bottom of a space, where its concentration would be greatest. Identifying a presence at the top of the confined space says immediate danger and appropriate actions should be taken.

Light gases quickly mix with air and rise to the top. As a result, any measurements in open atmospheres should be performed close to the leak, and increases in concentration should appear in the highest points of the confined space. Heavy gases, on the other hand, should sink and flow like liquids, pass obstacles or stick to them. They barely mix with air like light gases do, so their samples should always be taken at the lowest points of the confined space.

Determine the type/shape of the confined space: In an ideal scenario, each confined space area would be in an “even” or level position. This isn’t always the case, and a container may be placed on an inclined surface, making the highest point in the corner positioned toward the top of the inclined surface. Thus, entry may be nearer to where the heavy gases have accumulated.

Take tabs on temperatures. All matter is made up of atoms and molecules that are constantly moving. When heat is added to a substance, such as a gas, the molecules and atoms vibrate faster. As the gas molecules begin to move faster, the speed of diffusion increases. If the sun has been shining on a tank for hours, there’s a good chance the clearance measurement taken at dawn no longer reflects the current readings due to the increase in diffusion.

Vet the ventilation. Air currents change the position and concentration of air clouds, and often times, the way a confined space is ventilated can affect readings. Containers cannot always be separated from pipelines, or there may be leaks in the tanks that must be accounted.

Roco Comment: Not only is it required by certain OSHA provisions like alternate entry procedures, but Roco highly recommends monitoring the atmosphere prior to initiating ventilation. This is intended to provide a reasonable assessment of the potential atmosphere change should the ventilation equipment fail. The rate for a potential hazard to re-develop will be based on factors such as the effectiveness of isolation, any residual product within the space, temperature, humidity and passive ventilation which are among just some of the factors.

How do I safely conduct the measurement for an accurate reading?

People often question why they can’t just use the carrying strap of their device to lower the device into the confined space for a reading. Although this seems like a simple fix, it’s not a safe or recommended way to conduct the measurement. Lowering the device into the container this way not only obscures the way the display is read, but it may not audibly alarm. If the measured value is slightly below the threshold value and the alarm does not sound, a worker would not be notified of the dangerous concentrations lurking below. Not only this, but measurements may be inaccurate since the measured gases, due to their molar masses, may be concentrated at a higher or lower point within the container. Clearance measurements should be conducted on-site and on-the-ground of the confined space for accurate, safe readings.

Roco Comment: The points made in the preceding paragraph are certainly valid. The best solution that we can offer is to use remote sampling probes or tubes to actively draw (pump) samples from the stratified levels of the space while the direct reading instrument is in a position outside the space to observe the real time readings. To expound upon the point the author makes, if the pre-set threshold for the alarms are not enough to trigger the alarm indicating the presence of a hazardous atmosphere, and the individual performing the assessment relies instead on rapidly pulling the monitor from the space in the hope that they are able to read the display before the values change, is a very dangerous way of approaching this procedure. Depending on the sampling rate of the monitor, the hazardous gas(s) may have cleared from the monitor in the time it takes to withdraw it from the space, and it is very likely that the instrument will display a normal atmosphere by the time it is back within view. Additionally, for areas within the space that cannot be remotely assessed by remote sampling prior to entry, the only safe recourse is to limit entry to the areas that have been assessed and to take a monitor into the space to continuously assess the unreachable regions before venturing further.

What do I need to document during clearance measurement protocols?

Just as it’s important to remain thorough in clearance measurements procedures, it’s equally as important to remain thorough in the general housekeeping protocols surrounding samples. This includes documenting:

  • The container number
  • The measuring point of the container, and whether there was more than one measuring point
  • At which time was the clearance performed
  • Under what condition was the measurement performed
  • Measured hazardous substances
  • Name of person performing measurement
  • Equipment used for clearance

Safety, regardless of job title or responsibility, should be everyone’s top priority. When working in the midst of poisonous and explosive hazards, performing clearance measurements correctly and carefully means not only keeping one’s self safe, but keeping the working environment safe, as well.

About the Author:
Russell Warn is the product support manager for gas detection products at Dräger. He has been in the safety industry for more than 29 years, with most of this time dedicated to gas detection product and application support.

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