Latest News

I recently participated in conducting an OSHA 5810 course for a dozen or so oil and gas attendees from both Operator Companies, as well as, Service Companies in the oil and gas industry.  Most of the class attendees held safety and health supervisory duties for their respective companies.  One of the many topics that we covered during the course was recognition of hazards associated with permit required confined spaces.

My first surprise of that day was the number of attendees who were not familiar with what constituted a confined space according to OSHA’s definition.  The second surprise was that some attendees were under the impression that ISNetworld could give them an Exemption/Variance from having to follow confined space requirements for work performed on oil and gas sites.

Unfortunately, ISNetworld holds no legal authority over what is or is not a confined space.  Even if the Host Employer has granted an Exemption/Variance for needing to “upload” a confined space program to satisfy their ISNetworld requirements, this does not remove the service company’s responsibility under OSHA to recognize and properly address confined space hazards if they participate in this type of work.  This includes having a proper written program, safe entry procedures, and all of the equipment, training and rescue capabilities that are in compliance with 29 CFR 1910.146.

The OSHA definition of a confined space is as follows:

A confined space:  Is large enough for an employee to enter fully and perform assigned work; Is not designed for continuous occupancy by the employee; and Has a limited or restricted means of entry or exit.  These spaces may include underground vaults, tanks, storage bins, pits and diked areas, vessels, silos and other similar areas.  By definition, a permit-required confined space has one or more of these characteristics:  Contains or has the potential to contain a hazardous atmosphere; Contains a material with the potential to engulf someone who enters the space; Has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section; and/or Contains any other recognized serious safety or health hazards.

A case study that was reviewed as part of the OSHA 5810 course illustrated why the well cellar, an often overlooked space, is a permit required confined space.

Three oil field workers died after breathing carbon monoxide (CO) gas in an oil well cellar.

The incident occurred during perforation, a procedure to create holes in the pipe in the well to allow the well to be used for water disposal. During the procedure, water began flowing from a valve in the well cellar.   No plan had been prepared for actions by the workers in the event that this occurred. The first worker (decedent #1), a 22 year-old male, entered the well cellar to turn off the valve.  Upon entering the area, he collapsed and fell into the cellar. A second worker (decedent #2), a 24 year-old male entered the cellar to assist decedent #1 but was also overcome and collapsed.  A third worker (decedent #3), a 26-year-old male, was overcome while kneeling near the opening to the cellar and also fell in.

A lack of understanding and appropriate respect for the potential dangers associated with Confined Space Work still exists in many industries.  Host employers and contractors often fail to comply with one or more provisions of OSHA’s permit required confined space standard. Hosts often fail to exercise their authority over contractors or, even worse, ignored situations where a contractor demonstrates egregious at-risk behavior.

Many contractors lack an understanding of the complex nature of confined space hazards or demonstrate a conscious indifference toward the safety of their employees. Few possess sufficient experience, technical knowledge or skill necessary to manage a confined spaces program.

Hosts and contractors must provide for each other’s safety. This duty is overlapping and interlocking, because the host and their contractors are not only obligated to share specific information about confined space issues, but also must coordinate entry operations so that they don’t kill each other. The specific obligations of hosts and contractors are described respectively in 29 CFR 1910.146(c)(8) and (c)(9).

Host Employer Duties

Careful reading of 29 CFR 1910.146(c)(8) shows that host employers have six principal duties.

Advise of permit spaces. Hosts must advise contractors of any permit spaces on the host’s premises that the contractor’s employees may have reason to enter. Hosts need to be adequately familiar with what is or is not a (permit required) confined space based upon the OSHA definition as well as the 80+ letters of interpretation that has been issued by OSHA since the confined space regulation was published in 1993.

Compel compliance. Hosts must compel compliance by informing contractors that permit spaces can only be entered under the auspices of a written program that meets the requirements of 29 CFR 1910.146(d). As explained above, the host and contractor must also agree as to exactly what program will be followed.

Inform of hazards. The host is arguably the most knowledgeable person with respect to many aspects of the space. For example, it is reasonable to expect the host to know things like how the space is used, how often it is used, what it last contained, its volume and its dimensions. The host would also be likely to have access to piping and instrumentation drawings, material safety data sheets for substances found in the space and other similar safety-related information. Consequently, hosts are obligated to inform contractors of their previous experience with the space and of any hazards that make the space a permit space.

Inform of precautions. Hosts must also inform contractors of any entry precautions that have been implemented such as draining, flushing and rinsing a space; isolating the space by disconnecting lines, blanking or providing a double block-and-bleed system; locking out mechanical equipment; flagging or barricading the work area; de-energizing electrical equipment; providing temporary lighting; purging and ventilating the space; and performing initial atmospheric testing.

Coordinate entry. Hosts must coordinate operations with the contractor when host and contractor employees will be working in or near permit spaces.

Conduct debriefing. At the conclusion of the entry, the contractor must debrief the host regarding the permit program and any hazards confronted in the space during entry operations.

Contractor’s Duties

In addition to complying with all of the other requirements governing confined space entry, contractors must:

  • Obtain any available information regarding permit space hazards and entry operations from the host;
  • Inform the host of the provisions of the contractor’s written permit program if it is agreed that the contractor’s program will be followed rather than the host’s;
  • Coordinate entry operations when the host’s and the contractor’s employees will be working in or near permit spaces; and
  • Report hazards confronted or created during the entry to the host, either at the debriefing session or when they occur.

OSHA’s goal, as explained in the standard’s preamble, is to provide all employers with the flexibility they need to effectively manage their confined space entries. Hosts and contractors, however, must cooperate with each other to identify and implement a permit program that best suits their specific needs.

Although the final rule provides for this flexibility, hosts have ultimate control over their workplaces and should employ specific administrative procedures to ensure that contractors comply with the regulations. While there are many things a host can do to evaluate its contractor’s performance, three of the more important considerations are  Program review, Verify training proficiency, Monitor contractor activities.  This may mean going beyond the capabilities of a computer based contractor monitoring service.  Host employers might benefit from actually conducting their own audits of their contractors.

Host employers and contractors who work in or around confined spaces have overlapping and interlocking responsibilities toward each other. Each must communicate information concerning confined space entry operations to the other, each must consider and evaluate confined space hazards, and each must take an active role in controlling those hazards.

Failure to strictly abide by the contractor provisions outlined in the OSHA confined space standard may not only lead to employees being maimed, injured or killed, but also may result in a costly litigation for both companies.

A properly operating, properly calibrated four gas meter can provide us with beneficial information regarding the possible presence of contaminants in the atmosphere where we are about to perform some type of work. This information can then be used to formulate hazard elimination/control plan prior to starting our task. Let us now take a closer look at the four gas meter.

Although four gas meters can be set up to monitor a wide array of parameters, the vast majority of such pieces of air monitoring equipment are set up in a similar configuration to monitor the following parameters:

  • Oxygen Concentration (in percent O2)
  • Flammability (in percentage of lower explosive limit)
  • Carbon Monoxide Concentration (in parts per million [ppm])
  • Hydrogen Sulfide Concentration (also in ppm)

This configuration allows us to not only utilize the meter at our most common types of hot work, excavating work and hazmat incidents but also in confined space entry settings. Such usefulness of the four gas meter underscores the need for taking a closer look at the four parameters discussed above.

The percentage of oxygen concentration shown by the four gas meter is a valuable piece of information that does triple duty for us, as it displays not only the possible existence of an oxygen-deficient atmosphere, but also the possibility of an oxygen-enriched atmosphere or possible contamination of the atmosphere by other products.

The normal percentage concentration of oxygen in air is 20.9 percent. We define an oxygen-deficient atmosphere as containing less than 19.5 percent oxygen, and an oxygen-enriched atmosphere as containing greater than 23.5 percent oxygen. Although we often recognize the pitfalls of inhabiting an oxygen-deficient atmosphere without proper respiratory protection (i.e. unconsciousness and even death), we sometimes forget the hazards presented by an oxygen-enriched atmosphere. The existence of an oxygen concentration exceeding 23.5 percent naturally tells us that something is adding to the oxygen concentration and therefore may be enhancing our flammability concerns, which should lead us to exit the area of concern and determine the source of the enrichment.

As stated earlier, the four gas meter (and specifically the oxygen sensor) can also warn us of the possible contamination of our environment by other substances. If our oxygen concentration is less than 20.9 percent, we can surmise that something is lowering the concentration of, or displacing the oxygen in our environment. While we may encounter situations in which processes such as oxidation (i.e. rust), combustion, or microbial action can lower the oxygen concentration; oftentimes another contaminant is present and is displacing the oxygen present.

The four gas meter displays flammability in terms of the percentage of lower explosive limit (LEL). In simple terms, our percentage of LEL tells us how close we are getting to the point at which a substance is guaranteed to ignite or explode if an ignition source is present. The percentage of LEL is determined through the use of a combustible gas indicator (CGI) that utilizes oxidation (combustion) to produce a differential resistance between two filaments —one with a catalytic bead and one without —which is then displayed as the percentage of LEL. Our level of concern for flammability greater than 10 percent LEL. This level of concern gives us a built-in “safety margin,” as we then still have a cushion prior to reaching the LEL itself.

The remaining two sensors in the standard four gas meter setup —those used to monitor the concentration of carbon monoxide (CO) and hydrogen sulfide (H2S) —are electrochemical sensors that operate in much the same manner as the previously discussed oxygen sensor, but are designed to detect the concentration of the respective substance in parts per million (ppm).

Due to the fact that CO is a colorless, odorless gas that oftentimes imparts flu-like symptoms at lower concentrations, and can be fatal at higher concentrations, competent monitoring skills for CO detection are a must. The levels of concern for CO are generally accepted as 35ppm.

The final sensor in our usual four sensor suite is the H2S sensor briefly mentioned above. H2S sensing capabilities are many times utilized in confined space or below grade settings, as the existence of hydrogen sulfide (better known as sewer gas) in such settings in sufficient concentrations can be fatal to personnel making entry without performing sufficient air monitoring. In terms of a level of concern for H2S, 10 ppm is the generally accepted level at which actions should be taken.

Proper air monitoring techniques can enhance the accuracy of our monitoring efforts. First of all, we need to consciously remember to monitor in a slow and methodical manner.  With the lag time inherent in most four gas meters (i.e. the time required to either pump the air sample through the sensor array or allow the air sample to diffuse across the sensors; and the time required for the sensor itself to “recognize” the contaminant and display the correct information), personnel can actually misdiagnose the location of the contaminant if monitoring in too rapid a fashion.  In addition, we also need to remember the characteristics of the substances we are monitoring for, namely vapor density. The vapor density of a gas allows us to surmise whether the substance will ascend (vapor density less than one), descend (vapor density greater than one), or remain neutrally buoyant (vapor density equaling one) in the air column. While the vapor density does give us a general idea as to where the substance will be found (i.e. high or low), we must remember that certain atmospheric conditions can cause a gas to behave in a manner not indicated by its vapor density.

The question often arises as to what is the proper order for the monitoring of hazards.

  1. Oxygen Concentration —O2 deficient atmospheres can reduce the accuracy of flammability readings
  2. Flammability —Due to the hazards presented to first responders, even in proper personal protective equipment
  3. Toxicity —Due to the toxicological effects imparted to personnel

The final element of four gas air monitoring to be discussed is the proper calibration and testing of our meters. Calibration is simply the process of exposing the sensors to known concentrations of gases in order for the sensors to be adjusted to those values. Many meters allow for a multi-gas calibration, in which concentrations of all four gases are applied at once from a calibration gas cylinder to simplify the process. Following the exposure to known gas concentrations, a fresh air calibration is then performed in a non-contaminated area to set the “zeros” for LEL, CO, and H2S sensors and the 20.9 percent value for the O2 sensor. Such a calibration is performed on a monthly basis.

If we should calibrate our meters on a monthly basis, what should we do prior to every use? We should perform a “bump test” before using the meter. Always perform a function (bump) test in the field before use. Never perform a function (bump) test in the suspected atmosphere. The performance of a bump test should be a standard operating procedure before the use of the meter.

In conclusion, the four gas meter is a vital building block of our air monitoring capabilities. Not only can such a meter display the concentrations of the gases corresponding to the sensors commonly installed; a properly operating, properly calibrated meter can also give us accurate information about the potential atmospheric hazards of the job we are about to perform.

During the early days of sensor development, manufactures recommended that the instruments be fully calibrated before each use. This was very cumbersome for industry and compliance was difficult. As a result, industry began to lobby the manufacturers to relax the recommendation or offer some suitable compromise. The manufactures original requirement was based on the knowledge that sensors slowly fail over time, and fail at different rates depending on the environment in which they are used. In order to satisfy their customers and maintain the integrity of the instruments, the manufactures began recommending a function test or “bump test” option.

Bump tests are a quick and simple way to determine if a sensor still functions. The basic premise is to subject the sensor to the substance that it is designed to detect at a concentration slightly greater than the lower alarm limit. If the sensor alarmed, then the user has assurance that the sensor will offer protection, if it failed then the user could replace it with a functioning unit. This is a good compromise which, when performed correctly, will protect people from harm.

The trouble is, sometimes it’s impossible to determine if employees are actually performing the bump tests or if they truly understand the importance of the procedure. Every year, faulty sensors give a false sense of security to employees which could, and too often does, lead to disaster.


During a recent study* of over 4.7 million bump test records by a major manufacturer of gas detection equipment, it was found that on average, 3 instruments out of 1000 will fail to respond properly. When the bump test interval is extended to 20 days, the failure rate doubles. A further study combined this test data with an analysis of how frequently gas detectors are exposed to hazardous, alarming conditions. This study found that, on average, one out of every 100 gas detectors not bump tested before use will fail to respond and alarm properly to an actual gas alarm event every 25 days.

Sometimes monitors are on the shelf for months before they are used. When this happens and the period of time between bump tests are as much as 6 months, failure rates have been as high as 50%. Therefore, half of the detectors in service may actually lull employees into believing that they are safe when they are actually at high risk for exposure. All monitors, not simply personal monitors, should be tested before use. Multi-gas detectors have multiple sensors that can fail, which gives them an even greater chance of failure. A quick bump test can give employees the confidence that they will actually be protected by the equipment.

The exact time of failure for a single sensor is, in large part, impossible to determine. Sensor life depends upon, not only the quality of manufacture but also on the environment in which the instrument is used. Sensors are very sensitive to shock from drops, humidity, and exposure to the gasses that they are meant to detect. Generally, the more rigorous and demanding the environment is in which they are used, the shorter the life of the sensors will be. The only way to detect these failures is to perform a daily bump test of the instrument. Without the bump test, employees may be rolling the dice and hoping that they are not within the 3% that will not make it out alive. Take a minute to perform this quick and simple check. It might save your life!

_*Industrial Scientific_